The red is stock headers w/ HKS exhust (marginal/minimal gains over stock)

The blue is mugen headers, hks exhaust.

for other plots of my car visit
http://albums.photopoint.com/j/AlbumIndex?...76810&a=9809833

 

David,

This was discussed extensively before.

You should not jump into conclusions on how a car drives like from just looking at torque curves. You have to take into account the effect of gearing.

Gearing varies from car to car.

The S2000 has the shortest gearing I have ever come across in 200HP+ street cars, giving it a very significant advantage when compared to equal displacement cars.

 

 

In all the graphs the power/torque curve drops to zero (0) before it reaches 9k revs. Why is that? Does that mean that the S2000 has power up to 8800 revs and then it totally dies (ie lacks power)? I don't think so, as I remember the S2000 demo model that I drove having tons up power up to the redline. So why the drop in the graphs?

 

David, I think that's the rev limiter kicking in. I don't know why it's so low in the dyno charts because on my tach the rev limiter kicks in around 9,200. I suspect Honda tachos must be optimistic, either that or all the dynos read incorrectly!

 

Here is an interpolation of the chart on our cars without VTEC.

 

It's because the person doing the dyno let off on the gas. That's why run 03 ended sooner than the other two - it's not a mechanical thing.

 

Most people let off the gas before they encounter the rev limiter since you've already reached peak power anyways. I intentionally lifted off early.

 

"without vtec" ... hehehe... anyone actually dynoed the car w/o vtec engaging?

 

I've got the S2000, Boxter2.7 and BoxterS power curves mapped on the same graph. I'd post them here for people who are interested but I don't know how to isnert a picture (jpg) here. How is it done?

Anyway, the curves are very interesting. Both Boxters are way ahead of the Honda on kW/PS until 7K revs Then the Honda cathes (and passes) the 2.7 Boxter. By 8K revs the Honda has caught the BoxterS.

From looking at the graph, you need 1K more revs with the S2000 to have the same power as Boxter2.7 (that is, until 7k revs). To have the same power as BoxterS you need 2k more revs that the Porsche. Though, S2000 has 2k more rev range so it's possible to drive the car like that :-)

btw, I also made another graph where I mapped the Honda power curve over the Boxter (2.7 & S) - here I interpolated the power over the same rev-range (ie. 7k) - this is probably a little bit more accurate as it takes into account that S2000 has about 25% shorter gearing than the Boxter (S in particular). Intersting thing is that the power curve now lands right between the 2.7 Boxter and BoxterS. Though, below 4.5k revs it's still below Boxter2.7 ... though, not much.

ps. Anyone interested in the graphics, let me know, I'll e-mail them to you.

pps. Boxter2.7 and S2000 weight exaclty the same and BoxterS weights 40Kg more.