Another 120 project begins

[Offender90]

What started as planning and preparation of my V8 90 for the Canning culminated with an Isuzu 120 sitting in my driveway. :rolleyes:

Needs a bit of work to get it roadworthied in WA, but very happy with it so far. For its 24 years of age, and 400,000 on the clock its in pretty good shape. I've only got a few pics, but will take some more on the weekend.

In the transport yard
http://img98.imageshack.us/img98/5513/30102008247bx8.jpg

Isuzurover's
http://img98.imageshack.us/img98/5200/30102008250lg8.jpg

Next to its new sibling
https://www.aulro.com/afvb/


First impressions:
- Great low end torque,
- Gutless compared with the 3.9LV8 in the 90...

... I guess the first order of business is to look into turbo options :twisted:

Been trying to get up to speed on turbos by searching previous posts, trawling Garrett's Tech talk section and talking to isuzurover.

Seems that a T3 Saab turbo from the 80's might be a good fit on a budget. A/R 0.48 on the turbine and 0.42 on the compressor & oil cooled journal bearing... for about $300, a good fit?

What other options should I look at for up to say $700?

[Bearman]

The T3 is a good combination on the Isuzu. I presume it it a 4 speed considering the age. Which is the best combination for these motors. At 400K the motor shouldnt be worn out but I would suggest a compression check to ascertain condition before turboing, they should be around 440psi. I put a 4BD1 with 200K into my 110 and turboed with a watercooled T3 and did another 550K with it before the compression started to fall off. In the end it only had 200psi and was still going good but lacked grunt on hills or when towing. You will be impressed with the difference. Good luck.

[rar110]

Agree with Brian the T3 is a good option. T3's on SAABs had the low exhaust AR. T3s are the most manufactured Garrett turbo. However, T3 with small AR is not that easy to find. The T28 with a small AR like found on some imported Nissans is easier to find. The T28 has a similar compressor to a T3 matched with a T25 turbine. IHI is another possibility.

As Ben found a new manifold is still available from Isuzu. I found Isuzu in Brisbane hard to deal with. There are several formats and they couldn't tell me which format they were selling me. So I didn't know if the one turning up was top/bottom or side mounted turbo.

I used a GT28R which is a ball bearing version of the T28. I have been very happy. I paid $1100 new.

[rovercare]

Where'd you find that?:)

[Offender90]

I've got a great deal on the manifold - Dougal posted a link to in isuzurover's Budget 4BD1 Turbo Install post.

Was $160 US all up with postage (that's when the aussie was around the 0.8 mark).

They come up on ebay all the time, here's a link to an identical one if anyone is looking for one.

eBay Motors: NEW ISUZU NPR EXHAUST MANIFOLD (item 120330384720 end time Nov-14-08 09:12:00 PST) (http://cgi.ebay.com/ebaymotors/NEW-ISUZU-NPR-EXHAUST-MANIFOLD_W0QQitemZ120330384720QQcmdZViewItemQQptZM otors_Car_Truck_Parts_Accessories?hash=item1203303 84720&_trksid=p3911.c0.m14&_trkparms=72%3A727|66%3A2|65%3A12|39%3A1|240%3A131 8)

Cheers

[isuzurover]

No pics of the astroturf Bojan??? ;)

[Rangier Rover]

Good to see another 4BD1 120". Looks in fair shape. I like it in Red:D.
I have a Turbo on mine. Still is not a rocket but nice and punchy to drive:cool: Keeps up with traffic no worries. Just lacks a bit in top end RPM. Hope to sort this soon.

Tony

[Offender90]

The T3 is a good combination on the Isuzu. I presume it it a 4 speed considering the age. Which is the best combination for these motors. At 400K the motor shouldnt be worn out but I would suggest a compression check to ascertain condition before turboing, they should be around 440psi. I put a 4BD1 with 200K into my 110 and turboed with a watercooled T3 and did another 550K with it before the compression started to fall off. In the end it only had 200psi and was still going good but lacked grunt on hills or when towing. You will be impressed with the difference. Good luck.

Cheers,

Ben took me for a spin in his newly turboed suzi and it goes great... put a smile on my face... almost comparable to the V8! :angel: :wasntme:.

It's got the original 4 speed I believe and still going strong, except the CDL on the TC is not engaging - suspect vacuum line perhaps?.

I've also got an LT95a mated to a 0.996TC to go in, but am wandering if it's worth the effort of swapping. What are the benefits of the LT95a over the standard LT95?


Where'd you find that?:)

Central Coast NSW near brunswick heads. Accidentaly found it on country post while googling isuzu rovers .


No pics of the astroturf Bojan??? ;)

Will take plenty of pics on the weekend... , do you think I should pitch a tent up for extra effect! :twisted:


Good to see another 4BD1 120". Looks in fair shape. I like it in Red:D.
I have a Turbo on mine. Still is not a rocket but nice and punchy to drive:cool: Keeps up with traffic no worries. Just lacks a bit in top end RPM. Hope to sort this soon.

Tony

Thanks Tony... it's OK externally, the chassis is amazingly rust free, and it comes with a few goodies hidden away (namely front and rear maxis, winch and long range tank under the tray)... might have been resprayed at some stage as the paint looks pretty good (or it could be that I washed it really well prior to handing it over to Autotrans).

Could be a bit better internally (the instrument cluster is loosely hanging on by 1 bolt) but at least I've got easy access to all the wiring :D Has a few things that need sorting out (few electrical gremlins, leaky power steering, 30degree steering wheel play, warn belts, rusty wheels and well worn tyres), but nothing major so far.

Impressed with the 4BD1 so far - it will quite happily run with a diesel leak out of the supply line (as I found out) :angel:

What turbo do you have on yours?... and how do you plan on sorting it out for more top end power?

Cheers

Bojan

[JDNSW]

...........
It's got the original 4 speed I believe and still going strong, except the CDL on the TC is not engaging - suspect vacuum line perhaps?.

When I had that trouble it was the (live) wire to the reversing light switch had shorted where the connector hat touched the edge of the air cleaner and pulled enough undone to short - the melted wire cut the vacuum line on top of the bell housing under the air cleaner.

I've also got an LT95a mated to a 0.996TC to go in, but am wandering if it's worth the effort of swapping. What are the benefits of the LT95a over the standard LT95?

I think they are supposed to be more durable - I would not bother changing it if the case in there is good.


...........
Could be a bit better internally (the instrument cluster is loosely hanging on by 1 bolt) but at least I've got easy access to all the wiring :D Has a few things that need sorting out (few electrical gremlins, leaky power steering, 30degree steering wheel play, warn belts, rusty wheels and well worn tyres), but nothing major so far.

Loose instrument cluster is probably a function of the tendency of the Isuzu to shake everything to bits, but also the plastic tends to disintegrate - you may have to replace it - they are not that expensive. Steering play is probably tie rod end or panhard rod bushes, but should be easy to track down. As far as the wheels go, note the recent warning on Sunraysia wheels.

.......
Bojan


What I don't understand is with 120s as rare as they are, how did you manage to find a colour match to the 90?

John

[Offender90]

What I don't understand is with 120s as rare as they are, how did you manage to find a colour match to the 90?

John

Some peopoe say I'm starting a 'red army'. - I strongly maintain it was more by sheer luck than by design. :D

... the steering play is in the steering box, so I'll be topping up the steering fluid first, then adjusting the steering box if play is still there, and if still there after adjustment, I'll take the box out of the 110 I bought from lewy110 (Greg) and put it in the 120.

As for the CDL not engaging, it could be the same thing, because the revesing light has been wired up to a manual switch instead of being automatically switched.

I did read the warning on sunraisia's but these are so far gone (heavily corroded at places), I'll be replacing them with a spare set anyway.

[isuzurover]

Will take plenty of pics on the weekend... , do you think I should pitch a tent up for extra effect! :twisted:


I think a few garden gnomes would be better :D

[Rangier Rover]

Cheers,

Ben took me for a spin in his newly turboed suzi and it goes great... put a smile on my face... almost comparable to the V8! :angel: :wasntme:.

It's got the original 4 speed I believe and still going strong, except the CDL on the TC is not engaging - suspect vacuum line perhaps?.

I've also got an LT95a mated to a 0.996TC to go in, but am wandering if it's worth the effort of swapping. What are the benefits of the LT95a over the standard LT95?



Central Coast NSW near brunswick heads. Accidentaly found it on country post while googling isuzu rovers .



Will take plenty of pics on the weekend... , do you think I should pitch a tent up for extra effect! :twisted:



Thanks Tony... it's OK externally, the chassis is amazingly rust free, and it comes with a few goodies hidden away (namely front and rear maxis, winch and long range tank under the tray)... might have been resprayed at some stage as the paint looks pretty good (or it could be that I washed it really well prior to handing it over to Autotrans).

Could be a bit better internally (the instrument cluster is loosely hanging on by 1 bolt) but at least I've got easy access to all the wiring :D Has a few things that need sorting out (few electrical gremlins, leaky power steering, 30degree steering wheel play, warn belts, rusty wheels and well worn tyres), but nothing major so far.

Impressed with the 4BD1 so far - it will quite happily run with a diesel leak out of the supply line (as I found out) :angel:

What turbo do you have on yours?... and how do you plan on sorting it out for more top end power?

Cheers

Bojanhttp://www.aulro.com/afvb/isuzu-landy-enthusiasts-section/61601-4bd1-lr-120-turbo.html Tony:)

[Offender90]

Few more pics I took on the weekend:

The Bullbar comes off:
http://img160.imageshack.us/img160/4803/mg0239bq1.jpg

Winch on my "workbench"...
http://img145.imageshack.us/img145/7465/mg0253tp5.jpg

... My "workbench"... Astroturf and all (no gnomes, unfortunately)
http://img145.imageshack.us/img145/286/mg0254di1.jpg

Evidence of power steering leak (through the box?) - beefed up diff housing in the background.
http://img390.imageshack.us/img390/3015/mg0245bq7.jpg

Engine bay
http://img143.imageshack.us/img143/2365/mg0244jl0.jpg

The wiring may need a bit of neatening up (if only for aesthetic reasons) - I'm not a big fan of the garden hose :(
http://img525.imageshack.us/img525/1020/mg0247oz4.jpg

Replaced fuel lines - I accidentally drove with a cracked one (one with the old hose clamps) for up to 350km, no problems (gotta love diesel)
http://img525.imageshack.us/img525/3016/mg0248bx6.jpg

Interior pic
http://img135.imageshack.us/img135/1156/mg0249ll8.jpg

Now that I've got the bullbar off and the winch out, I'd like to open it up check the internals and service if necessary, but don't know how. Are there any instructions on how to do this? (I found a thread on the subject by rangieman (http://www.aulro.com/afvb/projects-tutorials/62049-interest-elec-winch-service-tutorial.html) but couldn't find the tutorial - does anyone know if there's one floating around?)

Thanks all

Bojan

[Jock The Rock]

Gday mate

Nice looking Landy you have there ( x2 :D )

If thats a Warn winch, have a quick trip over to your ARB store. I went into mine in Launceston, told them the model and they photocopied a blow out plan of the innards. Showing part numbers and all

Or just go to this website :) Just found it

http://www.warn.com/truck/ReplacementParts/replacementparts.jsp

Also there is this thread:

http://www.aulro.com/afvb/projects-tutorials/63426-winch-service-warn.html

Good luck with it

[Offender90]

... was surprised to find there's no brake inside!

Were only some Warn winches fitted with a brake, or is mine missing a vital component? :mad:

http://img360.imageshack.us/img360/5604/mg0257lz8.jpg

The winch has definately had water in it at some stage. The large ring gear has had a considerable amount of rusty gunk on the bottom side.

http://img517.imageshack.us/img517/3962/mg0263tj6.jpg

Not so much on the top
http://img504.imageshack.us/img504/4985/mg0262uc2.jpg

The rest of the gearset
http://img234.imageshack.us/img234/5048/mg0259yp2.jpg


They cleaned out quite well for the most part:

Large ring gear (worst part)
http://img205.imageshack.us/img205/2492/mg9998qr7.jpg

Planet gear
http://img205.imageshack.us/img205/704/mg9989ft0.jpg

Larger sun / planet combo
http://img401.imageshack.us/img401/3777/mg9992ke4.jpg

Smaller sun / planet combo
http://img145.imageshack.us/img145/138/mg9991vn1.jpg

Sun gear and smaller ring gear in housing
http://img140.imageshack.us/img140/1089/mg9995uc0.jpg

Sh
ould I be regreasing with wheel bearing grease, or should I be using something else?

Cheers

Bojan

[JDNSW]

Should I be regreasing with wheel bearing grease, or should I be using something else?

Cheers

Bojan

Wheel bearing grease is satisfactory - they are not that demanding on grease, I don't think, although if you are planning to run it under water as the previous owner obviously has, perhaps marine grease might be better.

John

[Psimpson7]

The brake should be inside the Drum. In those pictures you haven't got it apart far enough.

(If you knew that already and have fully stripped it - sorry!!)

Rgds
Pete

[isuzurover]

Looks in good nick! I would be using copious quantities of marine grease - best at preventing corrosion and resisting water washout.

E.g. Shell Nautilus, Castrol Boating Grease, etc, etc...

[Psimpson7]

As a side point, the more grease you put in, the harder it will be to freespool the cable......

[Offender90]

The brake should be inside the Drum. In those pictures you haven't got it apart far enough.

(If you knew that already and have fully stripped it - sorry!!)

Rgds
Pete

Hi Pete,

I have, but forgot to upload a pic, thanks for reminding me - its completely empty. Pics below

the "brake" side
http://img510.imageshack.us/img510/6576/mg0283fm6.jpg

got plenty of rusty mud in it tho :o)

and the other side

http://img230.imageshack.us/img230/1701/mg0271ox3.jpg

Cheers

Bojan

[Psimpson7]

Hi Bojan,

Do you have any idea what model number the winch is?

Rgds
Pete.

[Offender90]

I'll have a really good look at it when I get home, but not really.

I could find some part numbers / codes stamped on the gearbox housing (possibly motor housing as well) but most tags are hardly readable. I think I saw 8000 (lb) stamped in somewhere, but the model number was not visible from memory (some of it is still covered by caked on mud, so there's hope yet).

Forgot to say, it's likely to be from the early / mid 80s. Looking at the motor side of the drum and motor housing, there doesn't seem to be a mechanism / grooves for coupling the drum to the drum casing (i.e. to brake it) - see below

http://img511.imageshack.us/img511/7007/mg0275sh2.jpg

The motor shaft is tiny, so I'm sure it would not be breaked (broke? - Ron, advance appologies ;) ) through the shaft. :confused:

and the motor housing / attachment

http://img91.imageshack.us/img91/5245/mg0007er2.jpg

Cheers

[Shonky]

"braked"

;)

[isuzurover]

This any help??? Looks like a different model, but shows roughly what it should look like.

http://www.greatlakes4x4.com/showthread.php't=69459

[Offender90]

"braked"

;)

Ah... but of course, :BigThumb:


This any help??? Looks like a different model, but shows roughly what it should look like.

Warn winch brake repair - Great Lakes 4x4 (http://www.greatlakes4x4.com/showthread.php't=69459)

might be... the key points may be in the following posts:

__________________________________________________ _____


Quote:
Originally Posted by Jeeperz Creeperz View Post
It probably doesn't have a load-holding brake....

how does it hold then?

- - -

Quote:
Originally Posted by clarkstoncracker View Post
how does it hold then?

It doesn't, which is the problem you're having....

"Automatic Direct Drive Cone" does not mean "Automatic Load Holding Brake".
__________________________________________________ _____

[Offender90]

After a long break, the winch is finally back together.

http://img291.imageshack.us/img291/1318/img0610gb0.jpg



Do you have any idea what model number the winch is?

I recently found out it's a Warn M8000, - I found a bunch of pics of one pulled apart here (http://www.fourwheeler.com/techarticles/electrical/129_0708_warn_m8000_winch_breakdown/index.html), which is identical to mine.

Oh, by the way, it does have a brake within the drum, it's just recessed a lot deeper than I expected. I'd say its only about 6-10cm wide.

Now the M8000 is complete, I can focus on getting the 120 on the road and fitting a turbo. This is what I have so far:

http://img291.imageshack.us/img291/9250/31012009043es7.jpg

My first question is (plenty of others to follow, but I thought I'd start here and take it one at a time) , where can I mount an EGT probe pre-turbo?

Rijidij suggested drilling and tapping the manifold where the two branches meet (see here (http://www.aulro.com/afvb/isuzu-landy-enthusiasts-section/68674-egt-gauges-one-3.html). This would be simplest easiest and best location, but would there be any problems in drilling and tapping a cast iron manifold?

Alternatively, an adaptor could be made to fit the probe between the exhaust manifold and turbine mount, looking something like this:

https://www.aulro.com/afvb/

But this would be more work, so I'm wandering if it's necessary?

Cheers

Bojan

[Jock The Rock]

Mate well done with your winch thats an excellent job.

Now I wish I put more time into doing mine :(

http://www.aulro.com/afvb/projects-tutorials/69722-warn-winch-rebuild.html

Sorry cant offer any advice on the EGT sensor

[rijidij]

My first question is (plenty of others to follow, but I thought I'd start here and take it one at a time) , where can I mount an EGT probe pre-turbo?

but would there be any problems in drilling and tapping a cast iron manifold?

But this would be more work, so I'm wandering if it's necessary?

Cheers

Bojan

See my post in the EGT thread >>>>>>>> http://www.aulro.com/afvb/isuzu-landy-enthusiasts-section/68674-egt-gauges-one-3.html#post906171

Cheers, Murray

[Offender90]

It's been slow but steady. I've been attacking it from several fronts, but it can be frustrating to see little progress after seemingly so much effort.

After some deliberation I ended up making a spacer for the EGT probe. I've got to thank Adam (agrojnr) for the lasercutting work. Just brilliant mate, the fit is perfect for the turbo...

Spacer with EGT probe fitted
http://img48.imageshack.us/img48/8794/09032009070.jpg

Perfect fit all the way around...
https://www.aulro.com/afvb/

...which is more than I can say for the factory exhaust manifold! There is a massive lip in the cast on the LH side, and a smaller one on the top...

http://img140.imageshack.us/img140/2573/10032009080.jpg

Thankfully, its nothing that a good ol' dremel can't fix! :twisted:

I now have to get some longer bolts and additional T3 gasket (or some VHT high temp copper gasket cement) and bolt it al together on the 4BD1.

Does anyone here know the size of the bolt for the T3 "point-up type" isuzu manifold (same as isuzurovers' one shown here (http://www.aulro.com/afvb/isuzu-landy-enthusiasts-section/63176-budget-4bd1-turbo-install.html))?. The local Coventry Industrial don't have the right size, and getting to a Coventry Fastenders outlet during business hours is a nightmare for me. *** Update*** They're M10 x 1.5!!!

After that, the fun of fitting and plumbing the intercooler starts - I've got a 550x230x65 front mount air to air intercooler in the garage & need to get an AC county front panel to be able to fit it in. Thought I had one but found out it's been butchered to fit a non AC ARB bar onto an AC county! :mad:

I other works, the county radiator is buggered, so its time for a replacement. Original staggered core has seen better days:

http://img502.imageshack.us/img502/7815/09032009079.jpg

My options are:

a.) a new aftermarket (V8) radiator, or
b.) a rodded original (V8) radiator (cooling fins in good condition)

I've got one of each sitting in the garage (one for the V8 90 and one for the 4BD1T). I'm thinking of getting the original V8 one cleaned (rodded) and outlets swapped for the 4BD1 and using the aftermarket on the 90. The original has staggered cores (same as the original isuzu radiator as far as I can tell). Isuzu staggered core pic below.

http://img255.imageshack.us/img255/9755/09032009078.jpg

Thoughts - brand new in-line core radiator or original "staggered core" in good nick?

While I've got the radiator out, I'll replace the 3 bolt steering box which has serious leakage.

http://img502.imageshack.us/img502/8058/09032009076.jpg

I've got a spare 3 bolt sitting in the garage, but I've heard the 4 bolt boxes are stronger. I can get a S/H 4 bolt for ~$250. Given that the front end of the county will (eventually) be very heavy (4BD1 + PTO + Heavy duty winch bar) & I'll be running 33s, is it worth upgrading to a 4 bolt?

