SR20 button clutch

[Matej]

Dear Zilvia,
Has anyone you know used a button clutch and flywheel setup on an SR20? These two seem to be the most popular manufacturers:
Quarter Master® Home page
PowerTrain Technology Racing Clutches

Supposedly Quarter Master actually offers the button flywheels already pre-drilled for the SR20 pattern as a special order item. PTT sells blank flywheels that need to be taken to a machine shop. The universal diameters are 4.5", 5.5", and 7.25", and all can be made into single and twin disc clutches, while some discs can be used in triple or even quad disc configurations.

Here is a 7.25" twin disc on an LS1. The complete setup weighs about half as much as an LS1 flywheel alone.



For the ring gear/flexplate, while a custom one can be ordered, the flexplate from an automatic FWD SR actually works perfectly and does not weigh much. That is what both the SR20 button clutch setups I have found online used. Both were in Datsun 510 race cars with single 5.5" disc clutches weighing in at around 11lbs. for the complete setup, with the flexplate included.
My only concern is how long it would last for street driving. I want something as light as possible, but I would also like it to last a bit, so right now I am considering going with a single 7.25" disc.

If anyone has any experience or input, it would be much appreciated.
Cheers.

[TheRealSy90]

Originally Posted by Matej

Dear Zilvia,
Has anyone you know used a button clutch and flywheel setup on an SR20?

Came across this today on Instagram, username: "mikinyu_" running a Powertrain Technologies 5.5" ls button clutch on his sr20. Unknown what flywheel he is using, although they do offer "custom flywheels" on their website. There's a vid of him free revving the engine and it revs up insanely fast with this clutch. Like a street bike.

Video: https://instagram.com/p/BSOLJXhBA1o/

Pic: https://instagram.com/p/BRHnNn3BI9K/







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[LuckyX2]

Lol that necrobump. Anyway, I'll be running a 7.25" Tilton cerametallic twin disc on mine with the Clutch Master FW-727-TDA aluminum flywheel. All off the shelf, no custom work needed and should be about 16-18lbs total which is lighter than just the stock flywheel.

[hanzbrady]

We run a Tilton setup on our drag car here at the shop.

[TheRealSy90]

Well I wasn't gonna start a new thread when there was already an appropriate one.

I'm curious if anybody has ran the 5.5" clutch kits. Gotta figure out what flywheel that guy used [emoji15]


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[LuckyX2]

Quartermaster will make you a flywheel for a 5.5" Just need to send them a flex plate from an auto trans. I was quoted at $250 when I called them ~3 weeks ago.

If you're doing any kind of street driving, you'll want a 7.25" though.

[TheRealSy90]

I think his is customs from powertrain tech. I'm sure either works. Probably best to keep matching flywheel with whatever clutch is used.


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[bfellini]

As long as the clutch can hold more than your current engines peak torque, there should be no major issue... The torque rating of a clutch is more important the HP rating, and shocking loads (high rpm clutch dumps, etc) can potentially spike the torque load, so add a safety margin of torque when shopping around.
Also, you'll have incredible drivetrain noise due to harmonics when using a non-sprung hub clutch, or a clutch with even with a sprung hub clutch with incorrect spring tension, usually around the 2k-~3k rpm range, so be prepared... It is LOUD, but not a mechanical issue, per se...
Also, with such a significant reduction in mass, your clutch/flywheel life will probably be impacted when used for daily driving, as you'll have to rev a bit higher and slip the clutch more when moving from a standstill.
Just weigh the (very marginal, practically nonexistent outside of bragging) benefits from this setup and cost, and the fact that this is a daily driver....

As a very humble opinion, the same money (possibly even less depending on your setup) could be spent in other areas of overall performance for SUBSTANTIAL gains without reducing daily comfort.

[Def]

I definitely recommend the cerametallic clutches on the street (Tilton markets them as their "rally" clutches), rather than the much thinner sintered bronze clutches which get REALLY aggressive when you get some heat in them.

The cerametallic clutches are actually not hard to drive. I have a 7.25" AP Racing flywheel (looks like it's long discontinued), at about 7.25 lbs total weight, and very very low MOI (entire ring gear section outside the clutch friction surface is half stock thickness with huge lightening holes). The clutch is a Tilton twin rally cerametallic setup with the ultra high ratio pressure plate. This is very easy to modulate, and has a super light pedal feel even with the "grey" spring. I think it can hold something silly like 600+ ft-lbs.

The UHR PP gives a wide engagement window, so it's very easy to back the car out of the garage slowly or inch it around. The clutch does get more grabby when there's some heat, so it is possible to stall it out due to the very low MOI of the setup, but in general it's not too hard to just give it some revs and stop taking up the clutch as soon as it grabs. Not much chatter on engagement like larger pucked clutches tend to do, it just grabs quickly.

