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How do you like your twindisc?

Posted by YungTlon, Apr 24, 2020

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  1. YungTlon

    YungTlon Proven Member

    69
    4
    Joined Mar 6, 2018
    Pueblo, Colorado
    Hello all:) I wanted to hear your opinions on whatever twin disc you were running and how you went about breaking it in if you did at all! I see a lot of post about normal clutch break in on here but not twin disc. Dropping a fresh motor in the car and the first start up and drive is going to be on a twin disc not sure what brand yet. How do you like yours?? Thanks!
     

    Street Build 373  2

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  2. bastarddsm

    bastarddsm Proven Member

    5,262
    1,083
    Joined Aug 26, 2003
    Mendota, Illinois
    If you have to have one, do not buy any of them unless it has a gear-drive or common hub for both discs. It will trash you input shaft otherwise. Actually it's still going to trash your transmission.
     

    Showcar Build 6K  1

    1991 Eagle Talon N/T
    9.805 @ 144.00 · 1G DSM
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  3. 1cleangsx

    1cleangsx Proven Member

    353
    175
    Joined Sep 28, 2013
    Cheyenne, Wyoming
    Which is why I’m going with a single disc full face ceramic:rocks:
     

    Street Build 2K  11

    1990 Mitsubishi Eclipse GSX
    13.2 @ 104.64 · 1G DSM
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  4. YungTlon

    YungTlon Proven Member

    69
    4
    Joined Mar 6, 2018
    Pueblo, Colorado
    well what do you reccomend? I was looking at these options. Basically you’re just saying make sure Both disks “input shaft entry”/ splines where the clutch alignment tool goes in, you’re saying make sure those both math up exact instead of being separate like star shaped? ✡️
    https://www.tmzperformance.com/shop...isk-clutch-kit-dsm-4g63t-awdfwd-applications/

    https://stmtuned.com/collections/1g...products/act-dsm-twin-disc-sint-iron-race-kit

    https://stmtuned.com/collections/1g...quarter-master-6-leg-clutch-kit-1g-2g-awd-dsm

    thanks for your input
     

    Street Build 373  2

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  5. bastarddsm

    bastarddsm Proven Member

    5,262
    1,083
    Joined Aug 26, 2003
    Mendota, Illinois
    I'm saying that if you buy the clutches you listed from stm - the act, or the QM, they will destroy your input shaft. Some users have reported problems in as little as 1000mi. Any light weight clutch is very hard on the transmission as there is no weight to absorb the torsional virbrations from the engine. That just goes into the trans and beats the piss out of everything. Synchros, springs, hubs, sliders, ect.

    Lastly they all have just way to much torque capacity. If it's an extreme race application they kinda have their merits, but even then it's not a good idea anymore if you have a mitsu gearset. It just reduces the life of the already short life hard to come by parts. I also don't see any reason that you would need a twin with your mod list. .
     

    Showcar Build 6K  1

    1991 Eagle Talon N/T
    9.805 @ 144.00 · 1G DSM
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  6. Canadian_CD9A

    Canadian_CD9A Proven Member

    621
    230
    Joined Feb 10, 2012
    Winnipeg, MB, Canada
    For a GT3582, I would stay with a good single. How does an 18 year old afford a 6466 700whp build?
     
  7. jed344

    jed344 Supporting VIP

    862
    111
    Joined Jan 10, 2008
    Waterville, Iowa
    Honestly if you are asking about twin disks you should have a PPG dog box. That’s only time they make sense to me.
     

    1K  38

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  8. ist dwa

    ist dwa Proven Member

    371
    158
    Joined Nov 5, 2009
    Centerville, Ohio
    I absolutely love my twin disc, everything about it. I really like the noise as well, it's kinda like a bov, unique and you know you've got something going on.

    There are no draw backs except the drive train rattle on decel, I've just accepted it.

    I 100% recommend one.
     
  9. 98 dsm

    98 dsm Supporting Member

    65
    26
    Joined Mar 8, 2009
    milaca, Minnesota
    I have the act t1rr twindisk. Act recommends their race clutches to be broken in by a few hard slips letting the clutch cool down in between slips. I personally love the feel of the acts pedal compared to my wifes single disc act
     

    183  4

    1990 Plymouth Laser RS Turbo
    fwd · manual · 1G DSM

    Drag Race Build 242  8

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM

    Street Build 176  7

    1990 Eagle Talon TSi
    13.805 @ 99.67 · 1G DSM
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  10. YungTlon

    YungTlon Proven Member

    69
    4
    Joined Mar 6, 2018
    Pueblo, Colorado
    Haha mod lost hasent been updated yet LOL. Motor is fully built just hasent been put in yet . It’s getting a 6266 .82 ar . And I busted my ass in school and graduated college a few weeks after I turned 18 with an associates in Applied science.. aka welding .
     

