TD5 High EGT - Intercooler vs 3 inch

[TroyMortimer]

Hi Guys,
I know this has been discussed on lots of threads over the years, seemed to be only a few people out of each camp that went through the process of reducing EGT. Given the TD5 is quiet an old car now. hoping more people out there actually done both.

So Let me start with a little background.
EGT probe is just before the turbo in the exhaust manifold (as opposed to EGR blanking kit)
Car is 2003 Auto. So bigger intercooler, not Cat and mid silencer deleted, ooh yes EGR deleted as well. replaced hoses as well. Has a TD5Inside Map and boost box. Boost is about 24 PSI (taken from EGR delete)

So driving around putting my foot down around town I would see upto 600's to 700s max.

However when on the highway anything from 80 kms onwards the EGT's climb well to easily. I could comfortable get 800c or more I believe. When sitting on 110Km EGTs are perfect (450-500) Boost is around 11 PSI, its only when you need to over take or go up a long hill that the it has the problem.

So reading countless threads on here and other landy sites, has led me to look at two things.
1- Larger Intercooler
2 - 3 Inch Exhaust.

At the end of the day both are similar costs. I cant seem to get a serck or alisport for under $1000 delivered to Australia. Where are 3 inch mandrel using stainless is around $1200. or a mild steel mandrel for $800

I went to an exhaust shop yesterday who suggested a bigger intercooler over a 3 inch system based on a couple of things.
1- He doesn't believe I have flow issue from the dump as i not getting high EGT at low speed.
2- The other is he doesn't believe the dump is a 3 inch flange so its going restricted at that point.
3- The bigger intercooler will push more cooler dense air in.

So reading countless arguments around engine combustion I'm completely confused.

So does anyone have stories similar to mine that either upgraded the intercooler or exhaust that actually dropped the EGT at high speed.

[PhilipA]

I found my Serck intercooler drops EGTs by maybe 50C(estimated) in my 2002 EU3 auto

I run about 21-22Lbs and have a Powerflow lightly baffled muffler and your other mods.

I have a modified BAS tune with boost cut and MAF inputs modified.

I still have to reduce speed on hills when towing my approx 900KG camper trailer.

I really cannot use cruise control on anything but very flat ground or it flattens it on a hill and EGTs go to 750+. Mine also runs at about 350-400 average at 110 towing on flat ground.

AFAIK the outlet to the turbo is 3 inch, and really all that should be necessary is to increase maybe the first metre or two, as the gases contract as they cool.

However I can still climb quite steep hills running at say 650-700C . An example if you know it is the last steep hill southbound before Buladelah where I can start at 110Kmh and still be doing 100at the top locked which is far better than my modded RRC 3.9 could do.
You just have to drive by the EGT gauge. After all it is really a tiny engine to be pushing a block of Flats weighing 2.5-3 tonnes loaded.

Regards PhilipA
To answer your question .
Yes the intercooler reduced EGTs but maybe not by as much as expected, but it's hard to know. I felt boost increase achieved more. I have a Turbosmart boost controller that to me allows faster boost gain over 15PSI.

I doubt whether a 3 inch exhaust will give large gains. One way to testis to test the PSI in the exhaust by plumbing a pressure gauge in near say the front of first muffle location.. I have a Britpart first section which has a better design of the flexible part .

[Tombie]

The outlet of the turbo itself is about 1.75”
The pipe (dump) flanges out to 2.5”

Optimum on a worked TD5 is 2.75” and a 3” doesn’t gain anything.

The factory flex joint is often the restriction on later vehicles as it reduces on internal diameter.
Replacing this with a full sized bore helps immensely.

The intercooler and the above flex joint would be my first port of call

[Tombie]

Another good tip - take the wastegate boost feed from the EGR delete also, it is then real boost, not pre-intercooler.

[TroyMortimer]

ok, couple of questions.
so when you say bore. you are referring to the flex joint?

