Max EGT? Options

[technicalninja]

The title is the question.

I know what to look for with water-cooled stuff.

I have no experience with air-cooled stuff yet...

What say you?

Is there a normal range?

A never exceed number?

Anyone ever use 4 thermocouples?

Was there any noticeable difference (#3 is of concern to me)?


Thoughts, tips, any data would be greatly appreciated!

[gereed75]

No direct experience with Porsche but I agree that EGT would be the best method if you are trying to balance combustion in each cylinder. Maybe you could get close just by thermo imaging each exhaust runner without the need to actually mount thermocouples in each runner.

Also agree that 1.5 - 2” below cylinder is about right. More important is to make them all the same

There really is no right number for temp, it will always be moving and depends on thermo couple location and engine state. Maybe you could see delta between cylinders and tune accordingly.

Balancing is done in aircraft by changing out injection nozzles restrictors. They can be had in .5 gph increments. Even then you are not looking at absolute temperature values, you are looking at which cylinder peaks first as you lean at a set power setting. First to peak is the leanest cylinder.

Back in the day, It was common practice to tune go cart race engines on the fly using EGT and a driver adjustable mixture knob.

Chris, were you running 4 sensors and if so could you see any delta?

[ChrisFoley]

Chris, were you running 4 sensors and if so could you see any delta?

I had visual data only for all 4 cylinders, on a single digital readout, scanned in sequence at one second intervals. If one went out of range the readout stayed on that cylinder.
There was some variation but in general it was fairly uniform.
At times I reamed a jet orifice to make the spread smaller.