I say eventiually because I've yet to fit the Thomas PTO winch that I recently come into possession of. I've also got to swap the sump over to a wingless one to leave enough room for both the PTO shaft and a 3 inch exhaust between the chassis rails.

The only thing I'm missing for the PTO is the drive sprocket (I'm told the part number for it is FTC73). Does anyone know if the drive sprocket is fitted to all military (LT95a) boxes, or only the winch equipped ones?

Given that I'll have decent access to the engine and gearbox in the process of the work above, should I be thinking about any other maintenance work (i.e. replacing seals etc)?

Cheers

Bojan

[The Mutt]

Ben took me for a spin in his newly turboed suzi and it goes great... put a smile on my face... almost comparable to the V8!

I'll have to pull the finger out and do the wastegate pushrod adjuster mod done, our Suzi Rangie is a bit of a slug at the moment.

Glenn

[Offender90]

OK, I think its time to post an update or two on the 120...

... well first off, it's been sporting a Garrett T3 turbo with an ATA FM intercooler for a few years now. Fuel boost is only moderately turned up (~1.25 turns of the fuel screw from memory). EGTs rarely exceed 600*C. No major complaints so far. It's served the intended purpose well, that is overtaking on the freeway & being able to maintain 110km/h regardless of conditions.

I'll dig up pics of the conversion details later in the week, but here's the list of tasks I've tackled since the last post:
- 4 bolt steering box
- new radiator (V8 radiator with outlets swapped),
- dual spin on oil filters with spacer brackets + spin on fuel filter,
- new wingless sump, late 4BD1T dipstick tube + dipstick
- fitted a turbo style rocker cover with an integrated engine breather port connected to a Provent 200
- additional gauges (VDO boost gauge with an inline restrictor (stops the ticking), Auber instruments EGT gauge and thermocouple, EngineSaver TM2 temperature alarm)
- fixed up the small amount of rust found in the firewall
- fitted an ADF type brush bar / PTO winch cradle with a Thomas winch and a pair Hella Rallye 2000 spotlights
- New shocks and springs front and rear (standard Bilstein shocks, ADF 110 front springs, 130 rears (outer springs only))
- Superpro steering and suspension bushes all round - much improved steering and reduced driveline clunk afterwards
- A 130L long range tank
- rear sway bar fitted - made a MASSIVE difference to body roll when fully loaded
- new seat bases, new heater and vent controls, new instrument nacelle & supporting plastic trim / frame (the bits 4BD1s usually chew up) - no more rattles from there, but should have ordered a Raptor metal bracket that the instrument cluster affixes to. I can't see the new plastic one lasting too long.
- new Stainless steel sleeved clutch master cylinder and new clutch slave cylinder. Got tired of bleeding the clutch every 3 months.
- made a 3mm aluminium bonnet protector plate with integrated pioneer tool mounts (so I can take them off / replace with the plain chequer plate if so desired)
- new lights all round (headlights, position lights, indicators and reverse light), new grille and headlight surrounds

Here's a few pics for completeness (they've been posted elsewhere)

https://www.aulro.com/afvb/images/imported/2013/09/971.jpg

https://www.aulro.com/afvb/images/imported/2013/09/972.jpg

https://www.aulro.com/afvb/images/imported/2013/09/973.jpg

https://www.aulro.com/afvb/images/imported/2013/09/974.jpg

I've been living in the CBD for the last couple of years, so she's mainly been doing city driving. Pottering around town in (LT95) 4th from 40km/h onwards is a great way to save on fuel bills... not so good when you have to plant it to change lanes... SA style! :wasntme:

That got me thinking... wouldn't it be nice to have a bit more low end boost. :angel:

[uninformed]

very nice find. Did anyone else notice it came with front and rear Maxidrive diff locks fitted :cool:

[Sitec]

I've not seen this thread before!! A very familiar vehicle!!! How'd ya go with those wheels? :)

[Offender90]

Thanks Serg,

She was no show pony when I picked her up, but did have a few goodies installed including front and rear Maxidrive lockers in laminated axles. I've been working on the rest of the drivetrain to give the ol' girl a new lease on life.

I came across a couple of things I couldn't say no to, one thing led to another and well, I have a virtually new drivetrain waiting to come together, comprising:

- rebuilt 4BD1T block (new pistons, rings, liners, bearings, camshaft, oil pump)
- new (early) head with rebuilt injectors
- new injection pump from a 4BD2TC
- rebuilt old-school Garrett VNT25 with a mechanical dual port (pressure / vacuum) VNT actuator.
- turbo pressure plate, new clutch and throwout bearing (may need a new spigot bush as well)
- little used LT95 TRB box with bottom mount PTO drive. Not sure of kms travelled, but TC appears to have very little visible wear.
- refurbished PTO winch and drive shaft assembly
- used 70A Hitachi alternator to upgrade my original 40-amper
- rear disc brake conversion bits
+ lots of not so interesting body & interior bits and pieces

Obligatory pics...

Block - top end
https://www.aulro.com/afvb/images/imported/2013/09/945.jpg
Bottom end
https://www.aulro.com/afvb/images/imported/2013/09/946.jpg

Head (anyone know if the numbers next to valve stems represent cast date?)
https://www.aulro.com/afvb/images/imported/2013/09/932.jpg
Being cleaned up
https://www.aulro.com/afvb/images/imported/2013/09/947.jpg
Injectors
https://www.aulro.com/afvb/images/imported/2013/09/948.jpg

Injection Pump
https://www.aulro.com/afvb/images/imported/2013/09/949.jpg

https://www.aulro.com/afvb/images/imported/2013/09/950.jpg

Turbo complete with early Chrysler T3 (TK100) mount. the turbo has the same 60 trim compressor as Garrett's T25 (39.8mm inducer and 51.4mm exducer), with a variable nozzle turbine housing (0.64 A/R, 52.7mm inducer and 46.2mm exducer). Hoping it will flow enough for ~200 hp with boost on tap from almost idle.

https://www.aulro.com/afvb/images/imported/2013/09/951.jpg

https://www.aulro.com/afvb/images/imported/2013/09/952.jpg
Garrett P/N plaque
https://www.aulro.com/afvb/images/imported/2013/09/953.jpg

LT95 box
https://www.aulro.com/afvb/images/imported/2013/09/954.jpg

PTO Drive
https://www.aulro.com/afvb/images/imported/2013/09/955.jpg

Things are starting to come together, so will be asking questions as I go along.

Cheers

Bojan

[uninformed]

WOW! it just keeps getting better. Thats a parts list to make a lot of guys jealous. Should be a bloody good set up once done.

keep on truckin

[Offender90]

I've not seen this thread before!! A very familiar vehicle!!! How'd ya go with those wheels? :)

lol... yeah, keeps disturbing the tranquillity at your place, hey? ;)

Not too bad, the Compomotive centres are ready for soda blasting, but the chrome rims couldn't be restored economically (minimum cost of $250/rim) so I'm having it taken off & then sandblasted - will hopefully have them ready to paint by next weekend. Progress stalled last week - been called in to work a fair bit.

Have to take a few good pics next time I'm over and update my 90 build thread as well. These are the only ones I have at the moment.

https://www.aulro.com/afvb/images/imported/2013/09/935.jpg

https://www.aulro.com/afvb/images/imported/2013/09/936.jpg

Cheers

Bojan

[Bush65]

...

Bottom end


Head (anyone know if the numbers next to valve stems represent cast date?)
https://www.aulro.com/afvb/images/imported/2013/09/932.jpg
...

Turbo complete with early Chrysler T3 (TK100) mount. the turbo has the same 60 trim compressor as Garrett's T25 (39.8mm inducer and 51.4mm exducer), with a variable nozzle turbine housing (0.64 A/R, 52.7mm inducer and 46.2mm exducer). Hoping it will flow enough for ~200 hp with boost on tap from almost idle.

...

Cheers

Bojan
I don't know about the cast numbers, but I know the date in permanent ink was marked on my head under one of the posts for the rocker shaft. In your pick I can see similar printing, so have a good look at that.

I'm going to hazard a guess that a compressor wheel with 40 mm inducer is not going to flow enough air and the 52 mm exducer will not give enough boost at reasonable efficiency for 200 HP, but that is simply my gut feel and may be wrong. You could always rebuild it with a larger wheel.

[Dougal]

The vnt 25 turbo is ancient and a lot had been learnt about vnt design since then. While it works, any gt22 based vnt turbo will beat it for boost, power and economy.

You can get 200hp worth of air from the 51.4mm t25 compressor on our engines , but only just and as John said, it's not very efficient doing it.

[Offender90]

I don't know about the cast numbers, but I know the date in permanent ink was marked on my head under one of the posts for the rocker shaft. In your pick I can see similar printing, so have a good look at that.

I'm going to hazard a guess that a compressor wheel with 40 mm inducer is not going to flow enough air and the 52 mm exducer will not give enough boost at reasonable efficiency for 200 HP, but that is simply my gut feel and may be wrong. You could always rebuild it with a larger wheel.

Thanks John,

I saw the writing, but couldn't make out a date - a few Japanese (Kana?) characters. I've blown it up as much as possible if someone else can make out a date.

https://www.aulro.com/afvb/images/imported/2013/09/923.jpg

The reason I asked about the castings is I have access to three heads at the moment, and all three have different numbers, corresponding to what could be YY M DD dates. See below

Unknown vintage head
https://www.aulro.com/afvb/images/imported/2013/09/924.jpg

Late 4BD1T head (skinny injectors) - numbers don't come up well, but from memory 89 8 17
https://www.aulro.com/afvb/images/imported/2013/09/925.jpg

[Sitec]

Damn!!! That's not on!! If you are pulling 200hp out of the 4 I'm going to have to wind the pump out on the Cummins!!! Thought I was doing well at 240hp!! Still not sure how well the LT230 is going to cope though!!
Re the rims.. With the centers restored you could always do the 'satin black' option on the rims... There's a lot of the newer rims around now with that black outer look...
As for the Ninety.. Shout if you want pics putting up.... Off to try and find that thread now!! :D

[justinc]

Thanks John,

I saw the writing, but couldn't make out a date - a few Japanese (Kana?) characters. I've blown it up as much as possible if someone else can make out a date.

https://www.aulro.com/afvb/images/imported/2013/09/923.jpg

The reason I asked about the castings is I have access to three heads at the moment, and all three have different numbers, corresponding to what could be YY M DD dates. See below

Unknown vintage head
https://www.aulro.com/afvb/images/imported/2013/09/924.jpg

Late 4BD1T head (skinny injectors) - numbers don't come up well, but from memory 89 8 17
https://www.aulro.com/afvb/images/imported/2013/09/925.jpg


Youngest Daughter who is quite good at these things tells me that those are Kanji characters, and as she will be learning those next year at school (A HUGE amount of characters to learn, around 3000 IIRC!) she can't tell what they are about, so sorry can't help with dates :(

JC

[Offender90]

I'm going to hazard a guess that a compressor wheel with 40 mm inducer is not going to flow enough air and the 52 mm exducer will not give enough boost at reasonable efficiency for 200 HP, but that is simply my gut feel and may be wrong. You could always rebuild it with a larger wheel.


