With the ACT about to bite the dust, I'm debating two different clutches. First, the Exedy Hyper Single and second, the RPS Max series with a six puck sprung hub.

I'm pushing 400rwhp and plan on upgrading the turbo and possibly the engine in the not too distant future. I do mostly drag and road race stuff with lots of street driving (daily driven, but that'll change shortly). I don't mind a stiff pedal. I've put up with the ACT for 70K miles.

The RPS would be mated to a 9.5lb. SR Motorsports flywheel. The Max series features a replaceable surface in the pressure plate so theoretically, I'd never need another full pressure plate. I do not know what the RPS PP and 6-puck weigh.

The Exedy has a one-piece chromoly flywheel which apparently weighs about 21lbs. It has a forged aluminum cover and a six puck sprung hub. It's possible that the whole unit weighs 21lbs. but I'm not positive.

With that said, I have a few questions in regards to performance with a single turbo. First, it's my (limited) understanding that once the car is rolling, the flywheel is just dead weight so to speak. Therefore, lighter is better. Some have theorized heavier flywheels help with turbo spool. The RPS is a stamped steel pressure plate and thus, is probably heavier than the Exedy's PP. Not sure if everything would equal out.

The RPS seems to have the advantage of being completely rebuildable while the Exedy holds more torque but is not rebuildable. The RPS (and most clutches for that matter) use Daiken/Exedy parts, reengineered. The Exedy, from what I have heard, has a lighter pedal pressure than the RPS or ACT and is rated to 15K rpm (safer than a lightweight aluminum flywheel). The cost difference is about $150 when you consider that I have to replace the liner on the SR Motorsports flywheel and it isn't cheap (about $150).

Looking for feedback on what you guys think and any real world experiences. I know there are one or two people that have both and I've read your reviews. I'm interested in any updates, reviews, problems, etc...Thanks in advance.

 

The whole Exedy single plate weighs 26.5 lbs. I just weighed the ones I have in stock.

Chuck

 

The flywheel is about 12.5 lbs, the clutch cover is about 10.5 lbs, the clutch itself is about 3 lbs. Hope this helps.

Chuck

 

Michel - sorry off topic, is your extreme pressure plate and 6 puck sprung disc noisy?

 

I've run the ACT and the Exedy I prefer the Exedy, I remember it being over 25 lbs when we weighed it last for the whole unit. I've been going back and forth with RPS for awhile and still am so I have no experience with them. But they don't feel bad on the cars I've driven.

 

Chuck, check your e-mail messages, specifically from Nick Riefner. He's trying to get in contact with you. Thanks for the feedback guys...looks like I'll be going with the Exedy!

I was using an organic OEM clutch disk, not the 6-puck solid. I drove one of the 6-puck solids and couldn't stand it. Yeah, I stalled it. About three times trying to pull up a short incline into a garage :-) His wasn't too noisy, not that I remember. If you' re getting noise, does it go away when the clutch pedal is pushed in? My ACT tends to rattle the TOB with the pedal out, goes away with the pedal in.

 

Does anyone feel the heavier weight of the Exedy is going to be a severe disadvantage compared to the RPS/lightweight flywheel combo? Will the heavier flywheel help with spool/torque?

Chuck, seems AOL is bouncing ALL of Nick's e-mails. He sent one last night and it bounced. He can be reached at nick@ntechengineering.com 863-324-6692.

 

Well after going back and forth with Nick on the phone, he feels the RPS with the lightweight flywheel will be a better fit for my car. First, the rotating mass will be less than the Exedy (I'm already running a lightweight flywheel) allowing the car to rev faster. Second, the lower flywheel inertia will help me with wheelspin. If I were using slicks, a heavier flywheel might be a better choice. So, RPS it is. I'll report back when I have it in the car.

 

We know the weight for the Exedy... what does a light flywheel with an OEM-style clutch weigh?

-Max

 

The SR flywheel I'm using is 9.5lbs. and Nick estimates the RPS cover and disk to weigh about 6 pounds. I remember the ACT PP being heavier than that, maybe 10 pounds or more.

 

The cover and disc weigh 6 lbs? That sounds way too light.

-Max

 

That's what I was thinking too...so...I just got off the phone with RPS. The approximate weight for the clutch disk and Pro pressure plate is 14 pounds. Now, the Max is NOT rebuildable. Only the Pro is and they do not make a Pro for the the RX7 (not enough interest). There were a few reasons he gave for the development of the Pro with a replaceable liner on the PP but I won't go into it as it isn't relevant to us anyway :-)

So with a 9.5lb. flywheel and the RPS, I'll be at 23.5lbs. vs. 26 for the Exedy. How much of that weight is on the edge of each clutch package would make a difference but we're splitting hairs. I guess it would come down to engagement and pedal effort. The Exedy does hold substantially more torque than the RPS if Howard Coleman's stats of 600lbs/foot are correct.
Michel

 

I know several people who run Exedy hyper single's and they wouldn't go with anything else. I also know a few people that run the Exedy twin disc and they are all very very happy as well. I have driven 2 cars that run a hyper single and they felt like a stock clutch. But I can guarantee that they will hold better. Just my .02 Happy hunting.

Zach

 

Greaaaaaat. Now ya tell me Boosted! Already ordered the RPS. My "heart" wanted the Exedy to be honest but Nick thought it was the wrong way to go given the price and the RPS would be just as good. I'm sure the RPS will hold the power without issue. Just wondering if the Exedy's build quality is as good as I think it is. The whole rotating weight thing is still up in the air but I have a feeling the Exedy would have more weight in the center than the RPS. Forged aluminum cover vs. stamped steel. Same friction material. Would have been nice to have only a slightly heavier pedal too. The only downside to the Exedy is once it's done, it's done. You have to replace the entire unit (PP, disk, flywheel) whereas my current setup, I'll simply have to buy a $150 friction surface for my flywheel (way overpriced Ray!), new pressure plate and new disk. About $200 less expensive.

 

RPS is the way to go, they sponser my 12a turbo street car, its heavy (2,800lbs for NHRA street class and at 700+ hp it works great!!) i have used the same clutch for 2 seasons and still works great!!! dont worry you made a great choice!

 

It's hard to argue with that! The same clutch lasted two seasons with how many runs total? Thanks for the input 680.

Zach

 

Which RPS clutch are you running? Max series with a sprung six puck?

 

I dont' belive you 700 rwhp on a 12A lol



sorry to get of topic

I run a ACT with a sprung 4 disk from ClutchMaster and love it

 

Thought I was going to have to break out the popcorn out there for a second :-)

Back on topic, RPS is back-ordered til MID DECEMBER. The Exedy should be here by next Friday (right Chuck?) I should have it installed the following Monday.

Since I currently use something similar in weight to the RPS setup, it'll be interesting to see if there's a difference with the Exedy.

 

Yes, it went out by fed ex ground today to N-Tech. You should get it by Friday. Ask Nick for the tracking number. Thanks.

Chuck

 

Hey, I'm just glad you had one (well, several) in stock! Great price too, btw...Thanks again.

 

michel if you dont mind i would like to get a look at the clutch when it comes in. i've been thinkin about this clutch for my car

 

I think you'll really like the exedy hyper unit. I had it put on my car and the build quality is top notch.

 

gen3RxProj, what do you think about the pedal feel with the Exedy hyper installed?

Zach

 

My car is up at the mechanics still. I only saw it fresh out of the box, but, the mechanic has driven it around and he said its basically dead on with the feel, but has significant grab power.