what should my AFR be at full throttle?
what should my AFR be at full throttle? Have ported heads and cam with full boltons. With the wideband in the car it's about 12.9 to 13.1 at wide open. Is this about right? I hope so because I have no idea how to change it.
main mods are in my sig.....using EFI live as well
Im at 12.7-12.8 at WOT....seemed like it pulled the best there off the spray. Yours sounds about right(I would run a tad richer imho)....but everyone has different opinions.
Im at 12.7-12.8 at WOT....seemed like it pulled the best there off the spray. Yours sounds about right(I would run a tad richer imho)....but everyone has different opinions.
yea i was kinda thinking the same thing. Do you know what I need to change to get the AFR down some just a full throttle? There is alot I don't know about EFI Live yet.
FEEL BETTER NOW, Gh0st?
HP TUNERS RECOMMEND:
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
HP TUNERS RECOMMEND:
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
Banned
Joined: Apr 2003
Posts: 98
Likes: 0
From: CA
FEEL BETTER NOW, Gh0st?
HP TUNERS RECOMMEND:
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
HP TUNERS RECOMMEND:
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
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
If you run that a/f ratio I hope you make it richer when it gets hot. Is a few horse power worth it for a blown engine. how much horse power do u gain going from 12.7 to 13.0? 5? Lean is hotttt
TECH Fanatic
Joined: Feb 2004
Posts: 1,259
Likes: 0
From: Lexington, KY
If your tune is correct and your not running a custom OS, all you need to do to change WOT AFR is modify B3618. If it reads in Lambda, you can change it to AFR under edit, properties, then restart EFI Live. This table will change your commanded AFR for WOT. From there you just need to make sure actual is following commanded. If it doesn't then it is tuned differently then what I understand "correct" to be. Nobody can tell you what your optimal AFR and timing will be for your combo. Dyno or the track and some experimenting are the only way to find out.
Last edited by DaveX; Sep 17, 2008 at 08:18 PM.
I do have a custom tune. My commanded AFR is set at 11.7 but it's leaner than that. I mean it runs perfect just driving but I just thought it may be a little lean for safety.
Are you saying your car is tuned w/EFI Live, owned by someone else or are you saying that you don't know how to log knock w/ your EFI Live software?
If you have the software, we can explain how to log knock. Just let us know.
FEEL BETTER NOW, Gh0st?
HP TUNERS RECOMMEND:
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
HP TUNERS RECOMMEND:
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
Please let the people with experience comment here and keep your uneducated nonsense out of here
Ok, thanks for clearing that up. Unless she's running hot, there doesn't seem to be an issue. The best test may be to log some WOT runs on a 90-100*F day. Mine doesn't knock @ 13.0:1 on hot days running 8.54 DCR, 24.5 degrees of timing from 5200 to 6400 RPM, moving 430+ g/s of air through the combustion chambers (est. 288-291 CFM per intake runner), & having an ambient cold air feed (colder than normal under hood feed temps.). Hope this reference info is helpful. Although, it is just a reference.
Having said all of that; I don't disagree with the comments suggesting that mid to high 12's:1 is a safer A/F ratio.
So then running too lean should cause some spark knock? I have logged it many times and don't have any knock to speak of. One day when it was really hot I managed to get .1 of knock retard but that happened down low in the rpm range. I assumed since I don't have much if any knock then it must be about right. I know too much timing and too lean will both cause it. Since I'm good with knock I should be ok then?
So then running too lean should cause some spark knock? I have logged it many times and don't have any knock to speak of. One day when it was really hot I managed to get .1 of knock retard but that happened down low in the rpm range. I assumed since I don't have much if any knock then it must be about right. I know too much timing and too lean will both cause it. Since I'm good with knock I should be ok then?
Yah, that's what I was trying to convey, but, with supporting info. Just stick w/ high octane fuel for WOT & anytime you're gonna make prolonged, consecutive WOT runs (like for road course driving), make sure you log knock because the elevated oil temps are gonna cause the engine to be hotter than during street driving or even @ the drag strip.
Personally, I recommend 12.7:1 for N.A. AFR. That's where I've made the best power on my setups (I'm less than 1,000ft above sea level). That combined with about 27* of timing. This was on a 241 H/C car with a 23x/23x ~.600 lift cam.