The vnt 25 turbo is ancient and a lot had been learnt about vnt design since then. While it works, any gt22 based vnt turbo will beat it for boost, power and economy.

You can get 200hp worth of air from the 51.4mm t25 compressor on our engines , but only just and as John said, it's not very efficient doing it.

:Rolling:

I'm aware it's ancient... but that's the way I like it! ;) It complements both the 120's vintage and that of the git driving it reasonably well! :wasntme:

I thought it should be good for 200hp (may be pushing the friendship a bit, dunno?). It was roumored to have been designed for a 1.8L petrol, but fitted to a 2.2L petrol that made 175hp, developing 15psi boost from 2100 RPM onwards. I came across a few threads of people using it in diesels without reported adverse effects on VNT vanes fouling (my greatest concern), on both direct and indirect diesels.

My gut feel was that the turbine may be a touch restrictive for high power applications and was potentially contemplating leaving a provision for an external wastegate in the T3 to TK100 flange adapter, but am not sure it's worth the effort. Worst case scenario it'll be good for 180 HP with reasonable efficiency, which will still be more than sufficient to maintain my 110km/h and overtaking goals, but should see marked improvement in boost availability at lower engine speeds, which is where it will likely spend most of its time. I also like the simple VNT actuator control - it has potential for a simple boost controlled setup, with a in-cab regulated vacuum line for actuation point adjustment.

Time will tell how it behaves. I always have my T3 to fall back on if I'm unsatisfied.

[Offender90]

Youngest Daughter who is quite good at these things tells me that those are Kanji characters, and as she will be learning those next year at school (A HUGE amount of characters to learn, around 3000 IIRC!) she can't tell what they are about, so sorry can't help with dates :(

JC

Thanks JC,

Good on her. My better half's done about 5 years of Japanese in a previous life (throughout high school) but she reckons her Kanji was never good. That and she's been away all week. :P

Bojan

[justinc]

Thanks JC,

Good on her. My better half's done about 5 years of Japanese in a previous life (throughout high school) but she reckons her Kanji was never good. That and she's been away all week. :P

Bojan


Rose is off to Japan on a school trip on Friday for 2 weeks, and is busy packing in the other room!:( As a 15 YO she is very hard working at her studies, so she'll no doubt get a lot out of it. Has a good grasp of languages in general, it will be a life changing trip for her I reckon :)

JC

[Bush65]

I'm pushing my memory here, so some detail may be wrong. My recollection is that what was printed on my head was a month and year.

I don't recall seeing kanji characters, but that is how memory works - I would have just ignored them.

[Offender90]

I understand that headbolts are OK to reuse on a 4BD1. The manual is not as clear on the 4BD1T bolts (to me anyway), as it has different torquing procedures for new and reused bolts on the 4BD1, while the 4BD1T only has one procedure. Also, 4BD1 and 4BD1T blocks appear to use different headbolts (or the difference could be related to the age of the engine and have nothing to do with turbo / non turbo).

I have a set of headbolts that came off the 4BD1T block, which have a "0" forged on top of the head. The 4BD1 engine I have comes with headbolts with a "12" on the head. Are these bolts different?

Three bolts from the "0" set have been stretched (by 4mm, 2mm and 1mm respectively on the photo).

https://www.aulro.com/afvb/images/imported/2013/09/883.jpg

Do I only replace the stretched bolts, and if so, do I replace them with new "0" or used "12" bolts?

Do I use all new bolts (a $600 exercise for genuine head bolts priced from Don Kyatt), or if I am going all new, do I go the extra mile and splurge on ARP studs and nuts?

Thoughts?

Cheaper is obviously better as I'm not chasing stupid power out of the engine.

EDIT on the topic of head bolts, any suggestions for a good place to get Molybdenum Disulphide grease. The nearest thing the local Sprint store had was engine assembly lube "with moly-graphite". Loctite Moly Paste is probably ideal (65% MoS2), but none of the nearby auto stores seem to stock. United fasteners will be my next stop unless someone can suggest a place in the city or another suitable product.

[labrado]

Youngest Daughter who is quite good at these things tells me that those are Kanji characters, and as she will be learning those next year at school (A HUGE amount of characters to learn, around 3000 IIRC!) she can't tell what they are about, so sorry can't help with dates :(

JC
the first and last columns are in kanji:D, 1st column（佐藤） is the name of the inspector, the last column（检查） means "inspected". I can't see the middle column after enlarging the picture, too blurry:(.

[Bush65]

Just had a quick lool in a parts book, and Isuzu part numbers for head bolts look like:

4BD1
509009-0180 (14 required)
509009-0170 (4 required)

Early 4BD1T
894150-0250 (12 required)
894150-0230 (2 required)
894150-0240 (4 required)

Later 4BD1T
894367-4380 (12 required)
894367-4360 (2 required)
894367-4370 (4 required)

The quantity 2 bolts, are same size as the quantity 12, but have an integrated stud protruding from the hex head and they go at the front and rear of the head for a couple of accessory mounts.

I presume the later 4BD1T bolts are improved material or heat treatment, not different size, to overcome some issue found earlier.

I don't like the look of those stretched bolts :o

JIS (Japanese Industry Standards) for the numeral on the bolt head appears to be the same as the first part of the numeral on SI bolts, i.e. tensile strength of bolt material. The second part of SI property class, which starts from the decimal point is not a fraction of tensile strength.

So the 12 for a JIS bolt, I would take as the same as the 12, in a 12.9 SI bolt.

I replaced my head bolts with ARP studs some time back, so I can't check markings for the head bolts for my 4BD1T.

[Dougal]

:Rolling:

I'm aware it's ancient... but that's the way I like it! ;) It complements both the 120's vintage and that of the git driving it reasonably well! :wasntme:

I thought it should be good for 200hp (may be pushing the friendship a bit, dunno?). It was roumored to have been designed for a 1.8L petrol, but fitted to a 2.2L petrol that made 175hp, developing 15psi boost from 2100 RPM onwards. I came across a few threads of people using it in diesels without reported adverse effects on VNT vanes fouling (my greatest concern), on both direct and indirect diesels.

My gut feel was that the turbine may be a touch restrictive for high power applications and was potentially contemplating leaving a provision for an external wastegate in the T3 to TK100 flange adapter, but am not sure it's worth the effort. Worst case scenario it'll be good for 180 HP with reasonable efficiency, which will still be more than sufficient to maintain my 110km/h and overtaking goals, but should see marked improvement in boost availability at lower engine speeds, which is where it will likely spend most of its time. I also like the simple VNT actuator control - it has potential for a simple boost controlled setup, with a in-cab regulated vacuum line for actuation point adjustment.

Time will tell how it behaves. I always have my T3 to fall back on if I'm unsatisfied.

To make 200hp you'll need to pull about 18 psi intercooled to 3000rpm. That's doable on that compressor, there are just others that will do it will less drive pressure.
My concern is whether that turbine can pass the exhaust flow.

I am currently running a T25 with the same compressor and turbine but not VNT and not intercooled, it has the 0.49 A/R wastegated turbine housing. I'm getting 10psi at 1200rpm and 20psi a bit before 2000rpm. With the wastegate clamped shut it the exhaust turbine chokes out about 2,400rpm and kills power.
I run a wastegate to get around that.

The VNT turbine can deliver more boost sooner (just in case you need that) and flow more volume through the same turbine as the rpm rise. You need that because you don't have a wastegate. Instead all the gas needs to exit through the turbine. The more pressure and heat you put on a turbine the more gas you can fit through it.
But the more pressure and heat, the more power they produce. Which produces more boost and this cycle does nothing but kill power once an engine is too big for the VNT turbo.

To hit 200hp you need to fit about 23 lb/min of exhaust through that turbine and you need about 25kw of shaft power.
The limit of a 0.49 A/R T25 turbine at 700C EGT and an expansion ratio to deliver that power is 23lb/min. The wastegate is basically shut and drive pressure is about 25psi.
The 0.64 A/R turbine according to the maps can't quite deliver. It can only produce 22kw from that pressure and flow with 20psi drive pressure.
The lower efficiency of the VNT (I'm using 0.55 vs 0.65 for the T25 turbines) means it needs cranked closed to a corrected flow of about 11 lb/min. This will spike the drive pressure to ~33psi.

However. I'm finding my actual results are giving better turbine performance than the predictions. Which to me suggests that exhaust pulse energy is driving the turbine harder than the published charts which are for steady flow.
I was certainly getting more than 17psi boost from the T25 0.64 A/R turbine with the wastegate clamped at 3000rpm. 2500-3000rpm was the operating point where the T2560 turbo that I built with the 0.64 housing was truely impressive.

[isuzurover]

the first and last columns are in kanji:D, 1st column（佐藤） is the name of the inspector, the last column（检查） means "inspected". I can't see the middle column after enlarging the picture, too blurry:(.


From a colleague:

It means: "checked by Mr Sato" with the date in the middle.
dates in japan are : yy-mm-dd
It was hard to read the date but it's probably april 8.

[Offender90]

To make 200hp you'll need to pull about 18 psi intercooled to 3000rpm. That's doable on that compressor, there are just others that will do it will less drive pressure.
My concern is whether that turbine can pass the exhaust flow.

