I recently had an APR exhaust installed and was wondering if any one has experienced a popping noise when getting off the gas at higher speeds? Roughly at 75 - 85mph on the high I experience this. It can get pretty loud, like its right in between the driver and passenger side. Also I notice I am getting some black residue on the tips (see pic). I was wondering if it could be the gas oct. I'm using now 89 oct.with 91 map. Would this cause the popping and black residue? I appreciate any suggestions or ideas.


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Well,I doubt the backfiring has anything to do with the exhaust. Are you getting any codes?

Oh, and make sure you run 91, thats what your programming calls for, so running lower octane can cause pre-detonation and pinging. In fact even with a stock chip, you should be running 91.

I would scan it for codes and go from there. And run it down to 1/2 a tank and fill it back up with 93, make sure you hit a few hard corners to mix that fuel up!

 

Thanks Acetrebo, I'll do that.