@phill. you said 3inch but Tombie is saying 2.5. if I'm reading this correctly .

does anyone actually have measurements?

has anyone replaced the flex joint and what improvements where had.

so just to be clear im not after any additional power. only reductions in EGTs. without dropping my MAP back to standard lol

[shack]

ok, couple of questions.
so when you say bore. you are referring to the flex joint?

@phill. you said 3inch but Tombie is saying 2.5. if I'm reading this correctly .

does anyone actually have measurements?

has anyone replaced the flex joint and what improvements where had.

so just to be clear im not after any additional power. only reductions in EGTs. without dropping my MAP back to standard lolAre you running the stock turbo still?

If so I'd suggest that is a large part of the problem, coupled with the boost box, which is another bad idea.

The stock turbo is only good to about 1.5 bar boost at the most, after that the pressure ratio is off the chart, and it's also in over speed. At this point it's making more heat than air. So is probably not a cooling issue you have, it's a heating issue.

Having said that, that is some really extreme egt figures, I wouldn't normally see those, even on reasonably tuned vehicles running stock hardware.

Can you post a log up?

Cheers
James

Edit:

Also note that not all td5s whether EU2 or EU3 had a restrictive flex joint, I've gone to upgrade a few in the past, one that still had the cat, and it was already full size. I don't know which ones were restricted, but obviously some were, I've seen 3 or 4 of varying ages that were stock, but also fine.

[Tombie]

ok, couple of questions.
so when you say bore. you are referring to the flex joint?

@phill. you said 3inch but Tombie is saying 2.5. if I'm reading this correctly .

does anyone actually have measurements?

has anyone replaced the flex joint and what improvements where had.

so just to be clear im not after any additional power. only reductions in EGTs. without dropping my MAP back to standard lol

Mine are actual measurements.

[PhilipA]

OK I respect Tombie's measurements. Mine was a guess from observation I have often wondered what a straight turbo outlet and gently curved pipe would add .

I had a Daihatsu Charade Turbo once which had a right turn from the turbo into an empty cat box, and replaced it with a gently curved 2inch? pipe.
It made a tremendous difference to the car.
The cat delete pipe has a good sized flexible hose section.EU2 pipes could be a cheap source.
Regards PhilipA

[Kaaaiju]

I went 3 inch exhaust and manaul version of the Allisport intercooler with was $980 landed last year and with my td5inside hybrid turbo and remap I get 650-700c quickly but drops down when I let off, the sensor is on the collector of the Allisport Manifold

I run 25-28psi but will upgraded head studs soon I'll go 2.0bar with the turbo and map

[rick130]

Also note that not all td5s whether EU2 or EU3 had a restrictive flex joint, I've gone to upgrade a few in the past, one that still had the cat, and it was already full size. I don't know which ones were restricted, but obviously some were, I've seen 3 or 4 of varying ages that were stock, but also fine.

Hey James, it seems to be the bellows type flex joint that is the restrictive one.
I have measured it, it's ridiculously small in diameter.
Also the pipe steps down from 2.5" to about 2.25" where it enters the cat, muffler and resonator.
Why they did this when they use nice mandrel bends I have no idea.

[shack]

Hey James, it seems to be the bellows type flex joint that is the restrictive one.
I have measured it, it's ridiculously small in diameter.
Also the pipe steps down from 2.5" to about 2.25" where it enters the cat, muffler and resonator.
Why they did this when they use nice mandrel bends I have no idea.Thanks Rick,

I've got a bellows type cat pipe in the shed, ill have a look when I get 5...

[shack]

I went 3 inch exhaust and manaul version of the Allisport intercooler with was $980 landed last year and with my td5inside hybrid turbo and remap I get 650-700c quickly but drops down when I let off, the sensor is on the collector of the Allisport Manifold

I run 25-28psi but will upgraded head studs soon I'll go 2.0bar with the turbo and map28 psi is essentially 2 bar anyway.

I've run 2.2 bar , but in all honesty it's beyond the flow capacity of the manifolds and head, the old law of diminishing returns rears its head!

