what air fuel ratios you using
Thread Starter
Teching In
Joined: Feb 2006
Posts: 1
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what air fuel ratios you using Hi there, I am new to the site (all the way from little ol New Zealand) and have been trying to research air fuel ratio's.
I have had a VCM suite edit and OTRCAI on my LS1 and getting great power but wonder how lean is too lean and what others are running.
On the dyno I am at the peak hitting 13.4:1 - 13.6:1 between 4000rpm and 5500 rpm where it drops back to 13.25:1 up to 6400 rpm.
Sorry if this has come up before but I did a search and didn't find much at all.
Thanks
I have had a VCM suite edit and OTRCAI on my LS1 and getting great power but wonder how lean is too lean and what others are running.
On the dyno I am at the peak hitting 13.4:1 - 13.6:1 between 4000rpm and 5500 rpm where it drops back to 13.25:1 up to 6400 rpm.
Sorry if this has come up before but I did a search and didn't find much at all.
Thanks
TECH Enthusiast
Joined: Sep 2004
Posts: 564
Likes: 0
From: Omaha, NE
Usually WOT peak power and torque accur somewhere within 12.8-13.2:1 for NA engines. This varies from car to car, dyno to dyno due to different loads and the accuracy of various wide band A/F measuing devices. Sometimes being at the rich side of this spread in the peak torque area and the lean side in the peak HP area helps both, but not always. Hope this helps.
....... 4800-5200 is high torque it will be more lean there thats is not lean for a n/a motor. its fine there........
Originally Posted by brody05
Hi there, I am new to the site (all the way from little ol New Zealand) and have been trying to research air fuel ratio's.
I have had a VCM suite edit and OTRCAI on my LS1 and getting great power but wonder how lean is too lean and what others are running.
On the dyno I am at the peak hitting 13.4:1 - 13.6:1 between 4000rpm and 5500 rpm where it drops back to 13.25:1 up to 6400 rpm.
Sorry if this has come up before but I did a search and didn't find much at all.
Thanks
I have had a VCM suite edit and OTRCAI on my LS1 and getting great power but wonder how lean is too lean and what others are running.
On the dyno I am at the peak hitting 13.4:1 - 13.6:1 between 4000rpm and 5500 rpm where it drops back to 13.25:1 up to 6400 rpm.
Sorry if this has come up before but I did a search and didn't find much at all.
Thanks
heres a reference for you
9.0:1 BLACK SMOKE (NO POWER)
11.5:1 RICH BEST TORQUE @ WOT
12.2:1 SAFE BEST POWER @ WOT
13.3:1 LEAN BEST TORQUE @ WOT
14.6:1 STOCHIMETRIC AFR ( CHEMICALLY CORRECT )
15.5:1 LEAN CRUISE
16.5:1 BEST FUEL ECONOMY
18.0:1 CARBURETED LEAN LIMIT
22.0:1 EFI LEAN LIMIT
mostly for an NA mototr you want to shoot for 12.5 down low till you get to peak torque.....you want to then lean out slichtly on your way up to peak HP where you want to hit 12.8, then richen back up to 12.5 by redline...and makie it like 12.0 above redline for some safety dump in fuel....
with FI...just do the same...except 11.5~11.8~11.5~11.0
if you spray and Force air in...you might want to go another half a point richer again
also in general you want to be 2-4* less timing at peak torque than at peak HP.....
9.0:1 BLACK SMOKE (NO POWER)
11.5:1 RICH BEST TORQUE @ WOT
12.2:1 SAFE BEST POWER @ WOT
13.3:1 LEAN BEST TORQUE @ WOT
14.6:1 STOCHIMETRIC AFR ( CHEMICALLY CORRECT )
15.5:1 LEAN CRUISE
16.5:1 BEST FUEL ECONOMY
18.0:1 CARBURETED LEAN LIMIT
22.0:1 EFI LEAN LIMIT
mostly for an NA mototr you want to shoot for 12.5 down low till you get to peak torque.....you want to then lean out slichtly on your way up to peak HP where you want to hit 12.8, then richen back up to 12.5 by redline...and makie it like 12.0 above redline for some safety dump in fuel....
with FI...just do the same...except 11.5~11.8~11.5~11.0
if you spray and Force air in...you might want to go another half a point richer again
also in general you want to be 2-4* less timing at peak torque than at peak HP.....