I am currently running a T25 with the same compressor and turbine but not VNT and not intercooled, it has the 0.49 A/R wastegated turbine housing. I'm getting 10psi at 1200rpm and 20psi a bit before 2000rpm. With the wastegate clamped shut it the exhaust turbine chokes out about 2,400rpm and kills power.
I run a wastegate to get around that.

The VNT turbine can deliver more boost sooner (just in case you need that) and flow more volume through the same turbine as the rpm rise. You need that because you don't have a wastegate. Instead all the gas needs to exit through the turbine. The more pressure and heat you put on a turbine the more gas you can fit through it.
But the more pressure and heat, the more power they produce. Which produces more boost and this cycle does nothing but kill power once an engine is too big for the VNT turbo.

To hit 200hp you need to fit about 23 lb/min of exhaust through that turbine and you need about 25kw of shaft power.
The limit of a 0.49 A/R T25 turbine at 700C EGT and an expansion ratio to deliver that power is 19lb/min. The rest (4 lb/min) is wastegated and drive pressure is about 17psi.
The 0.64 A/R turbine delivering the same power passes 21 lb/min and drive pressure would be ~15psi.
To get the VNT to pass all of it you'd need the vanes to expand to an A/R ratio of about 0.9. At this point they'd pass the 23 lb/min (corrected flow is 18lb/min) with a drive pressure of ~13psi and a temp drop across the turbine of about 123C.

So whether it'll work or not depends how far the vanes will open. If they do open far enough, then you're sorted. If they don't then you'll overboost, get high drive pressure as a result and performance will be self limiting.
An external wastegate could be used to fix that problem. It's just an extra complication.

Yeah, I was working through the 4BD1T Turbo Sizing and Performance Prediction thread in my spare time & mapped out various power outputs for the T25 60 trim compressor map at 1000, 2000 and 3000 RPM, assuming "effective intercooling" and an A/F ratio of 18:1.

https://www.aulro.com/afvb/images/imported/2013/09/852.jpg

Compressor efficiency looks reasonable at around 70% between 2000 and 3000 RPM.

I wasn't certain how VNT turbine sizing works, but have guessed the 0.64 A/R marked on the casting to be scroll geometry A/R without the VNT vanes (or perhaps with vanes fully open). The closest dimensioned turbine I can find is the Garrett "Disco Potato" 53.9mm 76 trim turbine with a 0.64 A/R housing which seems to choke out at a corrected flow of 18 lbs/min. - Not sure what the flow is corrected to, but seems considerably lower than the mass flow at the compressor, and what goes in must come out, right?
That's why I thought I may need an external wastegate to make the 150kW / 200hp, however I still don't have an understanding of drive pressure / back pressure / shaft power, and how they relate to the turbine map & choke flow.
Keeping a keen eye on the turbo sizing and performance prediction thread.

[Dougal]

Yeah, I was working through the 4BD1T Turbo Sizing and Performance Prediction thread in my spare time & mapped out various power outputs for the T25 60 trim compressor map at 1000, 2000 and 3000 RPM, assuming "effective intercooling" and an A/F ratio of 18:1.

What are you using for VE? You are showing higher boost for the same power as my calcs.
Just picking on the 3000rpm 130kw point, I'm only showing 13psi with 70% comp efficiency and 60% intercooler effectiveness.

Compressor efficiency looks reasonable at around 70% between 2000 and 3000 RPM.


I wasn't certain how VNT turbine sizing works, but have guessed the 0.64 A/R marked on the casting to be scroll geometry A/R without the VNT vanes (or perhaps with vanes fully open). The closest dimensioned turbine I can find is the Garrett "Disco Potato" 53.9mm 76 trim turbine with a 0.64 A/R housing which seems to choke out at a corrected flow of 18 lbs/min. - Not sure what the flow is corrected to, but seems considerably lower than the mass flow at the compressor, and what goes in must come out, right?
That's why I thought I may need an external wastegate to make the 150kW / 200hp, however I still don't have an understanding of drive pressure / back pressure / shaft power, and how they relate to the turbine map & choke flow.
Keeping a keen eye on the turbo sizing and performance prediction thread.

The disco potato is a significantly bigger turbine. This one:
https://www.aulro.com/afvb/images/imported/2013/09/849.jpg
Has turbine measurements which match mine. My best guesstimates put my 0.49 housing as scaling the line down to about 13.3 lb/min corrected choke flow.

But yes the vane behaviour and equivalent A/R is the big ? Can it adjust either side of the housing A/R ratio equally or only much smaller and not much bigger? The turbine efficiency of the VNT's is also a lot lower (drag from all those vanes at a less than ideal angle).

This one is incredibly fuzzy, but it shows the limits of operation for an unknown VNT model:
https://www.aulro.com/afvb/images/imported/2013/09/850.jpg

There is an FSAE data dump on the web with GT1541V (#700960, application includes vw 1.2tdi allegedly) maps including turbine, the A/R is 0.42 if you want to compare against fixed geometry housings.
Turbine maps are corrected to STP. It's a mental battle doing the calcs for real flow to corrected as you have to juggle pressure at the inlet, expansion ratio and power or real flow to keep corrected flow on the target.

*edit*
I've just compared the GT1541V turbine map (0.42 A/R) against a GT1544 which appears to use the same 58 trim turbine with a 0.34 A/R housing.
It looks like the VNT maxes out at the stated A/R. VNT with 0.42 only hits ~7.5 lb/min corrected. Fixed with 0.35 A/R is ~6.3 lb/min corrected.

This does not bode well for your VNT25. It may choke and spike both boost and drive pressure to kill your top end performance.

[Offender90]

Using 0.9 VE at 1000 & 2000 RPM, and 0.8 @ 3000 RPM.

I suspect the difference may come from either my Density to Pressure ratio guestimate or the Air to Fuel ratio assumed. I assumed A:F 18:1 and a sliding scale for Density to Pressure ratio conversion from PR=1.25*DR @ DR<1.4 to PR=1.1*DR @ DR>2.0 without actually working out intercooling effects.
I used a spreadsheet to generate all the values & can email if you're interested.

When you say the disco potato turbine is significantly larger, I was under the impression both disco potato turbos used a T25 sized turbine with a larger compressor housing. I was using the data off the smaller one with a 53.9mm wheel, 76 trim in a 0.64 A/R housing.

Garrett's VNT-25 turbine on the other hand uses a 52.7mm wheel, 77 trim in a "0.64 A/R variable vane" housing. Wouldn't the two turbines be fairly similar in size, or am I missing something obvious?

This is the chart I was referring to:

https://www.aulro.com/afvb/images/imported/2013/09/827.jpg

When it comes to turbine charts in general, and VNT turbines in particular, I must admit it is all somewhat French to me - still a lot of reading I have to do.

[Dougal]

When you say the disco potato turbine is significantly larger, I was under the impression both disco potato turbos used a T25 sized turbine with a larger compressor housing. I was using the data off the smaller one with a 53.9mm wheel, 76 trim in a 0.64 A/R housing.

Garrett's VNT-25 turbine on the other hand uses a 52.7mm wheel, 77 trim in a "0.64 A/R variable vane" housing. Wouldn't the two turbines be fairly similar in size, or am I missing something obvious?

Gotcha now. I didn't realise the VNT25 had a much larger trim than the wastegated versions. The VNT turbos of now appear to be using the same turbine as the wastegated versions.

So yeah 17lb/min corrected choke flow would be the best number we've currently got. But turbine efficiency could be as low as 45%.
My earlier example of the VNT with an equivalent to about 0.9 A/R came out with corrected choke flow of 17.9 lb/min.
So now it's within the margin of error. Definitely close enough to try.

*edit*
Just a general disclaimer. I am still bug checking all these turbine calcs.

[Bush65]

...

I suspect the difference may come from either my Density to Pressure ratio guestimate or the Air to Fuel ratio assumed. I assumed A:F 18:1 and a sliding scale for Density to Pressure ratio conversion from PR=1.25*DR @ DR<1.4 to PR=1.1*DR @ DR>2.0 without actually working out intercooling effects.
...
I've been too busy to update the stuff I have been adding to the turbo sizing thread. I only intended the rough conversion for PR to be used for the first pass guesstimate of adiabatic efficiency. The proposed next post that I haven't had time to finish addresses PR to DR.

PR = DR x T2/T1
where
PR is pressure ratio (P2/P1)
P2 & P1 are absolute pressures at outlet & inlet, P1 = ambient - losses
DR is density ratio (D2/D1)
T2 is absolute Temp in K at outlet (after intercooler if fitted)
T1 is ambient temp in K

A problem with that is T2 increases with pressure (and reduces with increased efficiency), so making it difficult to calculate PR directly. I find it easier to calculate DR for a range of PR, to create a 'look-up table' to find the PR.

Then I will address some of the other stuff.

[Dougal]

To hit 200hp you need to fit about 23 lb/min of exhaust through that turbine and you need about 25kw of shaft power.
The limit of a 0.49 A/R T25 turbine at 700C EGT and an expansion ratio to deliver that power is 23lb/min. The wastegate is basically shut and drive pressure is about 25psi.
The 0.64 A/R turbine according to the maps can't quite deliver. It can only produce 22kw from that pressure and flow with 20psi drive pressure.
The lower efficiency of the VNT (I'm using 0.55 vs 0.65 for the T25 turbines) means it needs cranked closed to a corrected flow of about 11 lb/min. This will spike the drive pressure to ~33psi.

However. I'm finding my actual results are giving better turbine performance than the predictions. Which to me suggests that exhaust pulse energy is driving the turbine harder than the published charts which are for steady flow.
I was certainly getting more than 17psi boost from the T25 0.64 A/R turbine with the wastegate clamped at 3000rpm. 2500-3000rpm was the operating point where the T2560 turbo that I built with the 0.64 housing was truely impressive.

I found a bug in my spreadsheets (formula referencing wrong column) and have corrected the post quoted above.
The 0.49 T25 shows wastegate almost clamped to provide that 25kw.
The 0.64 T25 is showing as not making 25kw.
The VNT would need to be cranked down below full open vanes.

But my measured results (boost, drive, egt etc) are showing better than predicted. I'm putting this down to exhaust pulse energy where the turbine maps are developed using steady flow.
It looks like you can account for this in a rough way by bumping turbine efficiency up. But I'm hoping to find something better.
But I'm also unsure whether the temperature used for correction is 0C, 15C or something else. Borg Warner use 15C (59F), 0C is pretty common in chemistry and I can't remember what Garrett use for their compressor maps.

