Clutch Information

Last updated: February 16, 1999

Reviews of various clutches, flywheels, etc.


Date: Wed, 03 Feb 1999 13:50:12 -0800
From: Gene Kan

The stock one weighs 22 lbs. But weight is not the measure. The proper measure is rotational inertia. The less weight on the edges the better. If the weight is concentrated in the middle, the flywheel could weigh 100 lbs and it would rev faster than the 22 lbs stock one.

I have what I think is a 15 lb flywheel (I'm dumb and forgot to weigh it) but it has cutouts on the outer edges. It revs very quickly, and there is almost no flywheel runon (rev, then lift the gas and listen to your engine burble).

Noticeable performance difference? LOTS. Any time you accelerate, the engine spends quite a bit of energy accelerating the flywheel. With a lightweight flywheel, more of that energy is expended accelerating the car, rather than the flywheel. I get noticeably faster revving throughout and faster acceleration.


Date: Sat, 9 Aug 1997 00:38:29 -0500
From: "Kevin T. Wyum"

Sorry to hear about David's problem, but I think a little I told you so may be in order here as well probably a little apology to Chuck DDS. From a few people that blamed his failure on his incompetent driving. It's pretty obvious that the RPS wasn't all certain list members claimed it to be. I've been using the Centerforce for over 3 years now and I'm harder than just about anybody on a clutch in a third gen and they don't fail until you wear them out. As I said before use what works for other people that abuse things more than you and you will probably come out in good shape. For those that need to know, the centerforce dual friction is available from Mazda comp for 423.00 which includes the pressure plate. If you're not a member I think it's 500.00 even.


Date: Sat, 09 May 1998 19:13:20 -0500
From: brad barber

On clutches, I have a CFDF along with the Racing Beat steel flywheel. This flywheel, with counterweight, weighed 17 bs. My car was dynoed at 355.7 hp at the rear wheels, giving it, by most calculation methods, over 400hp at the flywheel. The CFDF has worked perfectly in autoX standing strats, drag racing standing starts, AND in stop and go traffic around town for over 5,000 miles so far. I recommend the CFDF for anyone who needs an all around street/race clutch setup.


Date: Sat, 31 Jan 1998 21:16:45 +0000
From: "David Lane"

Tri-Point has developed a performance pressure plate designed to be used with a stock clutch disk. It is available for all RX-7s and also for the Miata. The pressure plate provides 37% additional clamping power and increases pedal pressure by 10%. Cost for the pressure plate varies by car, but is no higher than $350.


Date: Sat, 09 Aug 1997 13:19:39 -0600
From: Jason Banks

I have had my RPS turbo clutch for about 8000 Miles and for about the past 3000 it has not felt near as strong as it did new. I think it is slipping a little bit. I don't drag race, although I have made a few hard launches on the street having fun racing my roommate(More like stomping on my Roommate in his Sentra SE-R). I can't remember ever having slipped it much at all. Most of my mileage is highway in long stretches at a time.(Dallas to Fisher La. to Dallas to San Antonio to Big Spring TX to Odessa TX to El Paso TX to Houston TX to Dallas TX to Boulder CO. About 3600 Miles). Needless to say I won't be getting another RPS. In defense of the RPS I loved it when I first got it. I will probably go back to a stock disk next time.


Date: Tue, 21 Oct 1997 18:11:30 -0700
From: Daniel Huang

I picked mine up for around $2000. Not bad considering in Japan, many claim to say that the clutch lasts a good 100,000 miles of hard driving. Very grippy yet the pedal feels good.


Editorial comment: For $2,000 for the Mazdaspeed I could replace a Centerforce CFDF four times! Having tons of experience with replacing the clutch in my '69 Firebird (~600 ft/lbs of torque!), I can guarantee that nothing will last 100K miles of drag racing. I had to replace it about every nine months. I got to the point where I could replace it in about 6 hours from the time the car was jacked up to the time it was properly adjusted (the first time it took 3 days). So I would recommend not spending this much money on a clutch. --Steve

Clutch Masters

Date: Wed, 21 Jan 1998 11:29:16 -1000
From: (Richard H Thomason)

I have now gone through FIVE clutches trying to get a decent 60 foot time from my car.

