RICH WILD

Hi,

Just interested here what the difference is between upipe and downpipe EGTs. Some people say it's around 150 degrees, others nearer 200. I'd like to get some hard figures though. Seems that 900-950 is about the max in the uppipe. What about the downpipe?

And will lagging make any difference to the temp?

Cheers

Rich

rroberrto

had it right beside the lambda probe in the downpipe, and the highest i've seen (my00 with Dawes, 16 psi held, Tek1 and slightly leaned-out A/F at .895v O2 sensor) was ~ 720 celsius

Robert

SCOSaltire

no wonder it glows!

rroberrto

also bear in mind that the gap in the reading between up- and downpipe is not fixed but rather depends on the ammount of thermal loss in relation to the ammount of exhaust passing thru, which means cruising = big gap while high load & speed the difference is considerably smaller

wrapping also helps decrease the discrepancy

Robert

Jay m A

iTrader: (2)

900 - 950 in the up pipe? I'm no expert but from what I gather I wouldn't want to see higher than that after the cylinder!

Justin

RICH WILD

Cheers for the replies.

Also, sorry what I meant was a max 900-950 in the uppipe was like the danger level, not that it was ok. Should be aiming around 850 peak really at worst.

Anyone else?

Rich

[Edited by RICH WILD - 10/16/2002 8:50:10 AM]

babber

Rich,

I put my probe on the exhaust maniford where the left and right hand manifolds joins, on the underneath of the driver side of the car at the front (this doesn't make sense to me)

I see around 775 deg (peak) on WOT, but I will go and check my peak readings now. Boost was 1.2 bar.

TEK 2.75 ver 2, etc with perfect fuelling.

On average the reading (driving normal) is around the 500 - 600 deg range, but I'll check that later

Cheers Phill C

PS I got waterspray as well if that helps ?

[Edited by babber - 10/16/2002 2:35:49 PM]

TonyBurns

iTrader: (3)

Ok, why put the sensor in the up pipe when the gasses still have to go though the turbo which runs at an even hotter temp?
Surely measuring the gasses on the downpipe is actually the correct way to do it (thus you already have a sensor there too?)
Isnt it also the fact that you want to measure the temp after its passed every part of the engine first to get a reading thats consistant?

Tony

Mo

Tony,

it's the temperature of the gas within the cylinder that we're interested in, all sensors placed in the uppipe/downpipe/headers etc are used as an indication of cylinder temps. The further from the cylinder the lower the reading.

Ideally I'd have a sensor for each cylinder as close to the head as possible.

RICH WILD

Tony,

The turbo EXTRACTS energy from the exhaust gases, as it is that kinetic energy that drives the turbine, therefore temps in the downpipe are cooler than in the uppipe, usually by about 150 degrees.

From a point of view of checking for leanness, the downpipe is a bad place as it will give you the impression that the exhaust temps are cooler than they actually are.

At least that's my understanding....

Where's John Banks when you need him?

Cheers

Rich

babber

Rich,

I thought I had the same understanding of it, as you. I was told the best place to measure the gas temperature was as close to the cylinders as possible. Lol, about the comments about the four readings that would cost a fortune to have four defis and where would I put them all ?

Normal driving temperate was around 600 deg, when I checked last night

Cheers Phill C