Pierburg Pump, Brakes, etc., etc.

[Brett Dikeman]

On May 10, 2006, at 3:58 PM, Steve Sears wrote:

> I cut horizontal slots about 3" long and about 1/2" apart in
> a strip in the wheel well liner, then used a heat gun to bend the  
> plastic
> into louvers.  It's set inside the wheel travel, and haven't  
> noticed any
> dirt in the vicinity of the louvers since then.  When the fan comes  
> on, the
> heat blasting out of the wheel well is amazing.  I have also  
> removed the
> foam rubber piece from on top of the fender liner and now there's  
> some heat
> escaping through the driver's door jamb.  I may do the heat shield  
> over the
> master cylinder as well - it's on my 'round tuit' list with  
> replacing the
> heat shield on the injector lines.

I know the temptation to armchair engineer is strong with many of  
you ;-) but give thought to the fact that Audi didn't see fit to  
install a vented wheel liner in any type 44 that I know of (I believe  
they did in the S-cars but only because of the ducted intercooler)  
and I have NEVER seen a vehicle with a heat shield around the master  
cylinder, even in an insanely packed engine compartment like the TT.   
Maybe it'll work and there will not be any downsides, but I would be  
concerned that there is -some- reason Audi didn't do it, other than  
"hee hee, let's make them buy new master cylinders every few  
years" :-)  I would also say that if you are going through MCs every  
few years- something's wrong.

Temperature of air coming out the radiator are pretty toasty, but I'd  
be astounded if they surpassed 200 degrees.  If your master cylinder  
is sticking, you need a new master cylinder, because it's failing.   
The one in my 200q20v started doing this, and I replaced it with a  
shiny new one- zero problems since.  Given the old MC lasted well  
over 160,000 miles and 15 years, I felt it wasn't a big deal.  It  
failed shortly after the car had been parked for a couple months, so  
I think the too-old brake fluid and storage are probably what killed  
it- not necessarily age.

If you want to lower underhood temperatures, the safest and most  
effective way bar none is to coat the exhaust and downpipe.  You can  
wrap it, but that won't be as effective and will reduce manifold  
life.  You'll get better emissions (EGTs at the cats will be higher  
quicker), and higher EGTs will offset the smaller interior diameter  
(unless you extrude-hone the manifold+downpipe, in which case you'll  
get the best of all worlds!)  You'll probably see less heat soak of  
the intake manifold on the 10v's, less heat buildup by the airbox  
intake, and the lower underhood temps will make for longer component  
life.  All sorts of nice side effects!

Brett