The latest victim is a Clutch Masters 8 nub brass puck and pressureplate I destroyed 2 weekends ago. Before that I smoked a Clutch Masters puck mated with an upgraded stock pressureplate. Before that a CFDF died, preceeded by a Tri Point set up, preceeded by the stocker, which actually never failed.

After killing the second to last clutch, I took a long hard look at what I could be doing wrong. To avoid excessive heatup during burnouts I installed a line lock. I also made sure to avoid virtually any slippage at launch. Clutch Masters assured me that if I only tried their pressureplate with their puck, everything would be fine.

Bullsh#t. After a lengthy breakin I took the car to the track, installed my M&H tires, used the line lock to perfection, dumped the clutch at launch, ripped through first and watched in amazement as my tach pegged redline on the second gear shift. Spectators told me that sparks flew out from under the car as the stupid puck slipped its way to a miserable death, no doubt destroying my heretofore pristine flywheel face as well.

Bullsh#t, bullsh#t, bullsh#t!!! I'm so stinking sick of clutches right now I thinking of getting an auto.

Anyway, puck clutches suck for street driving anyway, so now I'm either going with another CFDF or something by ACT.

BTW, the line lock is kinda neat. It makes big gnarly burnouts a snap and, though I haven't tried it yet, I think you can use it to prespool your turbo at the launch. This is most interesting


Another glowing review for clutchmasters (NOT!!!)

Date: Thu, 7 May 1998 08:26:56 -0700
From: " Ray Lochhead"

I would save your money and not waste it on ClutchMasters. They have a reputation for lasting very short time. It is a pain and $$$ to change it everytime it slips , even with a lifetime warrenty I wouldn't buy one.


Date: Tue, 08 Sep 1998 10:48:22 -1000
From: (Richard H Thomason)

>I looked at the clutch masters site and the clutch that is
>most appropriate for my car is the Stage II Kevlar, but they
>want more than $600 for it.

Been there, done that. Slipped in third all the time. Took it out for a Clutchmasters puck which also slipped (yes really, pressure plate was junk). Dumped it for the CFDF.


Date: Tue, 08 Sep 1998 10:48:22 -1000
From: (Richard H Thomason)

Before buying the CFDF at least check out ACT. Dirk Starksen @ is good to deal with. I plan on going with an ACT when my second CFDF burns up at the next street car shootout here in Nov.


Date: Tue, 6 Jun 2000 19:50:50 -0500
From: "Steve Obrien" (
Subject: RE: (rx7) (3) Difference between M2 and SRX7 clutch kits?

>I was about to order the package from Shane Racing but saw M2 had a similar
>Other than a price difference of $859 vs. $849, they look pretty much the
>same (both ACT clutches?).

The M2 kit comes with the pilot bearing, throwout bearing, and pilot seal included. Ray's kit doesnt come with any of the above hardware, he charges $99 extra so the total price is actually $99 more from


Date: Wed, 7 Jun 2000 00:00:31 -0700
From: Chris Moore (

My buddy and I just ordered and installed (6 weeks ago) an SR-supplied ACT clutch, which came WITH the pilot bearing, pilot bearing seal, and the "throw-out bearing" (which is really a "pull-out bearing," isn't it?).


Date: Thu, 30 Apr 1998 00:45:23 -0400
From: Jeff Hurst (

I just ordered an ACT pressure plate from Mazda Competition for $159 and got a metallic clutch disc directly from ACT for $77. This is the same clutch that Ray runs in his 85 rx7. I know that I don't really need the holding capabilities of this unit at this point but could definately use the durability. It's cheap, strong and it should last. I should be running it this weekend at the NIRA event up here at Englishtown.


Date: Thu, 30 Apr 1998 09:59:27 -0400
From: "DeanColver" (

Wise choice. I have ACT pressure plate but was running a stock disk. Finally cracked the center of the stock disk after 12k miles and about 20 runs at the track.

