Quote:
Originally Posted by Seb@SZ
Jumping in to clear the "air". When Mike's Z left California it was tuned for high 10s and low 11s. His environment (altitude, pressure, humidity) will attribute to changes in the tune. With that being said 10.5 under WOT on a high compression engine not intended for boost is perfectly safe. On the other hand if your idling and cruising at 10.5:1 AFRs then there is cause for concern!
Another thing to remember is air is 500x times lighter than fuel so when you first hit the throttle you'll see transient fueling enriching quite a bit to account for the huge rush of air entering the cylinders. You may see it dip down but otherwise it will stabilize.
Brand new forced inducted vehicles, for example GTRs, EVO Xs, etc., have a nice soot build up on their tips and the bumpers get "coated" black even after a minor amount of miles. This is with them having two sets of cats on them still. I think Mike's post was taking way out of context and the way it was written makes it sound like something is wrong.
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Correct -- thanks for clearing this up, Seb, and I apologize for any confusion caused. The black coating is nothing new. My Dad's GTR has a similar buildup but not quite as dark, but that is to be expected. Also, the exhaust tips with the Nismo are recessed due to the bumper design, so it's gonna get black faster than a standard Z rear bumper would.
Anyway, the 10.5:1 AFR is a stable reading while under WOT and full boost. Idle is right where it should be: 14's. I'm not concerned in the slightest -- you and the F.I. crew know what you're doing, and I would hardly peg 10.5:1 as off the deep end! That being said, I think 10.7-10.8 would help mileage, but I'm not sure if that's pushing the envelope too much. The tune is definitely rock solid. Another note with mileage, I had my turbo Mazda3 tuned to run mid 15:1s when cruising at highway speeds, which really helped mileage and didn't pose any issues on that particular car, but I don't know the ins and outs of how the Z would handle that.
Any other questions, post up and I'll try to answer them.
P.S. Yeah I took the Z34 PA plate
P.P.S. The F.I. oil cooler setup is incredible! I never top 180, even on 95 degree days. Granted, that isn't track driving, but I was hitting 220 before I made the switch, and that was N/A!