I also had an aluminum crank pulley on the engine and it was just too much. The engine revved up and down like a sport bike, and it was exceedingly difficult to get it to 100% catch the idle with my AEM Infinity 506. I put the stock crank pulley back on, and it got much more reasonable by slowing the engine response. It still revs way quicker than any stock sized clutch and flywheel, but at least it's "semi-streetable" now.

I think the setup would be much nicer to street drive with one of the Comp/ACT etc. 7.25" flywheels since they have about 3-4 lbs more mass, and it's mostly on the outside of the flywheel vs. mine. The setup I've got now is pretty sweet on track. There is no synchro drag at all when shifting, and the engine revs up and down effortlessly.

[LuckyX2]

Originally Posted by bfellini

Just weigh the (very marginal, practically nonexistent outside of bragging) benefits from this setup and cost, and the fact that this is a daily driver....

As a very humble opinion, the same money (possibly even less depending on your setup) could be spent in other areas of overall performance for SUBSTANTIAL gains without reducing daily comfort.

I'd argue that reducing rotating mass to get the revs up quicker is a significant change. Especially for someone like myself that autocrosses and wants to be able to accelerate as quickly as possible out of slow corners.

And then there's the improvement to the car's feel with the better shifting.

Originally Posted by Def

I definitely recommend the cerametallic clutches on the street (Tilton markets them as their "rally" clutches), rather than the much thinner sintered bronze clutches which get REALLY aggressive when you get some heat in them.

The cerametallic clutches are actually not hard to drive. I have a 7.25" AP Racing flywheel (looks like it's long discontinued), at about 7.25 lbs total weight, and very very low MOI (entire ring gear section outside the clutch friction surface is half stock thickness with huge lightening holes). The clutch is a Tilton twin rally cerametallic setup with the ultra high ratio pressure plate. This is very easy to modulate, and has a super light pedal feel even with the "grey" spring. I think it can hold something silly like 600+ ft-lbs.

The UHR PP gives a wide engagement window, so it's very easy to back the car out of the garage slowly or inch it around. The clutch does get more grabby when there's some heat, so it is possible to stall it out due to the very low MOI of the setup, but in general it's not too hard to just give it some revs and stop taking up the clutch as soon as it grabs. Not much chatter on engagement like larger pucked clutches tend to do, it just grabs quickly.

My Tilton cerametallic is getting delivered tonight. 8lb aluminum flywheel from Clutch Masters to go with it. Glad to hear you like yours and it's not a total pain to drive. I went with just the high ratio on mine since I didn't like how rapidly the clamping force of the ultra high ratio falls off as it wears. I did the orange spring for 580ftlbs. Kinda thinking the high grey (680ftlbs) or ultra high orange (670ftlbs) would have been better though now that I'm reading how easy yours is to drive. I should only be at 400-450ftlbs all said and done but headroom is always nice to have.

Also, I'm hoping to set up a test rig for my old stock flywheel and RPS clutch vs the new aluminum flywheel and 7.25" twin. Just a simple rod I'll put through the center, wrap a string around with a weight on it and drop it. Video both and figure out the acceleration difference to get the inertia difference. Wouldn't be surprised to see a 75% reduction in inertia considering it's about half the weight and that weight exists at a smaller radius.

[LuckyX2]

Got my Tilton/Clutch Masters setup. So light.

[slideways2004]

Sorry for updating an older thread, but how is it!?

[LuckyX2]

I only got it ~2 weeks ago. Waiting on the rest of my 350z trans conversion parts before I put it in. Just need my bellhousing to come back from the machine shop and the plate from collins will hopefully ship soon.

[ultimateirving]

Originally Posted by LuckyX2

I only got it ~2 weeks ago. Waiting on the rest of my 350z trans conversion parts before I put it in. Just need my bellhousing to come back from the machine shop and the plate from collins will hopefully ship soon.

If I may recommend, the z-speed hd CsC if you have a later model z trans with internal Slave. I went through an oem and aftermarket slave before I bought the heavy duty. If you have an external Slave trans I have no recommendations :-p

[TheRealSy90]

I wanna do an sr20de build with the 5.5" clutch for maximum rev up speed [emoji15]


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[LuckyX2]

Originally Posted by ultimateirving

If I may recommend, the z-speed hd CsC if you have a later model z trans with internal Slave. I went through an oem and aftermarket slave before I bought the heavy duty. If you have an external Slave trans I have no recommendations :-p

Already have the z-speed csc