Have fun with your new binary shifting - bark out of every gear :-) It settles down a little eventually. I installed one with a stock pressure plate and it worked great.


Date: Thu, 7 May 1998 11:05:40 -0400
From: "DeanColver" (

I was using ACT pressure plate and stock disk...worked great for 13k miles but then I (blew up the engine).

...but all that is beside the point... The clutch disk looked great other than the cracking in the metal around the hub(must of been the 20plus drag launches at 7000rpm). But there was plenty of material left. Looks like I will be going to the binary six puck clutch. BARK out of every gear. Oh well that's the way the rotor turns...


Date: Fri, 4 Jun 1999 16:50:09 -0500
From: "Brad.Barber" (

Regarding the ACT 6-puck clutch...

This thing isn't for wimps. Pedal effort is increased, clutch engagement happens in about 3/8" of pedal travel, it grabs like Vise-Grips on a wet noodle, and you can barely back the car up without snapping the ring gear.

Getting the car on the trailer is... well ... interesting. If your city has hills, forget it, you'll find the flattest route to all your regular destinations

Drive-throughs become as harrowing as the Nurburgring and every yellow light is your sworn enemy.

But, when you get the car on the track ... Ohhh, baby is it sweet. Shifts are crispy and quick. You can turn up the boost and never worry about clutch slippage. Put in Pettit (or your supertuner of choice) solid diff mounts, upper A-arm bushings, and Heim joint control arms and the driveline REALLY gets solid. Shifts feel almost sequential ...'click' 2nd, 'click' 3rd, 'click' 4th ... corner approaches .. quick heel-toe rev-match (WideFoot pedal helps) ... 'click' back to 3rd, power on. Damn fine stuff.

It's your call. Do you want to cruise around town, sunroof open, looking pretty with the chicky sitting shotgun and maybe have an occasional street race? Forget it. But if you drive the p*ss out of your car, on a real race track, and have enough power to spin mere mortal clutches, try one. You won't spin it, but remember, it's not for sissies.


Date: Wed, 04 Nov 1998 12:27:28 -0500
From: Shiv Pathak

I have been the first to use the Exedy cerametalic racing clutch on a 3rd gen, in the US. I also use an Exedy Chrome-moly lightened flywell. On the move, it's a wonderful combo. Quick, crisp enagement, positive pedal feel, liveable pedal effort, and super strong grip (seems to get better the hotter it gets). On the racetrack I have absolutely no complaint. Couldn't be happier.

On the street, however, stop and go traffic is unacceptable. The clutch is pretty darn noisy from a standing start and sounds as if my tranny is about of come loose. I would not recommended for street use in the RX7. Unusually the cerametalic Exedy clutch in SCC's Project Eclipse is just wonderful. I heard good things about their Prelude unit too.

I'll be trying another clutch on Project RX-7 since it is designed to be streetable as well as race-able. It initially looked as if it would break-in and be quiet, but after 4k miles, no luck.

The guys at Exedy feel that the 3-puck disk may not like working with the Chrome-moly flyweel and all would be good with a conventional flywheel. Could very well be true.


Date: Wed, 10 Feb 1999 22:27:00 -0500
From: "Jason B. Smith"

I am running the Quartermaster 5.5" dual clutch pack in my car with the Quartermaster four pound aluminum flywheel. This entire setup weighs maybe 12-13 lbs total, compared to 28 lbs for the stock flywheel alone. Basically, it revs to OHMIGODTHATS%*#$*REDLINE faster than you can even imagine. However, my car is also no longer street legal (prepped for SCCA) and driven ONLY on the autocross and/or race track.

This clutch is incredible - it hooks hard and will support Godzilla levels of horsepower, but it's not even remotely streetable. You'll light the tires at every stoplight, in front of every cop, in every school zone......and if you try to slip the clutch around town, you will fry it fast. I'd highly recommend it for RACE ONLY (not street driven daily driver) cars as the best solution possible.....

There's a reason it's listed as a "Competition" part in the Mazda Motorsports catalog.....


