Thread: Planned Upgrade of Stock Standard TD5

Phillip do you have with your tune a V8 TC fitted? If so did this assist in keeping EGT's down, went and purchased this already under the belief that this will go a long way to achieve this, so long as you don't put too high a tune in.

I don't know as I have had no experience with a modified TC ( I assume you mean Torque Converter).
I intuitively don't think it would make much difference when towing as the aim is to always have the transmission in lock up as much as possible.

With the lower stall of a V8 TC , it may be easier to keep the TC at stall (say 2500 instead of 2800) but with attention to gears this to me is not a big problem.

BTW the transmission temperature is only an issue with towing.
Regards PhilipA

As you mentioned that your'e not after a " weapons grade rockcrawler "and want something reliable , I'd suggest relearning how to tackle the steep stuff using the auto , lock centre diff , place it in to 1st low, press manual mode( and HDC if you wish ), let it get to 2000 rpm or above before you head downhill then take your foot of the go pedal. The torque converter will then lock down to just before stall.
The torque converter you bought will not help with EGT's but will help a bit with engine braking when unlocked.
It will also make it nicer to drive but only if remapped .
Maybe hold off with the gearing changes , 32" tyres, lockers etc as this can be done later if you need it.



I'd start with 245/75/16 or 265/70/16 , as they are a good compromise between having some clearance under the diffs and not affecting gearing too much .
I'd also be spending around half the budget on making it reliable and nicer to drive first , and unless you really know your way around these beasties that should involve getting an assessment from someone who does. ( you can always replace what is required yourself ).

Originally Posted by RRT

Interested in you observation of the diff ratio's you chose. Would you stay or in retrospect change to a different size. Assuming of course you used Aschrofts did you change the ratio in the transfer case as well?



32 or 33 " I think as I said initially, good deal get the 33"s but in wanting to go back to the SLS you get that extra height in reserve anyway.

I'd stay exactly where I am.
I run 285/75R16 tyre size as these are the largest that I could have legally engineered for fitment when I went through the modification plate process. They're approximately 33".
I only changed the diff gear ratios to compensate for the tyre diameter change, and left the transfer case alone. With the work to improve engine performance (both torque and power) it drives like a factory setup. I can outrun a stock standard D2, both V8 and/or Td5, off the line, my systems all work correctly, it's not over reving at highway speeds as it sits at the standard rpm, it tows well, etc.


[QUOTE=RRT;3030366]Exhaust, not overly concernedQUOTE]

If your wanting to keep EGT down then you want a well flowing exhaust to help extraction, so perhaps become concerned by that.

Originally Posted by RRT

VNT / EGT / Intercooler - hmmm, require a tune anyway for the auto TC so that's a given. Ultimate performance is not a priority, low down torque certainly is. Anything approaching 400Nm around 1500-2000 optimal. Am concerned re the EGT and setting myself a build that keeps to the low 600's if possible.

The one that I have to reassess is the VNT or Hyrbid core, dont think I have given this enough thought.

You need to realise that it all goes hand in hand and changing one thing effects others. More boost means leaner combustion which results in cooler temperatures and lower EGT. More power and torque means your often working the engine for shorter periods, or using less accelerator pedal to achieve the same thing, which I’ve found means lower EGT. Just because it can go harder doesn’t mean you need to drive it that way – you can still gain the other benefits.

If you want low down response and torque then a VNT is the solution. There’s plenty of information about these in other threads so I’d suggest reading.

Originally Posted by RRT

Terrafirma seem to the be the Melbourne Demons of Discovery support...

They are a cheap brand and you get what you pay for.

Originally Posted by RRT

Now the one I don't get re the Ashcroft ATB's, have read over the last year a lot on the choices of ATB's versus Lockers, if I was to keep the TDi 300 (no left knee so manual has to go) was going to use a locker in the rear ATB front. Yet to see a disaster story re Ashcrofts or that there may be an inherent design problem - worst or funniest was some bloke up to his axles in ooooppp and all four wheels churning round saying the ATB's aint effective, HELLLLLLOOOOO!!!

