Standard WOT Exhaust Gas Temp for Chevy LT1 1

[DMan1]

Hello,

Would anyone know what is the 'oem' exhaust gas temp for a late 90's chevrolet LT1 at WOT ?

We've since modified the engine with a blower, and are using EGT as a tuning indicator. But we neglected to gather baseline data for the stock motor running at stoich.

Any input will be helpful.

Denis Kefallinos

 

[MikeHalloran]

Time for a trip to the junkyard...

Mike Halloran
Pembroke Pines, FL, USA

 

[patprimmer]

The baseline will be no use unless you know the safety factor built in by the factory.

The main use of EGT is cylinder to cylinder variations if a:f ratio.

Plug readings and/or wide band oxygen sensors are better tools for measuring overall a:f ratio.

What have you done to increase and meter fuel to account for the increased air mass.

What have you done to avoid detonation.

If you are running EFI with the standard inlet manifold and injector location, what have you done to compensate fuel pressure for increased manifold pressure.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[DMan1]

Thanks Mike and Pat.

Typical compensations of fuel volume, pressure, and ignition timing for this forced induction application have been applied.

I'm looking to know what a baseline WOT EGT would have been for this engine (in a 1998 Z28).

If you know a ballpark number, that would be helpful.

Denis Kefallinos

 

[RossABQ]

A '98 Z28 would have been an LS1; if it is truly a '98 LT1 it is from a truck. There is a world of difference between an LT1 and an LS1, as I'm sure you know.

At any rate, I don't think the baseline idea is going to work because I seriously doubt you are running an EGR, whereas the stock engine is. That would skew peak EGT considerably. (It's the whole point of EGR)

 

[JOHNDOE333]

It can't be a truck either. To my knowledge they did not come in trucks. 1996-1999 trucks with 5.7L V8's were vortec engines. They had iron heads, standard flow cooling systems, and a distributor mounted in the rear\original location.

Good day,

 

[mattsooty]

DMan1

I have never worked on this engine before but I would say that a limit of 850 degC would be conservative - more likely 900 degC.

It sounds like this is somewhat of a 'special' and, since I also surmise you are American, I doubt fuel economy is at the top of your prioroty list. I would suggest keep it below 900 degC...Besides, I doubt that you will be running steady state at WOT for long.

RossABQ

The OP questioned exhaust temps at WOT. Since EGR will not be used at WOT therefore it is not really relevant whether he does or does not have the system.

MS

 

[dicer]

With all the variables I don't think you would find any 2 engines that would not be different.

 

[Lou Scannon]

Agree with dicer. For one thing, unless the temp sensors are more or less identical, and identically located, results will be skewed.
Back to back on the same engine is the way to go.

 

[Marquis]

It's an old engine now, this is some data I took some years ago in the US,It was a 2001 LS1 engine, pretty much standard spec. I agree with the comments made above about WHERE the temps were taken exactly and there being an offset. The temps in this case were taken at one bank in the manifold/pre cat region.


Temps in Deg F

985
1106
1220
1298
1396
1467
1521
1551
1605
1626
1641
1672
1695
1703
1683
1697

Correponding engine speeds/rpm
804
1201
1600
2000
2400
2800
3200
3599
4003
4401
4805
5201
5404
5603
5802
5999

Engine AFR at those speeds
12.54
12.57
12.58
12.47
12.48
12.4
12.54
12.67
12.56
12.51
12.4
12.37
12.38
12.37
12.28
12.22

Sorry that the temps are in deg F.

PS: I'm getting sick of people pestering me offline for free technical info and 'tips', solicitors in the UK charge a huge consultation rate and it should be no different with engineering- especially in view of the poor salary they get in many countries. What I post here is a privaledge. Sorry for sounding harsh.

 

[patprimmer]

Marquis

I used to send them a reply asking why they don't post here, but as the reply always was they could no longer post here, I just immediately blacklist them now, unless of course it is someone I really know and respect from here, and is not really about engineering.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[DMan1]

Thanks Marquis and everyone!

Denis Kefallinos