Date: Tue, 13 Apr 1999 21:21:59 -0400 (EDT)

To expand a bit on the McLeod RevLOK and RevLOK 2 clutches--from what I understood from their rep at this year's SEMA in Cincinnati, RevLOK focuses on using very high friction material in the clutch plate, along with heavily sprung hubs. They believe in being gentle to the driveline, and letting the high friction material do the work. If you look at the frictoion surface area of McLeod's RevLOK, and compare theirs to a typical performance clutch plate, you'd understand what McLeod's philosopy is about.

A correction. Abel Ibarra's car is the FLACO sponsored '72 Mazda R-100 powered by a 1.3 L Turbo Wankel. Abel broke into the 7-second range, not 9 seconds. He used the RevLOK multi-disc clutch configuration.

So here's the part number for the RevLOK 2 Pure Performance Version (as opposed to the RevLOK Street Performance):

For the FD ('93-'96) Rx-7 Twin Turbo, the number is 72745-02. The TO bearing number is 16509.

The RevLOK 2 comes with a max diameter clutch disc and pressure rings, max number of fully-encapsulated springs (for max grip and reduced drive-train shock). This is the version to choose if your vehicle has according to McLeod's lit: "highly modified, high-horsepower-producing engine that uses Nitrous Oxide, Turbo, Supercharger and blower equipped" Sounds like most of you guys' FD [3]s:)

The Street Performance clutch is intended for vehicles with "modified induction systems, mild cams (Not for Wankels:), exhaust system, pulleys, and modified computer systems" Sounds like the clutch for atmospheric pressure [2] and [1] Rx-7s.

You can call McLeod (Clutches, Flywheels, and Bellhousings) at 714-630-2764. They're located on the left coast--1600 Sierra Madre Circle, Placentia, CA 92670

Disclaimer: I'm not being compensated by McLeod. I don't even have a RevLOK 2 installed in my FD! I'm just providing information I picked up at the Cincinnati SEMA '99 back in Feb. I vidoetaped Mr. George McLeod during his talk, so if you're interested, Phil, you can view it yourself:)

FWIW, I do plan to buy one along with a Fidanza flyweight flywheel. I picked up Lou Fidanza's brochure on their superlight flywheels. With a group buy, we Rx-7 enthusiasts can support our own racing careers instead of Cam Worth's;) $800 for a Pettit Racing 8-lb flywheel---GIVE ME A BREAK!


Date: Fri, 8 Oct 1999 16:27:33 -1000 (HST)
From: (Richard H Thomason)

If the question is will a light f/w increase hp when measured on an engine dyno with the motor taken out of the car then the answer is no.

If the question is will you get higher hp/torque figures as measured on a chassis dyno such a a Dynojet the answer is YES. Make no mistake about it--a light f/w will generate more hp/torque when measured from the tires (the only figures anyone should give a rats ass about).


Date: Fri, 8 Oct 1999 17:25:06 -1000 (HST)
From: (Richard H Thomason)

The ONLY reason drag racers often (though not always) use heavy f/wheels is because they allow you to launch a bit better ON SLICKS--once the launch is over, the lighter the f/w the better the acceleration will be at ALL other points in the rev range in ALL gears (though the degree of superiority will lessen in the higher gears). At competative drag racing levels, the launch takes on an exaggerated importance which has no real relevance to "street" driving or even to drag racing on street tires. I have competatively drag raced my FD with both stock and 8.5 lb f/ws and know without a doubt that on street tires the car is significantly quicker in et and higher in trap speeds with the light f/w. There is not one single advantage to making your engine turn a crappy 26 lb mass of steel if you do not have the traction necessary to allow you to take full advantage of the "slingshot" effect you can get on launch (and only on launch) upon dumping the clutch. Any FD can spin its street tires on launch with even an 8.5 lb f/w with ease--meaning there is no way to really take advantage of the superior stored momentum afforded by the OEM f/w (indeed, you're more likely to run into terminal tire hop in an FD with too much launch energy). The same is true even with "cheater slicks" if you are making some decent hp. My best ever ets all came with my 8.5 f/w on M&H drag tires which I could light up quite well at will on launch if not careful.

