untuned i am currently running 12 in low rpm and 11.5 in high rpm

wow thats really lean for untuned....not a bad thing necessarily but not common at all! Reldas, you're right where the factory ecu should be. Its set to run richer in the top end to prevent detonation. The reason we run so rich is because they made the car to be able to run without premium.....even though it says it requires it, the tune doesnt. Firehawk MUST run premium or he will get detonation guaranteed.

I'm getting UpRev tuned at RT Tuning on Tuesday. Can't wait!

thing is i have stillen g3's, f.i CBE and stillen HFC's. stock my a/f was 10

Thats where I got my car done. Cool guys over there.

Highly recommend R/T. Vince is an expert tuner and very pleased with the tune he did on my Nismo.

So should I be alright with my AFRs? Or should I be worried?

After a little more reading up, with mid 13s you should be fine as long as you run premium. To be safe you could invest in an afr gauge to monitor it. If you get up to 14 then you should be worried.

Also, one more question... When we run lean like that, does that technically improve gas mileage? I'm just curious, I know with uprev we can get a economy map, but I'm just wondering for information sake if running lean gives any improvement over stock?


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Premium here in AZ is 91. So im hoping that's enough :ugh2:

uprev tuned, he should not have an issue with AFRs at that point. Where they are is where they stay as long as some freak burst of air floods his motor. NA VS FI is much more predictable which is why they run FI around 12:1 AFR's or lower cause there CAN be large variations in air. If 91 octane is what you had in the car when your guy tuned it you should be fine. He SHOUDLVE been able to tell if there was detonation or not when tuning it on the 91. If not, thats scary........

Switching between map 1 and map 2 on my tune switches between AFR targets of mid-12s and high 12s. The leaner the mixture, the slower my car feels. Going to stock map, which leans out to 13s and 14s and the car feels notably worse. All on 93 octane in NYC.

I'm a little confused why you'd call a lean mixture as more aggressive when it feels worse driving.

There has to be some misinformation going on SOMEWHERE because Z's come from the factory at low 12's, high 11's.

The amount of fuel being shot into the pistons remains the same, it's the amount of air being taken in that increases. They higher the AFR, the leaner the fuel amount is, and therefore more aggressive.


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X2..........plus :icon18: at your phone message :roflpuke2:

I was under the impression VQs are better off running ~12.5:1 mixture, as opposed to anything leaner. And that factory is a bit lean with 14s in the low-end and mid to make the car more fuel efficient...but tuning it to a mixture around 12s adds considerably more power down low, thus making the car more aggressive in every day driving. It only hits 11s and 12s under WOT when you're approaching redline. Anything below the 5500RPM mark, and you're around 15s 2-3K RPM, 14s 3-4K RPM, and 13s 4-5K RPM.

If that is not the case, then why does nearly every dyno chart and tuner strive to hit an AFR in the 12s for VQs? I'm not trying to be an ***, btw...I'm legitimately curious.

when you dyno it is under full throttle......when you tune it is under full throttle....Reason being they LEAN it out cause as yous stated yourself, it is rich down in the 11's. They lean it out to create power. MY personal AFR at full throttle am at 11.5 all the way through from 2k all the way up to 7800. I am rich through my entire powerband at full throttle which is what we are talkin about. FULL THROTTLE RUNS! Dunno if his tuner actually messed with normal driving tune. My tuner will be tuning for full throttle and daily driving which is what all tuners should be.

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