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It is certainly true that any time saved by not dropping the motor to R&R the clutch can be given back messing around re-installing the clutch fork a time or two. I remember first time DIY my very experienced tech pal wrestling with it for what seemed like an hour to line up correctly. Also definitely need a movable stand as pwdrhound says, for the box as it is pretty heavy and cumbersome! when still in the air. "We" DIY'd it on a rented lift once, for a total of eight hours wrenching, and that included chicken and a celebratory beer or two as it buttoned up properly.
My most recent clutch done at a shop, the owner said he preferred to do it all engine out and having unfettered access was the only reason why. I think I paid him 8 but could have been 10? hours labor as I had supplied all parts, Seemed more than fair, especially "these" days.
On my last vehicle with a Viper T56, I used a fully adjustable tranny jack from Harbor Freight. It was not the greatest piece of kit but the pitch and roll adjustments helped a lot to get the input shaft into the clutch splines. It also used a tranny face mounted slave cylinder that was very easy to install and minor measurement to get a spacer machined for correct gap to pressure plate.
It is a bit easier to do these jobs on the more race car type of setups
1) Tilton setup on the motor
2) and 3) Size comparion of the Tilton 5.5" to the RPS 9.3" Triple
4) Tilton hydraulic release bearing- Replaces the slave cylinder and no more messing with the stupid clutch fork and needle bearings and all that
5) Comparison of OEM rear upright (top) to 996 RS rear upright (bottom). The difference isn't as dramatic as the front uprights, but the Motorsport part is a much beefier. Control arm angles are improved (no longer angling upwards from subframe to the wheel). The upper control arm mounts are fully enclosed vs just bolting to one tab.
The size of that is impressive, and they hydraulic release is very, very trick.
As you move ever away from having a streetable car... I had a similar Cusco twin carbon setup in my STi - it was very difficult to drive it on the street with its on/off tendencies - locked up like a champ, but ultimately went back to a more conventional setup.
The size of that is impressive, and they hydraulic release is very, very trick.
As you move ever away from having a streetable car... I had a similar Cusco twin carbon setup in my STi - it was very difficult to drive it on the street with its on/off tendencies - locked up like a champ, but ultimately went back to a more conventional setup.
Yeah, not much streetable about my car anymore haha. The RPS triple carbon that came out was actually ok to drive once I got used to it, slippable but had a kind of short window of engagement and if you didnt give it enough rpm/throttle it would shudder as it grabbed, which led to looking like first time in a manual or a stall.. But once I got used to giving it more revs it was nice. I had a 7.25" Tilton in a Supra I built years ago and it was super smooth and light pedal, easy to slip, etc. Easier to drive than the stock clutch in the car actually. The Tiltons are so easy to drive which makes one think it would be great for dual purpose use, but the material wears really fast so you don't really want to slip it at all. Kinda gets you because it is so easy to slip and drive, but wears so much when you do.
Yeah, not much streetable about my car anymore haha. The RPS triple carbon that came out was actually ok to drive once I got used to it, slippable but had a kind of short window of engagement and if you didnt give it enough rpm/throttle it would shudder as it grabbed, which led to looking like first time in a manual or a stall.. But once I got used to giving it more revs it was nice. I had a 7.25" Tilton in a Supra I built years ago and it was super smooth and light pedal, easy to slip, etc. Easier to drive than the stock clutch in the car actually. The Tiltons are so easy to drive which makes one think it would be great for dual purpose use, but the material wears really fast so you don't really want to slip it at all. Kinda gets you because it is so easy to slip and drive, but wears so much when you do.
On the plus side, torque capacity must be very high; if memory serves, the Cusco unit would hold 750 ft/lbs, but the carbon disks were considered consumable.
On the plus side, torque capacity must be very high; if memory serves, the Cusco unit would hold 750 ft/lbs, but the carbon disks were considered consumable.
