911 Hi Perf clutch options

[joetiii]

So in all the parts catalogs I see options for 915, g50 hi performance clutches flywheels etc. Nothing for the 911/901 transaxle. Am I just not looking in the right place?

[TimT]

This is on my xmas list of things to get for myself


JB Racing - Porsche ULTRA-LITE Aluminum Flywheels



this is on my xmas list of things to get for myself

[jluetjen]

Based on my research, these are your choices:

1) Stock pull type clutch from a 70/71. I have to admit that I was surprised at how heavy the stock clutch was at 16 lbs. It definitely makes up the majority of the clutch-flywheel assembly's weight since the flywheel is 8 lbs. Going with an aluminum flywheel (which I have on the shelf right now and weighs 4.5 lbs) is really a fairly small reduction in weight. AJ USA also has a clutch with an alloy cover.

2) A Centerforce clutch at over $1100(!). It's not clear that there is any reduction in weight since it really seems to be a modified stock unit. I guess the big benefit is that it has a higher torque rating and a shorter action.

3) Backdate to a 901 style push type clutch. I don't think that there is any benefit to this except it seems like there might be 1 or 2 more bolt-in aftermarket options by doing this. This would solve any ring gear issues since the ring gear is attached to the flywheel.

4) Go for a full aftermarket clutch like a Tilton. A FF2000 style single plate clutch would be good for 250 lb-ft and would cost about $600 for either a 5.5 inch or a 7.25 version. The problem I believe is that these are push style clutches, so I guess I could use the existing push style clutch cable cable set-up in my '69 chassis and I'll just have to pick the correct throw-out assembly. But what to do with the starter ring gear which is normally attached to the clutch cover on the 2.2's?

4b) Smart racing lists a Sachs clutch package but doesn't elaborate much on it.

For my race engine, I ended up using an aluminum flywheel with an aluminum Sachs 915 "Power Clutch" kit from our host. I weighed it at the time but I can't find my notes now. The Sachs (including the clutch disk) weighs 15.6 lbs for shipping, which is less than the stock clutch. The stock clutch ships at 17.2 lbs. so you've got about a 2 lb savings right there.

[joetiii]

Originally Posted by TimT

This is on my xmas list of things to get for myself


JB Racing - Porsche ULTRA-LITE Aluminum Flywheels



this is on my xmas list of things to get for myself

JBs site says these are for track only, no street use.
I drive primarily on the street and am looking for something that will hold up better to my upcoming 3.2ss.

[Fishcop]

I'm running a Wevo Streetlite

Welcome to Windrush Evolutions - WEVO - Porsche Products

[David]

My recommendation: Kennedy Engineered Products

[TimT]

What I have on my car now is a lightened flywheel and an RSR 915 aluminum pressure plate.. haven't weighed it..




Its pretty easy to convert a push to pull, or pull to push on the 901/911 tranny.. if you look at the bell housing where the pivot ball is mounted you can find in the casting the location for the other pivot depending whether push or pull.

I cant find my pics of a 906 flywheel... the machining costs for that look tremendous

[Walt Fricke]

Tim

The RSR pressure plate is about 4 lbs. The 2.7PP with its aluminum housing but cast plate is about 8. And the stock PP for a 3.0 (and 3.2?) is about 12 lbs.

I disassembled one of my RSR units, had the aluminum plate replated by a flame spray shop (they then remachined it), bought a RSR diaphragm spring from Sachs in Germany (TOB issues had worn the fingers), and sent all this to Clutchmasters for reassembly and installation of stronger drive straps. These are scarce as hen's teeth nowadays, I think, but otherwise can't be beat for a full sized clutch. Would work fine on the street also, I think.

Unlike the Tilton/Quartermaster etc 5.5" clutches - those are purely for the track because you can't slip them at all and expect them to last.

Joe - the 901 and 911 trannies are not the same in the clutch department. The 911 uses the same flywheel as the 915, so you can purchase a lightened flywheel and all your 911 tranny clutch stuff and ring gear will bolt right up to it.

I don't know just what you could do off the shelf for a 901 tranny for the street, though. Drill lots of lightening holes in the flywheel and get it rebalanced?

Walt Fricke