You want a car that accelerates quicker, builds boost faster and is easier on your syncros in every single gear whenever you apply the throttle, then get a light f/w. You want a car that has the POTENTIAL on slicks to launch very quickly and get you a precious few extra tenths of a second (but slower trap speed) those few times you go to the strip, but accelerate slower in all real world (ie, street) situations thereafter (and chew up yer synchros to boot), then by all means keep that heavy OEM POS.

Anyone who thinks the differences in throttle response and acceleration are insignificant had better drive back to back with both setups. I've done it a bunch of times in 2 different FDs. The differences are large. Also, keep in mind that the quicker drop off in revs between shifts is a desirable trait since it allows you to shift much harder without fear of beating your synchros. On a turbocharged car it is quite a good thing to be able to shift fast and keep your boost up.

Just for those who haven't heard me say it before: Heavy flywheels suck.


Date: Wed, 17 Sep 1997 12:34:27 PDT
From: "Jeff Witzer"

Chippy1971 wrote:

> Hey Kyle, your interest is the exact same application I have in my
> 93. I have a Centerforce DFC and Pettit 8.5 flywheel. My car has
> mild mods and driving in stop and go conditions is easy. I had
> heard that light flywheels were difficult in traffic but mine has
> been no problem, so don't let that scare you. At this point in my
> mod stage I don't know if it made a significant difference however.
> Since the car had a bad clutch since I bought it, I don't know if it
> was the new clutch that made the improvement in performance or the
> flywheel. It did seem to have a bit more pep to it, but again this
> could have been because I wanted to feel something different for
> the $$ I just spent? Point is, the clutch/flywheel is user
> friendly and does have great holding power. I'm just breaking it in
> though and will let you know when I thrash my first Mustank with it!

I can vouch for this combo as well. I've had the Centerforce DF and Pettit 8.5 flywheel for 40,000 miles now and I've had the car since new. The new combo made the car feel much lighter, nimbler, and tossable. The engine wicks up quicker both under load and free (great for rev-matching blips) which helps get the turbos wicked quicker as well. I've got some pretty serious mods and I'm putting some ponies through it, but in 40,000 miles it's never slipped and when I dropped the trannie to put a close ratio 5th (I had to replace the 5th gear syncros anyway), the clutch looked fresh! For the first week I had to be careful not to stall it, but I learned to keep the revs up a few more and haven't had a problem since. This is a great combo with the short shifter kit... completely changes the personality of the car. When I drive stock RX-7's now, they feel kind of truck-like in comparison.


Date: Wed, 26 Nov 1997 12:15:00 -0500
From: Felix Miata

To recap what we know is available (flywheel plus counterweight): Mazda Comp (per Bill Lester) Aluminum (11 lbs) - $357 Mazdatrix (per Nowhere Man) Steel (17 lbs) - $364 Aluminum (12 lbs) - $430 Racing Beat (Felix) Steel #11446 - $373 Aluminum #11449 - $449 Pettit (per Nowhere Man) Aluminum (8.5 lbs) - $700 Aluminum (11.5 lbs) - $650

(Do those prices even include the counterweight? - (NM))

[At these prices they should include the clutch - FM]

Keep in mind a few things when selecting a flywheel:

A 12# flywheel isn't as much lighter than a 17# as it appears. Don't forget that the entire flywheel mass includes flywheel, counterweight, and clutch when making comparisons. The drop between stock & 17# is the largest because most of the difference is concentrated near the periphery.

If you drive in stop & go traffic a lot, you will probably be less happy with 12# or less unless using low ratio/high number axle gears.

Lighter flywheels can be counter-productive in getting a good drag-racing launch. Avoid the lighter aluminum flywheels if 60 foot times are important to you.

Racing disks, usually metallic compounds, wear out pressure plate and flywheel faces much faster. On pure race cars this is a non-issue that doesn't carry over to street use.