Before replacing my rear ATB with a Eaton Detroit I experienced a number of situations off road where I felt let down by the ATB. I had one wheel spinning despite both being on the ground, traction control and/or left foot braking was not working. The most embarrassing was a small muddy puddle on the side of a gravel/dity track that I had parked in.
I’ve since learnt and experienced that they may be sensitive to the gear oil used (see other discussion threads for more details) but over time their performance seemed to continually drop off more and more. This is part of my reason for recommending Eaton’s alternative product instead as they’ve been around for a lot longer, they’re from a company that specialises in this and have developed it for a wide range of products and I’ve yet to see anyone with one experience the issues that a number have with the Ashcroft units.

Originally Posted by RRT

Anyway, if I am wrong no problem, but as I have gleaned, ATB's with a lightly applied left foot on the brake, (aiding not replacing TC) will do at 95% if not more, the same as a Locker?

It's really just not as simple as that at all. Once you’ve driven a triple locked vehicle you will just know they’re not equivalent. It’s like telling a marathon runner to wear a pair of K-Mart brand running shoes – but when they blow out and get 95% of the way through leaving them 2km short of the finish line did it really matter if they were 10% or 99% equivalent – either way they were short of what was required for the job.
Diff choice needs to come down to what you need it to do – different things for different applications. But when it comes to the roughest stuff the various forms of LSD (including torsion such as AT are just not equal to a locker. For many this won’t be an issue though and the benefits of an LSD in the other driving applications might take a priority. Really it’s a question of suitability that only you can answer, but don’t kid yourself that you’ve got a portion of a locker.

Originally Posted by RRT

And if there is a requirement to upgrade axles as well, the budget gets stretched immediately.

There is not a requirement to upgrade axels. That depends on your vehicle use and how you drive it. There’s people who can destroy axels with a stock setup and others who can have modified setups retaining the stock axels and they last.

Originally Posted by RRT

Price wise there is (converted to Aus) $400 difference to the Trutracs, then another $400 to the Quaife.

As said previously, Eaton TrueTracs can often be found cheaper than the Ashcroft-Transmissions ATB and I believe they’re a superior product. There is a fairly recent thread in here with links and details – I’m sure you’ll find it with a search.
I wouldn’t bother extending out to the Quaife.

Originally Posted by RRT

One of the things I hadn't previously mentioned is that I very much want to put in a Davies Electric Waterpump - this does the job of a temp alarm with the benefit of being able to turn the engine off and keep cooling going.

I just can’t see why you’d want to introduce that expense and complication. The standard cooling system works well if maintained properly.

Originally Posted by RRT

Phillip do you have with your tune a V8 TC fitted? If so did this assist in keeping EGT's down, went and purchased this already under the belief that this will go a long way to achieve this, so long as you don't put too high a tune in.

Not all tunes are the same. Not all tunes from the same tuner are the same. If you have goals in mind (be in EGT range, fuel economy, power or torque levels, rev limiters, etc) you should be able to find a tuner who can assist you with achieving that. As mentioned above things go hand in hand, it's not always as simple as one mod will raise EGT while another lowers them.
Then there's also driving style. In general though, I found the V8 torque converter can assist in lowering EGT as you can keep the engine revs down and drive off the torque.

Originally Posted by RRT

Do you think I would achieve my 400Nm at around 1500 - 2000 RPM with a standard exhaust and keeping it as you have stated below 22 PSi??

I believe that the peak torque on the Td5 is closer to 2,000rpm - a VNT will get you more down low. 400Nm is almost a 25% increase on standard which is likely achievable but you might have to sacrifice EGT - you need to figure out what you want from both and which is priority.
As above a standard exhaust can be flow restrictive which can contribute towards higher EGT especially as you start to push it.
Likewise an intercooler upgrade would assist.

Originally Posted by discorevy

As you mentioned that your'e not after a " weapons grade rockcrawler "and want something reliable , I'd suggest relearning how to tackle the steep stuff using the auto , lock centre diff , place it in to 1st low, press manual mode( and HDC if you wish ), let it get to 2000 rpm or above before you head downhill then take your foot of the go pedal. The torque converter will then lock down to just before stall.
The torque converter you bought will not help with EGT's but will help a bit with engine braking when unlocked.
It will also make it nicer to drive but only if remapped .
Maybe hold off with the gearing changes , 32" tyres, lockers etc as this can be done later if you need it.



