MyE28.com DEV

Hello.
I'm thinking I'll need an aftermarket clutch very soon on my
M30b35 11-12psi is holding up ok with the stocker, but feel it might slip
if more pressure is added.
Nobody on the forum has been very clear on the holding power so 12psi is a good known holding point.


So what are you using and power levels etc.?
Looking for something full face daily driven 20psi ish.

http://www.cnsracing.com/CNS-Racing-BMW ... 634BMW.htm

This appears to be identical to the SPEC Stage 3+ unit. CNS rates theirs at 700 ft-lbs while SPEC sez 520. I asked both companies about this and was told that SPEC builds the clutches for CNS with modifications to the pressure plate to CNS' requirements.
See http://www.specclutch.com.


Thus far I am still in the break-in phase. CNS said to expect 500 or so miles of stop-and-go driving to accomplish smooth engagement with minimal chatter. As it has gone over the first 200 or so miles, there has been nearly zero judder. Takeup has been exceptionally smooth with no apparent slippage.
A few items of note:

1. I am using a new stock M5 single-mass flywheel. This was checked for potential runout before installation.
2. When tightening the 8 flywheel attachment bolts, care was taken to assure that there was no distortion of the f.w. friction surface, This was checked with a dial indicator.
3. The splines on the trans input shaft and the internal splines on the friction disc were lapped in with valve compound to assure no burrs and consistent dimensions.
4. All fasteners were tightened with a torque wrench--flywheel, pressure plate, trans mounting bolts.

All this to assure proper alignment and no distortion.

This setup is holding 567rwhp/562 rwtq on the chassis dyno @ 7.25# boost. Higher boost levels (15 psi) wasn't done at this time. CNS said to work thru the break-in before pushing things.
This setup calls for smooth, progressive engagement. It is NOT used in quarter-mile, drifting or HPDE type usage.

FWIW, this engine has done dyno-measured 710/725 at the rear wheels at 15 psi and a different clutch.

HTH

I've posted a few times about how fantastic my segmented kevlar ClutchMasters clutch is. Its held up to 380+rwhp/rwtq.

woooah, that cns clutch is off the charts expensive. :0

Dan, was it this one?
http://www.clutchmasters.com/shop/?page ... &AppID=765

110% over stock meaning if it slips at 13psi it'll be good to 20psi?

Shadow wrote:woooah, that cns clutch is off the charts expensive. :0

Dan, was it this one?
http://www.clutchmasters.com/shop/?page ... &AppID=765

110% over stock meaning if it slips at 13psi it'll be good to 20psi?

That's it but I charged him $100 less.

I've got the clutch masters 6 puck ceramic
I love it
holding up under stupid abuse @ 350 hp
marc

Shadow wrote:woooah, that cns clutch is off the charts expensive. :0

Very true.
But in researching a clutch for LH that would hold 845+ fwtq, there isn't much out there.
This led to conversations with South Bend Clutch, SPEC, Clutchmasters, Tilton, UUC, AP Racing, Centerforce and a few others I can't remember. Short and sweet: nobody builds one that will both hold the torque and be anything close to street driveable. Tilton and South Bend thought they could make a run at it but it would be a custom deal; time and materials.

FWIW, South Bend's thinking was that they could modify a multi-plate setup they build for the Viper, adapting the pressure plate fixation points to match up with a stock M5 single-mass flywheel. Failing that, they could CNC cut a custom billet flywheel. Not exactly beer money.
Tilton wanted to modify one of their carbon fiber 2-plate rigs designed for Champ cars. Their numbers got stupid.
Everyone else wasn't even close on holding capacity.

I got put in contact with CNS via a friend who was having similar issues with an S6 Audi.
Mark at CNS thought that their 2-plate clutch would simply have a too-harsh engagement for anything but track use. This was exactly the problem I was having with my QuarterMaster 8.5" sintered-iron 8-puck.
Based on my driving style, he thought CNS' single-plate would work fine, despite the hold # being less than my dyno'ed torque values. A lot has to do with how you engage the thing: dump the clutch @ 5 grand out of the hole or be slipping it like crazy when drifting and it won't live long. Do smooth engagements in long-distance endurance type use and it's a different story.