"Aluminum" flywheels are more expensive to make because they must use a steel friction surface. This multi-compnent composition offers an additional opportunity for failure, making all-steel a better reliability value.


Date: Wed, 26 Nov 1997 00:03:55 -0500
From: Carlos Iglesias (

BTW, the Mazda Comp (flywheel) is actually a Centerforce alum. unit. Or at least they must have had a bunch of CF (flywheel) boxes left around to pack it in ;-)

While I'm talking about Mazda Comp, Dean Colver and myself have been very happy with a stock clutch disc, and Mazda Comp's 150% pressure plate. Not muss, no slip, no (big) buck.


Date: Mon, 16 Mar 1998 13:05:39 -1000
From: (Richard H Thomason)

Oops, one thing I forgot to mention. If you want to really spruce up your low end get a light flywheel. I have Tripoint's 8.5 lb unit and it really helps. My butt dyno is always suspect, but with the lite f/w, there is no doubt. The lighter unit only helps once you have fully released the clutch however. Initial throttle takeup during clutch release is probably worse than stock because you have less kinetic energy flowing into the drivetrain as the lighter f/w comes online. Throttle response after the clutch is out however is much crisper.

I have had occasion to drive my car back to back several times with and without the lite f/w and I found there to be little difference in initial throttle take up (you need just a tad more revs), but much better response at all other points in the throttle.

You will always get a lot more good old smokin tire spin if you rev up and dump the clutch with the stock f/w though if that's what you like.

On the other hand, the lite f/w allows you car to rev faster and the faster it revs, the quicker your boost will build. This is nice if a Honduh is bearing down and you are fudging along at 2k in any gear.


Date: Tue, 09 Feb 1999 12:26:54 PST
From: "Jeff Witzer" (

The 8.5 pound flywheel (Pettit sells it, I don't know who makes it) has a replacable (bolted - well, machine screwed, really) friction surface, and is ENTIRELY STREETABLE. I've been running it with a CF DF for 70,000+ miles!

The area outside of the friction surface is the minimal amount of metal required to get a toothed surface out to the starter. Very nice design, really.

> The aluminum one that Racing Beat sells is 11.5 pounds, and has a
> steel friction surface, which can be changed. It does come with the
> counterweight. The counterweight moves the mass of the weight closer 
> to the center of rotation, so its effect is not the same as adding
> weight across the entire surface. It has proven quite durable, and I 
> and many other people have suffered NO streetability problems. I
> would not go with the 8.5 pound flywheel, because I would *think*
> that you may see a difference then, but I am not sure, because I
> have no first hand experience with this FW. As for the performance
> end of it, I will concede that you lose some inertial effect during
> a launch in a drag race, BUT, I believe you more than make up for it 
> with the engines ability to rev up faster.

Plus, for racers and street performance, the useful advantage is in the power that you can apply coming out of a corner when you're at 3000+ rpm anyway. And for rev-matched downshifts, an amazingly small blip is all that's required. You loose engine braking, but that's a misuse of the engine, anyway.

>> PLUS, the Al flywheel with counterweight is less durable and much
>> more expensive.

How is it less durable? I've gotten 70,000+ miles out of mine with no ill effects. When it's time to replace the clutch, I'll just bolt on a new friction surface. Piece of cake. The whole car feels lighter and more nimble.

>> Al is used primarily in race applications, where once you get
>> going, how the clutch and flywheel interact is not as imperative
>> (ie - Al is not as good for autoxing and dragging as it is for road
>> racing).

While a heavy flywheel might help your 60' times, it'll rob you in the top end. Besides, you're tire limited anyway. Autocrossing is probably the optimum place for a light flywheel. Lots of delta V.

>> I beleive you can go as low as an 8lb Al flywheel (RP?), but again,
>> streetability is hindered.

Not true. A few extra rev's and a slightly more delicate clutch foot at take off, that's all. Everything else is improved. Up shifts are smoother, downshifts are AMAZING, roll-on acceleration (the kind that most of us use most of the time) is much improved.


