Bigpower

What EGT do people consider an acceptable safe level? Obviously this will be dependant on where your EGT is plumbed in and how accurate it is.

I use an Autometer EGT gauge with the suppled probe fitted into the exhaust manifold at the collector point of all four branches, just before the Turbo. I suspect this will the hottest point of EGT but even so the readings are get seem well over the top, even though the fuelling is good.

The gauge goes up to 1600F (871c) but it always goes over this point, sometimes to approx 1700f (926c) and beyond...

Reading up it would suggest that anything over 900c is too hot, i've been running like this for 7 years and never had an issue, and i'm suspecting that the gauge is both inaccurate and the placement of my EGT probe at it's hottest point is misleading as people may be using other areas for taking the EGT from i.e after the turbo or on just one exhaust port.

Thoughts and comments please.

Gareth[/u]

Guages are only an indication and are only likely to be somewhere near true in the middle of their range, top end could be anything. I tend to use mine as a warning of something not right i.e. higher or lower readings than expected from observing over time rather than a true state iyswim :-D

I have a Defi EGT with the sensor at the collector, just before the up-pipe (Impreza). I used to get 900C+ and was told, by the guy who was mapping it, that's about the limit to go to although I usually see 700+ on cruise at 70 ish.

It used to be a PITA on track as any long straight would see the temps beyond 900. I ended up fitting water injection and that keeps it under control nicely. I've asked the question of other mappers but not had a definitive answer.

Hope that makes sense

the peak egt will be dependent on your engine components, and be limited by the weakest link.

in my case the maximum recommended egt measured at the port is 1750 degrees F. this is due to the standard apex seals in a rotary engine being rated to just a smidge over this.

N/A engine's and forced induction engines will have different maximum value.

Ollie

Pretty much goes along with what i've found out.

The current problem i'm having is excessively high EGT's and low boost, aswell as a drop in response and MPG. I've looked at everything and it could be pointing at a leak at the turbo to manifold join, a crack in the manifold itself, or a leak post turbo on the downpipe ( a custom job by MIJ performance which hits the gear linkage, the front subframe and now the back bumper as its dropped)

My theory being that the exhaust vibrating against the front subframe has allowed the gasket to leak because the bolts have loosened off... a PIA to do on my car because the turbo is at the back. I wont find out for sure because i dont have the facilites to do a turbo off job here and it also needs another gearbox, so looks like progress will be stalled for a few months as tax is needed at the end of the month too!

Gareth

or it could be you are using too much ignition advance at low boost.

Your egt is on indicative on the road unless you can hold the engine in specific load cells like on a engine or chasis dyno. If you think you have a leak then i would 100 % sort that. It will dilute all your readings ie afrs and egt. You cant use the rotary egts as borgue has quoted. they will most likely be far to hot for you.

Your egt could vary according to out side temp or any other variables. In a idea situation you should see peak egt at you highest gear change point. The rise should be gradual and quite linear.

1. be sure of your afrs in all load points
2. Be sure and aware of the knock in these points
3. be aware of peak tq and remember peak tq is ppp. the place in the combustion process that yields the most heat and pressure. it has the most danger
4. Try and hold the engine in specific load point. On the road you will need to use a hill and left foot brake. Monitor the egt very close and have a bale out temp. If possible set up a camera to record for you. that way you can review the logs at home. I always listen closely to the sound of the engine. if it sounds odd then bale out.

Scott

I've had the gauge for a few years and when running well, i would see a peak of about 1650-1700f, even flat out in 5th, the highest point of EGT would be as it came up to peak torque, about 1000rpm after full boost.

Saab used to do test runs with peak's in excess of 1100C, dont think i would ever push it that far but the safety margin may be bigger than alot of people realise. Before fitting the EGT gauge i never worried about it :oops:

I cant do anything for timing, TBH it doesnt run that much advance low down and too much mid range hence why i have W.I, the only time it would knock would be at the peak torque point in the higher gears and very good fuel and W.I eliminates that completely.

I'm pretty certain its a leak pr- turbo, the exhaust manifold gasket itself is good as i did it last week and fitted a higher spec item but its definatly 'chuffing' when you rev it at idle from the turbo area, and i also dont think its the DP as that wouldnt affect the boost pressure and would be alot louder.

Couldnt see any evidence of carbon around the turbo flange when i changed the manifold gasket last week, but the whole lot will come off when i do the gearbox for a better look and a new turbo to manifold gasket fitted, and some new locking tabs.

The problem with issues like this is its so gradual you dont realise it's happening until one day it dawns on you :?

Gareth

On my SR20DET I often get 950* on track, been told thats fine for that engine with its sodium filled exhaust valves.
On my CA18DET I havent I clue what I get .... but been told due to different valves that I should run about 900max on track to be safe.

SM wrote:On my SR20DET I often get 950* on track, been told thats fine for that engine with its sodium filled exhaust valves.
On my CA18DET I havent I clue what I get .... but been told due to different valves that I should run about 900max on track to be safe.

FWIW worth my engine also has sodium filled/cooled exhaust valves

Something i remembered which may be of relevance -

A while ago i noticed a metallic like dust in my engine bay in the turbo area, originally there was quite a bit on the bulkhead and surrounding pipes.


You can see some on the red hose


On this one you can see dust on the bulkhead where the brake pipes are, and also the heater hose.


At the time i couldnt figure out where it came from but its now just clicked - must have been the turbo to manifold gasket blowing out :roll: