[QUOTE=Saki GT,Nov 8 2009, 01:14 PM] Once again folks, its not the CDV, its the weak sauce pressure plate compared to the heavy AP2 flywheel.

 

That's the thing I like about Honda Engineers, they're thoughtful.

And they don't suck.

You can pretty much count that they didn't leave a whole lot of performance left on the table and that everything is engineered to work together.

When you start changing things, you have to change a LOT of things in order to actually make an improvement.

Ebay coilovers, cold-air intakes and pulling ABS fuses aren't going to do much to improve performance.

Clutch delay valve falls under that umbrella.

 

Imo there's no advantage to adding a lighter flywheel, unless you want the engine to rev freer. This means the rpms will fall more quickly from redline when you shift, or rise quicker when you blip the throttle, but I don't think its needed in the AP2.

The AP2 flywheel is 10 lbs heavier sitting on a scale. Spinning in the transmission, the weight increases exponentially, and the pressure plate is what dictates how strongly the friction plate can grab. Afaict, Honda added a heavier flywheel to better keep rpms up between shifts, but neglected to compensate for the increased rotational mass with a pressure plate that exerts more force on the friction disk. The CDV has nothing to do with this engagement - fast or slow, if there's not enough pressure, you're going to get slippage. The CDV is fast enough to minimize both shock and slippage, which is what its designed for - removing it will allow you to engage the pp faster, but if it can't stop the flywheel, what's the point?

Afaik, Billman250 and S2oooNvegas probably have the most hands on time with S2000 clutches, and they both agree that the pressure plate is most likely the issue. As well, I've talked with many owners that have removed the CDV and admit it doesn't help with slippage even if things feel quicker.

Look at some of the things Honda changed about the drivetrain - bored engine with revised VTEC and cams so there is real power below 6k rpm. Heavier flywheel to assist with keeping rpms up between shifts. CDV to reduce shock to the driveline and protect the diff. Why not a stronger pp though? I think its an oversight by Honda that it was never beefed up.

 

[QUOTE=Saki GT,Nov 8 2009, 11:14 AM] Once again folks, its not the CDV, its the weak sauce pressure plate compared to the heavy AP2 flywheel.

 

Go autocrossing, it's the best way to "unlearn" all the Hollywood misconceptions of what "fast" driving is like.

Especially before you make things more hairy with FI.

 

You can get away with jerk-shifting in an AP1, but the AP2 doesn't respond well to it. Too many people think a fast shift is synonymous with jerking the shifter around as fast as possible, and thats false. If tires chirp on gear changes, its supposed to be because of inherent engine power, not popping the clutch at speed, and you don't want to chirp tires - its a sign that you are shifting incorrectly and upsetting the balance of the car. That can be disastrous in an S2000.

The AP2 uses heavier components and you can't move them as fast. Take a chopstick in your hand and you can wave it back and forth quickly. Try the same with a hammer, and you'll notice you can't wave it as quickly - same basic concept with the AP1/2 transmissions. The CDV is like a ring on your finger - it doesn't effect your ability to wave. The AP2 still needs a stronger pp though.

 

This is a fantastic thread. Thank you, everyone, for the insight.

Is it easy to check whether or not the pressure plate is stock? Or does that involve removing the transmission?

 

Well, if you perform a redline WOT 1-2 shift, pop the clutch and the rpms float for a second or two, I'd bet you have a stock pp. Otherwise you'll have to pull everything apart.

 

I agree, great information. I have removed the CDV, it does seem to "help" slightly, not the improvement I was hoping for, in my case though, as well with my MY06, I think its more of the DBW.

I hadn't really given too much thought to a different pressure plate until now.

 

Man ive got over 70k and well over 150 passes down the strip in my 05. and my stock clutch is still holding strong. the CDV came out at about 15k.