Mustang Clutches

[Quinn Whipple]

Alright all you Mustang guy's. I need to ask some advice. Project car is 2010 Roush Stage 3.

I now have 1000 miles on the car and decided to see if I could get this car off the line. Car comes with Aluminum Flywheel and up-rated Exedy Cerimetalic disk and shimmed pressure plate. They claim the clutch is good for about 630ft# torque. For reference, the car dyned at 560tq on the rollers. Car was solid 500+tq from 2500-6000 rpm. Maybe I am just use to driving a high reving 4cyl but I was a V8 guy before the imports and I have driven many manual trans cars. Anyway, here are the symptoms. I turn traction control and car stability control off. I then try and get the car off the line and typical 2 foot drive the car. I figure that it should rip the tires off. Tires are the Sock 275 20" Coopers rs3's. Clutch will not deal with launching the car if rpm's start over 2500ish rpm. Maybe I am just trying to get it off the line with too many rpm. Car has 3.55 gears in the back which is as low geared as Roush would ship with the car. Now that being said, ease the car out of the hole so that clutch is fully engaged, slam the gas and it shreds the tires. To me it feels like a clamping force issue what do you guy's think?

Is anyone making a quality Twin disk for the 2010 platform?

Thanks

[David Buschur]

What did the car run ET and trap speed Quinn?

If it shreds the tires I don't think it's the clutch slipping. I haven't had my Shelby on a Dynojet so I don't have power numbers to compare. My car runs the stock Mustang clutch though and has held up good so far.

[Quinn Whipple]

Dave, Races are next week so the car hasn't been to the track yet. I was just out in the country trying to see how the car would leave the line. If I can figure out how to get this pig off the line without clutch slippage then we should be in good shape. I'll take it out tomorrow again and see if I can drive it a bit better. From what I am reading people are saying to not try and leave above 2500rpm. I though would think that if anything it would rip the tires off vs clutch slipping. But once car is moving and clutch is fully engaged, nail the gas and it holds in all gears even when shifting it in the power in 3rd and 4th. I've also read that quite a few people have had clutch breaking times that took longer. Maybe I'll be a bit harder on the clutch. It will either shell its nuts or bead the disk to the surfaces. Either way I have a result and we can move forward.

Dave, do you know if the Mustang has a hydraulic restrictor in the clutch slave cyl to protect the drive train?

[David Buschur]

No, I don't know what the car has as far as any clutch components. Mine, as I said, is running the stock Ford Mustang GT clutch. The car only has 12xx miles on it but I bought it to drive hard and have. On our dyno with the offroad pipes and manifold porting it put down 426 whp this spring. Last year with 396 whp it ran 12.003 at 120.66 mph, no problems from the clutch. I'm not expecting it to last too long as I've read the stories of them not holding up to much power. The car on a Dynojet was suppose to put down 520'ish, given the gains with the porting I'd say now Dynojet it should be close to 550'ish. Our dyno reads low in AWD in 2wd mode it reads insultingly low! haha Stock the car made 240'ish.

One more thing, I try to leave with mine between 2500-3000 rpm and ride the clutch out "slowly".

[Quinn Whipple]

Dave,

I took it out today, and it wanted to leave at 1500-2000 rpm, much more than that and the clutch didn't want to play with riding the clutch out of the hole. I'm starting to get alot of noise/vibration out of the trans when it's hot. Shifter is also sticking and not returning to center. I've reached out to the Roush factory rep and the sales guy where I purchased it with a video to see if what I am experiencing is typical (doesn't seem typical to me) and it just needs more break-in time on the clutch.

[David Buschur]

That really sucks, sorry to hear that Quinn, I hope they take care of it for you. I don't know what shifter is in your car, mine has the retro Hurst style shifter in it. It's notchy as hell but Shelby says it is suppose to be like that, it's the "old school" feel. It does shift well but the actual feel of the shifter makes you chicken to actually shift the car hard and fast.

