Automotive Forum for Supercars Lamborghini Ferrari Porsche

I ran my 928 at last weekends Pony Express 130 Open Road Race.
I had entered the SuperSport Division 160 mph class with a 200 mph
tech. I've been tuning the car for the last 4 months, trying to get the
AFR "right" (i.e. http://www.pcars.us/viewtopic.php?t=4115 ). New
Adjustable Fuel Pressure Regulator and new LH and EZ chips, and
still not where I wanted it. On Tuesday (8/19) I got the latest chips,
installed them on Wednesday and drove to Battle Mt on Thursday. I
did a few "test" runs on the way there, and adjusted the fuel pressure
to as close as I could. Friday was practice, it was hot, about 95 degrees.
After a few runs I was only able to get to 192 mph. This is only 3 mph
over what I'd done last year with 100 less rwhp. Something was not
right. I studied the LM-1 logs and saw a lot of knocking at over 180 mph.
I decided I better run Race Fuel (104 unleaded) and replace the EZ-K
chip. Doing a few late night test runs on Saturday, I adjusted the
fuel pressure again, but it running too lean at 4-5K rpm, then got
richer at 5+K rpm. On Sunday (race morning) I bumped up the fuel
pressure again, and ran the race.



We left about 11:40 AM, it was 100 degrees out with a 5-10 mph
head wind. It turned out the AFR was still too high up to 5K rpm,
which made it difficult to accelerate up to 160 mph. Once I got up to
5K, the AFR was in the 12s, and the car ran well. On the first Spe ed
Trap (5 mile unlimited speed limit), the car did pretty well, I got close
but I was not able to hit the 200+ mph that I was hoping for.



We continued the race, but in "The Gap", a slow twisty section
of the course, the engine died, and we coasted to a stop at Check
Point 6. Race over again .



I got the car home on Tuesday, and Saturday we checked out the
car. Turns out the new engine is ok, but we blew another MAF boot
(same as at the Bonneville 100).



Looks like next year I'll be running something different then the stock
part...

Here is a video of the run through "The Gap":

http://928.jorj7.com/2008-pony/103/2008 ... he-Gap.wmv

and another one of the run through the first Speed Trap:

http://928.jorj7.com/2008-pony/103/2008 ... ed-Run.wmv

Thanks for the comments Aren and Rich. Yep, it's disappointing,
that's for sure. The engine builder and the supercharger kit builder
are both looking for a better solution. At least the engine is still
good. I'll continue with the tuning, so next year I'll have a better
run at the 200+ mph.



Just missed it by "that" much...

1 mph is better then 5 mph . But if it wasn't for the 5-10 mph headwind,
I could have gotten it. Even the fastest car, which usually hits 214-216
mph only was able to hit 205... Hopefully I'll get there next year.

Wow! What a rush it must be to go that fast...One of these days...

I too enjoy your posts...keep up the great work.

Todd

Thanks Val and Todd. I appreciate your comments.

We installed a new MAF boot and "Y" fitting last weekend, but
the car would not run (started, but then died). I guess we'll have
some more trouble shooting to do...