    Street Build 373  2

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  11. YungTlon

    YungTlon Proven Member

    69
    4
    Joined Mar 6, 2018
    Pueblo, Colorado
    But anyway thanks guys, when I was breaking in the motor I was gonna do a lot of engine brake pulls and leave it at 10psi gate pressure , I was just asking because I didn’t know if 10psi on a brand new clutch would murder it .. I know I broke in my 2600 but after watching some toms turbo garage started looking into the twindisc
     

    Street Build 373  2

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  12. BLKGSX23

    BLKGSX23 Proven Member

    91
    0
    Joined May 1, 2009
    Sullivan, Missouri
    I know your car makes some power, what clutch are you running if you don't mind me asking?
     
  13. bastarddsm

    bastarddsm Proven Member

    5,262
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    Joined Aug 26, 2003
    Mendota, Illinois
    No the only clutches that really need a break in are the kevlar disc ones. They transfer some material into the mating surfaces that improves grip.
    Like a 2600 and 6 puck is good to go out of the box. IDK maybe like an ACT street disc might need some use before it develops full holding power, but I've not seen it

    Dude I've had everything. QM twins, Baller Tilton Carbon Twin, The full line of act. Back in the day I used eBay XTD stuff religiously.

    Right now the car is on an XTD Stage 4 pressure plate, and an ACT 6 puck disc. The XTD Stg4 is from what I can tell from measuring clamp load, basically a stock parts store replacement pressure plate that is painted. From what I've seen an ACT 2100 is essentially the same thing - though they may have better iron in the shoe. I'm not sure what the car makes for power, but it's gone [email protected] on this setup, and it weighs 3150 with driver right now. And it's a fairly torquey setup, I'd bet it makes 550ft*lbs, and probably over 700whp. I'm also using a PPG dogbox, which has a really long first gear (20% more than stock), and on 26" hoosiers, so I just murder the clutch on the launch.
    A few weeks prior the car had gone 9.90 at 143 on a 2600/6puck. The disc was shot at that point, and I felt the 2600 was too much, so we tried out the XTD. I'm shocked that it holds. I think a twin disc might last longer in this application, but it's really hard to beat the $100 ACT disc and $70 pressure plate, vs the $500 QM discs.

    When I have a synchro trans in the car, my favorite is a ACT2900 and a solid hub street disc. I have been mid 10's at 139 on that combo, and I think it will hold more. A 2600 might even hold it. The only draw back is that using it with slicks is hard on the disc. So if you drag race on slicks a lot, I'd probably opt for a puck disc and a lighter pp.

    I've also had good luck with a 2600 and a 4 puck solid in my car. An ACT 4 puck solid is the lightest full size disc for these cars. I need to measure it, but I'm 90% they have less MOI than a set of quartermaster discs. But I think as I've learned, I'd probably say 2100 act disc is the most you want on a stock trans.

    I personally really like the ACT discs. They are pretty low cost, available anywhere, and I think they hold the best per clamp load. The drawback on them is the friction material is soft and wears fast, but that's what makes them hold good.

    I used to always run sprung hub discs, but any more just solids. The springs ACT puts in a sprung hub are so stiff, they might as well be solid. And then there is less risk of interference with the fingers and the hub preventing full release of the clutch, and shifting problems.

    A lot of you younger guys were not around back when the setup for all the fast guys was an ACT3200 and a oem 2g clutch disc. They wore fast, but guys were going 8's at 160 on stock transmissions back then and they were easy to drive. Everyone got all caught up in the hype with this new technology, and we took several steps backwards. Who cares if the QM lasts longer, if you can't get the car off the line.....

    .
     

    Showcar Build 6K  1

    1991 Eagle Talon N/T
    9.805 @ 144.00 · 1G DSM
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  14. GST with PSI

    GST with PSI DSM Wiseman

    2,658
    1,350
    Joined Jul 27, 2005
    San Diego, California
    How about the Exedy tripple? It's supposed to have the weight the twins lack for better drivability and smoother operation.
     

    Street Build 26K  18  143

    1991 Mitsubishi Galant VR-4
    12.030 @ 119.39 · Galant VR-4

    914  23

    1982 Yamaha Virago
    rwd · manual · Misc Vehicles

    Street Build 5K  74

    1992 Mitsubishi Galant VR-4
    awd · manual · Galant VR-4
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  15. bastarddsm

    bastarddsm Proven Member

    5,262
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    Joined Aug 26, 2003
    Mendota, Illinois
    Have not had one of those. I did have my tilton on a 25lb flywheel, so it had essentially the same flywheel inertia as a streetlite/act pp. Defiantly improved drive ability, and reduced harmonic damage to the trans. but it still has a big problem, 900 ft*lbs capacity, which is what the excedy triple probably has. And now you have a real BFH behind that to really hammer the trans. FWIW if you wanted to try it, you can get a heavier flywheel for the quartermaster. Same results, much less $$


