Jay m A

iTrader: (2)

Can someone advise me of the type of EGT you can expect to see when running at a considered 'safe' EGT. What do people on here consider a 'too high' EGT?

I'm about to mount my EGT probe in the exhaust manifold, where the lambda sensor used to be on the early imprezas.
I know that EGTs are less at the turbo when compared to just after the cylinder, can anyone tell me typically by how much? how much do you think it would reduce by in the position I'm mounting it in?


Thanks in advance

Justin

P.s. I can get some more adapters made up if anyone wants to mount an EGT probe in the old Lambda position.

john banks

Mine is in a similar position and I haven't seem higher than 740 C despite trying to get them higher for power. More advance to a limit reduces them, retard increases them. More fuel reduces them, less fuel increases them. Less restrictions in your exhaust should reduce them. Typical drop from manifold to turbo said to be 50 degrees C. I will stop if I see 800 C in the manifold which I gather is still conservative, and some recommend going to at least 850 C there. I think you will be surprised to see that often the figures are in the high 600s even on full load!

Jay m A

iTrader: (2)

Excellent info John, just the type of response I'm after

I'm running fully decatted, and I've heard/read elswhere that temps in the downpipe can drop as much as 200deg from the cylinder

Anyone else?

Justin

RICH WILD

Hi,

Had my probe (oo-er) in the downpipe at first, just behind the lambda sensor and saw peaks of about 750 degrees.

When HKS headers were fitted I had the probe moved to where the 4 pies meet in the header.

Now seeing temps of just over 850 degrees so far but by that time you are running out of road

Temp does drop rapidly though when you lift off, so it's not at 850 for long. When the probe was in the downpipe, the gauge which starts at 500 degrees never moved until you gunned it through several gears.

Running 1.45 bar peak, holding around 1.4 in 5th, so my temps aren't probably what you'd call safe!!

Cheers

Rich


[Edited by RICH WILD - 5/20/2002 4:34:00 PM]

Cosie Convert

Rich, You are showing total disrespect for global warming you should attach a disclaimer to your post. If everyone was to follow your example the world would end and it would be all your fault.



PS Why do you have 4 pies in your headers ? Does that not cause a restriction



[Edited by Cosie Convert - 5/21/2002 1:14:18 AM]

JamesS

`Normal` temp limits for a small capacity production engine is 920Deg C. This could have a time-limited peak of about 950Deg C.

This is on non-performance, shopping car type engine......

mattski2

I see generally about 600 degrees, had it go upto about 650 or so... thats on a run when everything is nice and 'warm'

M

RICH WILD

RATFLMAO @ Cosie Convert.

That has made my morning.

PIES!!! Hadn't seen that, no wonder my car feels slow!! They are handy on long journeys and the manifold temps give them a nice crispy coating.

CAUTION: Putting pies in your exhaust should not be attempted without grown up supervision. Do not try this at home. Can only help slimming or weight control as part of a calorie controlled diet

Cheers,

Rich

mattski2

I know a chap who once wrapped spuds up in tin foil and baked em on the manifold of his van on the way to scotland :-D

mattski2

oh - re: too high, well, I've set my indicator threshold to about 800 degrees as I consider that to be way out of the norm - this may be revised after my first track day

john banks

Is he not helping global warming as yourself by putting out a nice lean mixture ?

Jay m A

iTrader: (2)

Mattski, where have you mounted your probe mate? <he said in a very non-camp manner>

Justin

mattski2

it's mounted in the downpipe - as near to the turbo as pos and accessible from the top.

M

RICH WILD

Just a quick question myself too.

My downpipe is wrapped and I was considering wrapping the manifold too to keep engine bay temps down as the OEM jobbie has heatshields, the HKS one doesn't.

However, I was worried that doing so would keep EGTs artificially high as the manifold obviously won't be able to cool as fast as the air flows over it.

Anyone any thoughts about this?

Cheers
Rich

Cosie Convert

Rich

I have my downpipe, uppipe (scoobysport stainless) and turbo exhaust housing thermally wrapped.
I have discarded the original heat shield and fitted a turbo blanket instead.
My engine bay/chargecooler stays nice n cool and my exhaust temp gets up to spec quicker.
Yes the turbo remains hot for longer after shutdown but it has a water cooling jacket to stop the seals being damaged so I don't think it is causing any harm. Even with the engine off, there is a natural circulation of water through the turbo to the header tank.

The max EGT I see at turbo inlet is 750 deg C and that's at 26 psi boost, 850 mv O2.

I did hit 850 recently after changing my turbo to front entry but that was due to the increased airflow not having enough fuel, the voltmeter dropped momentarily (till I lifted off) to 120mv

Andy

JamesS

All heat should be kept in the pipe and transfered to the turbine.

You don`t want the manifold to radiate heat. High EGT will damage exhaust valve and the bridge between the valves. Can also cause det. But basically if the temperatue at the exhaust valve is safe, you want to keep all that heat in the gas until it is trasfered to the turbine.

The manifold wraps round the oil filter and sump, the collector section and upipe run VERY close to the cyclinder head. Wrap everything, twice!!!

The only thing I have not wrapped is the turbo. This has a re-shaped heatshield. I did this on the recommendation of two turbo specialst`s - `It may reduce the life of the bearing`......

RICH WILD

Thanks for that.

Better get myself some wrap I think.

Cheers

Rich

p.s. Andy, what do you use to moderate your fuelling running that kind of boost? I've got an HKS AFR and I run an equal mix of petrol and octane booster , well almost. I could do with a better alternative.

Cheers

Rich

[Edited by RICH WILD - 5/22/2002 9:13:56 AM]

Jay m A

iTrader: (2)

Thanks for all your inputs people, much appreciated, even the muppetish ones I'd never considered the pie theory - mind opening stuff

Thanks

Justin

Cosie Convert

Water and Methanol mix injection. Takes care of det and weakness

Oh, and an adjustable fuel press regulator & HP pump.

Andy

[Edited by Cosie Convert - 5/22/2002 2:22:56 PM]

jonno

Hi Guys,
On a cruise iam seeing 890c @ 5000 rpm in 5/6th, recorded on the defi, have the sender in my up pipe before the turbo.

Seems a bit high?? What do you guys think??

Thanks Jonno. 01 STi7 JDM

Trout...

I have had up to 975 at 140mph on track - typical peaks of 950 - Defi in the uppipe.....to high - you bet - fine on road tho, around 890 peak.

No matter how much remapping - no improvement - until fitted uprated fuel pump - EGTs now nicely under control and will aim for 900peak on track - that will be at around 140mph plus.

It is probably too late - everything is probably cooked now - but it shows how something as simple as slightly loiw fuel pressure can ruin thousands in tuning.

Am kicking myself for not working this out earlier!

Trout