Re: Kamm and exhaust smells

["Dean W. Cains" <dwc@xxxxxx>]

Hi Group:

This has been addressed on the Digest several times in the last few 
years.  On the Kamm tail Spiders, using the proper turned-down original 
tail pipe, immediately eliminates exhaust gases in the cockpit, and keeps 
the rear of the car unstained from exhaust gases, too.  There was even a 
factory service bulletin discussing this issue, which has also been posted 
to the Digest a few times.  If one must use a non-original rear muffler, 
Borla makes a very nice stainless steel tip that can be welded onto an 
aftermarket muffler to approximate the shape of the original.

Regards,

Dean W. Cains
Lutz, FL
'74 & '87 Spider Veloce's


At 09:17 PM 4/15/2003, you wrote:

> Date: Tue, 15 Apr 2003 18:50:39 -0600
> From: C M Smith <cmsmith@domain.elided>
> Subject: Re: Kamm and exhaust smells
>
> As anyone who has a station wagon (sort of the ultimate expression of the
> Kamm tail) knows, the shape drags a blob of turbulent air behind it. That
> is why the back window gets so dirty so quickly, unless a suitable spoiler
> is mounted to the end of the roof to deflect airflow over the back window
> (not recommended as this increases drag a lot) or one does as SAAB has done
> for many years and design hatchbacks or sedans with proper rear
> aerodynamics to keep a decent boundary layer on the rear surfaces to allow
> good airflow over the rear of the car.
>
> The effect of the chopped tail is felt if the exhaust happens to exit into
> this area of turbulence the exhaust will be drawn into the blob and,
> because the effectively stationary blob of turbulent air is at higher
> pressure than the flowing air, and often the air inside the cabin, exhaust
> can be pushed into (or drawn in if you prefer)  the cabin area, or over the
> cockpit of an open car.
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