whats the best number to try to go for ive heard varying opinions from 12.2 to 13.1 under full throttle in PE mode of course, the motor would be an ecotec



1989 Turbo Trans Am #82, 2007 Cobalt SS G85

I run about 12.9 to 13.2 WOT

Under boost i like about 12.0-12.4 WOT


-Aaron
www.TurboTechRacing.com

Performance Parts For Cavalier, Sunfire, Cobalts and More!!!

damm im running 13.2-13.5. i hope thats not too lean.

Turbo Tech Racing wrote:I run about 12.9 to 13.2 WOT

Under boost i like about 12.0-12.4 WOT

I agree.

I really don't see too much of a problem with 13.5, although it doesn't give you much of a margin for error. IMO, shoot for about 13.0-13.2 NA and 12.0-12.5 FI and you should be in pretty good shape. Don't forget to check for knock as well though - timing will also play a big part.

13.5 on a stock engine is fine, even with a header and intake, but IMO i wouldn't go much less.


-Aaron
www.TurboTechRacing.com

Performance Parts For Cavalier, Sunfire, Cobalts and More!!!

Ideal AFR is whatever AFR keeps your EGT's in check and your motor not detonating... its really different for any particular setup, but as a general statement, it'll be in the 12.5-13.5-ish range for a modded motor (higher than stock compression, advanced timing, cams, etc). On a stock engine with bolt ons there's really no need to go richer than 13:1. Likewise, on any motor, if you're not getting knock retard, and your EGT's are within reason, there's no reason to go richer unless you're tuning on a dyno and can actually see a power gain from running richer.




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'Nuff said

I hate using hear-say but I have heard that ecotecs do like it a bit on the richer side.

I've been playing with my afr's and even tho I haven't been doing dyno tuning and there is a lot of variables, I think 13:1 is a good all motor a/f ratio for the eco.

I'm throwing my car on the dyno aug 11th so we'll have some actual information soon