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Old 10-10-2015, 11:24 AM   #357
thstone
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,669
OK, let's talk horsepower.

At the AutoClub Speedway race, the POC had a dyno to measure power output at the rear wheels (there is currently no maximum power spec). The top 3 qualifiers and top 3 race finishers were required to have their cars tested. I had mine tested of my own desire.

Here are three data points;

My Car: 196hp
Car 2: 187hp
Car 3: 203hp

From my perspective, its good news that my $1,800 salvage yard, never been opened, previous tiptronic, engine with 90,000 prior miles still managed 196hp at the rear wheels!

Of course, you might be wondering: with a rating of 200hp at the crank, how can I get 194hp at the rear wheels from a stock engine?

200hp at the crank
- 20hp 10% driveline loss
+ 7hp TopSpeed cat back exhaust (verified on dyno: Spec Boxster Build)
+ 5hp Removal of cat's (verified on dyno)
+ 5hp Under drive pulley (per other testing)
________
196 hp net at the rear wheels

Of course, there are some uncertainties in the above calculations:
  • Rated horsepower (could be higher or lower than 200)
  • Driveline loss (could be higher or lower than 10%)
  • Differences in dyno testing (lots of variables)

Car 2's engine was professionally rebuilt last season and has only been used for racing and driving to/from races. Interesting that it has slightly less power than my never-rebuilt engine. This engine reportedly was dyno'd at 192hp when rebuilt.

Car 3 is making quite a bit more power than my car. Even if I add a few more HP for a fully open exhaust (which my car does not have), there still isn't an obvious path to get my engine to 203hp.

In fairness to Car 3, a combination of the uncertainties listed above might explain the difference. Impossible to know one way or another, but interesting to consider the possibilities.

Now, for the drama... (Oh! The Drama!)

Because of this situation, Car 3 was protested by Car 2. This meant that Car 3 had to post a $3,500 check to pay to have the engine of Car 3 inspected. Car 2 refused the inspection, and thus, was disqualified for all three races for the weekend (and the $3,500 was returned to Car 2).

I don't want to indict Car 3 for refusing the inspection but it does raise eyebrows. I'd let anyone inspect anything on my car at any time (including tearing down the engine).

I don't know what, if anything, further will come of this situation for Car 3, but I found the horsepower numbers, situation, protest, and refusal to be inspected to be interesting and worth sharing.
__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor

Last edited by thstone; 10-10-2015 at 11:39 AM.
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