Orpheus

Hi,

Just got back from Ballade Sports where Alex and Mike did a clutch job for me. As always, they went out of their way to make sure I was happy with the work, which I was.

Originally:
Exedy Hyper Single clutch (assembly includes flywheel, clutch plate, and pressure plate together)

Changed out to:
ACT HD Presssure Plate (H021)
Exedy (indentical to OEM?) clutch plate
Science of Speed (SOS) Ultra Lightweight Flywheel (which turned out to be a Competition Clutch Ultra Lightweight Steel Flywheel 2-669-STU)

While doing my research in deciding the new setup, I found actual weights to be very hard to find, so I though you guys might appreciate some measurements. So, here are some pics for you:

The old:

OEM Throwout Bearing:


Exedy Hyper Single + Throwout Bearing:


Exedy Hyper Flywheel:


Exedy Hyper Clutch Plate:


The new:

Science of Speed (SOS) / Competition Clutch Ultra Lightweight Flywheel:


Exedy / OEM Clutch Plate:


ACT HD Pressure Plate:


Whole setup that will be installed (without throwout bearing):


Same setup, but with OEM Pressure Plate:


So, after doing some math, we have (weights in lbs):

Exedy Hyper, CC / OEM / ACT, All OEM (AP1)
Flywheel 10.8, 8.6, 14? (assuming)
Clutch Plate 1.9, 2.8, 2.8
Pressure Plate 8.5, 10.1, 10.1
Total 21.2, 21.5, 26.9

Engine Weight 19.3, 18.7, 24.1
Reduction 19.9%, 22.4%, n/a

So, purely by weight, it would appear the new setup offers less inertia to the engine by a little bit, despite greater overall rotational weight. However, in actuality this may not be true, as weight towards the outside of the rotating assembly contributes more to inertia. Seeing that the Exedy Hyper PP is actually quite a bit lighter than the ACT (which appears to be the same weight as the OEM PP), and it appears most of the mass of a PP is around the outer portion, the Exedy Hyper might have less inertia than just its pure weight would suggest. So, the two setups might have very similar effects in improving engine acceleration/decceleration (revs.)

Anyway, so there you go.

funkemonke

i got the same flywheel. this flywheel is sick. she runs so much quicker now. love sos ultras.

McHeizer

nice, great measuring of all parts!

why did you get rid of the Exedy clutch?

Orpheus

thanks man.

i loved the exedy hyper a lot. i beat the exedy hyper to death, and it was slipping. so, i needed a new clutch plate and pressure plate anyway. to rebuild the exedy was just a bit more than the setup i replaced it with, and my preliminary research showed this setup would be significantly lighter, based on data i got from exedy tech support. well, they were wrong, as you can see--the weights are very similar.

i actually miss the exedy hyper a lot--it grabs more precisely and actually, after driving the act + cc setup around, i think i was right--the exedy, despite a similar overall weight, actually has less enertia! just subjectively, the exedy setup did seem to rev up/down a little faster.

well, anyway, when the time comes, i'll probably go back to exedy hyper. maybe their carbon single, which is supposed to be even lighter.

McHeizer

OK fair enough.
I'm currently running ACT PP + Comptech FW and was looking for a lighter setup, especially on inertia.
The Exedy carbon single was tempting, but due to budget I opted for the the hyper single.
..waiting to be installed now

McHeizer

oh maybe a bit OT, but I read in your RB-thread that you messed up the clutch slave cyl.
sorry to hear, but how did you do that?

Orpheus

ha ha.... well, i had some strangeness in the pedal, and so i decided to bleed it again. i followed billman's suggestion to unbolt the slave, and tip it upwards to gravity bleed. but even with the nipple full open, nothing came out! so, stupid me had a friend step on the pedal to push out some fluid. at first it was going great, and i saw a ton of air get pushed out. but then i think the pressure pushed out the plunger from the the body! i couldn't get the thing to fit right again. so, now my car's on jack stands in the rain. so... yes, please learn from my stupidity and do not step on the pedal without the slave bolted down.

yeah... i think that hyper single is one of the lowest enertia setups you can buy, but the Carbonetic single is even lighter, by almost 4 lbs! it's amazing. you might want to look into it. and it's not as expensive as exedy's carbon single. i drove someone's car with it installed, and the revs are almost instantaneous. the only downside is it requires you to install their own slave that converts to pull operation. that kinda put me off it. i think the Carbonetic is the lowest enertia clutch made for the S2000.