light/mid load EGT 3

[partsguy22]

What is an acceptable EGT range for light/mid cruise?

Right now they hover in the 1350-1400*f range while at cruise (50-60 kpa @ 3000rpm)

the engine is a 1755cc mitsu 4cyl
9.5:1 compression
Ive tried AFRs from 14.5 to 17:1
and ign lead from 36 to 42* btdc

No mater what Ive done they wont seem to go down

 

[DigitalGT]

Sounds like the problem I had tuning a 1.8T 20V with a stand alone ECU a few years ago. Got the car running with the timing locked at 10° BTDC. Unfortunately I had to guess at the position of the crank timing trigger as the motor was already installed and unaccessible. Thus the timing was truly locked at 2° ATDC. With an intentionally rich mixture to keep things cool on the slow drive over to the dyno, the EGTs skyrocketed at cruise due to the large portion of still burning fuel being dumped into the exhaust manifold. (Gee that explains why the engine could make 15 psi at a stand still!) Added more fuel to try to cool it down but the EGTs just went up further and briefly pegged the gauge at 2000° F. That's when I realized I had a timing error and reluctantly locked the timing at 20° BTDC (which really brought it to about 8 degrees BTDC) and did an across the board fuel reduction. That got the EGTs down to reasonable levels.

If anything I've noticed that post turbine EGTs on a turbo car are a bit lower at cruise than they are on N/A cars. Granted it's comparing apples to oranges but turbos are pretty good at converting thermal energy into mechanical energy after all

 

[partsguy22]

I found the problem...

I had a turbo failure yesterday so I spent the better part of to day pulling all of the turbo stuff off and putting my old 4-1 header and N/T exhaust back on .While I was at it I welded an egt bung on.So after it all was back together, I took a test drive and egts under the same circumstances temps were 1100-1150*f

So I guess the turbo/manifold combination was to restrictive ...so that combined with the failure means its time for an upgrade

Thanks to all of you for the help