darkside7

iTrader: (12)

i need a clutch pretty bad, but i;m really low on funds.... Can anyone tel me how much can a stock clutch hold???? my mods are dp, mp, catback, m2 med ic, m2 box, fuel pump, greddy pullies, mazdacom rad, pfc, and a boost controller set at 11.5 psi.

littlemilla3

iTrader: (1)

It probably won't last very long. I would guess that you would be making around 330-340 rwhp with those mods. Just keep it until it blows, then get an ACT Street/Strip clutch.

jimlab

At 11.5 psi? More like ~290-300 RWHP.

obviousboy

well your probably making around 300rwhp at that psi and the stock clutch should be good enough.....

when you say you need a clutch bad..is it slipping or chattering???

the_saint

My stock clutch would slip in 3rd/4th/5th above 4500 rpm.
The clutch disc was perfect when removed.

The mods at the time were intake/IC/DP/MP/CB/underdrive pulleys 12 psi. 10 psi was fine. 12 and higher there was slipping

Switched to ACT S/S clutch/pressure plate and there have been no problems since

darkside7

iTrader: (12)

its chattering a little, but its old, and hard to get in gear..

Mahjik

iTrader: (1)

darkside7,

If your clutch is going out, then obvisously another stock clutch will eventually go out again. It would be in your best interest to do it right the first time and get an upgraded clutch.

As a matter of fact, there is a clutch for sale right now:

https://www.rx7club.com/showthread.php?t=321025

jimlab

The stock clutch has always been a potential issue. There's even a Technical Service Bulletin relating to it. If you're going to go to the trouble and expense of replacing it, replace it with something better.

adam c

iTrader: (2)

That was my opinion too. I replaced my stock clutch, which lasted almost 50K and was not worn out, when I decided to get a light weight flywheel. I did the research, and decided on the ACT SS clutch with HD pressure plate. After 6000 miles, the clutch is starting to chatter when its cold. I'm obviously dissapointed. Maybe the stock clutch would have been better for my needs. I estimate around 300 rwhp with my mods, and I don't plan on more.

Street King

Exact same thing with me but it would mostly slip in 5th gear or a hard first gear pull. When it was pulled the disc still looked like it had some good life left, put the ACT on in and it took care of the slipping problem.

*EDIT* I just had DP, MP, catback, 11psi, K&N.

alberto_mg

Hard to get in gear might be something else. I remember just b4 my clutch fork went out, the effort to engage the clutch and shifting was more difficult.

jimlab

My stock clutch gave up without warning at roughly 5,000 miles on the odometer... at WOT in 4th gear. Coupled with the lack of a rev limiter in my reprogrammed ECU (thanks to Mostly Mazda/M2 Performance) and the rev limiter not being set on my Crane HI-6 (I didn't set it because I assumed it was redundant), my engine easily saw 10,000+ rpm. In fact, it seemed to take an eternity for the tach to fall back below 9,000 rpm, even though I'd gotten off the gas as soon as humanly possible. The end result was that despite idling fine afterward, a corner seal eventually came loose and took out my rear rotor, rotor housing, and turbo.

No one warned me that the stock clutch wouldn't hold 300+ RWHP, and I had no idea that it was something that needed to be replaced while I was upgrading or removing everything else. It definitely wasn't a money issue, it was just something I didn't think of, and an unfortunate combination of circumstances and modifications resulted in a dead engine in a car that would still have had 30,000 miles on the original warranty if it had been stock. Lesson learned.

jimlab

Another word to the wise... replace the throw-out bearing while you're in there, and if your car has high mileage, replace the clutch fork too. It's a lot easier to do it while you've got the car apart than it is to find out the hard way that you should have done it while you had the chance.

adam c

iTrader: (2)

Jim, do you know (or can you estimate) how much over 300 RWHP you were running at the time? Mods?

John Magnuson

Darkside7,

I have almost the same set up at you (M2 Stage 3, running 11psi) and I have no problems with the stock clutch.

Jim,

Your reprogrammed M2 ECU had no rev limiter? My M2 Stage 3 ECU does at 8100 rpms... I've hit it a few times... oops!

-John

jimlab

I upgraded pretty much everything about 3,000 miles after buying the car in April of '97.

Home-made cold air intake with K&N filter
Tri-Point stainless downpipe
Tri-point stainless midpipe
PFS single tip cat-back
Full non-sequential conversion with ported wastegate and exhaust manifold
ASP Racing large IC
GReddy underdrive pulley kit
HKS EVC III electronic boost controller
Mostly Mazda reprogrammed ECU
Crane HI-6 ignition amplifier
SX rising-rate fuel pressure regulator, set of ~40 psi base line pressure
Cosmo fuel pump

I was running 15 psi on the street, so probably 340+ RWHP as a guesstimate. I never managed to get the car on a dyno while it was running right.

adam c

iTrader: (2)

Jim, I agree with your RWHP estimate. So we know the stock clutch won't hold at 340+.

The guys at Mazda Motorsports told me that some guys are running the ACT HD pressure plate with the OEM disk, and having good results for street use.