[Bush65]

I found a bug in my spreadsheets (formula referencing wrong column) and have corrected the post quoted above.
The 0.49 T25 shows wastegate almost clamped to provide that 25kw.
The 0.64 T25 is showing as not making 25kw.
The VNT would need to be cranked down below full open vanes.

But my measured results (boost, drive, egt etc) are showing better than predicted. I'm putting this down to exhaust pulse energy where the turbine maps are developed using steady flow.
It looks like you can account for this in a rough way by bumping turbine efficiency up. But I'm hoping to find something better.
But I'm also unsure whether the temperature used for correction is 0C, 15C or something else. Borg Warner use 15C (59F), 0C is pretty common in chemistry and I can't remember what Garrett use for their compressor maps.
AFAIK Garrett use 545 R and 28.4" Hg for their compressor maps, and Borg Warner use 873 K for turbine, 293 K and 981 mbar for compressor.

[Dougal]

AFAIK Garrett use 545 R and 28.4" Hg for their compressor maps, and Borg Warner use 873 K for turbine, 293 K and 981 mbar for compressor.

So back in useful units.:angel:
Garrett 30C/303K and 96.3kPa for compressor. I had 298K/25C written down for garrett with the same presssure but I didn't write down the source.

Borg Warner are using 59F (15C/288K) in the matchbot for turbine correction. Where did you find 873K?
I'm very happy with the correlation I'm getting on turbine results with borg warner using 288k and 101.3kPa for turbine correction. But the compressor power doesn't make sense, I've got some figures I've you'd be kind enough to check them in the prediction thread.

[Dougal]

Another bug found.

145kw at 3000rpm data points.

17psi boost = 18.3kw shaft power.
~21psi drive pressure on a 0.49 T25. Wastegating 5 lb/min
~19.5psi drive pressure on a 0.64 T25. Wastegating 3.5 lb/min
~20psi drive pressure on a VNT25 with corrected flow of ~17 lb/min it's trying to produce ~20kw of shaft power. So you'll be into the boost spiral but not much. It should cool your EGT enough with only a few more psi boost to reach equilibrium.

Now I've got work to do.:angel:

[Bush65]

So back in useful units.:angel:
Garrett 30C/303K and 96.3kPa for compressor. I had 298K/25C written down for garrett with the same presssure but I didn't write down the source.

Borg Warner are using 59F (15C/288K) in the matchbot for turbine correction. Where did you find 873K?
I'm very happy with the correlation I'm getting on turbine results with borg warner using 288k and 101.3kPa for turbine correction. But the compressor power doesn't make sense, I've got some figures I've you'd be kind enough to check them in the prediction thread.
I took the temp and pressure for Borg Warner compressors from the example map
https://www.aulro.com/afvb/
from this page from Borg Warner (http://www.turbodriven.com/en/turbofacts/designCompressor.aspx) and it is the same as every Borg Warner 'K' series compressor map I have ever seen clearly states same reference values, i.e. 293 K and 981 mbar.

From another page of the same Borg Warner website (http://www.turbodriven.com/en/turbofacts/designTurbine.aspx) I took the reference temperature from this example turbine map
https://www.aulro.com/afvb/

I've had a look and seen where you got the turbine reference temp (59 F) from Matchbot. It strikes me that 59 F (15 C) is a strange temperature to correct exhaust gas temperature to, but we have to work with what we have!

Matchbot only works with 'EFR' and 'S' series turbos, which causes me to wonder if the difference is whether the Borg Warner turbo is from Europe 'K' series, or from USA 'EFR' and 'S' series?

[Dougal]

I took the temp and pressure for Borg Warner compressors from the example map
http://www.turbodriven.com/img/turbofacts/img_21_principle_g.gif
from this page from Borg Warner (http://www.turbodriven.com/en/turbofacts/designCompressor.aspx) and it is the same as every Borg Warner 'K' series compressor map I have ever seen clearly states same reference values, i.e. 293 K and 981 mbar.

That all makes perfect sense. Numbers are as expected.


From another page of the same Borg Warner website (http://www.turbodriven.com/en/turbofacts/designTurbine.aspx) I took the reference temperature from this example turbine map
http://www.turbodriven.com/img/turbofacts/img_29_principle_g.gif

But that 873 makes no sense. 873K (600C) is a perfectly reasonable temperature to use for actual turbine inlet temp or EGT, but to use that value in correcting flow is odd. The 288K and 101.3kPa is commonly used for gas correction in chemistry processes.
But that map also has no units for turbine flow (though it could be gleaned from the formulae given) and a scale that doesn't match any of their other plots.
I wonder if it were created solely as a website example with a different t-ref used to disguise sensitive information? Basically to keep it not comparable to garrett maps.


I've had a look and seen where you got the turbine reference temp (59 F) from Matchbot. It strikes me that 59 F (15 C) is a strange temperature to correct exhaust gas temperature to, but we have to work with what we have!

Indeed and if we do use 288K (59F) and 101.3kPa as reference pressure and temp for correction then these maps:
http://www.turbodriven.com//performanceturbos/matchbot/images/turbinemap.jpg
make perfect sense, match the internal calculations on the website and correlate well with Garrett maps for turbines of simiar wheel size. It's easy to calculate the "Phi" number for other turbines and overlay their curve on the same graph.
In fact it would be relatively straight-forward (but a fair bit of work) to overlay all publicly available turbine maps on the same graph.


Matchbot only works with 'EFR' and 'S' series turbos, which causes me to wonder if the difference is whether the Borg Warner turbo is from Europe 'K' series, or from USA 'EFR' and 'S' series?

Here's the interesting point, matchbot is simply dropping points on top of graphics. It is the user who must check and align the dots. If you know a savvy web developer (mine are all busy) then an equivalent can be created to drop points onto any compressor and turbine maps.
I'm doing the same thing in Excel to do the calculations then plotting points and curves on top of compressor and turbine maps. It works well, but it's tedious with a lot of goal-seek involved.

[Offender90]

Revising my estimated T25 compressor map with calculated values assuming 60% effective intercooling gives the following map:

https://www.aulro.com/afvb/images/imported/2013/09/383.jpg

Compressor efficiency looks even more reasonable between 2000 and 3000 RPM.

Next step is to work out how much fuel the 4BD2TC fuel pump can deliver at low RPM

- 132cc/1000 strokes @ 1000rpm produces 57 kW / 540Nm of torque
- 143cc/1000 strokes @ 2000rpm produces 140kW / 660Nm of torque
- 123cc/1000 strokes @ 3000rpm produces 150kW / 470Nm of torque

pumping more fuel at 3000 rpm pushes the shaft speed off the compressor map, which I take is somewhat bad for turbo longevity.

The 4BD2T pump full load map looks somewhat different to the 4BD1T pump in that it can deliver more fuel at low pump speed, and has a longer boost compensator stroke (0.7mm compared with 0.5mm for the 4BD1T)

The first adjustment point is A, rack position R1 (11.9mm) @ 950RPM pump speed.

https://www.aulro.com/afvb/images/imported/2013/09/384.jpg

Full load map at the top

https://www.aulro.com/afvb/images/imported/2013/09/385.jpg

Differences between 4BD1T and 4BD2T covered in this post:
http://www.aulro.com/afvb/isuzu-landy-enthusiasts-section/177561-4bd2t-inection-pump-4bd1t.html

I can confirm both pumps have the same mount BTW.

Cheers

Bojan

[Dougal]

Revising my estimated T25 compressor map with calculated values assuming 60% effective intercooling gives the following map:

Compressor efficiency looks even more reasonable between 2000 and 3000 RPM.

Next step is to work out how much fuel the 4BD2TC fuel pump can deliver at low RPM

- 132cc/1000 strokes @ 1000rpm produces 57 kW / 540Nm of torque
- 143cc/1000 strokes @ 2000rpm produces 140kW / 660Nm of torque
- 123cc/1000 strokes @ 3000rpm produces 150kW / 470Nm of torque

pumping more fuel at 3000 rpm pushes the shaft speed off the compressor map, which I take is somewhat bad for turbo longevity.

You'll struggle with vibration at the 1000rpm point. With my t25 I have 10psi boost from ~1200rpm. That's on the limit of usable. 1600rpm is the point where I can begin to smoothly apply full throttle in higher gears. I plan some flywheel inertia additions to help.

I've been using 140cc as the fuelling limit until we get better information. I'd like to build a test-stand for my spare pump, but don't hold your breath. That gives about 132kw and 19lb/min at 2000rpm with my figures. It's nicely on my map too.
Coincidence, I've also had 3000rpm at 122cc, 154kw, 24.7lb/min. It's just off the map but I reckon it'll be fine.

Here are my graphs from 24psi intercooled. Cap the boost to 20psi and that's what I'm currently looking at.
https://www.aulro.com/afvb/images/imported/2013/09/380.jpg
https://www.aulro.com/afvb/images/imported/2013/09/381.jpg
https://www.aulro.com/afvb/images/imported/2013/09/382.jpg

[Offender90]

Dougal,

How do you determine how much fuel the pump delivers at full load at each pump speed. Rack position doesn't correlate to pumped volume as I understand it, as pumping efficiency increases at higher pump speeds.

From the pump calibration data I posted earlier - Point A (rack position R1, or 11.9mm) supplies 77mm^3 / stroke (or 77cc/1000 strokes). Point B on the other hand (rack position R1-0.15, or 11.75mm) supplies 79cc/1000 strokes. Is there a way to convert rack position and pump speed data into a volume of fuel delivered at full load?

My pump has a big red 180cc written on it, although the text in Katakana next to it I understand says something about engine oil (my better half didn't understand the Kanji characters).

https://www.aulro.com/afvb/images/imported/2013/09/371.jpg

Anyone know what this refers to? Oil flow required for initial lubrication or max fuel flow?

Also with regard to the turbo, does exceeding maximum shaft speed (i.e. moving off the compressor map upwards) have significant consequences for turbo longevity? I assume the interrupted efficiency islands generally follow the shape of the ones that fit on the graph.

[Dougal]

I think 180cc is lube oil quantity for pumps that aren't on the pumped engine oil circuit.

