Jamie_GT3

Just talked to Eddie for a bit, seems I might be chasing my tail a bit.

What we know.
1. Tracked cars go through PP's and TOB's faster than non tracked
2. Tracked cars generate substantially more heat that the clutch stack has to deal with

Are we dealing with a heat issue and should be chasing cooling the bellhousing area with some cold air? I've heard that Cup cars have a bellhousing cooling duct but haven't seen it yet or understand where it is supplied from...

TRAKCAR

That's how I see it, the stuff just melts, we need more cooling!
That and better tranny oil, the farmer and Eddie used something different in the GT2.

997gt3north

Alex of sharkwerks sold me a non spring pressure plate and I don't even notice the difference from a streetability perspective. I know he also uses an even 'better' one for their 3.9 kit - I would give him a call and see what he suggests.

I also agree that what the turbo guys use for high HP cars is not likely the solution although there may be parts they use like a certain friction disk that could be very useful.

When I built 2 previous high HP VW family turbo cars, I ended up going with hybrid / mix and match solutions and had good results after learning some painful lessons. For the highest HP car I ended up finding a SPEC Pressure Plate without springs and using what they call a stage 2 type friction material Friction Disk. For the slightly lower HP car that the wife use to drive, I went with an Audi RS pressure plate that was spring loaded but went with the same SPEC friction disk.

My experience has taught me to use a non spring pressure plate if it is tolerable - my lowly 3.6gt3 now has one and it is fine (from Sharkwerks). For you higher tq guys, the 3.6 and 3.8 friction disk (think they are the same) does not look robust enough for those that track a lot - in the SPEC speak it looks like what is called a Stage 1 friction disk - I think just finding a better disk (lets say stage 2) is the way to go for the 4.0+ rebuilds.

I say all the above assuming you can reasonably well rev match.

M3EvoBR

Disc is not the problem in this case. Pressure plate and throw out bearing, and of course high temps...

Jamie_GT3

Talked to Matt at GT.

Cup Cars do have a bell housing "vent" about 2" in diameter off the side to let out hot air. Not sure if it's there on our transmissions. anyone care to comment on the 997 GT3/RS tranny's?

Also discussed that the cup car TOB and clutch kit will mount right up to our cars, need to run the hydraulics and get rid of the slave cylinder. I don't think any of us want to run a cup clutch, but it looks like fitment isn't an issue. Saw that the SACHS RCS 200 clutch has a twin organic option, asking them now if this might fit and work for our needs...

Ur20v

Drill a hole with a 2" tank cutter in the bell housing and run air hose from a external high pressure area...

Jamie_GT3

Likely need 2 holes, one in and one out...

Mvez

SPEC clutches offers a kit for our car, and they have an option for a "Super Clamp" heavy duty PP....maybe this is something to look into. Not sure how it even compares to the Sachs/OEM 4.0 PP......there are some good aftermarket parts out there, just have to find them.

Agreed, the disc is totally fine for what we are doing.

modoz61

First outing yesterday for new 4.0 Clutch, PP, TOB and LWFW ( approx. 100 easy street miles being drive from workshop to home then to the track)

4 laps to get tire temps up

first reasonable speed lap during a 4 - 3 - 2 downchange sequence left pedal stayed on the floor after going for 2nd and that's all she wrote

Data shows no overrevs, braking was straight line so no lateral loadings either (heel toe being used)

day over before it even begun

cant get workshop space until next Monday

Question is where to from here?

considering ERP Triple Plate Carbon - feedback seems to be favourable for being able to slip rather than on/off of full race clutches.....

Mvez

I think Porsche is paying Sachs to build flawed OEM clutch kits, so they break, in an effort to make the purists move on to their 991 GT3.

Jamie_GT3

It was the PP that let go, not the slave cylinder? If so that really really sucks and has me worried as my 4.2 is going together with a factory 4.0 PP and disk just like I have in my car now...

Working with some flywheel makers on an organic multidisk solution, but the ERP carbon or Tilton triple carbon gets good ratings. Super expensive and you have to adjust them about every 6-7k miles... Means dropping the tranny every year for me...

Jamie_GT3

Erp has a twin disk as well... Let me know what you find out for pricing etc... Maybe a small group buy is in order?

modoz61

Hi Jamie

$5K for triple

$4K for twin

Supplier is GMG as I have had great dealings with them over recent months

anyone interested I could go back and ask what they could offer

I need to move quickly as I have bucket list trip and track day in 3 - 4 weeks

but I was shattered at the 4.0 fail, the current standard clutch had done at least 14000 kms of track time and was on the list for replacement, I had anticipated more than 14kms out of the replacement

Jamie_GT3

I'm checking with carbonclutches.com they are supposed to be the ERP reps for the clutch. I'm asking about a group buy pricing (they're on 6 speed mainly in the turbo forums...)

If GMG has had good luck with it and has run it on GT3/RS at 8500 RPM then there's hope for us yet!

Very sad to hear the 4.0 went bad, maybe installation error?

modoz61

I trust the workshop I use implicitly, they also prepare and support a Cup car

that said they are reserving judgement until they do to tear down next Monday/Tuesday

w.r.t. GMG and ERP I may have it wrong but I was certain that ERP make to GMG spec I will be checking

It would appear the slave is okay as once the pedal came off the floor you could feel the slave cylinder working up to a point where there is clearly some obstruction in the movement.....