I'd start with 245/75/16 or 265/70/16 , as they are a good compromise between having some clearance under the diffs and not affecting gearing too much .
I'd also be spending around half the budget on making it reliable and nicer to drive first , and unless you really know your way around these beasties that should involve getting an assessment from someone who does. ( you can always replace what is required yourself ).

Listen to this man. Not only is he a guru mechanic, but he also knows how to drive and play with D2a TD5s!!!!!

Originally Posted by discorevy

As you mentioned that your'e not after a " weapons grade rockcrawler "and want something reliable , I'd suggest relearning how to tackle the steep stuff using the auto , lock centre diff , place it in to 1st low, press manual mode( and HDC if you wish ), let it get to 2000 rpm or above before you head downhill then take your foot of the go pedal. The torque converter will then lock down to just before stall.
The torque converter you bought will not help with EGT's but will help a bit with engine braking when unlocked.
It will also make it nicer to drive but only if remapped .
Maybe hold off with the gearing changes , 32" tyres, lockers etc as this can be done later if you need it.



I'd start with 245/75/16 or 265/70/16 , as they are a good compromise between having some clearance under the diffs and not affecting gearing too much .
I'd also be spending around half the budget on making it reliable and nicer to drive first , and unless you really know your way around these beasties that should involve getting an assessment from someone who does. ( you can always replace what is required yourself ).

Thank you all the for advice given, it was why I asked, I didn’t know and just reading pages and pages helps form an opinion but how it relates to you is sometimes hazy. Yes will have to relearn, but do like to have some basic mechanical aids to back me up first, i.e. clearance and gearing!

Had a bit of a chuckle to myself, as with so many things they are counter intuitive, looking down a near vertical hill and revving the engine up is one, I am CDL on at all times on the trails man, but do get it I think, the rev in this instance engages the box ? or for want of a better term, removes the sloppiness stopping run on??


With all of this have some clarity.

As I now see that the price for an Eaton Rear Locker is basically the same price for an ATB, this will be the rear diff whilst the ATB to be at the front will most likely be the Ashcrofts , this will not be done till summer now.

As I will already have to take the diffs apart, the opportunity to fit lower ratio’s is opportune and would say that I am 90% sure these will be the 4.37 set. Already have a reasonable set of 32”on the car and may even keep the 32” muddies on the TDi I’m selling.

Know I am not going to approach the low range gearing of the TDi but sits reasonably comfortably as what I see is a good compromise.

Ratio	TD5	TD5 4.37	TDi
First Gear	29.15:1	35.98:1	43.39:1
Second Gear	17.39:1	21.47:1	25.06:1

RPM @10 KPH	First	Second
D2 TD5 32”	1903	1136
D2 TD5 4.37 32”	2350	1402
D1 300 TDí Stock	3127	1806
D1 300 TDí 32”	2834	1636

The difference on the highway is not as great as I anticipated and should be bearable, will put off the Transfer box

100 kph	TD5 Stock	TD5 3.54 32”	TD5 4.37 32”
Third Gear	3089	2800	3456
Fourth Gear	2294	2038	2516

Have read extensively up on the VNT and although there are no graphically ‘show and tells’ I have found, all seat of the pants, I do understand the technology.

Now where the conundrum lies is whether to go to a roughly $2K expense when a basic tune (already have the NNN and V8 TC to do it) will provide a better experience for roughly $500?

No doubt the VNT is a great bit of kit and transforms the vehicle, especially if subsequently tuned, but could this for instance without further modification provide enough low down torque so the V8 TC works, or do I still need more ‘power’ with a tune to get the TC to lock up early?

This is where I am finding the lack of imperial data frustrating as to torque profiles / dyno sheets - must have looked at over 100 pages yesterday and not one had showed the improvement graphically, even the manufacturers who it must be said are charging a bomb for old technology do have not have the proof of claims… Or did mr google just miss those pages!!

