930 Clutch

[DohertyCM]

My 930 is putting out about 475 in torque... 1988 930 3.4 engine..

I need a new clutch.....I have looked around and decided to get a
SPEC Stage 2+ clutch...it says it will hold up to 600 in torque.

Anyone have any experience with these?

Maybe a better clutch without breaking the bank?

As far as I know I have a stock clutch installed. I dont know what the guy put in the car when he built it.

[Kraftday]

Impressive power stats there.

If your 3.4L revs free spirited you may already have a lower profile sport clutch in there. If not, the lighter mass flywheel / clutch is HUGE for performance.

I haven't seen any of the SPEC 930 specific clutch covers..the pictures of the actual product seem elusive. I do recognize other Sachs product photos in their catalog. I suspect they maybe painting Sachs covers and offering a different disc depending on Stage #?

I also know Centerforce doesn't compete / modify Sachs RE clutches for several of their Porsche sport offerings. Also, Sach RE has standardization on the sport disc linings with the sprung hub centers...GT3, RSs, etc...tried and true (As pictured on SPECs sight).

With that, I'd recommend checking the synopsis here for this lightweight conversion package and the RUF-5 Speed PN: 88 3082 999 594:
TurboKraft : Catalog Home : 930 Lightweight Clutch Adapter Kit [930 116 020 COM TK] - $420.00

And: 2010: An EFI Hot Rod Odyssey

Also sending your flywheel for scalping and resurfacing would also be appropriate.

[magic930]

I had a Spec stage 2 in my 930.. it was in the car for 7 months or so before I got rid of it. These clutches may be fine for racing but they are horrible for daily driving, very on off, and rough moving from a stop. (They do grip well though) I eventually replaced with a KEP and it was smooth as it should be and held just fine with a 3.4lt EFI engine.

[proffighter]

I still have a new Spec stage 1 pressure plate with lightweight option (it's only about 1kg less than stock) and yes, it's a modified Sachs clutch







Bought it from Lindsey Racing

[lin7310948]

give kennedy engineered products a call.....ask for monty. several on this forum run their stage one or stage two packages including myself. i have a stage two with the organic clutch facing which works well on the street. my engine is a bit above 600 ft/lbs torque.

[wjfk32]

My wrench just put in Stage 2 KEP-Lightweight PP and KEP-Organic disc. in my 915. Went in perfectly...Changing other parts by the pedals since out..bushings,clutch wire,etc.etc..Haven't driven the car yet..Some other little upgrades are in the works.

Monty expressed going kevlar instead of organic will have some chatter...Choose wisely.



Walt

[philip j]

I just did a stage 1 Kep. Can't get the pedal adjusted to where it was before. Are you saying your wrench has to adjust it inside the cab? I've only tried adjusting it under the car at the cable end so far. I can't get the pedal to return to the up position. Would like to hear back on how it goes. Philip

[Kraftday]

Originally Posted by proffighter

I still have a new Spec stage 1 pressure plate with lightweight option (it's only about 1kg less than stock) and yes, it's a modified Sachs clutch







Bought it from Lindsey Racing

Thanks for sharing the photos..

It looks like they casted their own scalloped pressure plate surface? With that maybe they changed the fulcrum point to change clampload? Also the chamfered vent holes are notable...neato but not so inexpensive! The KEPs have the aluminum outer housings and I've seen circular hole pattern to save even more wight on the PP surface and also outer housings. I'm curious about the SPEC limiting straps, beefier?..2 or 3? Also are you running their kevlar sprung hub disc?

Still lean the way to low pro and Sachs RE ..594 though.

[proffighter]

Originally Posted by Kraftday

Thanks for sharing the photos..

It looks like they casted their own scalloped pressure plate surface? With that maybe they changed the fulcrum point to change clampload? Also the chamfered vent holes are notable...neato but not so inexpensive! The KEPs have the aluminum outer housings and I've seen circular hole pattern to save even more wight on the PP surface and also outer housings. I'm curious about the SPEC limiting straps, beefier?..2 or 3? Also are you running their kevlar sprung hub disc?

Still lean the way to low pro and Sachs RE ..594 though.

I never fitted this PP and newer will, because I felt it too heavy and so I decided to fit a KEP Stage1...

Spec does not give any details about force etc... So I can only tell it should hold more torque than stock

[Ken911]

had on in my car lasted less than a year. it was too much on off chattered a lot. so driving in traffic just tore it up. currently have a kep in my car and very happy with it. It is rebuildable also, So when it gets worn and the disc needs replaced you can send it back for a rebuild for a fraction of the cost of buying another new pressure plate.

[DohertyCM]

Ok so if I am hearing this correctly

I should get the KEP stage one pressure plate....(600 lbs torque / 3200 clamping)
now what about the clutch disk and other parts?

Can you give me a shopping list..?

Im only finding the pressure plate. Do I need a stock pressure plate or do I need to get the adapter set?

[proffighter]

I have the KEP stage 1 PP and a fidanza flywheel. The disc is out of the Spec kit. It's organic, so no problem for a daily driver. The flywheel may be too much for someone as it's easier to stall the engine, but idling is still stable





Here is what I found on the Kennedy page about

Torque Capacity with stock disc (in Ft. lbs.)

