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thstone · 03-02-2018, 09:47 PM

Horsepower. Everyone talks about it. Rarely is there ever any real data.

I had my engine dyno'd again at the POC event last month because, with about 80 hours of racing time on the engine, I was worried that it might be losing power due to age, wear, and a little bit of driver induced abuse (I'll say more about the over rev's in another post). If you recall, this engine came from a salvaged Boxster with 92K miles and I paid $1,800. The engine has been well maintained with oil changes after every 2-3 racing weekends, air filter every 4 weekends, and spark plugs every year.

Here are the dyno charts from Sept, 2015 and Feb, 2018 showing almost no difference (~1hp) in power. Same dyno and same operator. Same exhaust (no cat's + TopSpeed muffler). Same UDP. Same oil/weight. Same stock ECU. Different weather conditions. Fuel injectors were recently cleaned/calibrated. Not exactly apples to apples but as close as practical.

I could probably pick up a couple of hp by ditching the TopSpeed muffler and going to straight pipes like most of the Spec Boxster field, but since this car is still driven to/from the track I worry that it would simply be too loud to drive on the street.

The good news: my engine is as strong as it ever was and appears to be running very well.

The bad news: I can't blame slow lap times or poor finishing positions on my engine. (Damn).

Its hard to say how racing hours correlate to miles but 80 hours of continuous operation above 5000 rpm has to be hard on an engine.

For comparison, the range of horsepower for other Spec Boxster's that were tested (and who shared their results with me) was 199 hp at the upper end to 188 hp at the lower end. And one car that still had cat's and the stock exhaust put down 182 hp.

September, 2015

February, 2018

03-02-2018, 09:47 PM	#992
thstone Certified Boxster Addict Join Date: Nov 2010 Location: Los Angeles Posts: 7,669	Horsepower. Everyone talks about it. Rarely is there ever any real data. I had my engine dyno'd again at the POC event last month because, with about 80 hours of racing time on the engine, I was worried that it might be losing power due to age, wear, and a little bit of driver induced abuse (I'll say more about the over rev's in another post). If you recall, this engine came from a salvaged Boxster with 92K miles and I paid $1,800. The engine has been well maintained with oil changes after every 2-3 racing weekends, air filter every 4 weekends, and spark plugs every year. Here are the dyno charts from Sept, 2015 and Feb, 2018 showing almost no difference (~1hp) in power. Same dyno and same operator. Same exhaust (no cat's + TopSpeed muffler). Same UDP. Same oil/weight. Same stock ECU. Different weather conditions. Fuel injectors were recently cleaned/calibrated. Not exactly apples to apples but as close as practical. I could probably pick up a couple of hp by ditching the TopSpeed muffler and going to straight pipes like most of the Spec Boxster field, but since this car is still driven to/from the track I worry that it would simply be too loud to drive on the street. The good news: my engine is as strong as it ever was and appears to be running very well. The bad news: I can't blame slow lap times or poor finishing positions on my engine. (Damn). Its hard to say how racing hours correlate to miles but 80 hours of continuous operation above 5000 rpm has to be hard on an engine. For comparison, the range of horsepower for other Spec Boxster's that were tested (and who shared their results with me) was 199 hp at the upper end to 188 hp at the lower end. And one car that still had cat's and the stock exhaust put down 182 hp. September, 2015 February, 2018 __________________ 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; 03-02-2018 at 10:04 PM.