    Something that few people understand/know about is that what makes the QM shift good isn't the weight, it's the clean release. The QM cover and diaphragm is very very rigid compared to a stock type pressure plate. There is much less flex in the system, and thus much less lost motion. It only takes about 0.100" of tob movement to release a QM, where as a stock dsm clutch takes like 0.250" and a 2600 is over 0.300" Stock our tob moves about 0.350" IRCC (these numbers are pulled off the top of my head, i have it written down somewhere) You can see why a QM shifts good, it gets plenty of release, and a 2600 barely gets released. This is also why the QM has such brutal engagement - it builds up it's clamp load so quickly, and not only that, it build up a TON of torque capacity quickly. Just ballpark it and say a QM gains 7ft*lbs per 0.001", a 2600 is only 1.6 ft*lbs per 0.001" If the cover and fingers on a QM flexed more it would be more manageable. I say QM because it's easier than saying twin, or PTT/QM/TIlton/Excedy, but they all work the same. PTT, QM, Tilton all have softer springs = less torque capacity. For some reason they all ship them with the stiffest springs. If you try and talk to them about it, they won't work with you, because in their eyes the clutch should never slip, the tires should. Well, fastest cars in the world use clutch slip to manage power, not tire slip. In our cars we just break sh** if we try and use tire slip. If we could spring them down to like 450-500 ft*lbs that would be a much better deal. Both tilton and QM used to make 8.5" singles using a forged cover like a qm. Those would have been a sweet setup for us I think. I'm pretty sure tilton offered one for a dsm at one time.

    From my experiments/testing, I'm pretty sure a stock dsm driveline has a torque capacity of about 350-400ft*lbs in first gear. Anything more than that, and it either spins tires, or breaks parts. Obviously this isn't a hard/fast rule, but generally. Run a welded diff, and the capacity comes up, but also moves more toward breaks parts. What this mean is that you gotta be able to find that 400 ft*lbs point in your clutch, and hold it there till the disc speed matches pressure plate speed. Then let er lock up.

    What a lot of people try and do is hit the tires, and let them do the slipping until track speed catches up to tire speed. That's hard because once a tire spins, it takes less torque to keep it spinning then it did to break it loose. So you use 2 step rpm and excess clutch capacity to knock them loose, then hope the track speed does not catch tire speed until you are going fast enough to stay on top of the turbo.

    After having a Tilton carbon for a while, I think a single 8" carbon setup to hold like 400 ft*lbs cold would be tits. It'll shift killer, launch easy, and the little bit of slip it has will put enough heat into it to make it grab down track. Excedy was close with the single carbons, but missed the ball by using it on steel floaters.
     

    Showcar Build 6K  1

    1991 Eagle Talon N/T
    9.805 @ 144.00 · 1G DSM
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  16. YungTlon

    YungTlon Proven Member

    69
    4
    Joined Mar 6, 2018
    Pueblo, Colorado
    Good information , thank you
     

    Street Build 373  2

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  17. We're on Boost

    We're on Boost Proven Member

    1,080
    88
    Joined Aug 25, 2007
    Seattle area, Washington
    Cool, I've been wanting to know these numbers for a while!
    If you can find where you've got these numbers written down, could you give a holler back to verify?
    Also, if the TOB stock moves 0.350" then I suppose the end of the fork would move about 0.650" right?
    I mean, that is just by scaling the "rocker ratio" off the drawing in the FSM, and the 0.650" I'm talking about would be measured where I put the red arrow on the drawing below:

    DSM clutch fork side view w red arrow at end of fork.jpg
     

    4K  20

    1990 Eagle Talon TSi AWD
    650 whp · 510 lb/ft · 1G DSM

    2K  0

    1990 Eagle Talon TSi AWD
    manual · 1G DSM
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  18. clutchtamer

    clutchtamer Proven Member

    35
    7
    Joined Apr 29, 2015
    Concrete, Washington
    ...which is exactly what my Hitmaster system was designed to help a racer do....

    hitmasterreleasecurve.png

    Grant
     
  19. clutchtamer

    clutchtamer Proven Member

    35
    7
    Joined Apr 29, 2015
    Concrete, Washington
    Here's a comparison of my ClutchTamer and Hitmaster products, notice how the stepped curve of the Hitmaster is able to hit deeper in the clutch's sweet spot zone without blowing thru it too quickly. Also notice how the stepped curve of the Hitmaster can get to full clutch clamp pressure much quicker than the ClutchTamer...

    clutchtamerhitmastercomp.png

    The next graph shows why simple hydraulic restriction (Magnus/Clutchmasters/Tilton) is a poor way for a drag racer to control clutch engagement. Notice how long it takes for them to reach the sweet spot, then how they blow thru the sweet spot too quickly...

    magnusreleasecurve.png

    You can change the rate of clutch engagement by changing the size of simple restriction, but there's always a compromise to be made between reaction time and having an effective amount of clutch slip.

    Grant
     
  20. ceedawg

    ceedawg Supporting Member

    1,532
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    Joined Jun 2, 2004
    laurelton, New York
    Pmd
     
    ceedawg

    2K  0

    1995 Eagle Talon TSi AWD
    manual · 2G DSM
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