The only figure I have to base this off was Randy (Carcrafter22)'s measurement of max pump flow before he got his one modded. John has his own measurements and right now I'm trying to nudge a Canadian who's getting his pump rebuilt to get us some figures from across the speed range.

A test bench would be reasonably simple to setup. Variable speed electric drive, measuring pots for each injector line and that's about it. If you've got ideas on how much power it takes to turn a pump under test, then I'm all ears. I'm limited to single phase power at the moment, about 3kw max.

Exceeding turbo shaft speed all depends which map you beleive. Some maps run to higher rpm than others for damn near identical turbos. I'm fine with running them a little off the top of the map. But you can't go far before hitting flow limits anyway.

[isuzurover]

Dougal,

How do you determine how much fuel the pump delivers at full load at each pump speed. Rack position doesn't correlate to pumped volume as I understand it, as pumping efficiency increases at higher pump speeds.

From the pump calibration data I posted earlier - Point A (rack position R1, or 11.9mm) supplies 77mm^3 / stroke (or 77cc/1000 strokes). Point B on the other hand (rack position R1-0.15, or 11.75mm) supplies 79cc/1000 strokes. Is there a way to convert rack position and pump speed data into a volume of fuel delivered at full load?

My pump has a big red 180cc written on it, although the text in Katakana next to it I understand says something about engine oil (my better half didn't understand the Kanji characters).

https://www.aulro.com/afvb/images/imported/2013/09/371.jpg

Anyone know what this refers to? Oil flow required for initial lubrication or max fuel flow?

Also with regard to the turbo, does exceeding maximum shaft speed (i.e. moving off the compressor map upwards) have significant consequences for turbo longevity? I assume the interrupted efficiency islands generally follow the shape of the ones that fit on the graph.

Translation from my colleague:

~= When installing pump engine
Oil injection volume

[isuzurover]

Dougal,

How do you determine how much fuel the pump delivers at full load at each pump speed. Rack position doesn't correlate to pumped volume as I understand it, as pumping efficiency increases at higher pump speeds.

From the pump calibration data I posted earlier - Point A (rack position R1, or 11.9mm) supplies 77mm^3 / stroke (or 77cc/1000 strokes). Point B on the other hand (rack position R1-0.15, or 11.75mm) supplies 79cc/1000 strokes. Is there a way to convert rack position and pump speed data into a volume of fuel delivered at full load?

My pump has a big red 180cc written on it, although the text in Katakana next to it I understand says something about engine oil (my better half didn't understand the Kanji characters).

https://www.aulro.com/afvb/images/imported/2013/09/371.jpg

Anyone know what this refers to? Oil flow required for initial lubrication or max fuel flow?

Also with regard to the turbo, does exceeding maximum shaft speed (i.e. moving off the compressor map upwards) have significant consequences for turbo longevity? I assume the interrupted efficiency islands generally follow the shape of the ones that fit on the graph.

From my colleague:

~= When installing pump engine
Oil injection volume


To me it sounds like the volume of oil to add to lubricate the pump on install???

[Offender90]

From my colleague:


To me it sounds like the volume of oil to add to lubricate the pump on install???


It's handy having a japanese speaking colleague... or in my case colleague of a japanese speaking colleague ;)

[isuzurover]

It's handy having a japanese speaking colleague... or in my case colleague of a japanese speaking colleague ;)

He is a native French speaker who is fluent in English and Japanese. Makes our education system look sub standard...
(His girlfriend is native Japanese for any hard translations...)

[Bush65]

...

A test bench would be reasonably simple to setup. Variable speed electric drive, measuring pots for each injector line and that's about it. If you've got ideas on how much power it takes to turn a pump under test, then I'm all ears. I'm limited to single phase power at the moment, about 3kw max.

...
I'm lead to believe that pressure pulses, which (for other readers) travel as longitudinal waves at the speed of sound, play a significant part in diesel fuel injection systems. It is not as simple as positive pump displacement.

Thus diesel IP test benches use injector piping (length diameter) with test injectors specified for the calibration. IIRC you can read this information in a section of the calibration sheets Offender90 posted before.

I also believe this pressure wave issue was one of the reasons behind the move to unit injectors and common rail systems, i.e to shorten the wave path when seeking higher performance.

[Dougal]

I'm lead to believe that pressure pulses, which (for other readers) travel as longitudinal waves at the speed of sound, play a significant part in diesel fuel injection systems. It is not as simple as positive pump displacement.

Thus diesel IP test benches use injector piping (length diameter) with test injectors specified for the calibration. IIRC you can read this information in a section of the calibration sheets Offender90 posted before.

I also believe this pressure wave issue was one of the reasons behind the move to unit injectors and common rail systems, i.e to shorten the wave path when seeking higher performance.

We're in a situation where any data is going to help. It's not difficult to use the injector pipes and injectors from the same engine. Why bother with a calibrated reference when you've got the real parts?

Recently on 4BTswaps.com one of the members had has injection pump tested for delivery both with and without injectors attached.

Results here: Got my VE flow benched! results inside!!! (http://www.4btswaps.com/forum/showthread.php?28519-Got-my-VE-flow-benched!-results-inside!!!&p=242272&viewfull=1#post242272)
and here: Got my VE flow benched! results inside!!! - Page 2 (http://www.4btswaps.com/forum/showthread.php?28519-Got-my-VE-flow-benched!-results-inside!!!&p=242394&viewfull=1#post242394)

Cummins VE pumps can do 190cc at 3000rpm with an aftermarket fuel pin and differeng governor springs. But our engines flow air better.

[Offender90]

Speaking of the pump specifications, I've scanned the pump test data & parts list for the 4BD1-T pump in its entirety and uploaded it to Files / Technical Manuals section of AULRO (link below).

http://www.aulro.com/afvb/local_links.php?catid=7

I have a hardcopy of the same document for a 4BD2-T pump, and can scan and upload if anyone is interested.

Cheers

Bojan

[Bush65]

We're in a situation where any data is going to help. It's not difficult to use the injector pipes and injectors from the same engine. Why bother with a calibrated reference when you've got the real parts?

Recently on 4BTswaps.com one of the members had has injection pump tested for delivery both with and without injectors attached.

Results here: Got my VE flow benched! results inside!!! (http://www.4btswaps.com/forum/showthread.php?28519-Got-my-VE-flow-benched!-results-inside!!!&p=242272&viewfull=1#post242272)
and here: Got my VE flow benched! results inside!!! - Page 2 (http://www.4btswaps.com/forum/showthread.php?28519-Got-my-VE-flow-benched!-results-inside!!!&p=242394&viewfull=1#post242394)

Cummins VE pumps can do 190cc at 3000rpm with an aftermarket fuel pin and differeng governor springs. But our engines flow air better.
I agree on using the stock injectors and lines, I just wanted to point out what is done in practice, to calibrate these pumps.

I've only had time to read a few posts from those threads you linked to, but one of your posts caught my eye from the 2nd link.


Honestly I can't see larger injectors being any help. Your fuel flow is limited by the fixed volume pump, not the injector.

I used to think the same, and had trouble reconciling why they claim HP increase with larger injectors. That was before reading Taylor's 2 volume book The internal combustion engine in theory and practice (not sure if I have the title 100% correct).

This book contains a lot of data with photos from laboratory experiments. And some show clearly what happens when injector size is changed to optimum for the fuel rate injected.

At large rates with small injectors, the finish of injection duration at the injector lags by a considerable number of degrees of crank angle behind the injection pump. This hurts BMEP and torque. Clearly when the fuel rate is increased significantly above stock, not only is the finish of injection at the pump increased (with stock plungers) but the injection into the combustion chamber is further increased past TDC.

Also at high PR and thus air density in the combustion chamber during injection, the spray from larger nozzle holes penetrates further and combustion is improved.

[Dougal]

The reason I stated that larger injectors won't help is to crack these guys out of the petrol engine tuning. Where fuel is a constant pressure with plenty of it and the injector is the bottleneck.
I can appreciate fully the effects you mention from Taylors book (which I haven't read), but trying not to confuse the issue too much at the same time.

The aftermarket larger cummins injectors just seem to be good at making smoke. Possibly a mismatch between injector spray angles and the piston bowl.

[Offender90]

Don't have too much progress to report but am finally about to get some garage time to put the engine together. I've cleaned the block and head mounting surfaces - gave it a clean with diesel and a Stanley blade to remove light surface rust, followed by a thorough clean with paint thinners to remove any oily residue.

Replacement 4BD1T headbolts have been ordered. Thanks for the part numbers John! Isuzu were great once they had the part numbers - the early 4BD1T bolts were replaced by the later ones, as you suspected.




4BD1
509009-0180 (14 required)
509009-0170 (4 required)

Early 4BD1T
894150-0250 (12 required)
894150-0230 (2 required)
894150-0240 (4 required)

Later 4BD1T
894367-4380 (12 required)
894367-4360 (2 required)
894367-4370 (4 required)

I presume the later 4BD1T bolts are improved material or heat treatment, not different size, to overcome some issue found earlier.

Had a chat with Isuzu about what type of molybdenum disulfide grease to use - they use a Fuchs Lithium based high temperature grease with MoS in their service centre. I ordered a small tube and am pretty sure its Fuchs RENOLIT MOREPLEX 2 HV, but will confirm once the order arrives.

In other news, I've got my hands on a copy of "Turbocharging the internal combustion engine" by Watson & Janota, and am soldiering through to wrap my head around all things turbo.

It quickly became apparent that my assumption of 60% intercooler efficiency may not be particularly accurate, and that it has an impact on sizing calculations. I have a reasonably large front mount air to air intercooler, and comparing published IC effectiveness figures for similar sized FMICs, it's more likely to be in the mid 70% range at highway speeds. The intercooler has a core area of 550mm x 235mm x 65mm and has virtually no obstruction to airflow. Fortunately an efficiency increase works well with the T25 compressor. I've plotted the 75% IC effectiveness points corresponding to engine power in light colours next to the 60% points I had earlier:

https://www.aulro.com/afvb/images/imported/2013/10/647.jpg

Increasing IC effectiveness makes the compressor efficiency peak lower in the RPM range (1900 to 2300, depending on load), which should provide more torque backup as well as increase engine efficiency at highway speeds. It also puts my 150kW / 200hp point at 3000 RPM on the compressor map. :twisted:

Reading about turbine design however has only confused me further... or rather made me realise that what I thought I knew is wrong.

