Re: Boxster brakes on a V8 - I reformatted it :-)

["Mike.LaRosa" <Michael.Larosa@East.Sun.COM>]

The testing of the Boxster calipers/A8 rotors went great.  Here are my
findings:

Test conditions:

The track conditions were ideal -- ~ 70 deg. F, sunny, and perfectly dry
 asphalt.  To keep this a real world test, I kept the V8 in street form:
spare,  jack and tools left in trunk, new DOT 3 brake fluid, Porterfield R4S
(street)  pads.  The car weight was exactly 4005 lbs. without passengers.  The
total on  track weight was about 4400 lbs. with me and either one of the two
of my Audi  fanatic friends riding along.  This represents the worst case
scenario for an  Audi: the heaviest Audi with an automatic transmission that
doesnt provide much  if any compression braking.

Portland International Raceway is an approximately 2 mile long road course 
consisting of a long front straight and a long back straight sections of track 
connected by mostly right hand turns.  The course is run in the clockwise 
direction.  See http://www.teleport.com/~autorace/pir/ for details.

On track sesssions:

The event was put on by the local chapter of Porsche Club of America.  There 
were approximately 85 cars there.  I ran with the touring group as I expected 
to only get up to 120 mph at the end of the front straight.  This proved to be 
OK, but I had to pass a few cars each session or pull off and let the traffic 
in front of me pass so the V8 had room to run.

The first three 20 minute sessions went very well.  The brake setup brought
the  car down from 115-120 mph at the end of the front straight and from about 
90-100 on the back straight rapidly, repeatedly, and consistently.  It 
surprised one of my friends as I didnt have to brake until about the same
point  he has to in his turbo coupe GT with Wilwood brake kit!  I can go
deeper into  the pocket in my urq, but that car weighs 1000+ lbs. less and I
can dial in the  front to rear brake bias as well.

After each session, we drove the car into the staging area and checked the 
brake pads.  They were holding up great with very little wear.  I wasnt so 
lucky in the last 20 minute session.  I decided to push the car harder, going 
further down the front straight before braking and doing a bit of trail
braking  (my end of straight speeds were faster as well).  After a couple of
laps, I  could feel the brake force reduce as the fluid boiled and the pads
started to  leave slag on the rotors!  In that one 20 minute session, I lost =
the  thickness of the brake pads!

I havent had a chance to take the caliper brackets off and examine them 
closely, but should be able to tonight.  From my under car inspections, they 
appear to be fine.  All indications are that Greg Amy did a superb job 
designing those brackets!

Conclusion:

The Boxster calipers/A8 rotors brake system worked great.  In my opinion, it
is  an excellent street braking system.  I pushed the braking system harder
most  anyone ever would (or a sane person would anyway) on the street, and the
system  did great.  I am very satisfied with what we have done and am glad we
did it!

The system could be an acceptable occasional Drivers Education (DE) track 
braking system if the brakes are prepared for track use (ATE superblue and
some  Porterfield R4 or R4E brake pads).  Heck, if I hadnt INTENTIONALLY
pushed the  brake pads past their limit, I would not have worn them down so
much.

I know that I was using the wrong brake pads for as hard as I pushed the car 
during the 4th session.  Previous experiences with the urq using street brake 
pads on the race track have had much worse results (the urq could go though a 
set of metal master, jurid, or any OE metallic pads in ONE track day).

If I were going to consistently track the V8, Id have to agree with what Scott 
Justinson told me last year at Colorado Motorsports Speedway: You cant get
good  (track) brakes on the V8 without going to at least a 17 wheel and using
a rotor  the barely fits under that.

Once good 4 piston calipers are installed, the only problem that remains is 
heat dissipation.  Thus, if you want to track a two ton plus car and be able
to  left foot brake, trail brake, and do it consistently all day long, you
need to  use a huge diameter rotor.  A rotor that is twice as thick wouldnt
hurt either!

Other comments:

The Dunlop D40 M2 tires (225/50/16) were near the wear bars so were the
perfect  cheap racing tire.  I was very surprised at how well the 2 ton boat
handled.   The car was very easy to drive fast.  There was almost no tire
squeal and no  surprises.  The car is very balanced.  Audi did an excellent
job with the V8.   I have done NOTHING with the suspension except replace the
dead shocks with  Boge Turbo Gas units (the OE shock replacement for the V8).

Let me say, however, that our urq is a much better track car than the V8.  If
I  had been driving that, I could have run with the prepared cars and harassed 
some P-cars!  The V8 may see track duty again on a quattro club day, but 
probably wont be run with the other German marques again.  Those Porsches are 
just too light and fast!

P.S.  I cant access my home e-mail address: johkar@teleport.com easily as our 
modem is dead.  Please direct questions/comments to our business e-mail 
ksquaredmotorsports@eudoramail.com.  It is checked at the end of the work day.

Happy Motoring!

John Karasaki
Ksquared Motorsports