t_g_farrell

iTrader: (1)

So it sounds like its time to get a new clutch setup on my 7. The old centerforce stage 2 is probably wearing down now and I hear some bearing noises that I assume are either throwout or pilot bearings. Looking at mazdatrix and racingbeat, they only offer an OEM level Exedy clutch for the 12A 215 size flywheel. I know I want something that has at least 50% more holding power than stock given the mods I have. I started searching around and sites like Jegs had some alternatives but then I stumbled onto the THMotrosports site:

https://thmotorsports.com/drivetrain...30&aid=9229074.

Oh my! We have 5 different clutch vendors to choose from with most at 2 or 3 power levels. The clutch vendors are:

Centeforce
Clutch Masters
EXEDY
Ralco RZ
SPEC

I probably should also post this in the performance section but I'd love to hear any stories/recommendations about THMotorsports and/or any of the mentioned clutch vendors.

I'll knock EXEDY and Centerforce out of the running because one is just OEM and I've had the other for awhile and fancy something different, er maybe better?

Maybe this discussion will be useful to others and not just myself.

rwatson5651

iTrader: (5)

Have you thought about a lightweight flywheel?
You could go with a 225 mm size which opens up your clutch choices. And it does rev quicker!
Exedy offers several clutches in that size that are upgrades from OEM.

I would not recommend the Centerforce Series 1.

I put one in my 13B a couple of years ago by mistake, (I thought I was getting the series II) and it slipped from day one.
I replaced it with a Exedy , cannot remember which one to be honest, but its not oem, and I have been very happy.

Banzai-Racing

iTrader: (11)

Clutches 79-85 RX-7 Clutch & Flywheel

t_g_farrell

iTrader: (1)

I have the 82 flywheel now which dropped me from 30 down to 23 lbs. I don't think I want go any lighter but it does open up more choices for sure.

If memory serves me right I have the "stage 2" centerforce, whatever that meant 20 years ago. Its got to have at least 30-40K on it now, its due in my opinion.

t_g_farrell

iTrader: (1)

Good link! Forgot all about you guys.

Is there a favorite recommended or one that seems to see the least returns or issues?

Banzai-Racing

iTrader: (11)

Never had a return on a clutch. We sell more ACT, next would be Exedy, then SPEC.

GSLSEforme

30-40k is not a lot of miles in such a light vehicle. That's the kind of life expectancy i saw street racing big block 400hp muscle cars years ago. Have grown up a lot since then(matter of opinion) and clutches last me a lot longer. My Tacoma has 200k+on original clutch with lots of life left in it. If you're an aggressive driver,keep that in mind when selecting clutch kits. I get a wild hair occasionally so installed an Exedy stage 1 clutch in my own Se,very slight increase in pedal feel but very smooth,excellent modulation/grip. Would suggest resurfacing flywheel and replacing e-shaft rear seal while off. Understood you have smaller flywheel which limits selection. My top choice would be Exedy,with LUK and Sachs offerings after that.

elwood

iTrader: (1)

I also like the Exedy Stage 1. I swapped from the OEM pressure plate / disc to the Stage 1 because the OEM pedal effort was too low for me. I own 4 cars with manual transmissions, and the OEM '84 pedal effort was much lower than any of them.

I've also had good luck with TH Motorsports, but I think you'll find the pricing for the Exedy clutches is almost the same everywhere.

Qingdao

iTrader: (3)

I use the three puck clutch from Exedy. I like it, but I think that is way too much clutch for your car.

I have a "stage 1" Exedy clutch kit in my garage I'm looking to get rid of, if you are interested. That stage one clutch held fine on my old 13B setup with an edlebrock; so I think it'll hold onto any 12A power.

I like the exedy products for our cars. I've heard horror stories about exedy from my buddy who does the Mitsubishi Evo thing. But I take that as a grain of salt because when you try to move 4k pounds with 800hp things are bound to get messy.

Jeff20B

iTrader: (13)

I like Exedy products in our cars. I'll settle for centerforce too. Valeo if you must. Avoid spec.

LongDuck

Another vote for Exedy Stage 1 for a street vehicle with mild modifications. I went with it in 225mm for -SE and with a RB light aluminum flywheel, which makes a very rev-happy combination. It doesn't idle nearly as smoothly as it once did, as I had to bump it up to about 1100rpm to smooth things out, but it is definitely more fun to drive now. I DD this car in traffic for the nice weather months and never feel like the clutch pedal is too stiff or engagement is too quick.

t_g_farrell

iTrader: (1)

I would use Exedy but I have a 215mm flywheel and not intending to swap to a lighter flywheel. Exedy doesn't offer the stage 1 in anything but 225mm sizes.

