Lean or Not ?
 

Hey guys I drove down to so cal and got a tune on a 91/C16 mix. I drove back to Vegas and noticed a light gray soot on my exhaust tip and was wondering if this is normal from running C16? or do you think its running lean? Im going to pull the plugs and look at them tomorrow, but I read in this thread:

https://www.evolutionm.net/forums/sh...t=running+lean

and noticed someone said that race gas will leave a white/gray deposit on the plugs.

Any ideas of things to look for ? I dont hear the car pinging or anything like that and if feels really strong and smooth with the new tune.

that is correct about the color. Def check the plugs cuz they probably are the same color too.

So yes its due to the race gas ? or its lean ?

I know Leaded gas likes it leaner like 12 to 12.5

It's the gas.

yeah its the gas. Race gas will make you run more rich but tuned it's gonna get leaned out to near mid 12's. white is lean black is rich

So if I throw good old 91 back in it will get black on me again? Or do I need to worry about the tune?

It's not the tune. Leaded gas causes the exhaust to turn white. It's of 0 concern.

who did u get tuned by?

def the race gas, the whole inside of my muffler used to be white, the spark plugs will also reflect the use of a leaded fuel.

The only way to know if you run lean is with a wideband, there are about 100different things that change exhaust content by effecting the burn.

Why not try 100% C16, mixing it with the enviro 91 garbage would be like pissing in a glass of Taittenger

Leaded fuels leave a light colored ash on the ehxaust tip, and everything else it passes through. I remember having to explain it to a curious emissions inspection station tech right after he passed my car. A little lead never hurt anyone... :D

Yea its the C16 .. on a new tank and the exhaust is getting dark again. Pulled the plugs and they look all good.