Fatman0203

I want to dyno my car, and I hear that dyno puts a bit extra strain on everything, also your intake temps get hotter and hotter after every run. Will adding a bit of 100 octane, to maybe put it at 96 or 98 affect the AFRs if I left it as 93? From my understanding octane is mainly for detonation right?

Fatman0203

^

books

iTrader: (8)

maybe this will help https://www.rx7club.com/showthread.p...88#post3703488

scroll for Pluto's threads

rynberg

Changing the octane has very little effect on AFRs. I run 100 octane at the track due to the continuous high boost levels with corresponding high intake temps/water temps. If you are still on the stock ecu, there is really no point in running higher octane gas, as you shouldn't be modded enough to require it with the stock ecu anyway!

Fatman0203

Exactly, thats what I wanted to hear. Its not if Im modded enough its just another safety layer because of the heat + stress of the dyno just incase. HEard many stories of cars going on the dyno so I thought it would just be a little safer.

Kevin T. Wyum

Stock ECU doesn't care about AFR outside of closed loop which only happens at idle and constant speed cruise for the most part where it reads the narrow band O2 sensor in an attempt to reach near stoich. AFR's will be completely ignored by the ECU at heavy throttle.

Fatman0203

I understand that, I know it has pre-based maps regardless of AFRs, but I will be measuring the AFRs with a wideband so I know exactly where there at, and just incase they get to high I can rely on the octane to make sure of little to no knock. Thanks! Even though it shouldnt detonate just a safety pre-caution.