My clutch is probably still good but I know I have bearing noise which I think is the throwout bearing, so if I'm dropping the tranny I'm redoing the clutch as well. Not pulling the flywheel but will dress it up some on the car. Last time I had the flywheel surfaced and replaced the rear main seal, so that should be fine. Since the clutch isn't down to rivets yet the surface should be fairly good. I'll wait until I see it to make sure its fine.

Thanks for all the feedback, really helps to hear it. This will probably be a late Feb or Mar project based on my other projects happening at the moment.

Jeff20B

iTrader: (13)

I'm voting against a Stage 1 Exedy because you have a 12A which is NA and is only a fat Nikki with unknown size venturis (in other words, you aren't making quite as much power as you ultimately could). You don't require the extra torque handling capacity of the Stage 1 so I recommend a stock duty setup. You also probably don't want to have such a heavy pedal in an SA which can wear hydraulic components more quickly than a stock duty pressure plate. It's also more pleasant to drive.

Note: only the 84-85 have a "helper spring" assembly at the clutch pedal and a longer stroke making the pedal effort noticeably easier than previous years. This is why Mr Duck suggests a Stage 1, and is why I'll probably go with one as well. We both have 84-85 cars. I've also had my stock duty pressure plate slip in 4th gear while boosting. The disc is one of those solid HD style jobs from ACT which glazed pretty hard while slipping but recovered probably due to the copper woven through the friction material. Smelled like burned broccoli mmmm.

TG, if you haven't done this yet, you might consider swapping to an '81-82 flywheel for the nice reduction in mass while still working with 79-80 rotors. I'm sure you are already aware of this nice upgrade, but I'll mention something you are probably not aware of. The 81-82 flywheel has a 225mm friction surface, though you still need to stick with a 215mm pressure plate unless you perform one task to enable use of a full 225mm pressure plate. You need to have just the outer edges of the three rivets machined just enough to allow fitment at the flywheel. These rivets anchor the three springs which connect the p-plate's friction surface to the "basket". I have some pics on the forum somewhere showing a backyard mechanic's version of this mod, but I worry about causing an imbalance. Though the flywheel and rotors were also drilled (not by me) to static balance them so who knows where the vibes really came from.

Something tells me you probably won't bother with this 225mm mod, and I will probably skip it as well, but will most likely go with a 225mm disc on my 81-82 flywheel at least. I'm also swapping in an 81-82 front cw while it's apart. These weigh about 1 pound less than the half-circle SA 79-80 front CW and replace them perfectly.

Oh, one more thing that popped into my head. "While you are in there", I suggest looking at your trans mount. They are easy to overlook and they tend to cause clutch chatter or shimmy after a clutch job which people attribute to a disc that is still breaking in even though there honestly should be zero chatter at that point. I wouldn't mention it if I hadn't seen it in person.

Jeff20B

iTrader: (13)

Oh, one thing I forgot to mention about the 225mm pressure plate upgrade is you need to get the long bolt and spacer kit from RB or MZTX for the light steel flywheel.

t_g_farrell

iTrader: (1)

Thanks Jeff, already running with the 82 flywheel. Wasn't aware it was 225.

My 12A is putting down probably the max that a non-ported 12A can do. This based on comparisons while running with a buddy who has a Petit built RX8 which can barely get away from me. I need to measure this sometime to really have some numbers, all I know is its fun.

Good tip on the 225 PP fitment. I think I'll stay with the 215 for now. Kind of leary of the balance issues as you stated.

When I put on the 82 flywheel, I got some very minor new vibrations. From what i could gather, thats normal because that flywheel is close but not perfectly balanced to the rotating assembly but its within tolerances. That trick with the front CW might just be the answer but then you are into the front cover. If I build or rebuild a new engine (ported of course) I will definitely keep it in mind.

t_g_farrell

iTrader: (1)

Going to go for the stock Exedy for now. If I don't like it or it has issues then I would probably go to Banzia or THMotorsports and get better clutch.

Ckforker

That's next on my long list. Keep us posted on how you like it. Since mine is bone stock, I won't be getting anything too exotic.

t_g_farrell

iTrader: (1)

I normally don't change clutches until I hear noises or it starts slipping. The stock Exedy from rockauto is a good price, hard to beat it anywhere else.

I'll try to give you notice when I do this so you can observe the shenanigans as it happens. I have a tranny lify now since doing the F150 clutch so its even easier now.

Qingdao

iTrader: (3)

I got my stage II three puck clutch from Rock auto. I got the part numbers and typed them in the search bar on the rock auto site. Cheapest I found, and nothing wrong to date.


If you don't already have one... this dudad helps more than its weight in gold. https://www.harborfreight.com/slide-...-pc-62601.html

t_g_farrell

iTrader: (1)

I/m already way ahead of you, have those for many years now. Thanks tho.

workaholic

I've been using the Exedy. It has a nice crisp grab. Very driveable but "sporty-feeling".

workaholic

Ah! I was wondering why my pedal was so light. Got my pedal box from an 84 when I swapped over to Manual.