Isuzu diesel 3.9 extractors

[County3.9]

G'day,
I'm interested in fitting a set of extractors and free flowing exhaust to an Isuzu 3.9 diesel County. I'm hoping to improve performance when towing. What's everyones thoughts?

[EchiDna]

G'day,
I'm interested in fitting a set of extractors and free flowing exhaust to an Isuzu 3.9 diesel County. I'm hoping to improve performance when towing. What's everyones thoughts?

I hope you are ready with a fat wallet...

the P.O. of mine had it turboed and had a custom exhaust manifold made to suit....
not much change from $5k :eek: according to the receipts!!

[County3.9]

Was quoted $140 per cylinder + $280 for exhaust system. Total $840. Thats a lot if it doesn't make much of a difference.

[JDNSW]

I don't think the exhaust is particularly restrictive - certainly it is noisy! While less restriction would not hurt, as far as I can see, I would not expect it to make more than a marginal difference, especially if you keep it so as not to attract unwanted attention!

It is rather difficult to think of any easy options to upgrade this engine significantly - possibly mild turbocharging, but remember that there are significant differences to other parts of the engine in the turbo version, so without going the whole way more than a very small boost could risk other problems.

Of course, you could always just adjust the maximum rpm up a little - but there is presumably a reason why they set this at (I think it is) 3200.

[Bigbjorn]

Correct, JD, and the factory turbo 4BD1T is governed at 3000. Mine has the next to useless factory air-con fitted, and with the consequent lack of under bonnet space on that side (that side also hosts the alternator and vacuum pump, regulator, the windscreen washer bottle & pump, the starter motor, crancase breather, and assorted untidy crap, I think a proper length extractor system would be bloody difficult to house. A big bore straight through system from the manifold exit on, say a 3" all the way, should make a difference. Remember a diesel engine can only burn as much fuel as the air being fed to the cylinders can accomodate. Whilst the intake and exhaust pulses can be tuned to provide a charging effect this is more the norm on straight out racing or very high performance engines and really does need touches of skill, knowledge, and witch-craft, plus lots of dyno time. Perhaps cleaning out the ports in the cylinder with a die grinder and port-matching the manifolds would be as much as you could achieve with a slow running engine. Try these first.

[Larns]

Don't wast your time with extractors, as brian stated extractor are only benifical above around 4-5000rmp, and lets face it, the Isuzu isn't no rev mechine. Their toque peaks around 1800rpm and useful hp really max's out at around 3k rpm.
I've done a fair bit of messing around with these engines and for the n/a version, my suggestion would be a snorkle of some form, a good quality air filter, have the injectors serviced (if it blows smoke) , a good diesel fuel conditioner, and perhaps adjust the fuel pump alittle.
Other wise I'd turbo it. Just need new injector tips (different spray pattern), camshaft, adjust the pump timing, full flow 3" mandrel exhaust, good aftermarket air filter (or a donaldson...so,so), turbo style inlet manifold(you'll also find you have to change the fuel injection lines as the n/a ones don't fit around the turbo manifold), different crankcase breather, then you need to remove the sump and braze a return line for the crankcase breather, you also need the coolent lines to the turbo and return, which means you need a turbo style water pump, and a turbo style thurmostat housing, the oil feed lines, a different dipstick is also needed , the turbo and manifols themselves and to top it all off you need to throw the car on a 4wd dyno and tune the pump to supply the correct fuel for the turbo.This is off the top of my head.
As stated by others, you'd be lucky to get change from 5500.

I'd probably just stick with the n/a set up, I did the conversion hence why I know what needs to be done, and the only thing that I didn't do were the piston sprayers from the oil gallery. So far the car has never gotten above 86 degrees so I think it'll survive without them. Keeping in mind that this engine was designed as a truck engine, not to tow a 4wd around. So in an everyday enviroment they are generally underloader. The army 6x6's are probably the only LR's that load the engine up sufficiently to what they were designed for (and their often tipping 6.5Tonne).
Hope this gives you some food for thought.

Cheers

[rar110]

Larns, how is the n/a compared to the turbo motor for towing, sand driving, highway overtaking etc.? Did you change gear ratios after turbo fitted for better highway cruising?

