View Full Version : just wanted to double check, AFR for 91 octane

steve shadows
03-02-2005, 01:20 AM
alright ive always belived in runing about a 11.5:1 -11.2:1 ration on 91 ocatne (since thats the best piss we have in CA). Anyways anyone have any other experience with 91 octane. I usually tune with 100 octane or higher but im setting the car up for the street right now. On my old setup i ran 11.0:1 with about 14-16 psi.

Anyways i have a 50trim to4e /t3 with .63 are turbine and stage 5 turbine wheel. the sr20det is basically stock in terms of the long block just rocker arms stoppers. fmic, with 555cc injectors, base fuel pressure is 40psi. Tomei fuel pump.

so anyways, ive always been doing 11.0-11.5:1 and i keep having rereads telling me to run 12.0:1 -12.5:1. so just to clarify, ethalpy, ken , i know you guys have 93 out there anyone with 91 experience.

03-02-2005, 02:59 AM
im tuned for 91 octane. my dyno in my sig was 91 octane, 11:1 AFR

steve shadows
03-02-2005, 02:03 PM
ok, 11:1 sounds about right still kind of low? no? just curious. Im thinking it should be safe to run 11.5:1.


03-02-2005, 09:24 PM
Yeah, I'd imagine 11.5:1 or even 12:1 is safe.. just depends on your setup. I was running 370's

steve shadows
03-03-2005, 05:12 PM
well my fuel system is nismo adj fpr at 45psi base (no vacum) 555cc injectors, tomei fuel pump. stock intake manifold, stock long block, trust fmic, to4e/t3 50trim, top mount, 38mm tial, 3 inch exaust, set at stock timing 15btc,
tuned ecu. Ecu promotes rich from 3k-6k mostly.

03-03-2005, 05:58 PM
your fine.. stick it on the dyno, see how it does