Individual EGTs.

[k4nnon]

Hey all I finally got my individual EGT set up done and fired up the car yesterday. Link g4x PnP for Evo 9. I have not adjusted anything from the original tune I had on the car. Lambda hovers around 1.0 with an average correction of +/- 1.0 or so. My egts per cylinder at idle temps are around 680 degrees F for cylinders 1 and 3 and cylinders 2 and 4 show about 80-100 degrees higher. I’m assuming individual cylinder temps + or minus 100 degrees is pretty average. But if I want to get these temps closer to the same. Say within 50 degrees of each other, what is the best method to doing this. What I mean is how do I tell if the cylinder that need adjusted are the hot ones or the cool ones. Like are the cooler ones getting too much fuel, or are the hot ones too little fuel. And is it better to adjust this by individual cylinder fuel trim, or individual cylinder ignition trim. I feel all of this is slightly irrelevant at idle and cruising and most important for full throttle purposes but I haven’t had time to do any dyno tuning as of yet. Just looking for others opinions. Thanks!!

[David Ferguson]

Generally speaking, more ignition advance will lower EGT temps.   Usually more fuel will lower EGT temps, but this can interact with ignition timing.

You are correct that the individual cylinder trims are the way to find this out.   Since you can monitor this live, I would make changes and see what happens.

There is a lot info on the internet about how small plane pilots find the ideal mixture for a given cruise conditions using EGTs, they tune for maximum EGT, then lean the mixture from there.  Try this Google search if you have time:

https://www.google.com/search?client=firefox-b-1-e&q=Tuning+mixture+with+EGT

Where individual EGT really shine is when the engine isn't running right (misfires, etc).  You can immediately find the cylinder that is missing with the EGT as it will be colder from the lack of combustion.

[k4nnon]

Thanks for the input. I’ll check that link out.