Normal A/F Mixture Rate

carguy1985 · 09-19-2005

I have a o/r xpipe and i know my cars most likely running rich, whats the normal air fuel ratio for a car with my mods (mods in sig) so i can adjust it using my lap top and predator.
let me know thanks

88_stanga · 09-19-2005

for best mpg and complete combustion and what not. 14.7 is perfect. if u want a lil bit of performance 13.5 is around where u wanna be.

carguy1985 · 09-19-2005

Ok going to use my friends lap top to determine my a/f mixture. I can adjust it from 204K and 4-7K with my predator how should i set it to to have best performance with my mods...... what numbers should i read?

BlueStreak03 · 09-20-2005

WOAH!!!!!!!!!!!!!! 14.7 will grenade your motor. You want it in the high 12's 12.7-12.9 is ideal the last time i talked to my dyno guy.

GTRaptor · 09-20-2005

BlueStreak is right, 12.7 to 12.9...13.2 max

The 14:1 ratio is the IDEAL air fuel ratio at which fuel will burn its best, but in real life you are at the BORDER of detonation.

carguy1985 · 09-20-2005

is there anyway to read it with my diablo predator and see what it is at? i know i can change it but i dont know how to see what the A/F ratio is at, i wanna use my friends laptop he has a program that can do dyno runs with laptop and he can see codes and airfuel mix but cant change it, how ever i can change it with my predator to lean it or rich it.
Let me knw

Ill be on look out for my a/f mixture i expect its in 11-lower 12s right now.

carguy1985 · 09-20-2005

is there anyway to read it with my diablo predator and see what it is at? i know i can change it but i dont know how to see what the A/F ratio is at, i wanna use my friends laptop he has a program that can do dyno runs with laptop and he can see codes and airfuel mix but cant change it, how ever i can change it with my predator to lean it or rich it.
Let me knw

Ill be on look out for my a/f mixture i expect its in 11-lower 12s right now.

Twitch · 09-20-2005

Quote:

Originally Posted by carguy1985

is there anyway to read it with my diablo predator and see what it is at? i know i can change it but i dont know how to see what the A/F ratio is at, i wanna use my friends laptop he has a program that can do dyno runs with laptop and he can see codes and airfuel mix but cant change it, how ever i can change it with my predator to lean it or rich it.
Let me knw

Ill be on look out for my a/f mixture i expect its in 11-lower 12s right now.

There is no way to know A/F ratio with Predator. You need a Wideband A/F Ratio sensor, either you buy one or get you car dyno tuned with it.

BlueStreak03 · 09-20-2005

If you don't have the cash to drop on a dyno tune at the moment, the best thing to do is to VERY gradually cut back on the fuel mixture. I can't tell you right off the bat how to tell when it's perfect but I'm sure someone here has an idea. I also can't stress to you how important it is to not cut back on it too much. You absolute best bet is to tuck away a few bucks each week for that dyno tune.

carguy1985 · 09-20-2005

My friends laptop has a prog to check all cars parameters it can check pretty much everything for you but you cant modify it. Now.. i can with my predator so i think me and him are going for a drive around back roads to see where i am at.....

were can i get a Wideband A/F Ratio sensor?

BlueStreak03 · 09-20-2005

kickass, sounds like you got whatcha need to get this taken care of. Can you monitor A/F ratio with what you have now?? If you can I wouldn't even worry about a wideband, the last time I saw one for sale it was like $200.

Twitch · 09-20-2005

Just came back from the track tonight. Since I did my dyno run, I saw taht my A/F ratio is around 12:1 - 11:1 which is rich. The mechanic suggested me to lean out about 5%, but too be safe since I have no A/F ratio sensor, I leaned out 2k-4k by 1.5% and 4k-6K by 3%.

After 10 runs, I couldn't do ANYTHING under 14.0xx, my best trap time was 102.8mph.

After I reseted to original Predator settings and ran again. First run, 13.984, second run, 13.875, then third run 13.873 and my trap speed improved too. My best of the night was 103.273

So I dunno what's happening, maybe my A/F ratio at the dyno was off.

My mods are:
- Mac ProChamber O/R
- Diablosport Predator
- Granatelli Intake Plenum
- Ghetto CAI

carguy1985 · 09-21-2005

You leaned it out without actual guages and monitoring... thats kinda like guessing in a way. I am going to use my buddies lap top and tune iwth my predator... i think its the best way to go and then next track meet ill see whathappens..... of course ill be running gears then =)

Quote:

Originally Posted by Twitch

Just came back from the track tonight. Since I did my dyno run, I saw taht my A/F ratio is around 12:1 - 11:1 which is rich. The mechanic suggested me to lean out about 5%, but too be safe since I have no A/F ratio sensor, I leaned out 2k-4k by 1.5% and 4k-6K by 3%.

After 10 runs, I couldn't do ANYTHING under 14.0xx, my best trap time was 102.8mph.

After I reseted to original Predator settings and ran again. First run, 13.984, second run, 13.875, then third run 13.873 and my trap speed improved too. My best of the night was 103.273

So I dunno what's happening, maybe my A/F ratio at the dyno was off.

My mods are:
- Mac ProChamber O/R
- Diablosport Predator
- Granatelli Intake Plenum
- Ghetto CAI

Monkey Boy · 09-21-2005

Quote:

Originally Posted by Twitch

Just came back from the track tonight. Since I did my dyno run, I saw taht my A/F ratio is around 12:1 - 11:1 which is rich. The mechanic suggested me to lean out about 5%, but too be safe since I have no A/F ratio sensor, I leaned out 2k-4k by 1.5% and 4k-6K by 3%.

After 10 runs, I couldn't do ANYTHING under 14.0xx, my best trap time was 102.8mph.

After I reseted to original Predator settings and ran again. First run, 13.984, second run, 13.875, then third run 13.873 and my trap speed improved too. My best of the night was 103.273

So I dunno what's happening, maybe my A/F ratio at the dyno was off.

My mods are:
- Mac ProChamber O/R
- Diablosport Predator
- Granatelli Intake Plenum
- Ghetto CAI

You've got to remember that when the engine is under a heavy load it likes a richer A/F ratio. At the track and at the dyno you are running at full throttle and the engine wants more fuel. During normal driving conditions, the engine prefers a higher A/F and the computer will lean the mixture out.

carguy1985 · 09-22-2005

Yea i know we are going to go through some gears =) on the back roads. 1,2,3 through WOT. because i can adjust 2-4K and 4-7K

So thats cool.

Quote:

Originally Posted by Monkey Boy

You've got to remember that when the engine is under a heavy load it likes a richer A/F ratio. At the track and at the dyno you are running at full throttle and the engine wants more fuel. During normal driving conditions, the engine prefers a higher A/F and the computer will lean the mixture out.