And on most td5s, when you lift, the egt's drop really quickly, I can be at nearly 600 just before home, and a lift off and coast for the last few hundred metres will have it under 300

[TroyMortimer]

thanks guys, really appreciate the feedback.

sounds like a couple of things to check and replace.

at the end of the day with the intercooler change and possibly flex joint and bottom elbow of exhaust im really on only going to see 50c drop. which is better than nothing.

as always still keep driving by EGT gauge.

[slug_burner]

Pushing a turbo out of its efficiency island in search of extra pressure ratio result is more heat. Best not to generate that extra heat in the first place and if you do you will have to try and cool the air via a better charge cooler.

Gale Banks runs a Banks Power YouTube channel and has a video where he explains that the boost gauge is dead to him, it is air density that makes power not boost. Make sure you don’t push your turbo into an area of the map that drops efficiency meaning extra heat therefore lower charge density.

The size of the exhaust will effect when the turbo drive pressure will be greater than the boost. That is when the turbo is running out of legs. That is when the bigger exhaust and turbo will help.

I’d monitor the inlet temp after the charge cooler and try to drop the temp to increase the density of the charge. Done by more efficient cooler, maybe slightly less boost or bigger turbo and exhaust.

Driving by the EGT gauge is basically a manual form of derating the engine. Modern diesel management system do that for you. D2s don’t monitor EGTs, you have to do it yourself or modify the the parts of the system that provide best results in improving charge density not just boost.

[shack]

I agree entirely, and I think as Gale once said, boost is only used to sell turbo's/super chargers to the Vehicle owner, after that, who ever does the tuning is only interested in aircharge figures, or whatever the term he used was.

Boost is essentially meaningless, it's a bit like selling tubs of water of unknown size, but insisting the purchaser should be happy to buy them sight unseen, as you have checked yourself and they are all full to the top...but how much is in the "full" container?

Unfortunately if you say you have a turbo that can do 1400 mg per stroke on a 5 cylinder 4 stroke revving at 3500 rpm, most owners wouldn't know what that meant, why should they?

But boost is easy to understand/compare against itself.
If I had a stock td5 running 19 or 20 psi, and I then found a turbo that could deliver 30 psi boost, that sounds impressive...but means nothing, other than I guess it can handle a pressure ratio of about 3!

[Tins]

this is a fascinating topic, but one that is over my head. I grew up on petrol engines, points and coil ignition, and an incredible array of carburettors. Wasn't bad with tuning twin or triple SUs, not so good with Webers. Understood advance curves. Did a bit of stuff with heavy diesels, GMs and Cat, but mostly repairs. My 300TDi and TD5 are the first diesel cars I have ever owned. I can work out the Bosch VE pump. But then I'm stumped. Is there a 101 type of thing to understanding maps? I don't expect to be tuning TD5s in five minutes, but I would like to have a handle on it.

[Kaaaiju]

DiscoTD5.com | Discovery 2 Td5 ECU Tech and Tuning (https://discotd5.com/) read all you want and you can make your own maps
this is a fascinating topic, but one that is over my head. I grew up on petrol engines, points and coil ignition, and an incredible array of carburettors. Wasn't bad with tuning twin or triple SUs, not so good with Webers. Understood advance curves. Did a bit of stuff with heavy diesels, GMs and Cat, but mostly repairs. My 300TDi and TD5 are the first diesel cars I have ever owned. I can work out the Bosch VE pump. But then I'm stumped. Is there a 101 type of thing to understanding maps? I don't expect to be tuning TD5s in five minutes, but I would like to have a handle on it.

[slug_burner]

Try this one it will get you started
Turbo Compressor Map Explained [GO FAST BRETT] - YouTube (https://m.youtube.com/watch?v=Mzia8smn9rc)

Here is another, this goes into some petrol/gasoline related stuff but don’t let that put you off. He brings in the charge cooler to the conversation.

https://m.youtube.com/twatch?v=0Lv4yjiuJSU