Have you dynoed your 2.7L Boxster?

[ohioboxster]

Well if my math is correct the numbers you posted seem to make perfect sense at about 15% loss. If your car is advertised at 220hp I would have to say they are using flywheel hp. 220 x .15 = 33 ......... 220-33=187 hp at the wheels you have 198 at the wheels so a ball park figure would bring your mods in at 11hp. You are probably somewhere around 231 hp at the flywheel.

You can look at it this way too:

1) Your increased HP (11) cost about $181 per horse ($2,000/11).

2) Comparing a 2007 987 vs. 987S the HP increase is 50 and costs $9,900 or $198 per horse. A 2006 comparison would be $242.50.

Looks like you did OK. The most important thing is that you are happy. And that has far greater value than anything!

[mtch]

The explanation of driveline loss from engine to wheels sounds right. My last car was an Acura RSX-s. It advertised 200 HP and I dynoed it with 3k miles. It dynoed at 174, which is 12%-13% loss. After bolt-on mods mods it dynoed at 204whp, very easy and cheap to make power.

After a couple of years, with no further mods, whp went up by 6. It dynoed @ 210whp @ 30K mi. I think cars perform better from 25K -75K miles. I dynoed my Z28 every year I owned it (it was free), and it didn't begin to lose power until 85K miles. Power was down 7% at 140K miles, so unless you have major engine problems you shouldn't lose power anytime soon.


One last thought.... When comparing AWD-RWD-FWD power loss, these are ordered most loss to least loss, but wouldn't a mid or rear engine be more similar to a FWD than RWD. Based on proximity if engine to drive wheels, there is no drive shaft or rear diff that most RWD cars have, which causes most of the additional loss. The Boxster's drivetrain would probably lose closer to 12%, which is more consistant with FWD.

Just my thoughts

[Adam]

Originally Posted by mtch

One last thought.... When comparing AWD-RWD-FWD power loss, these are ordered most loss to least loss, but wouldn't a mid or rear engine be more similar to a FWD than RWD. Based on proximity if engine to drive wheels, there is no drive shaft or rear diff that most RWD cars have, which causes most of the additional loss. The Boxster's drivetrain would probably lose closer to 12%, which is more consistant with FWD.

Just my thoughts

That's a real good point. I was thinking about that the other day myself. I would think that the boxster would be more efficient than say a front engine Rwd car that has a long heavy drive shaft to spin?