Turboing is something I keep thinking about. But the cost is a killer if done properly. Garrett turbo was about $2500 on its own. My current thinking is buying a 4bd1t import and selling the existing motor is the most economical way to do it. Probably about $3000 change over cost.

As to the question about extractors. My first isuzu 110 had extractors. My current 110 doesn't. I don't think there was any difference.

[100I]

extractor are only benifical above around 4-5000rmp,
I would not entirely agree with this. Different styles of headers will produce different results. For example a good tuned 3y setup will generally produce lower RPM results but do little to nothing for high RPM. Whereas a 4 into 1 style generally lends itself to high RPM power but does nothing for low RPM and may often be a backward step. As Brian said, there is a great deal of witchcraft involved and unless you find a manufacturer who has done the hard yards & designed a system specifically for the engine & it's intended use then you would be wasting your coin.

[Bigbjorn]

An "extractor" exhaust system, as opposed to a "free flow" exhaust system, requires pipes of a specific length and diameter and a collector box and final pipe also of specific length and diameter. The dimensions vary with application. I can't imagine an application where a 3200rpm low output diesel engine would require an "extractor" exhaust system. Determining these dimensions is what takes the skill, experience, witch-craft and dyno time. "Extractor" systems are usually matched with a single cylinder intake system with appropriate length and size intake trumpets. Once again, much experimentation is required to get the optimum dimensions. These systems usually give a power band as required by the application,and mostly quite narrow, except in the case of the American big block racing engines wherethey use varying length intake trumpets to spread the torque band.

[1103.9TDI]

I've had my 4BD1T fitted for just over two years, now. The 4BD1T transforms the vehicle to close on V8 performance, without the massive fuel consumption. I installed mine as close as possible to the standard 6x6 setup, even purchasing oil filter extensions to clear the bypass assembly and the complete, correct Donaldson air filter and canister, fed by a 3 inch snorkle. I run a MaxiDrive strenghtened LT85/230, never shown a hint of trouble. Exhaust exits through a 3inch unrestricted pipe, just in front of the left rear wheel. We do extended remote area touring, and it's an ideal vehicle for this now.
Next month I'm fitting a WTA intercooler in Brissy.:D

[Blknight.aus]

I'll back larns...

if your going to turbo it (and use all the potential of the engine)

the list of what should be done is a lot longer than hes lead you to believe..

if you only want a fraction more his mods are on the money.... but to guess Id tip hes only set up for say max 50% over a NA isuzu. much more than that and hes going to cook the na piston tops or fatigue the rods...

tweaking the pump, a better set of injectors to deal with the fuel and a better air intake system (match and port the manifolds and head) has the potential to free up about 15% more from a stock as a rock isuzu.

The normal Isuzu pulls like a tank, through the midrage and even with overloaded FFR 110's with trailers Ive never had any real problems with getting from a-b.

Passing can need a bit of a wind up but usually isnt too hairy.

[Bigbjorn]

Check the Isuzu parts books and repair manuals and you will see that the 4BD1 & 4BD1T, whilst the same engine family, use almost totally different components. New 4BD1T's were being advertised for $7500 in one of the monthly "Just" or "Trader" magazines not long ago. Bargain, I think. Add an intercooler from one of the bling bling doof doof shops and away you go.

[County3.9]

[QUOTE=Blknight.aus;521051]I'll back larns...


tweaking the pump, a better set of injectors to deal with the fuel and a better air intake system (match and port the manifolds and head) has the potential to free up about 15% more from a stock as a rock isuzu.


This is great...keep it coming!
What sort of "tweaks" to the pump do you recomend? If properly done will it adversly effect fuel economy? Also, what injectors and where can I get them?

[rar110]

Gerry, any chance of seeing the set up when your in Brisbane?

Might even turn into a 110 isuzu get together.

[Blknight.aus]

[QUOTE=Blknight.aus;521051]I'll back larns...


tweaking the pump, a better set of injectors to deal with the fuel and a better air intake system (match and port the manifolds and head) has the potential to free up about 15% more from a stock as a rock isuzu.