One thing led to another and here we are.
I didn't pay list for my CNS. If it holds up, fine. I'd rather pay once for the right item than multiple times for not getting the job done.

marc79euro645 wrote:I've got the clutch masters 6 puck ceramic
I love it
holding up under stupid abuse @ 350 hp
marc

What's the engage like on the six puck? Is it rough in traffic?

easy pedal, I think it's a stock m5 pressure plate.
occasionally a little chatter for slow release,but, no issues, under normal take off,or double clutch,stab & burn.I'm much happier than with previous spec 3 plus which was very stiff.
marc

marc79euro645 wrote:easy pedal, I think it's a stock m5 pressure plate.
occasionally a little chatter for slow release,but, no issues, under normal take off,or double clutch,stab & burn.I'm much happier than with previous spec 3 plus which was very stiff.
marc

It's not a stock pressure plate. It's a Sachs shell though.

How much hp can a new sachs clutch and pressure plate handle?
My clutch is now slipping anywhere over 10psi and since I have two units, one with 9.7mm of material, I was thinking of installing it.
I've not dyno'd the car yet, but with a k27 setup, I know my numbers at the most optomistic will be in the low 300s at 16psi.
My current clutch I know for sure has about 200k miles that I put on it.
If the PO was truthful, its the original clutch, add another 127k miles, which was the mileage when I purchased it almost 10 years ago.

^Good question.

I'm going to be slowly testing that limit.
Made a vid. Didn't log it but looks like 13psi?

The trick I think is don't slip it AT ALL meaning no hard shifts.


http://www.youtube.com/watch?v=j9txX1iCjuk

Shadow wrote:^Good question.

I'm going to be slowly testing that limit.
Made a vid. Didn't log it but looks like 13psi?

The trick I think is don't slip it AT ALL meaning no hard shifts.

http://www.youtube.com/watch?v=T0d9BKxJ ... msilde7zSD

Yeah dude, I was good running 10psi. I compressed my stock wg and got 20psi. It scared the shit out of me. I didn't expect it to go that high. I was only expecting 17psi max.
I try to keep it under 15psi and now that the clutch is slipping, if I do get on it, its a slow increase, but I've been rather mellow lately.

Same here.
Looks like 10psi is a solid safe limit.
Turned it up to 14-15psi it slipped and kept slipping....

Still can't decide what clutch to go with.
In addition to that, my tranny has over 300k miles on it.
It hasn't made a peep until I pushed it past 10psi, and I'm still not sure it was the tranny I was hearing, and not the center bearing screaming under pressure.

Shoud I source a low mileage unit before I do the clutch?

The CSB sees no additional load with increased power output. Transmission noise isn't a serious issue. Might as well run it.

turbodan wrote:The CSB sees no additional load with increased power output. Transmission noise isn't a serious issue. Might as well run it.

Thanks.
I just didn't want to grenade the tranny.
We all the what it took for me to get this far.......
I just want to be able to dyno the car, soon, so I can get a solid #.
Hoping for 300rwhp, but wont be hurt if its less.
15psi, b35 cam, intercooler, and freeflow exhaust should have me close either way, right?

I've only heard stories of blown Getrags. Having known what I've done to them and never had a problem, I feel pretty confident that you won't have a catastrophic failure.

I'm running a 1 1/2 year old stock Sachs clutch that started slipping about a month ago. Luckily I just recieved one of Todd's modified clutch masters setups. I'm going to install it Monday and post back what I think of it once it has some miles on it.

clutchnet 4puck sach sport pressure plate..good up to 610lbftorqe :

Just installed TCD's clutch masters 6 puck style clutch yesterday. Car drove great on the ride home. Will report back once it's broken in.

clongo wrote:Just installed TCD's clutch masters 6 puck style clutch yesterday. Car drove great on the ride home. Will report back once it's broken in.

It's doesn't require a break in period.

My portal to tq is here.

Shadow wrote:My portal to tq is here.

Who makes it and how much can it handle?

Clutchmasters, and not as much as I would have liked.

dynoed today and it melted on the 3rd run and now and forever will slip on the street.


Anyone know of a disc that can handle 500hp back to back, not just once?

Shadow wrote:Clutchmasters, and not as much as I would have liked.

dynoed today and it melted on the 3rd run and now and forever will slip on the street.


Anyone know of a disc that can handle 500hp back to back, not just once?

Dyno sheet?

The dyno sucks. It runs out of injector but I think I just need
something more aggressive and not as delicate as kevlar.

Shadow wrote:The dyno sucks. It runs out of injector but I think I just need
something more aggressive and not as delicate as kevlar.

Dan has successfully used that disc for almost 400rwhp.

382 foot pounds at the wheels, and it didn't make as much boost on the dyno as it does on the street. Its probably seeing 400 or more on the road.

I can't remember exactly when this clutch went in but its got to be going on four years at this point. You may have a bad flywheel, oil or grease contamination, clutch hydraulic problems or you're using the clutch improperly.

You should post that dyno too. It doesn't have to be good.