Outer Limits 4x4 Board

Hi all,

Just after some help with what sort of EGT's I should be running in my car. Its a stock TD42 with a modified GU turbo set up, I've got the pyro set up on the engine side of the turbo, so between the turbo and the motor itself, not on the exhaust side. So I need to know what sort of EGT's is a safe maximum?

Appreciate the help in advance.

Cheers, Paul

max 550 is reccomended

dirtyGQ wrote:max 550 is reccomended

Thanks for the quick reply! So tat is a safe maximum, that means I need to turn the fuel down just a touch me thinks.

Depends on the vehicle and the location of the pyro. Late Catalytic style vehicles run at 650 degrees in order to light the Catalytic(after the turbo).
Before the turbo will be potentially a couple of hundred degees hotter (750) compared to after and the size of the exhaust housing/backpressure will change this also. 550 after the turbo within 4" of the turbo outley is generallt accepted for older mechanical pump type diesels.

Joel

its a comp only car now isnt it? run it at 650 if the turbo can spin that fast for max boost and fuel

It is a comp car, but it is being a daily driver for a little while at the moment so want to look after it for a while . The probe is located pre-turbo, tapped into the manifold, so from what I am reading up to 700ish will be okay on my setup?

i think the earlier mention of 550 is AFTER turbo temps not before. pre turbo is more like 750, so the 700ish is fairly safe.

I've been running my Isuzu up to 750 for the last 5000km or so. Seems to love it.

The occasional accidental excursion past that too.
Add your own safety factor in.

i've always been told post turbo, but still within 4" or so of turbo (like on the 90 deg elbow of dump pipe) then 700 deg for a very short time before melt down,

and pre turbo, aka a manifold tap, 600 deg before damage starts, but it should still take a long hill climb flat out to reach these temps though.

def90 wrote:i've always been told post turbo, but still within 4" or so of turbo (like on the 90 deg elbow of dump pipe) then 700 deg for a very short time before melt down, .

post means after, 700deg 'post' turbo is way bad.

def90 wrote: and pre turbo, aka a manifold tap, 600 deg before damage starts, but it should still take a long hill climb flat out to reach these temps though.

pre means before.

600deg would be as far as i'd like to go post turbo, i reach 500-550 easily towing, been as far as 600, just drop it down a gear and get the revs up and it cools down. more rpm, more boost, less heat. (air fuel mix evens out, where as labouring up a hill the mix runs rich)
i'm sure cast alloy (pistons) melts around 800deg. now you guess how much the gas cools before the turbo.....

this is what i believe can someone correct what is not right..

think about each cylinder, they get the same amount of fuel, do they get the same amount of air?? (turbo speaking) you got to wonder what the temp is inside each cylinder. air is like water, lazy, will favour the easiest path. easiest path in a patrol manifold is 3&4, 1&6 will run hotter (less air compared to 3&4) therefore if you get 730 PRE turbo, you might have 760 deg in 1&6, 700 deg in 3&4. when you start winding in the fuel and boost the difference will widen, when you think 750deg is ok, actually two cylinders might be more than that...and closer to melting than you think.

does that make sense...

rover1 wrote:
does that make sense...

Yep.

yep oops

wording round the wrong way, 600 deg post and 700 pre

after turbo for a td42 recomended 550 degrees if you want longevity.

dirtyGQ wrote:after turbo for a td42 recomended 550 degrees if you want longevity.

After turbo is useless if you want to protect your engine.
The 550 deg is based on a guessed drop of 200 deg across the turbo. The real temp diff across the turbo changes based on boost and EGT's.
I have heard (but not found the document myself) that Isuzu recommend 750 deg C as the max at the turbo inlet.

Many engines will suffer heating issues when run at this power level for sustained periods, so EGT isn't your sole consideration.

KiwiBacon wrote: I have heard (but not found the document myself) that Isuzu recommend 750 deg C as the max at the turbo inlet.

on most of the yank turbo kit sites (dodge, chev) recommend 750 before the turbo.

rover1 wrote:

KiwiBacon wrote: I have heard (but not found the document myself) that Isuzu recommend 750 deg C as the max at the turbo inlet.

on most of the yank turbo kit sites (dodge, chev) recommend 750 before the turbo.

Yeah it's the closest thing I found to a universal figure.

Thread hijack..

just figured while we have the egt gurus here

ive just fitted a 1hd-fte into my 80 series. it has the egr pipe going onto number 6 exhaust port. if i remove this and use a blanking plate to seal it off can i put my probe in there or does it really have to be in the middle of the exhaust bank?

cheers mark

In the middle where all the manifolds runners merge so you get an accurate reading.

are you guys talkin farenheit or cels

Celsius.

Kiwibacon is correct in that pre is more accutate, as mentioned earlier the restricion of the exhuast housing and exhaust system will effect the heat after the turbo, having said that every aftermarket turbo diesel kit manufacturer and even large mobs in the States like Gale Banks use post turbo temps, they have ecu controlled fuellers that remove fuel based on preset post temp exhaust temps. So I think its fair to say both are acceptable if you are experienced with the engine configuration.

Joel

chunks wrote:In the middle where all the manifolds runners merge so you get an accurate reading.

should be 'average reading', the 6 pots will burn at different temps depending on how much air they get.
more air = less heat
less air = more heat

the more 'open' /better flowing your manifold is the more even the temp acroos the board. (with turbo charged motors)

cooter wrote:are you guys talkin farenheit or cels

750c = 1382f
550c = 1022f

Thanks for all the replies everyone, just drove my truck down from Sydney to Geelong and on the really long pulls on two or three hills it got to 550, if I had held my foot flat I reckon it would have gone higher, but it had plenty of power still so I just drove it by the pyro on the hills.

I have spoken to a few contacts of mine who have had a bit of experience and what Kiwibacon and PGS are saying is right, so I won't be going over 550, unless under comp conditions, then its only for short stints anyway.

Thanks heaps for the help!

Cheers, Beretta