A/F ratio to lean to race?
03-09-2007, 02:09 AM
#1
A/F ratio to lean to race? I hooked up the inovate wide band the other day and had my wife watch the guage for me while I went through the gears. turns out that the a/f ratio at the top of every gear goes to about 12.8 (91 octane), which I know is way to lean for forced induction. I turned up the bap all the way (it was at about 1/2 to 3/4 b4) and mixed 6 gallons of 91 to 2 gallons of 110 leaded which I think gets me 93. anyway went back out and the a/f never went into the 12.0 range it hung around 11.8. any way I just wanted to get some suggestions, would you guys take it to the track or would you get it retuned first?
I did lift a head prior to this. Now I have installed studs and MLS cometics. What do you guys think?
I did lift a head prior to this. Now I have installed studs and MLS cometics. What do you guys think?
03-10-2007, 02:10 PM
#4
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yea depending on how safe you want it, you have forged bottom end, so that's good, but run it around 11.8:1 to be safe with timing at 16-19.
the best way to see what is going on is datalog with the wideband n the car.
we found that is what works best but real street/track conditions are a lot different that then dyno.
the best way to see what is going on is datalog with the wideband n the car.
we found that is what works best but real street/track conditions are a lot different that then dyno.
03-10-2007, 08:29 PM
#6
Originally Posted by otherwhitemeat
**** with race gas, 25's deg. timing, and 25psi boost, i'll let the air fuel run in the very low 12's.....no problem
Hes running 91. who knows after the mix, but lets just assume its straight 91
03-11-2007, 12:30 AM
#7
i don't think you need to run richer for pump gas,.....its the octane.....so you don't predetonate..... thats why you run race gas. i don't think anyone runs it much leaner while on race gas....just more timing and boost..........correct me if i'm wrong.
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03-11-2007, 12:36 AM
#8
the richer the condition also leads to less heat, and heat is what causes detonation. Sure if he tossed something in with a higher octane, he would run less of a chance of lighting the fuel mixture off prematurely.
he can do 4 things:
run less compression
run less boost
run less timing
run more fuel.
the adding more fuel trick only works for so long. He very well may not be detonating now, but when the time comes and its hot, or the cars running a little warm...he will.
he can do 4 things:
run less compression
run less boost
run less timing
run more fuel.
the adding more fuel trick only works for so long. He very well may not be detonating now, but when the time comes and its hot, or the cars running a little warm...he will.
03-12-2007, 10:32 AM
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Originally Posted by nvmy2000ss
dont run any o2's. speed density tune. do you think the race gas will lower the a/f.
if its a street driven car your not gonna wanna run race gas all the time!!