might be the white stripes.

 

No soot here. When I pull up behind the GT, I can see clear into the muffler. Real shiny inside the pipes.

 

The inside of my exhaust tipsare clean and shiny, no soot or other dirt at all. You must be running rich.

 

I've got a white Mustang as well, and I've definintely noticed the soot problem on the entire back surface of the trunk and nearly all of the rear bumper. Exhaust is also covered in it. Service Manager at my dealership said I was running rich, but didn't suggest octane as a probable cause.

Strangely, you mentioned octane rating. When I ordered my tune from Ford Racing, I selected 91 octane, but run 93 octane. I sure hope what you say is true, because if it is, then I found a way to alleviate this problem. Right now I'm not looking to spend any money on a tune (dyno or canned).

 

I have a c@l with a brenspeed 93 octane tune .I cant say if it had soot on rear bumper before this or not because it has had the tune for most of its life.Like I said ,only 800 or so miles on car.I am using the recomended 93 octane gas.

 

I have the same problem on my yellow. All over trunk lid, behind spoiler, on and between taillights and bumper. One of my more "mechanically inclined" friends noticed a smell from my car that I asked him about and he mentioned the car smells like it is running a bit rich. But he also said it is better than running it lean.

 

Just talked to Dave at brenspeed.He said it is completely normal due to there being rich spots at few throttle positions in the tune and the fact that the pypes muffler is not chambered like the stock muffler it may not catch as much soot.I guess thats why a dyno tune would be much better in the fact that all throttle positions would be right on.
Thanks

 

Nothing here. I'm running a 93 octane tune with clean tips.

 

I get a bit I the tips (side exhaust) and all the stangs I have hadget a little bit on the tips of the exhaust. Its not alot but it is dyno tuned and running 93 octane with an SCT tuner. I asked my installer if that was normal and he said it was fine but not the crazy amt that some of you have mentioned. He thinks its the 60# injectors andrecheckedthe tune on the dyno with a wideband A/F. Had that done and sure enough she was a little rich in the 6000 RPM range....I pulled more ponies as well about 465 RWHP but it was 35 degrees cooler and the humidity was about 65%. In my sig it showed 454 RWHP but it was 93 degrees and 90+ humidity. I am happy to say the least.

 

I never said from my original post that it was on my tips,just avery light black dust on my rear valance and bumper that is mostly only noticable when you take a cloth over it and it turns the cloth black.