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Racing clutch advice


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Hi gang,

I am planning to upgrade the clutch on my dedicated autocross F Prepared 280Z and was looking for some experienced advice. I currently run the Nissan Motorpsort 11lb flywheel/Centerforce bi metal PP/solid bronze puck disk setup and it has been bulletproof for over 15 years. The downside is the complete assembly weighs 23 lbs and I considering the 5.5 or 7.25 multi disk assemblies that weigh a lot less.

Is anyone running this type of setup and have any recommendations? Are you running the automatic flexplate or did you buy the custom flywheel? What about throwout bearings? Did you switch to an anular setup or can you keep the stock lever arm?

The few cars I have driven with a 5.5" clutch were a bitch to launch but those cars didn't have near as much reciprocating mass or torque as my Z, is the 7.25 better in that respect?

What about brands? I assume all of the major players are about the same. Are there any friction materials I should stay away from?

Any advice is appreciated.

 

Thanks,

Tom

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You may want to try some searches, I do believe this has been discussed in the past. With that said, I've had a Tilton 7.25" dual disc setup on my road racer since day one (5 years now) and LOVE it. It's been absolutely trouble free for the duration and disc life has been much better than expected. In my case I stumbled across this setup (used) as the original owner was upgrading to a 5.5. It uses OEM slave components (not annular) except for a Tilton throwout bearing on the sleeve. Unfortunately it uses a one piece flywheel which as far as I know is NLA, but you might want to check into that.

 

I've heard Tilton has a slight edge on Quarter Master quality-wise but if the flywheel ever fails or the friction surface wears beyond spec I'll probably go with a Quarter Master button clutch setup using the auto trans flex plate as all the parts are readily available.

 

The clutch discs are sintered metallic (copper in appearance). Again, wear has been exceptional; over 30hrs on the current discs and they're still within spec. It's my guess that the 5.5 would not last as long, I've read 15hrs between replacements is the norm. Like you say, starting can be tricky, especially when they're hot, I still stall the car on occasion. I did run one autocross as a trial run after the initial build and found the constant start/stops in line irritating, but doable.

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I have had both. One thing to have from the beginning with these units is a winch for the trailer. No winch and you burn up parts way quicker than tires.

 

I sold Phil the full size 7 1/4" Tilton unit. I now have the 5 1/4" Quartermaster setup.

 

For autocross you would like the full size better with stock type final drive gearing. If you have anything lower than 4.11 and not over 23.5" tall tires you could use the 5 1/4" unit.

 

The button setup with the flex plate is lighter than the small flywheel. I have not done a MOI analysis between the two. The flex plate saves you the starter adapter.

 

With either one starting on and incline will be tough on them. You must make SURE you have room to go and then go. Starting only to roll five feet will do you in.

 

When I roll out of the paddock on cold 23.5" tires and a 3.7 rear gear lighting up the tires is no problem. So I feel with a 4.44 or 4.88 you should get a wild ride:)

 

Hope this helps,

 

Alan

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I ran the Quartermaster Pro Aluminum 5.5" dual carbon/carbon disc setup and loved it. Launching was tough but that was more a function of the 2.391 first gear in the Quaife and 25.2" tall tires then the clutch. But on a road race track having just a 1,500 rpm drop in each gear from 3rd through 5th made things real nice.

 

I could run 65 mph in first gear at an autocross and it just made each run silly.

 

2003MSAautox.jpg

 

Notice which way the course is going, which way the car is going, and which way the wheels are turned. None are the same.

Edited by johnc
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Hey Tom! You might remember me from the 2008 Solo Nats... I was with UTA FSAE and I think you observed a little 'argument' in the pits while you were working... =) I think you also helped collect cups for our awesome beeramid.

 

Anyways, while I was working at Taylor Race Engineering, I heard nothing but good things about the carbon/carbon clutches, the initial investment i high, but from what I heard they last so long that some race teams say that in the end they save money... They are also supposedly friendlier when launching. Unfortunately, I don't have any practical experience with them, just what I hear.

 

Last time I checked, both Tilton and Quartermaster listed a flywheel in their catalog, I don't know if they're still available or not. Taylor Race Engineering could make you one if needed, but it probably would not be cheap.

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Thanks guys! I still haven't pulled the trigger yet, but I'm leaning towards the 2 disk 5.5 Quartermaster with the "rally" friction disc. It's supposed to be a little more forgiving of some slipping... It will require the anular TB, but one thing I might do after I give it a try, is to swap the clutch MC to a smaller dia. to provide a little more pedal travel. My car tops out at about 20 in 1st, so the launch will probably be pretty painless once I get used to it.

 

It's good to hear the flexplate setup is the lightest, especially on top of being the cheapest .

 

...and I remember you Eric (correct?). I was very happy not to work grid for the SAE guys this year! Way to much drama! ;)

 

Tom

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You must make SURE you have room to go and then go. Starting only to roll five feet will do you in.

 

Exactly! As I told my co-driver who was having trouble getting the car moving, "3,500 rpm and come off the clutch while squeezing on the gas! Bitch slap the thing!" And be really, really smooth with the throttle at low speed. Its easy to get the car lurching and your foot will move in sympathy with the lurch and just make things worse.

 

And then there's the issue of trying to run the car on a chassis dyno...

Edited by johnc
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It takes around 1,000 F to blue metal and a regular organic clutch can create blue spots on a flywheel. Getting the carbon clutch to an even higher temp might vaporize the oil but it will certainly ruin the friction surface of the flywheel.

 

Its probalby better to make sure the rear main seal is good, the front trans seal is good, and install a good, non-leaking, throwout bearing.

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