EGT's high with E85?

[Flyin Brian]

I have been running E85 for some time but recently got an EGT gauge. My EGT seems to be running high. On a recent run the EGT hit 1660F with an AFR of 10.8 to 11.0 on the gas scale. The AEM EGT is mounted in the header pipe on # 6 right by the head. Timing is 20/18 deg. Boost is 20 PSI, IAT 130F in plenum. IDC arount 90%. The EGT gauge/powerlogger seems to be reading right. No trace of knock. I have run it WAY leaner accidentally with no knock (13.0 AFR with 1780 EGT), I know... My question is is an EGT of 1660 dangerously high even with a relatively rich AFR? I can get the EGT under 1600 by running it rich at 10.0:1 or even lower but it seems to lose a little power. Should I believe the EGT? Does anyone run the EGT probe closer to the turbo? I have been hammering it on E85 for months now at 11:0 to 1 AFR with no EGT probe and everything seemed fine. Plugs seem ok too.

 

[jasjamz]

I bet if you took the timing up to 23/21 it would go down and make more power. Try that...
90% DC....better look into that soon also.

 

[Reggie West]

Are you sure your fuel pump and injectors are up to the task? If you are at 90% DC that is on the ragged edge. Those EGTs might be off because of where that probe is located. Most people put the EGT probe in the downpipe to get a reading. Maybe Razor or Don Wang can chime in here too. From what I have read the power AF ratios on E85 seem to be 10 and 9 to 1.

 

[jasjamz]

Not to be argumentative... But I see egt probes pre Turbo on most cars. True he is on the edge though. I went past 100% on small injectors. From my understanding. Duty cycle is calculated through a formula and some argued its real value in tuning.

 

[Flyin Brian]

I think my fuel pumps and lines are up to the job. No doubt I could use 120 lb injectors instead of 80's. I can turn the fuel pressure up a bit and get the duty cycle back down into the 80 something percent range. I can for sure run it richer. I have tried advancing the timing but even a few more degrees will get some knock signal in third gear. It seems strange that I can run it way lean with no knock but even a little more timing will get knock. I have seen EGT probes in the header pipes close to the heads on many race cars but have seen them before the turbo too. I guess it depends if you are trying to make sure you don't cook the turbo or see the EGT close to the exhaust valve. I am way more worried about cooking something in the engine than hurting my old turbo. Turbo easier to replace. I do have stainless steel valves and forged pistons but those EGT's still worry me. Thanks for the input!

 

[Hot Air]

Anyone know the temperature ceiling is for a turbo? I would think that the oil flow would do a lot to protect the bearings. Turbine has carbon seals so that should be good! Incoming air should cool the compressor. Plus, I just purchased a ceramic cover to enclose the turbine to protect the paint on my hood (no hood liner).
Conrad