[s-cars] Just Finished The OTC 23rd overall

[Trevor Frank]

Chris Leal and I , just finished the www.opentrackchallenge.com
<http://www.opentrackchallenge.com/>   in my S4.  We came in 23rd
overall even though we had a shock that blew up on us and we damaged our
trans, a ham fisted driver bent the shift fork.  The Bennett bro's put
in a new trans for us so that we could finish.  The sad news is that we
lost to a mini, the good new is that it was a gutted mini that was
pretty modified.  We would have beaten it if not for the damaged trans
for sure, and possibly if not for the broken shock.



So thanks to the Bennett's, Koni, Spec, Innovative Turbo, Eurospec,
Spec, MPD/JB, Blau, EuroTech, Cobra,



For there work on the car, Thanks to Chris Leal for co-driving/hot
lapping, keeping the car on the track etc

            Brian Billotti, for getting spares, letting me borrow parts,
having an extra shock and a new shift nob, for the work on the car to
help get it prepped and for the multi orifice inflatable.

            Javad Shadzi for help wrenching on the car and general good
conversation, also buying some of my, "those part's are to extreme for
my car", parts.

            Chris Frank, and my Dad Richard Frank for lending a helping
hand, taking pictures at Thunderhill.  A special thanks to Chris, who is
getting the ham fisted drivers award.



Our car is awesome in the rain, it is softly sprung and has small tires
compared to other "race" cars.  At sears point with a passenger we where
up to 10 seconds faster than any other car in any class, even cars on
rain tires/rain slicks.  The next fastest car was a new S4 dedicated
track car, cage, gutted interior, etc...  They where trying to catch up
to Chris Leal and actually ended up spinning twice the second time they
hit the wall.  This was all for not because soon the sun came out and we
no longer owned the road.



Car set up.



Cars basic set up, ET42 8.5 x 18 rims, 255x35x18 Pilot sport 2's.
Larger avant front bar, larger rear hap bar, koni double adjustables up
front, singles in back 400lb front springs 400lb rear, 13.7" fender well
to center of tire in the front, approx the same in the rear. Corner
weighted car.  Shortened front struts to give more suspention travel.
1.9deg negative in the front 1.6 negative in the rear.  Car weight
without driver 3605.



We also used the Dynostar and have some nice data that includes, intake
temperature, Before turbo and after turbo temps, gps data on the tracks,
speed, time, g's, hp torque and rpm.  Very cool stuff to see who is
making speed and who is losing speed, a highly recommended tool although
this particular one turned out to be less than track worthy, lot's of
duck tape helped keep it working.



What we learned



We have plenty of power, we didn't really have an issue with to little
power it was more an issue with not being able to get the power down,
i.e. to small a tire.  255-35-18's on Pilot sport 2's.  We ended up
running the street chips most of the time, 20psi, we ran the race chips
with more advance and 25psi on occasion and also ran 25psi on the street
gas chip. 



We played with the suspension quite a bit and got a lot more out of the
tires by increasing the rear bar to full hard.  Doing this made the rear
tires start to really work and roll over, we also widened the front
track with spacer.   Narrowed the rear track by taking spacers out.
This I think helped to balance the car and reduce the under steer that
is prevalent when turning into a slow speed turn.  It also didn't seem
to increase the over steer to much and with the fact that the rear tires
started to roll over even though we should have increased the roll
resistance tells me that we did good things.



We kept on having to increase the front tire pressure, like 38 cold and
coming off hot right at 50psi, with the outside of the tire still
rolling over.  So I think with more camber we can run lower tires
pressures and get a bit more tire on the track, still it is obvious that
the amount of tire verses weight is the real issue when we look at the
power to weight that we have.  The evo's with 500lb less weight and
about the same power where running 265's.





What to change



Larger tires, slicks might be fine this small but street tires to get
any power down would have to be at least 275's if not larger, 285 the
bigger the better.



More front camber, I am thinking of trying 2.5 in the front and 1.8 in
the rear, or a lot of front caster if some how possible, like 5-9 deg or
more.  Apperently audi's IMSA cars  ran nearly 12deg of caster. 



Re-valve the rear shocks for more spring, and also I suspect more low
speed rebound, this should help turn in and also should help balance the
car.  It will also allow us to move on the spring rates in the front and
rear to take advantage of larger tires.   I have some nice double
adjustable that I will be getting valved soon, external reservoir fox's.
This might also lead to needing more rear brake, or at least should
start to really work the rear brakes, so I might need to adjust the
proportioning valve.



I also would like to try the rear torsen but think that most of this is
a waste of time until I get larger tires.







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