[Quinn Whipple]

David,

I called Roush, I have to admit I received excellent and personal customer service. It was a welcome surprise. I was told that the "sticky" feeling is the shifter. It was "intentionally" designed for tight tolerance and when the parts come up to temperature and thermally grow dimensionally the expansion rates of the different metals cause the parts to stick. They say give the car 3000 miles if driving and if it's still doing it then they will fix the issue. I took the car out for drive when it was 90+ degrees out and once the parts started to get sticky I parked the car, pushed the clutch in and with the motor running, I rowed the gears 1-2,2-1,1-3,3-1,2-3,3-2 etc Let the car cool went for drive and it was noticeably better than before. I was also reading that the clutch system is self bleeding. Where it's a sealed system, i pulled the filler cap to normalize the pressure between here and where it was built (closer to sea level) to make sure that there wasn't pressure differential stopping the air from working it's way out. This also seemed to help but only time will tell.

[David Buschur]

Looking forward to how it runs, keep us posted.

[eric32]

Mustang clutch systems for Ford performance cars offer several alternatives for the proper blend of performance and drivability for your application.It's safe to say that the biggest vintage Mustang sore spot-outside of leaking cowl vents and failed window mechanisms-is unreliable clutch operation.

[Quinn Whipple]

I followed the factory manual on bleeding the clutch. Consists of pugging the brake reservoir and drawing vacuum for minimum of 60 seconds After bleeding procedure clutch is now behaving. Had a wonderful time at Miller last visit. The most rewarding part was pulling a Viper Venom 650 and running away from him to 145mph, then hard on the brakes for the turn.

[androdz]

As far as mustang clutches I have tried quite a few... Spec Stage 2(POS) Centerforce Dual friction(ruined stock tranny because of a recall on the clutch, it had too much weights and wouldn't release contact at high rpm due to the inertia. Dont you just hate it when companies don't r&d...) Changed to a gt500 built trans and a ADJ slave cyl and a centerforce DFX. The centerforce DFX clutch was a pretty on/off clutch and added like 5 lbs of calf muscle to my left foot from being so damn hard. After a while the clutch would engage higher and higher on the pedal until it was strangled effectively. I thought it was the clutch so I went and ordered a Mcleod RXT twin disc.

When I lowered the trans I saw the adj slave cyl had over extended and that was why the clutch was strangled. Either way I changed the clutch and that has been the BEST clutch I have ever had in my life. Like always if you do some research on the rxt/rst you will see some people stating that the rxt shutters and is too aggressive but like always none of them have it and are working on hear say. The clutch is very very lighter and is very gradual yet it holds over 1k tq. I wouldn't recomend anything other than it, Every single person that has driven my car has swapped to the mcleod rxt set-up. Mcleod has been making twin disc clutches longer than most companies have been making single discs.

As far as clutch issues on the mustangs I dont know on the 2011, But on the 05+ there is a big bottle-neck on the brake line, obviously no seller wants to tell you that because they will prefer to sell you another clutch set-up. For example here is the stock gt line vs the FR500S Clutch line.



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I ended up returning the FR500S clutch line because it interfered with my down pipe. I ended making a S/S braided line and reused the stock fittings on both ends. I did drill them to open them up a lot like on the fr500 line. That stopped the line expanding after the fluid was all heated up and flows better because it has a larger effective diameter now.

All things aside, David you never brought the bad bish down here to PR, I hope you bring the 2011^^

[David Buschur]

Good information, thanks for posting it all.

I'm installing an Exedy clutch in my car, next week I hope. Factory clutch is no disengaging with 765 miles on it. The car is sitting here.

I don't see a trip to PR in my future, just not into it enough to justify a trip.

[androdz]

NO prob when you remove the clutch inspect the clutch line to see if it is the same

[Quinn Whipple]

Androidz,

Good to see you here. Much less BS here.

Based on your pictures, My 2010 Roush has the brake line that is on the right.

[androdz]

both are clutch lines! one is the oem and the one in the right is the fr500s clutch line. It is made of bent metal and then changes to S/S mesh.