Pumped-up 915 clutch?

[spuggy]

915 Power clutch kit seemed to deal OK with stock 930 power.

Unscheduled rebuild and restrained bolt-on goody frenzy ensues. Seemed just fine during break-in, made about 395 HP/350 ft/lbs (crank) when we checked the AFRs.

Seemed just fine for a while longer, too.

Now the clutch is obviously not happy and is polishing the flywheel with less provocation each time. It's got to come out and soon.

I want to pull the trigger on buying parts in the next few days, but I'm undecided what to put back in (although I'm leaning towards a Sach competition cover).

What you guys with 915's and > 300 ft/lbs torque running for a clutch setup, how much (if any) difference in streetability is there, how long are they lasting you and how much power/torque is your motor making ?

Thanks for any help!

[RarlyL8]

The Sachs sport clutch is really nice for a street car. I'd put another one in. They don't like drag racing but niether does the 915!

[jess p]

I have a centerforce dual with around 400hp and 375T. The
pressure plate has 33% more clamping force than stock. I
don't care for the disc. It takes a lot of foot pressure. I
wonder about my cable breaking. I really need a hydralic
clutch with that pressure plate. It seems that with kevlar
clutches you get a lot of chatter. They are on or off.

[spuggy]

Cool, thanks.

Brian, do you have a part # for the Sport clutch? Any specs? (I can probably get the latter with the part #'s...)

Is it a complete kit or an uprated plate? I'm told Sachs do a pressure plate they rate @ 350 ft/lbs, and I'm wondering if that's the same as you're referring to.

The power clutch had an original # (for the kit) of 3000961101, which apparently references or supercedes the following parts:

91511691100
91511600116
91511600127
91511601122

Must look up all the part #'s...

Jess, thanks for your reply too - I was told (by a competition clutch guy) that the 225mm Sachs 915 organic friction plate is rated (by Sachs) @ 600 NM, or about 442 ft/lbs. I was considering trick friction materials until I heard that...

Another competition clutch guy told me that all ratings quoted by Sachs have a 20-25% margin built in. (He was talking specifically about pressure plates in that instance, mind you - but seems like a fair bet it's across the board)...

KEP told me that their Stage 1 kit (which they rate @ 417 ft/lbs) uses the stock Sachs friction plate with their pressure plate.

One of the clutch guys I spoke to laughed when I mentioned the 930 motor and the Power Clutch, said "yeh, that won't work" and told me that the Power Clutch is a stock 915 pressure plate, and they just cherry pick the top 10% of the batch into the Power Clutch boxes (like Harley did for Cafe Racer motors in the 70's)... So there's apparently a pretty fair chance you could buy a stock Sachs clutch kit and end up with one with an identical rating to a Power Clutch...

Seems to me a pressure plate rated @ 350 ft/lbs with a 25% margin will hold up to 437 ft/lbs, which seem to be a good match for the stock friction plate.

I like off-the-shelf stuff, but I don't want to have to get a gym membership to change gear...

[ivallt]

So what did you end up buying? How do you like it?
I myself am going to replace the clutch in my supercharged 911 carrera (1986) $340 HP. Too much power for standard clutch.

I drive on the street and rarely go to track events. I was thinking the Sachs Sport clutch might be good, but ive heard good things about Spec stage 3 clutch, and Kennedy. The Centerforce duel friction clutch sounds to be too extreme. "either your in gear or out, no in between"

Any follow up ?

[NathanUK]

Stock disc and a KEP pressure plate would be good. They offer different stages.

[spuggy]

Originally Posted by ivallt

So what did you end up buying? How do you like it?
I myself am going to replace the clutch in my supercharged 911 carrera (1986) $340 HP. Too much power for standard clutch.

I drive on the street and rarely go to track events. I was thinking the Sachs Sport clutch might be good, but ive heard good things about Spec stage 3 clutch, and Kennedy. The Centerforce duel friction clutch sounds to be too extreme. "either your in gear or out, no in between"

Any follow up ?

I spoke to a few people, including Kennedy who were fairly helpful. I don't recall exactly why I didn't go with them, but something bothered me at the time. I don't recall exactly.

I used a Sachs competition pressure plate, and just replaced the stock friction plate.

Pedal pressure is higher than stock, but the clutch doesn't slip. Not at all. I checked.

Got about 8,000 miles on it now, seems to be holding up well.