Thanks again to all

Just reading up pages on 4WD auto down hill and after getting Disovery advice




Originally Posted by discorevy
As you mentioned that your'e not after a " weapons grade rockcrawler "and want something reliable , I'd suggest relearning how to tackle the steep stuff using the auto , lock centre diff , place it in to 1st low, press manual mode( and HDC if you wish ), let it get to 2000 rpm or above before you head downhill then take your foot of the go pedal. The torque converter will then lock down to just before stall.
The torque converter you bought will not help with EGT's but will help a bit with engine braking when unlocked.
It will also make it nicer to drive but only if remapped .
Maybe hold off with the gearing changes , 32" tyres, lockers etc as this can be done later if you need it.



I'd start with 245/75/16 or 265/70/16 , as they are a good compromise between having some clearance under the diffs and not affecting gearing too much .
I'd also be spending around half the budget on making it reliable and nicer to drive first , and unless you really know your way around these beasties that should involve getting an assessment from someone who does. ( you can always replace what is required yourself ).




Low range
To enhance off road control, particularly when manoeuvring at low speeds, torque converter lock-up does not occur
when there is any degree of throttle opening. When the throttle is closed above a preset engine speed, the lock-up
clutch engages to provide maximum engine braking.
Increased load/reduced torque compensation


Read this excerpt from RAVE, essentially then the TC does lock up in low gear but only if there is no throttle and the rising revs take it to Stall Speed, AAARRRGHH THE LIGHTS ARE ON!

Originally Posted by RRT

Now where the conundrum lies is whether to go to a roughly $2K expense when a basic tune (already have the NNN and V8 TC to do it) will provide a better experience for roughly $500?

No doubt the VNT is a great bit of kit and transforms the vehicle, especially if subsequently tuned, but could this for instance without further modification provide enough low down torque so the V8 TC works, or do I still need more ‘power’ with a tune to get the TC to lock up early?

VNT (with suitable tune to accompany) completely transforms the engine with huge improvements to lower down response and torque and midrange gains. A standard turbo setup tuned well will not match. The extra expense is well worth it in terms of improvements gained.
Consider the age and kms on your vehicle and what that reflects on the lifespan of your current standard turbo charger and there's an argument that some of the extra expense is justified in preventative maintenance aspect.
The VNT gains and V8 torque converter work perfectly together due to the torque converter facilitating you being able to drive at lower revs off the improved VNT torque.

Originally Posted by RRT

Have read extensively up on the VNT and although there are no graphically ‘show and tells’ I have found...

This is where I am finding the lack of imperial data frustrating as to torque profiles / dyno sheets - must have looked at over 100 pages yesterday and not one had showed the improvement graphically, even the manufacturers who it must be said are charging a bomb for old technology do have not have the proof of claims… Or did mr google just miss those pages!!

There's not that many 4WD dyno's around. I think in the UK they are more popular for part of the MOT process, but down here most of the tuning shows work on rear wheel drive cars so don't go to the extra expense. Couple that with the fact that most of the top end Td5 tuners are over in the UK so their tunes come in remotely and are adjusted by driving data collected through diagnostic devices like the Nanocom, rather than tuned on a dyno. The end result is lack of dyno results.

Alive Tuning in the UK have been putting some dyno results up on their Facebook page lately. Both before and afters so maybe check that out?

You might be able to find a member locally with one fitted who would take you for a drive.

Originally Posted by RRT

whilst the ATB to be at the front will most likely be the Ashcrofts

I'll say it again, there is a large, and growing volume, of customers who've had issues with the Ashcroft Transmissions ATB including parts failure and not working effectively as they age. The Eaton Truetrac is available for cheaper locally and hasn't had any such negativity.

Thanks twr7cx finally got to see some graphs!

Was pleased to note that they appeared to develop the serious torque at around 2K rpm and although the maximums may be higher at 2.6K rpm they nearly all produced my target figure 400Nm at around 2. This for me would be a great result and no doubt be extremely drivable in the wild and certainly work well with the lock ups in the Auto TC out on the road.


When reading up on VNT's came across the use of VW / Audi replacements and mentioned to my BIL who happens to have one sitting in the shed... Any suggestions as to worthwhile,, if it cost less than a $1K to fit etc. it would still be a whole lot cheaper...

Arty