This is great...keep it coming!
What sort of "tweaks" to the pump do you recomend? If properly done will it adversly effect fuel economy? Also, what injectors and where can I get them?

start with a really good calibration and balance of the pump... from there you can add a bit more fuel and if you drive it fast lots you can mess with the timing a little but it will run like a pig when its cold... Putting the turbo injectors in a stock motor gives a better spray pattern and lifting the crack pressure will make the atomisation of the fuel a little better but at the expense of the life of the injector nozzle.

The bueaty of diesels is to a certain extent if you take a stock motor and work its nipples off it will be as economical as it was if thats all the power you ask of it, as you ask for more power (heavier right foot) your fuel economy goes down...

port matching the heads to the manifold, if your patient can be a DIY if your confident with the spanners, bearing blue and a die grinder but a full port polish and reflow of the heads is a black art.

a K&n filter setup should be part of your first upgrade for more flow, but I dont really trust them for hard offroad use or prolonged periods. Its nothing I can proove its just that wierd gut feeling.

If your going to get all that work done on the injector pump you can also have the torque cam and the governer springs tweaked for a sharper rise on demand rate which will make the rack react faster but will lead to more black smoke out the back.. It also has the potential, if overdone to cause overheating and fouling of the combustion chamber...

now, IF it were me Id get the fuel delivery system back to spec, then play

1. new injector nozzles and reset the crack pressures to the higher nominal setting (if they have a tolerance of say 12-15mpa have them set at 15)
2. get the injector pump on speck +/- .5% and retime it (the timings easy)
3. new airfilters, and cleaner hoses on the engine intake to let it breath.
4. grab a laser thermometer and watch the manifold temps at the exhausts as it warms up to see if everythings on balance.

drive it and see what its like after that...

for every % that one of the first 3 is out you loose about 4% of your available power (and thats compounding down not lineal subtraction) untill you hit the point where the engine just wont run at all.

[DRanged]

Best thing to remember is its just a 4BD1. Its not a multi valve/cam engine. Its not ECU controlled. Its just a fruit truck motor that has enough torque to pull stumps, and is all gear driven for reliability. Perfect 4wd motor??

If your interested I rebuilt mine with a turbo rebuild kit from Isuzu. Got a TD5 turbo brand new from LR for $680 and made an adaptor manifold to suit an Isuzu turbo manifold. 100 series toyo intercooler on top.

Ask anyone in the Gold Coast club, it goes very well. Dial up the fuel untill the EGT says no more. Dont waste your time and money with dynos and crystall balls.

Its not a race motor and never was designed to be. Sold world wide as a genset motor.

There is an importer on the Gold Coast bringing them in (4BD1T that is ) for around $4k.

Regards Justin

[County3.9]

DRanged, do you know the name of the importer?

[DRanged]

DRanged, do you know the name of the importer?

How did I know you'd ask that before I could remember.

Get yourself a Gold Coast yellow pages and look up deisel engines etc. I think the guy was at Labradoor or Ashmore?????.

Justin

ps I have a Switzer turbo to suit a 4bd1 you can have a play with if you like.
No waste gate, just a larger turbo than the garret. Basically at the engines max RPM it developes 8lb boost. You pay the postage and I'll send it down. If it works a case or 2 of my favorite ale will see you right.

[Blknight.aus]

oh incidentally, before it gets too mis-interpreted...

the torque cam is in the governor housing (not the camshaft that runs the valves) and its responsable for a handfull of things but by twiddling with this bit you can change the repsonse carachteristics a bit.

[Larns]

Mate, you'd be better off finding the importer for an 4BTI-T and selling off your existing.
I havn't changed my gearing at all running the 1:1 Lt95 and it sits on 100 all day and chews 11-100 not bad.
Like justin is running, I converting to the r380 pretty soon, hopefully this will bring down fuel consumption alittle.
At the later stage of production alot of the isuzu's were all fitted out with the treated crank and pistons. I discovered this when I was rebuilding mine, hence why I took the path of the turbo. I still don't have the oil sprayers but, they are a severly over engineered engine.
I havn't yet tweaked my max fuel delivery adjustment as I was pretty damn happy with the power as it was, and it blows almost nil smoke under max acceleration. Which I like.
Like black night stated, I'm not running 100% out of mine, the pump dose need tuning, and I couldn't afford the camshaft.
I'll be looking at getting a new cam or getting crow to grind one up for me. As it really is a half hearted conversion without the cam.
It dose lack just a smidgen when towing big loads, I'm talking over 1-1.5t, and when I say lack I mean you can feel it behind you. But at higher RPM the turbo is fantastic! Instant acceleration on the tow or not. Doing a 100, if you want to overtake the power is there instantly.

