ok, I know that these vary quite a bit from car to car & on where they are placed, but a vague idea would be good...
With the probe just before the turbo, what's a typical 'motorway cruising' temperature & peak? I just have a thought that mine may be a little on the high side at the moment & have burnt out my lambda sensor oops!

 

Mine is between 1100 F and 1200 F typically between 70 - 80 mph cruise, EGT probe in the headers where the old lambda use to be on the pre downpipe location cars.

Justin

 

Hmm, ok - 600 to 650C or thereabouts. A tad lower than mine.
Ta - good to have a 'reference' figure

 

Mines in the upipe,where just before the turbo.I get a steady 800c at a 90mph cruise.

 

Mine's in the turbine housing, before the turbine. I have yet to see more than 820C... ever. 70MPH cruise is circa 510C. Wouldn't know what higher cruise speeds produce egt wise, occifer!

 

Similar to Moray's But I must cruise faster or is it the Ra gearing
Town drive 250-350C
4000 rpm cruise 610C
Max trackday 870C

Measured at turbine inlet

Andy

 

Hmm. Ok. EGTs are all a bit weird & wonderful, then!
I seem to be getting the 650C at the correct motorway cruising speed and, I'd hazard a guess that cruising at 90 would be around 740, not that I'd be able to check that . But I do manage peaks of 870 somehow...
I think, then, that I'm higher than most, but nothing suspicious is going on That's one good thing that's happened today, then. (ps anyone know if it's possible to retrieve data from a hard drive that's had a mechanical failure? )

Any guesses at what sort of temperature your common or garden lambda probe starts evaporating at if it's at it or too long? Tricky one to find out, I imagine

 

Just happen to have some results logged from Elvington on Sunday.
Best time 12.28 sec 1/4 ml and 116mph going on to a best top speed of 159.7 mph at around 1.25 mls with an evident head wind.
Headers probe is at the 4 into 1 collector on the Ion Spec headers and the down pipe is within 3" of the turbo.
8 or nine runs in total for these results.
Temp. @ headers: 865-877 deg cent.
@ down-pipe: 700-721.
Made some induction changes the night before and knew from the Link AFR Meter that engine was rich at top end and in cruise and believe these readings bear this out. Expect temp in headers to increase 20-30 deg with further adjustments.
Headers are presently ceramic coated and will fit a set that are exhaust wrapped to see if there is any difference in heat retention.

[Edited by harvey - 4/2/2003 8:13:46 PM]

 

Interesting.Do mine sound a little on the high side then?

 

Depends who you listen to - seems that Mark A's in the past have been up around 1000C on boost, & 750 at cruise is fine.
So, whatever

 

My cruise EGT figure was taken running 15.4:1 AFR. Would be interesting to know what others are running on cruise to get the figures they are quoting.

 

15.4 works OK running at cruise, then? About as lean as possible without nasty things happening?

If things don't blow up with that , I'll give it a whirl & see what it does...

 

14.7:1 closed loop cruise

 

Highest recorded on mine was 975 degrees C in the manifold!!

My other car has the probe in the downpipe and it never goes above 700.

Cheers

Rich

 

A lot will depend on the actual location of the probe but I think that anything over 930cent in the up-pipe for any length of time is heading for trouble.

 

Please note I have editted my post.
My probes are at the collector in the headers and in the down-pipe immediately after the turbo.

 

So where is the best place to have the EGT sensor

Mark

 

Best place is at the bottom of the Up pipe adjacent to, or in the headers for general measurement, anywhere else will do as long as you bear in mind the temperature drop from that point to the probe when tuning.

My own temps are fast cruise typically 820/830, if cruised at very high speed then temps rise to circa 860, if run hard through the gears I see about 920/940 deg C, highest recorded has been 969 under very hard driving conditions, probe installed in the collector. My cruise afr's are circa 0.97/0.99 lambda at higher "unloaded" engine revs, 1.0/1.03 at sensible cruise levels. My headers and up pipe are very well lagged.

Moray either you are running very rich or with relatively low timing, since afr is 15 to 1 or so then timing or, are you running with headers that are not lagged?

Deep, yours don't sound like a problem at that level assuming you are on the closed loop.

 

Thanks

 

I can now report that there appears to be little difference in the effectiveness between wrapping (the light brown wrap that you have to wet before application) and ceramic coating although they are both very effective in reducing heat loss and contribute to lower under bonnet temperatures.
Wrapping these headers and up-pipe took the best part of three rolls so not cheap. To make a neat job takes care and practice is a help. I had the benefit of a wire puller which is a pair of pliers that twists the tie wire as you pull it. Without this the job would have been labourious. I guess at some point a re-wrap will become necessary.
The engine was way too rich as I suspected and now that has been sorted, with sustained W.O.T. for just over a mile the temp was 908 deg cent and rising. Cruise, subject to speed and topography (read hills) is high 700's or low 800's.