AFR's at idle

NoDOHC · 03-02-2011, 11:05 PM

I know that a six port will idle at stoic. I was able to do so using the factory narrow band sensor when I had to pass emissions (at 5 degrees ATDC Leading and 20 degrees ATDC trailing). If the timing is set retarded enough to idle closed-loop, you are using much more fuel than you would at 15 degrees advance and 13.2:1. I was listing the information to correct previous erroneous information that I posted, not to endorse idling with 10 degree ATDC timing.

TTT, shoot for 16.2:1 AFR (1.1L) and about 50-60 degrees BTDC for fuel economy (at -45 kPA, 2,700 rpm). You will have to run rich of that if you pull more than about 45 kPA vacuum driving down the road.

03-02-2011, 11:05 PM	#19
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 18	I know that a six port will idle at stoic. I was able to do so using the factory narrow band sensor when I had to pass emissions (at 5 degrees ATDC Leading and 20 degrees ATDC trailing). If the timing is set retarded enough to idle closed-loop, you are using much more fuel than you would at 15 degrees advance and 13.2:1. I was listing the information to correct previous erroneous information that I posted, not to endorse idling with 10 degree ATDC timing. TTT, shoot for 16.2:1 AFR (1.1L) and about 50-60 degrees BTDC for fuel economy (at -45 kPA, 2,700 rpm). You will have to run rich of that if you pull more than about 45 kPA vacuum driving down the road. __________________ 1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers) 1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)