kumar75150

Anyone know of someone with a 2004 S2000 thats broken in?

I would really like to see if it actually dynos significantly higher than the previous models on a Dynojet dyno.

Elistan

Here's one:

http://www.vtec.net/articles/view-article?...4&page_number=2

Summary: 26 hp peak gain over an '02 dynoed at the same time, averaging about 20 hp gains. So over 260hp at the crank? Wow. (It's a press car, by the way, though hopefully not a ringer.)

kumar75150

Ya I saw that thread. I dont have that much experience with a Dynapack though so I dont know exactly what to make of it.

Maybe next dyno day we can get an 04 to get on a Dynojet.

QUIKAG

Very interesting. I'm wondering how much quicker it's actually going to be than the '00 to '03 models. Dyno numbers are great, but it's what it translates to on the road.

Elistan

Kumar, basically just pay attention to the difference between the '04 dyno and the '02 dyno in the article. It's a different sort of machine than the Dynojets we've done our local dyno days with, so you cannot compar them that way. However, with two different cars dynoed on the same machine on the same day, you get an accurate measure of the difference between them. The '02 that was dynoed was within the normal range for '02 cars on that machine, so you can pretty much assume that the dyno accurately measured an actual 26hp difference.

I personally have no reason to doubt that the car they dynoed makes over 260 hp crank.

Now then, the only issue that remains is whether this press car is a ringer or not, with a specially tuned ECU. The article speculates about possible reasons there might be for such a difference. One of the factors is that it's running a fair bit leaner than the '02. It's already been demonstrated that with a VAFC, worthwhile gains can be had by leaning out the mixture. The speculation has been that Honda made the F20C run deliberately rich to help protect the engine at 9000 rpm. Notice that the F22C1 torque does not drop off in the last 1000 rpms of the rev range like the F20C does - it actually has a significant spike in the last 500 rpm. In fact, F22C1 hp peak happens after redline. (8030 rpm vs fuel cutoff of 8200 rpm.) Take away that torque spike and extrapolate the established curve to 153 lb-ft at 8000 rpm (vs 159 at 7800) and peak hp would have been about 233 on the Dynopack. Still an 18 hp gain. (Which seems reasonable given the displacement increase, the redline drop, and how much gain is seen using a VAFC on '00-'03 cars.)

So did Honda go with a more agressive fuel map for all '04 S2000s? Hopefully a privately owned '04 S2000 will get dynoed soon...