Help! What Kind Of Fuel?

[arceec014]

Is best for n54? 89 or 91?

[Stohlen]

Is it running lean or retarding timing?

[Stohlen]

Originally Posted by arceecola

it's running lean but just a little.

Then octane isn't your issue. Octane ratings are gasoline's resistance to detonating. A higher octane allows you to advance ignition timing for more power, but if the car isn't pulling timing with the tune you have now you're okay with what octane you're using.

Upping the octane of your fuel isn't going to richen the air/fuel mixture. Whats probably the reason for your lean issue is the E85 you're throwing into the tank. The car doesn't know you're running E85 which requires a different mixture and cannot adapt as easily as a result.

The JB4 doesn't do a great job in some areas of the tune because its trying to cover too many possible conditions at once (such as the self tuning map, which is a bunch of crap imo, it will never be as good as a pro tune.) which is why most people use a flash on-top of the JB4 to make bigger power. Course then why wouldn't you just get a pro flash tune and ignore the JB4, but that's a different rant of mine.

[GMD]

What are your AFR's? 15:1 is normal for idle, and 12's is normal under high load.

[moveswiftly]

Perhaps running a mixture of 100 / 91

[Stohlen]

Originally Posted by arceecola

about 13:1 during WOT.

Extra octane isn't gonna do anything for that. Thats the tune.