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Discussion Starter · #1 ·
Just wondering guys, what is the "ideal" air/fuel ratio for a nice street/strip tune? I have read 11.4-11.7 is optimum, but I am by no means a tuner and it's all greek to me. I am just wondering guys with the cars that know their stuff, and tuners in general.....what would it be? I also acknowledge that not all cars are the same, but for arguments sake, what would it be?
 

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Our cars are safe at 11.5.
 

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Discussion Starter · #3 ·
Well, what A/F ratio would be good for a steet/strip tune? I know 11.5 is real safe, but would that ratio make the most power? Like I said, I know absolutely nothing on this, so I went to you guys for help. Thanks toofast4u for the reply.
 

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I think 11.5 is the best street/strip tune especially in summer as when winter comes around the air will be denser and colder and if you are running on the edge now you will pass it then. If you are going to do multiple tunes or want to run on the edge you can go up to 12.0. There are some here that might feel more comfortable going leaner, but I just don’t feel it is worth the risk.
 

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From what I've learned from some talented and experienced tuners: 12.2 to 12.3 is optimal; although leaner makes more power.

12.0 is safe. Keep in mind that 12.0 in the summer is not 12.0 in the fall or winter.

Also, there's a BIG difference between safe and conservative. Conservative is for 4-banger owners who want to save money for fuel economy. We don't buy Terminators to be conservative.

Safe? Yes. Conservative? Uuuuh...no.
 

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Discussion Starter · #7 ·
Awesome replies guys....I appreciate it...keep 'em coming!!!!
 

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How much could temp change the A/F? If someone is at 12.0 in the summer, than could the winter change it as much as 13.0?
 

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KevinJKD said:
How much could temp change the A/F? If someone is at 12.0 in the summer, than could the winter change it as much as 13.0?
That, is the 64,000 question!

From my understanding of MAF's and barometric pressure sensors, It shouldn't matter. But with my car, the A/F changed, don't know if it was due to mileage and the computer adapting, or to different weather conditions.

Jim from JDM says that the superchip he installed will keep it very consistant, I'm sure it will vary a little , but not more than .1 or .2 We will see.

FWIW, depending on you boost level, these cars can run a lot leaner than 12:1. Check my curve in the Tunes and times thread, it was close to 14:1 and other than when my IAT went bad, it did not ping on a splash of race fuel, and generally, wouldn't ping on 93. It did once, when I got no name 93, but not on name brand 93. that was 13+ to 1 with lots of timing. When we pulled the plugs, they looked fine, no sign of detonation.

I was afraid to see what would happen with that tune in the colder air. Maybe it would stay the same, but if it didn't, I'm sure 15:1 would not be good.

JT
 

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I can't beleive no one has mentioned timing. A safe a/f is more dependant on timing than anything.

You can have a 11.0 a/f and with too much timing your motor will be pinging like crazy.

--Joe
 

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thanks for the response JT. Let me squeze in one more quick question. If someone's A/F is 12.0 -12.1 with a pulley/chip, and then added an accufab or BF TB, how much leaner would it make the a/f? Sorry, its alittle off-topic but I didn't want to waste your guys time with a new thread about that.
 

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Discussion Starter · #12 ·
I am wondering about a catted x-pipe also, which is part of the reason I made this thread. I think I may have to get a bit more fine tuned with this latest mod, the car has to be more lean with the less restriction there. So, just wondering what number I should shoot for when dyno tuning....
 

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Discussion Starter · #13 ·
JT, I have tried to PM you for a week.....clean out the mailbox dude!!!!
 

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I like my air-fuel between 12.0-12.4 that is where my car runs best and the plugs look alot better in that range anything richer the plugs are to black with lots of composite build up on them.From going to summer to winter as far as air-fuels are concerned the most you will ever see is .5 point change but more likely .2-.3 is the usual.I have over 200 dyno passes between both my Lightnings and now my Cobra and that is what i found it to be. Kevin,I have installed both the Billetflow and Accufab throttle body and no need for a reburn it does not change your air-fuel hardly at all.Headers and different size Pulleys is mainly the mods that will require a reburn for your chip.
 

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Discussion Starter · #15 ·
HIGH ROLLER, what chip do you use, and who burns them?
 

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I am currently using a Superchip from JDM and i have a Autologic from UPR that i am very pleased with both programs.
 

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Discussion Starter · #17 ·
Thanks HIGH ROLLER. I appreciate it. I currently have an average A/F ratio of 12.4 from JD's that I am happy with. Autologic custom tuned on the dyno.
 

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soap said:
I can't beleive no one has mentioned timing. A safe a/f is more dependant on timing than anything.

You can have a 11.0 a/f and with too much timing your motor will be pinging like crazy.

--Joe
That is absolutely true. I have no idea what my timing is, but when the Predator finally comes out I will have an OBD II scanner that will hopefully be able to provide more information. Timing and A/F work hand in hand. What timing is everybody running as there daily driver tune.
 

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Every chip i have had checked was around 22-23 degrees timing at WOT,I have seen 25-26 degrees on some race programs.If your running nitrous or a K.B most of the tuners will back out at least 2 degrees of timing usually around 19-21 degrees is what i have been told for added safety.Hope that helps!
 

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Discussion Starter · #20 ·
From what I have been told, my timing is stock on my Autologic from JD's.
 
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