Clutch Stock Stage I Stage II
KEP 930 - '75-77 374 550 650
KEP 930 - '78-86 423 530 650
KEP G50 - '87-89 460 550 650
KEP G50 90+ 374 550 (Turbo) 650 (Race)
KEP 944 turbo 378 530 650

[wjfk32]

Originally Posted by philip j

I just did a stage 1 Kep. Can't get the pedal adjusted to where it was before. Are you saying your wrench has to adjust it inside the cab? I've only tried adjusting it under the car at the cable end so far. I can't get the pedal to return to the up position. Would like to hear back on how it goes. Philip

I haven't been by the shop for awhile (work). The engine is out. What I know is that I changed the cable arm-& inner bushings-clevis-pin-fork-brake-bushing-pedal shaft was shot..new clutch wire....etc..

Will try to go shop this weekend and see the progress--
I have a few leaks-- rocker shafts have to be replaced-engine..and some other minor things..etc..etc..

Will give an update and try to get some pics..


Walt

[DohertyCM]

I was going thru some photos making a shopping list, and I came across this photo....so I went out and retook the photo in a different angle so I could post it and maybe have you guys tell me what it is....and if it is what I think it is, tell me what type...

[philip j]

centerforce. they are that colour.

[Kraftday]

Roland, nice LW setup you have there. I'm a bit weary of the aluminum flywheels but looks fairly sturdy. Any chance you measured the disc thickness? Same segmented puck lining on both sides?..curious. Looks like no use of interfacing springs in-between the linings...that may help it bite rougher!

[Kraftday]

That’s a Centerforce DF252252 clutch package. Base Sachs parts and are modified by Centerforce in Arizona. They come only as a matched set with the modified cover and a sprung hub disc sold together. The DF stands for dual friction disc which features a full faced sport lining on one side and their segmented carbon/Kevlar lining on the other. They also update to add 3 limiting straps to prevent kinking damage on hard shifting (and a few other trick updates). These are higher clampload/performance and durable clutches but with the TQ your putting down it’s probably just not adequate.

Just found this nifty vid explaining a few trade secrets on the Centerforce line..



If you have some loyalty to this brand clutch..they have a DF255255 "low profile" that would suit your needs. What are your impressions of what you have? Is it slipping? How long has it lasted?

[Kraftday]

Originally Posted by DohertyCM

Ok so if I am hearing this correctly

I should get the KEP stage one pressure plate....(600 lbs torque / 3200 clamping)
now what about the clutch disk and other parts?

Can you give me a shopping list..?

Im only finding the pressure plate. Do I need a stock pressure plate or do I need to get the adapter set?

You will only need the adapter kit (starter ring gear & release bearing spacer extensions) if you go with a “low profile” clutch.


- Showing above a Sach RE ...594 PP with the starter ring gear extension (less ring gear) and the billet 304 stainless steel release bearing extension (work of art)
--------

So here are two ways you could go,
1, get a KEP pressure plate cover (standard, taller, default) or
2, get a ZF Sachs RE “low profile” PP cover and appropriate sport disc with the adapter kit.

The main concept here in your parts list decision is understanding the difference between the standard clutch and the “low profile clutch”. That original street friendly, rubber hub disc Porsche used fated a taller (heavier assembly) clutch cover and “deep bell housing” gearbox.


The KEP offers a 930 Stage I and II pressure plates with the standard (original taller) offset. These work fine and are less expensive with slight increase in pedal effort and stage II with heavy pedal effort. They feature aluminum cover assembly so they are lighter weight. Stage I with stock disc lining would work but updating to sport disc (w sprung hub) advised. Ensure when ordering the proper disc thickness is called out..this is critical! And yes they can be rebuilt.

Sachs clutches have many unsung engineering features and wrote the books on clutch technology. For the standard replacement 930 clutch they don’t offer a light weight aluminum cover housing. But they do offer lightweight, high performance (RE) clutches that are “low profile”. I personally prefer the lighter Sachs RE covers and to bring the majority of the mass further in towards the engine crankshaft. These in combination with the Sach RE sport disc will be more expensive but higher end quality. And yes Sachs has been reconditioning old clutches as exchange units since 1962 but the resellers are unfamiliar with recycling policy.

Probably best to describe your car, configuration to an expert reseller and have them generate a parts list estimate. That contact and ability to speak with experienced workshop experts will help ensure you get a solid package. Chances are your stock flywheel is ok to resurface (also the bolt surface of the cover assembly) but as an option you can have it scalloped on the outer most edges to reduce mass (and best to rebalance too). That will help free up some more power and response.

For the basic 930, 1978-88 clutch renewal job regardless of which package you go for..

999.113.264.40 Seal, rear main
930.102.042.00 Pilot bearing
930.102.206.00 Flywheel bolts X9
900.067.045.02 Pressure plate bolts X9
N.012.241.8 Spring washer X9
930.116.081.11 Release bearing
Lube for intermediate shaft splines! (Comes standard with Sachs discs)

[DohertyCM]

Thanks for all of the info...

But, if I already have a centerforce pressure plate, cant they rebuild the clutch plate as well? even though its a matched set?

I am about to get it out, started preping it for the drop.

The mods were done in 2006, there has been some stolen history with the car, so there is no telling what or how the car has been driven. But the clutch is bad.

I am giving the car the TLC that it needs, especially since I want to put it on the track.

Thanks for the info...

[proffighter]

Originally Posted by Kraftday

Roland, nice LW setup you have there. I'm a bit weary of the aluminum flywheels but looks fairly sturdy. Any chance you measured the disc thickness? Same segmented puck lining on both sides?..curious. Looks like no use of interfacing springs in-between the linings...that may help it bite rougher!

Brian

Here are some pics from both sides an thickness measurement: