Dyno Day!

[944boy]

I went to a dyno day today for fun and to get a base line on the boxster. It was about 60 and lightly raining. There was a Mercedes E55 AMG and a 964. There was also a Fiero with a caddy V8 that only managed 197hp.

Anyways there may be video later. I was happy with the results, nice flat torque curve and a smooth HP curve. 230 at the wheels isn't bad for a rated 240 flywheel HP.

[Adam]

I take it you have a 987 2.7L since you said 240 hp flywheel? 230 at the wheels is really really good. Stock?

[944boy]

Yeah it's a 2005 Base 987. I forgot I didn't have a sig on this forum, I'll change that someday.

No mods what-so-ever. 58,000 miles. Not even 60K maintenance. A true baseline.

[Adam]

Wow, I think you have a factory freak. I doubt my 260 hp 3.2L would be over 230 hp at the wheels. Nice!

[edevlin]

Wow, thats great, both HP and torque. I guess it shows what the little 2.7L can do. Has your car always felt fast and have you compared it to any of the late-generation 986 S cars, which should have similar HP? Enjoy,

Ed

[blue2000s]

I'd be wondering about the accuracy of that dyno. I really have to wonder if a stock 987 is making 265 bhp.

[Jake Raby]

That looks like a very generous dyno... The drive train pulls at least 15% from flywheel numbers.

[944boy]

I am not defending those numbers as pure fact. But there is some rational. I've got the six speed, not the five. So it could have been done in a lower gear than 1:1. Also Porsche has always had a tendency to underrate their cars so the listed HP is a 'minimum' of sorts. Driveline loss is very low compared to most cars. At 60K the motor is well broken in and spinning freely. Also as in the case of my 944, if the car was driven conservatively then there is carbon building up on the pistons and effectively raising the compression. At 200K the compression numbers on my 944 were all between 200 and 210 psi.

So;

1) Dyno error
2) Wrong Gear
3) Good Luck

I could make runs on 5 different dynos and get 5 different numbers, so take it for what its worth.

Overall I don't care, the curves show the motor is healthy and making power exactly where it should. If I do anything to it I can go back to that dyno and make a comparison run.


I did drive a slightly modded '02 'S' a few hours after the 987 and it felt a little bit faster, but my '05 has always felt quick. Also after 3 runs it gained some HP each run. So the computer could have been adjusting itself for the aggressive driving. First run was about 219.

Who am I to complain that my car is making too much HP!

[blue2000s]

I can't nor would I want to tell you what kind of service to be happy with.

But if it were me, and I'd paid MY money to get an accurate dyno reading for a baseline or to evaluate the health of my engine, I'd expect accurate results. If a shop were off with their calibration due to negligence or through intention or didn't know what they were doing, I'd be spending some time trying to get them to make it right. These things are notoriously inaccurate, but there are calibration procedures and if some shop didn't keep up with them, I wouldn't be spending my money there.

[easyc]

correct me if I'm wrong.... but don't dyno dynamics dynos usually run lower numbers?

[blue2000s]

Originally Posted by easyc

correct me if I'm wrong.... but don't dyno dynamics dynos usually run lower numbers?

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