As for the extractors, I know there are alot of variables out there and you DO have to know what your doing, I've built some pretty serious engines over the years, some in excess of 500hp streetable. And we had to play around with the extractors a fair bit. If you change one variable on your engine your engine harmonics change and you really have to change the length of the extractors to obtain 100% out of them. Thats why engine builders make the extractors the last thing to bolt to the engine.

I love the engine so I'm pretty biased. I like Justin belive that it's a truck engine and should be driven accordingly. If you want something zippy then get the 3.5 V8.

Hope you get something useful out of this

Cheers

[Phil Stage 1]

G,day all

This is my first post here.

I fitted 4BD1 to a HQ Holden in 1988. It was the family car for about 12 years.

I made a set of extractors for it as I was curious to know what effect it would have.

The extractors were a four into one design. I bent them up on a friends exhaust pipe bender. They were a tight fit in already tight engine bay. The exhaust system was 2.5" right through. The header pipes were about 1" I think.

The net effect was a major increase in decibels and a zero increase in kW, Nm or fuel economy.

The best effect though was whenever the revs passed through about 2200rpm. The exhaust pulses must have all been lining up nicely because it would cackle really well. Especially good if you were pulling up a hill at that rpm. You really needed earmuffs.

After the novelty wore off I took them off.

[Blknight.aus]

.
Like black night stated, I'm not running 100% out of mine, the pump dose need tuning, and I couldn't afford the camshaft.
I'll be looking at getting a new cam or getting crow to grind one up for me. As it really is a half hearted conversion without the cam.


This is potentially the confusion I was talking about.....

With a turbo conversion you dont really need to touch the torque cam as the engine should respond faster due to the extra air available to it which will make the rack respond proportionally. Changing the camshaft over will allow you to get more air to flow through giving a cleaner "charge" in the cylinder and more air inside to boot.

Without the turbo, changing the torque cam makes the rack move faster to increase your response by more quickly changing the fuel delivery quantity.

Crow will grind up a camshaft for whatever you need them to, to the best of my knowledge they dont do torque cams, you need a pretty serious diesel fitting shop to do that and even then Im pretty sure that theyd just pick one off of the shelf in a profile thats more like what you need and/or fit different springs.
.

[KhunMoo]

Gents, I installed a 2.5" straight through exhaust on my 4BD1 and it made a useful difference with fuel consumption on my annual 2 weeks bush bashing in the Kimberley dropping from 14.8 to 12.9 lt/100km. Extra grunt, especially pulling up big hills was noticeable. Extractors would be a pain as there is just no room to do it. Not cost effective.

JohnS

[Phil Stage 1]

This is potentially the confusion I was talking about.....

With a turbo conversion you dont really need to touch the torque cam as the engine should respond faster due to the extra air available to it which will make the rack respond proportionally. Changing the camshaft over will allow you to get more air to flow through giving a cleaner "charge" in the cylinder and more air inside to boot.

Without the turbo, changing the torque cam makes the rack move faster to increase your response by more quickly changing the fuel delivery quantity.

Crow will grind up a camshaft for whatever you need them to, to the best of my knowledge they dont do torque cams, you need a pretty serious diesel fitting shop to do that and even then Im pretty sure that theyd just pick one off of the shelf in a profile thats more like what you need and/or fit different springs.
.

There seems to be some confusion about cams here. The 4BD1 and the 4BD1T have the same inlet and exh valve overlap and duration. In other words they use the same camshaft.

The torque cam is a different animal that lives in the injector pump. It is what determines the shape of the torque curve by determining the maximum amount of fuel that can be injected at a particular rpm.

The 4BD1 and 4BD1T have different torque cams. The 4BD1 has its max torque at 1800rpm. The 4BD1T has it's max torque at 2200rpm. The industrial 4BD1 has its max torque at 1600rpm. It will have a different torque cam.

I don't see a problem with turboing and leaving the NA torque cam in place. The max fuel setting can then be increased until the EGT reaches the limit.

Hope this clarifies things a bit.