I have noticed that my exhaust tips have a cream / beige / tan residue after hard driving with Race Gas and ECU in "Race" mode. Normally residue is black.

Coincidentally, I just read an article in a tuner magazine where the writer comments on the "tell tale tan exhaust residue from a lean/aggressive" tune.

In my paranoid mind, the tan residue is from important metal bits inside the engine getting vaporized.

Does anyone know the technical reason for the change in residue color and if it is something I should worry about?

 

Only guessing here but I bet its the difference in the gasoline. Might ease your mind if you get it dyno'd and measure air fuel ratio?

 

chris, this is normal. Specific fuels like Sunoco tend to leave a residue. I have been told it is due to anything from the additives in the fuel to the dye used to distinguish the fuel. I have never heard of any problems from it.

 

hey chris... you and me must be going to the same gas stations Same stuff here coats my RS, TT and Cayman Tips all the time I'm guessing it's either VP or Sunoco? You can put that same gas in a stock car and get the same result thanks to the additives....

 

Thanks guys-- I was feeling guilty burning the "good stuff" in there more and more. Oddly, the price of 100 have not gone up, so $5.79 is seeming not too bad next to $4.10 for 91 octane.

I'll try a tank in my Civic Hybrid and check the residue color (I wonder if GIAC makes an ECU for that thing).

Sharky: I usually grab a tank from the place on Andrade & 680 after visiting your shop-- helps with the testing.

-Chris

 

Sssh.. don't give away all the good spots Aye that's where I get mine. Interestingly enough they have 110 leaded too!