Exedy clutch

Discussion in 'Boss 302 and S197 Technical Forum' started by Boss2620, Jan 19, 2019.

  1. Boss2620

    Boss2620 TMO Intermediate

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    I spoke to Evan Kline at Exedy about a fix for our Boss clutch problem. I explained that the Hyper Single seemed to be the hot setup and asked him what his opinion was. He was familiar with the issue and thought the cause was deflection of the pressure plate housing at high rpm. He didn’t think the Hyper Single was the best option though if your primary usage was street driving. He suggested to use their Stage 1 racing clutch and mustang GT flywheel or one of their lightened flywheels. Exedy doesn’t make a clutch that will directly bolt to a Boss flywheel so no matter which Exedy clutch you use it will require a flywheel change in our Bosses. He said all their clutches are tested for functionality at 18000 rpm and their pressure plate assembly was made with sheet metal that is approximately twice the thickness of the OEM unit. He said their Stage 1 unit weighs two pounds more than the stock Boss pressure plate due to the beefed up housing and theirs is much more rigid. He told me that the organic material disc would last twice as long as their ceramic disc and would have better street manners. Has anyone tried the Exedy Stage 1 racing clutch and if so what were your results on the track at high rpm?
     
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  2. 80KM2E

    80KM2E Canada, Eh?

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    Yes The Stage 1 or "mach 500" 07807CSC with Exedy lightened Flywheel EF502 is what I've been using after my OEM exploded on track. Its held up great so far for mixed use and was very cheap! Once this one explodes or wears out I'll likely go for the Hyper Single - just because.
     
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  3. gww52

    gww52 TMO Advanced

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    I have the Stage 1 ready to install.
    Sounds like I made the right choice.
     
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  4. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    Get it in there! :) :D
     
  5. Boss2620

    Boss2620 TMO Intermediate

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    Gww52 let us know how it works out. Which flywheel will you be using?
     
  6. Boss2620

    Boss2620 TMO Intermediate

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    80KM2E did this setup solve the high rpm lockout?
     
  7. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    Looks like he has a GT. Should have solved his exploding clutch issue though!
     
  8. gww52

    gww52 TMO Advanced

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    I'm using the Exedy light weight flywheel and its a Boss 302.
    My original clutch has never been a problem but the springs in the disc have me concerned, hence the changeout.
    I also have a Calimer Stage 1 ready to go.
    My MT82 has never given me trouble but 31,000 miles and lots of track time I think it's a good idea.
     
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  9. blacksheep-1

    blacksheep-1 TMO Addict

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    Surprised to find that he doesn't recommend the Exedy Hyper Single since every PWC, IMSA, TA and SCCA Boss 302 that I've ever seen or heard from uses one.
     
  10. 2012-Boss

    2012-Boss TMO Addict

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    I think the recommendation is for a street car that is used for some track days. Keep in mind that the Hyper Single disks are extremely thin compared to a more street oriented clutch. Brand new, the Hyper Single disk is only 6mm thick, that includes both sides of the friction surface and the metal disk they are bonded to. I suspect that repeated stop and go street use would rapidly wear the Single out compared to a thicker OEM style disk.

    For pure track use, the Hyper Single is awesome. I have three seasons on mine and when I had it out this winter it still measured over 5mm thick.

    I do wish Exedy made an aluminum flywheel for our cars...
     
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  11. smallblock

    smallblock TMO Advanced

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    I have the Exedy Mach 500 Clutch and stock flywheel on my dual purpose 11 GT. It makes 440 RWHP at 7400RPM redline. It has been great. No lock-outs, drives like stock, just a stiffer pedal. About 15,000 miles on it so far.
     

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