re: problems still persist with soot

["Ken Keith" <ken.keith@specialdevices.com>]

"Buchholz, Steven" <Steven.Buchholz@kla-tencor.com> wrote:
> 
> > Regarding the repairs on my '90 Audi Coupe (VIN WAUGD08BXLA000639), I am
> > still amazed that your shop can't solve the soot issue on the rear
> > bumper. Bob, I don't believe for one second that the amount of
> > accumulated burnoff can be attributed solely to the exhaust tips
> > pointing up. That is to me just a crock of ---- and is a cop out on your
> > part.
> > 
> ... I don't know where this post came from, but if you're saying that you've
> got an aftermarket exhaust with the tips pointing up I wouldn't be surprised
> if you had more of a problem with soot on the back of the car.  The stock
> exhaust is usually set up to try to put the exhaust into the slipstream around
> the car ... there is a low pressure area behind the car and if you put exhaust
> gasses back there they are going to tend to pile up on the back of the car
> more so than they would on the stock system ...  

I had a Toyota pickup with a shell, and when I changed the exhaust to point 
straight out (not up, btw) the back, it resulted in an increased amount of soot 
and the like on the rear of the truck.  This was partially alleviated later by 
the addition of an "air foil" ("Blazer wing") on the top of the shell at the 
rear.

So, I concur with Steve.

Ken