borgue

hey just got my engine back in (streetport 13b-rew pinapple mild streetport),

have charnged injectors to 850 primary and have changed map accordingly.

but, have noticed a higher than normal egt at cruze, between 1300 and just shy of 1600 degrees F. measured at the port.

the problem seems to occur at 3-4000rpm in 4th and 5th gear.

i tried to richen the mixture to 12.5:1 to cool the egt but the effect was minimal.

is my problem with the ignition timing? i have an hks twinspark, do i need to adjust the dwell time?

or is it advance that is causing my problem? i am running low 20 degree advance with a 3 degree split.

any advice or comment greatly appreciated,

Ollie

cewrx7r1

iTrader: (2)

F1: just got my engine back in (streetport 13b-rew pinapple mild streetport)
A1: You should have ask Blake for a starter map, did you?
You can send me you dat in zipped format for a private analysis. A complete list of engine mods/setup should be included. Send to cewrx7r1@yahoo.com.

F2: have charnged injectors to 850 primary and have changed map accordingly.
A2: I hope so!

F3: have noticed a higher than normal egt at cruze, between 1300 and just shy of 1600 degrees F. measured at the port.
A3: Timing would have to be really far off to cause higher than normal EGTs.
You could use the commander to make temporary changes to fuel and timing as you log or view the egts. For cruise, lean out the AFRs to 16 - 17 range for better mileage, less carbon buildup, and also lowers the temps.

F4: the problem seems to occur at 3-4000rpm in 4th and 5th gear.
A4: There is your initial target area to modify as mentioned abiove.

F5:i tried to richen the mixture to 12.5:1 to cool the egt but the effect was minimal.
A5: 12.5 AFR is slightly leaner than an AFR for max power for NA or low boost. Too rich for cruising.

F6: is my problem with the ignition timing? i have an hks twinspark, do i need to adjust the dwell time?
A6: Do not touch anf of the PFC dwell settings. Only adjust timing and fuel.


F7: or is it advance that is causing my problem? i am running low 20 degree advance with a 3 degree split.
A7: timing for a modded engine only needs changing in the idle and for high boost. If you look at the stock IGL map for 3k-4K (N7 - N10) , your cruise should be in rows P6 - P7 approx. By that you timing is about 2 - 10 degrees too low.
Go back to stock IGL with 3 split for cruise!

dhcernese

I also have 4x850s. I was able to push my EGTs to 1800 easily while cruising if I held the throttle at just the right point shy of hitting vacuum. 1300-1600 was common (cruising only mind you). My EGTs died/melted/whatever, so now that the car is tuned I can't tell. I have a feeling that high EGTs under cruise are the norm close the the port output, but not many people have a good reference. Most people have a single EGT farther down the pipe. If/when I get my EGT fixed, I'll pipe back in.

borgue

cheers for the input guys, gonna change the exhaust to a more free flowing system and once this is done i will have another bash.

thanks for your help.

Ollie