Egt

Hello,

i have tuned a turbo charged 6cyl car for 1km race and have seen that there is a big difference in the egt’s as shown in the attached photo, i have my max boost set at 2.9 bar boost, running e99 fuel 14 degrees of timing (reached MBT) on peak boost 7000 rpm, cylinder 3 has been trimmed 15% of fuel but stills seems hotter than the others.

my questions are:

1. As a peak temperature of 850c is it safe to run the engine for 1km?

2. what could cause this much of difference in the egts?

all egts has been set 1inch away from the cylinder head

Have you tried swapping probes? All at the same depth in the runners? Were the injectors flow matched?

From my limited understanding, if temperatures near the head are stabilising at that level you should be ok provided coolant & oil is following where it should.

All injectors flow were matched and probes has been set equally in the runners

As Michael suggested, swap the probes and the injectors to different cylinders and retest. If it follows one, or the other, it's a fault there.

With modern engines, and tolerances, etc. it's quite unusual to see one cylinder that's significantly different from the others, and that's quite a spread, which could be partly down to the exhaust manifold design holding more exhaust gas back (restriction) and/or intake manifold design. EGT is very handy tool, but restricted in use as it can cause interpretation issues - any way you can check the lambdas for each cylinder? Oh, you didn't actually mention what difference, if any, the fuel trim had?

The peak EGT allowed for the turbo-charge will vary between manufacturers and the material they use for the turbines and housings.

He said 15% on cylinder 3 which is a fair bit for matched injectors.

Have you done a leak down test of each cylinder?