I understand that turbine housing A/R ratio is an important descriptor for a vaneless housing. The A/R ration determines the gas exit angle from the housing (volute) onto the turbine wheel. As I understand it, the angle is almost independent of mass flow rate through the turbine.

In a vaned turbine housing however, this angle is determined by the geometry of the nozzles, and the only purpose the volute serves is to deliver a uniform flow to the nozzles. In otherwords, the A/R ratio of the VNT / VGT turbine housing has little impact on turbine performance / choke flow rate as this is essentially determined by the nozzle geometry. So it depends on the range of nozzle movement possible which, of course, isn't published! :mad:
The nozzles have a considerable range of movement (see below). The graph on the right shows the influence on choke flow that a 20 degree change in nozzle angle can have (80, 70 and 60 degrees from radial shown).

https://www.aulro.com/afvb/images/imported/2013/10/648.jpg https://www.aulro.com/afvb/images/imported/2013/10/649.jpg
VNT ring out of the housing
https://www.aulro.com/afvb/images/imported/2013/10/650.jpg

The good news as far as I can determine are that:

1.) Fixed nozzle turbines typically achieve a higher efficiency than nozzleless ones, but over a narrower flow range. Variable nozzle geometry should theoretically extend the range of flow where high efficiency is achieved.
2.) All other things being equal, a high trim turbine wheel flows better than a low trim one, so there's hope for the VNT-25 yet.

I think it will be a case of throw it on and see what happens. I may have to drill a pressure tube and a thermocouple housing both pre and post turbo and do a few test runs. But first I need to put it together and into the truck. Any ideas for a T3 to TK100 (early Chrysler T3 turbo mount) adapter? From an airflow perspective, I understand it is better to gradually blend the larger T3 port into the smaller TK100 one, rather than having a sharp step between the two - can anyone confirm?

Cheers

Bojan

[Dougal]

I've found some interesting stuff about VNT turbos recently too.

The A/R on the housing is pretty much the max the vanes open to. The adjustment range is all on the side to mimick a smaller A/R, not bigger. Obviously you get the best efficiency when the blades aren't changing the flow angle and this is best kept for the high flow and high rpm to get max power from the engine.

I've also found a very good way to correlate max corrected choke flow based on exducer and A/R. So what are those measurements for your VNT25 again?

The learnings I've done over the last few weeks mean my GT2256V will be up for sale. It's just no good on an engine like this. It could be modified with the higher trim (larger exducer) GT2260V turbine wheel. But it'll still be ****ed all over by a wastegated TD04HL-19T.

As for intercooling. I'd hope you can do better than 60%. But I use numbers on the safe side for all my calcs. I'd rather have the machine beat predictions than not meet expectations.

[Offender90]

The variable nozzle turbine housing has an 0.64 A/R housing with a 52.7mm inducer and 46.2mm exducer (77 trim).


The A/R on the housing is pretty much the max the vanes open to. The adjustment range is all on the side to mimick a smaller A/R, not bigger. Obviously you get the best efficiency when the blades aren't changing the flow angle and this is best kept for the high flow and high rpm to get max power from the engine.

Are you sure this is the case? This is what I used to think until I started reading the radial flow turbine section of Watson and Janota... now I'm not so sure.

To summarise my understanding of turbine efficiency / choke flow...

https://www.aulro.com/afvb/images/imported/2013/10/624.jpg

As I understand it, the nozzle angle affects the throat size, which is one of the factors determining the choked mass flow, but it also determines the gas flow inlet angle, which affects the turbine efficiency for a particular mass flow.

On the diagram showing the rotor blades and a single nozzle (below left), resolving the gas flow inlet velocity (C4 on the vector diagram on the right) into a tangential component (Ctheta4 on the diagram, where "theta" looks like a B - apologies for the poor scan) and radial component (Cr4) relative to the rotor blades, the tangential component of velocity (together with mass flow and the effective radius of the rotor blades) determines torque applied to the shaft. Rate of energy transfer at the wheel then becomes the product of torque and angular velocity of the rotor. The radial component of the inlet velocity determines how quickly the gas moves through the rotor (i.e. it impacts on the choked mass flow).

https://www.aulro.com/afvb/images/imported/2013/10/625.jpg

At very low mass flows, the turbine is most efficient when the flow is almost tangential to the rotor blades so that most of its energy is transferred into the wheel. Because the mass flow is low, the radial component of velocity doesn't need to be very high to clear the gas through the rotor blades.

As the mass flow rate increases, the radial component of inlet velocity needs to increase for optimum efficiency in order to prevent choking through the rotor blades. Torque applied to the wheel increases even though the tangential component of velocity decreases due to the greater mass flow through the rotor. So as mass flow through the turbine increases, the inlet angle at which the greatest efficiency is achieved shifts from tangential to radial direction, in order to allow (or rather force) more gas to flow through the turbine without choking.

Frictional losses occur due to nozzle angles not aligning with the gas inlet angle dictated by the A/R of the housing, but these are considerably lower than the gains in turbine efficiency by matching the gas inlet angle to the mass flow through the turbine. In other words, the nozzles reduce the overall efficiency of the turbine, but extend the range of mass flows at which the turbine operates at optimum efficiency.

On a vaneless / nozzleless turbine, the angle at which the gas enters the rotor is determined by the relative area of the turbine scroll (A/R ratio of the housing), and the angle is almost independent of mass flow through the turbine.

It is now my understanding that the A/R ratio of the housing on a VNT turbine (or a fixed nozzle turbine for that matter) doesn't have a large impact on the choke flow through the turbine. Obviously, the exducer diameter and the combined throat area around the nozzle ring also contribute to the choke mass flow, but at which flow rate they start becoming dominant is anyone's guess.

Hence my confusion... and belief there's no way of predicting what the turbine choke flow will be without trying it out.

Cheers

Bojan

[Dougal]

I pretty much agree with all that. The eureka moment came when I was studying the only two official garrett VNT turbine maps I've been able to find. Max choke flow on each was comparable to the same exducer size and housing A/R on a fixed geometry housing. Vanes at full open and it's behaving just like the A/R on the side and the wheel inside say it should. The vanes are just a slight efficiency killer in that position.

Remember the blades on an angle to modify the flow are an inefficiency. To maximise the energy extracted by the turbine and power of the engine you need to combine highest flow with best efficiency. This is when the blades aren't changing the flow direction.

Choke flow prediction, I'm pretty sure I've got it. I've got a table with all the available turbine maps in sizes that interest us with A/R and exducer size. Suffice to say I can empirically line them all up with choke flow based off A/R and exducer.
There is a drift in the absolute prediction numbers as turbines get much larger and rpm gets lower. But the trend is very clear and interpolating within the data I have is quite straight-forward.

[Offender90]

It makes sense for the manufacturer to use the equivalent A/R ratio to specify the choke flow for the turbo. What choke flow do you have for a housing that has an 0.64 A/R, a 52.7mm inducer and a 46.2mm exducer (77 trim)?

[Dougal]

It makes sense for the manufacturer to use the equivalent A/R ratio to specify the choke flow for the turbo. What choke flow do you have for a housing that has an 0.64 A/R, a 52.7mm inducer and a 46.2mm exducer (77 trim)?

I make it around 17lb/min.

[Offender90]

A bit more progress to date.


Block cleaned up and prepared for the head to go back on (spot the new bolts)

https://www.aulro.com/afvb/images/imported/2013/11/18.jpg


A couple of head bolt threaded holes needed cleaning out. An old headbolt with a line of a thin angle grinding disc through it did the job beautifully.

https://www.aulro.com/afvb/images/imported/2013/11/19.jpg


The head's been cleaned up and is back on.

https://www.aulro.com/afvb/images/imported/2013/11/20.jpg
Word of warning on workshop manuals - the one I have shows the reverse head bolt tightening order from what it should be. (Bolts should be tightened from the centre of the head (stiffest part) spiralling outwards, rather than from the outside in (as shown in my manual). I'll post a pic of the manual and a source if I can find it.

Rocker arm assembly on, valve clearances set and a 4BD2-T injection pump trial fitted, timing marks aligned

https://www.aulro.com/afvb/images/imported/2013/11/21.jpg

Fits well for the most part. As far as I can tell, I only have to modify the throttle cable retainer that's bolted to the oil cooler, in order to match the height of the new pump's speed control (throttle) lever.

https://www.aulro.com/afvb/images/imported/2013/11/22.jpg


That and a couple of other things to do before I have to pull the engine and gearbox out of the truck to progress further. It'll have to wait until after next weekend. Hopefully all the other bits and pieces I need will arrive before then.

[DT80series]

Was the 4BD2t pump adjusted to match the needs of the 1T or is it a straight up 2T pump?

I ask because 2T pumps are very easy to find over here and where the only ones that had the boost compensator and I would like that.

[Bush65]

Was the 4BD2t pump adjusted to match the needs of the 1T or is it a straight up 2T pump?

I ask because 2T pumps are very easy to find over here and where the only ones that had the boost compensator and I would like that.
Early 1T's (before the change to Garrett turbo's), had the boost compensator. I would be surprised if you couldn't swap the compensator from a 2T governor to a 1T governor.

[Dougal]

Was the 4BD2t pump adjusted to match the needs of the 1T or is it a straight up 2T pump?

I ask because 2T pumps are very easy to find over here and where the only ones that had the boost compensator and I would like that.

I swapped my boost compensator over to a newer pump without. Before I found out the newer pump had a different taper for the drive-gear and wasn't usable.

It's just a hole through the rear housing for a plunger rod and a flag on a lever inside for the plunger to push against and restrict rack travel. The rest just bolts on the back of the pump.

[Offender90]

It's a straight up 2T pump, but I'm using a VNT turbo that builds boost a lot sooner. the differences between a 1T and a 2T are discussed in the thread below:

http://www.aulro.com/afvb/isuzu-landy-enthusiasts-section/177561-4bd2t-inection-pump-4bd1t.html

I'll let you know what the verdict is once its up nd running.

Cheers

Bojan

[DT80series]

Thanks guys, Been keeping an eye out for a 2T pump cheap that I can grab one off of. Not sure it will work with my filter adapter though now so want to keep the investment minimal.

Cheers,

Jeremy