Honda S2000 baseline dyno run - stock

My completely standard 2005 S2000 dynoed on Automotive Performance Tunings very accurate (soul destroyingly so - no smoke blown up your arse here) Dyno Dynamics rolling road. S2000s never make their quoted power and my 40k mile example was no different. As normal with these cars, best power was made on fourth run once all transmission fluids had got up to temp (had cooled down for a few hours after I arrived). Quite pleased as the last one he had on there made 210bhp, but that was a much higher mileage car. After the third run, power starts to reduce slightly as IATs then climb from the heat soak. As said, they always make the best power on the third or fourth run.

[athaothao]

nice honda s2k s2000 base line dyno run stock loud s2000

[actuis]

The dyno screen says it's calculating flywheel hp, but that doesn't seem right. The only real way to calculate flywheel hp is to use an actual engine dyno. It's almost impossible to accurately do it with a wheel dyno since there is no standard for drivetrain loss. Some people say estimate between 15-25% for drivetrain loss depending on the dyno and the age/weather/condition it's in, but that's a range of ~25hp on S2000, so not very accurate. That's not even considering the differences between drivetrain components between cars, like different wheel/tire weight, driveshaft weight, differential efficiency, and so on.

On other RWD cars, the drivetrain loss factor may be more (like Mustangs, Camaros, et cetera) or less (like an Elise, Evora, Cayman). It's not very likely this shop has an actual engine dyno to find the literal drivetrain loss factor of an S2000, so I wouldn't trust that flywheel hp number. I'd ask them for the wheel hp graph instead.

If that dyno screen is just mislabeled and it's actually giving you wheel horsepower, then 218 whp is pretty good. Most AP2 S2000's dyno at around 210-215whp. Speed.Academy dyno'd a junkyard AP1 S2000 at 215hp, so 218whp on a healthy AP2 is very believable. That's within 237 flywheel hp range.