These Tilton 5.5" RSR clutches are awesome but as T10 said they will wear quickly if slipped. I run the same clutch and we had to rebuild mine after about 150 dyno pulls and driving the car onto the trailer a few dozen times which necessitates slipping the clutch. The dynojet we used for the initial tuning was particularly hard on the clutch as you are continually spinning up a very heavy drum from a standstill for each pull which necessitates slipping the clutch. You don't wanna street drive it and always wanna use a winch to get the car on the lift. I have an electric winch on my trailer now. I anticipate getting a few seasons out of the clutch at this point. People just need to understand this is 100% a race only part and is the clutch that Porsche uses on the sequential transmissions in the GT3R and RSR. There is also a Sachs version of this clutch although I think that uses metal discs instead of carbon.
The torque rating on this clutch is 750 ft.lb but from the factory it's tested at over 900. Really amazing for such a tiny unit.
Last edited by powdrhound; 09-10-2024 at 02:58 PM.
On the plus side, torque capacity must be very high; if memory serves, the Cusco unit would hold 750 ft/lbs, but the carbon disks were considered consumable.
Yeah it'll hold more than I'll ever throw at it. The RPS is rated for more, 1200 ft lbs or something I think. Tilton rates the 5.5" at 750 ft lbs but they test each clutch before shipping and include all of the documentation and mine held 974 ft lbs. The RPS isn't compatible with the sequential gearbox I'm planning for down the road otherwise I would've stuck with it, but Tilton also has some benefits being so much smaller and lighter.
People just need to understand this is 100% a race only part and is the clutch that Porsche uses on the sequential transmissions in the GT3R and RSR. There is also a Sachs version of this clutch although I think that uses metal discs instead of carbon.
These Tilton 5.5" RSR clutches are awesome but as T10 said they will wear quickly if slipped. I run the same clutch and we had to rebuild mine after about 150 dyno pulls and driving the car onto the trailer a few dozen times which necessitates slipping the clutch. The dynojet we used for the initial tuning was particularly hard on the clutch as you are continually spinning up a very heavy drum from a standstill for each pull which necessitates slipping the clutch. You don't wanna street drive it and always wanna use a winch to get the car on the lift. I have an electric winch on my trailer now. I anticipate getting a few seasons out of the clutch at this point. People just need to understand this is 100% a race only part and is the clutch that Porsche uses on the sequential transmissions in the GT3R and RSR. There is also a Sachs version of this clutch although I think that uses metal discs instead of carbon.
The torque rating on this clutch is 750 ft.lb but from the factory it's tested at over 900. Really amazing for such a tiny unit.
One would think that with the advent of composite materials that have extremely high heat and torque ratings (I'm thinking PCCBs or similar), a carbon clutch could handle a little more slippage.
Yeah it'll hold more than I'll ever throw at it. The RPS is rated for more, 1200 ft lbs or something I think. Tilton rates the 5.5" at 750 ft lbs but they test each clutch before shipping and include all of the documentation and mine held 974 ft lbs. The RPS isn't compatible with the sequential gearbox I'm planning for down the road otherwise I would've stuck with it, but Tilton also has some benefits being so much smaller and lighter.
It'll (most likely) be a Holinger MXT, pneumatic actuated paddle shift setup. They make a "kit" designed to fit the 996/997TT. The factory race car sequentials don't have the torque rating for these setups.
OMG, that's a thing of beauty - "Torque rating for 24 hour endurance events is 900Nm (660ft.lb). This is not a failure rating but an indication of life expectancy in long events with 100% reliability."
Got to love that kind of product development and support. Curious about its street-ability...
OMG, that's a thing of beauty - "Torque rating for 24 hour endurance events is 900Nm (660ft.lb). This is not a failure rating but an indication of life expectancy in long events with 100% reliability."
Got to love that kind of product development and support. Curious about its street-ability...
Hollinger is producing the MXT for my car as we speak. I ordered mine about 5 month ago and should have it in about 2 months. The reliability factor is what sold me on it. The performance benefit with this gearbox will be huge on a racetrack. I do not believe this could be used on the street mainly due to the clutch constraints
Last edited by powdrhound; 09-11-2024 at 12:28 AM.
Hollinger is producing the MXT for my car as we speak. I ordered mine about 5 month ago and should have it in about 2 months. The reliability factor is what sold me on it. The performance benefit with this gearbox will be huge on a racetrack. I do not believe this could be used on the street mainly due to the clutch constraints
So will you limit torque for the purposes of durability, or will you have spare gearsets on the shelf and let it rip?
09-09-2024 | 10:07 PM