Date: Fri, 18 Jun 1999 14:00:12 PDT
From: Firas Arabo (

Shane racing sells the 9.5# flywheel, a nice compromise between the 8.5 and 11#. He sells it on its own, and as a kit with the ACT disc and plate for $816. I'm also sure he will sell the flywheel separately. Definitely worth the call. The flywheel comes with a BOLT-ON (crucial)(not riveted) replaceable friction surface, counterweight and all necessary hardware included.


Date: Thu, 4 Feb 1999 04:52:32 EST

(stuff on which clutch he bought snipped) As for the flywheel, I went with JUN's Ultralight Cromoly Flywheel. What I was able to find out is that aluminum flywheels are weak and need replacing often. Cromoly probably never needs replacing and rarely does it even need resurfacing.

There are two types of flywheel JUN offers, lightweight and ultralight which are both cromoly. Lightweight is more ideal for daily drivers but I needed something for real performance and that is why I chose the ultralight. UL weighs 9.2 lbs and requires the use of automatic tranny counter weight. Ultralight is what JUN uses in their 250mph skyline and 8 sec. Silvia.

JUN's products are backed by their name and I have no doubt in their products. UL flywheel is $475 and counter weight is $130. Now as far as drivability. I have had the car back for about two weeks now and its been hard driving it daily. With the combination of the clutch and flywheel, I have basically given up my daily drivability. With careful engagement, the car can be driven OK but hills are almost impossible. Living in San Francisco does not make this easier. I have to avoid driving where there are hills :-) During the first couple of days, I killed the car atleast 10-15 times per day due to its on or off action.

As far as performance, I haven't broken in the clutch yet so I have been drivng the car very lightly. I will update the info on how it performs. The total cost of all this was

Clutch Masters stage 4     $ 691
JUN UL flywheel            $ 475
Counter weight             $ 130
6 required bolts           $  25
Shipping of all (next day) $  80
Labor (discounted)         $ 200
TOTAL				   $1601


Date: Sun, 4 Apr 1999 22:26:13 -0500
From: "Nelson J. Starbranch"

...I purchased a Centerforce Dual-Friction from MazdaTrix for ~$450 with shipping. I chose the CFDF due to it's popularity and success with my fellow Houston RX-7 Club members although I decided to keep the stock flywheel(more on that later).

...After speaking with Rick, he suggested I drive his car w/CFDF and 8lb flywheel so that I could determine whether or not I wanted to stay with the heavy stock unit. I took Rick up on his offer, drove his car, and was flabbergasted! Where had this been all my life! I was surprised when I drove the car without any stalling or bumping, there were none of the negative effects that I had heard and were wary of(my personal findings, YMMV). The RPM's shot up fast and the car seemed livelier. Now I had to order a flywheel.

I checked all the websites I could think of(results posted below) and decided on the 8lb flywheel from Mostly Mazda or should I say M2. Mostly Mazda is a fairly well known rotary shop and quite frankly not knowing the differences in flywheels, I went with the cheapest. I placed an order with M2 for the 8lb f/w with Brian(who was most helpful and patient with my questions). Brian commented that most people chose the 11lb f/w for street use and that the 8lb was more race oriented. He mentioned that although there were no real drivability or performance issues with the 8lb, there was a possibility of some drivetrain noise due to the thinner 8lb f/w. Now before everyone jumps in and testifies that there is no drivetrain noise, let me just comment that my 3rd gen is my daily driver, and although I'm sure there are many folks with the 8lb that experience no noise, with my luck, I'm sure I would be the one with loudest drivetrain known to man. With that in mind, and not completely convinced of a huge performance difference, I ponied up the extra $10 and ordered the 11lb f/w.

Source            Weight   Cost  Counterweight Incl?*
Mostly Mazda        8.00   425          Yes
MazdaTrix          12.00   430          Yes
Racing Beat        12.50   430          Yes
Mostly Mazda       11.00   435          Yes
Shane Racing        9.50   450          N/A
Rotary Performance  8.50   500          Yes
RX-7 Fashion        8.00   550          N/A
Rotary Performance  9.25   650          Yes
Pettit             11.50   650          N/A
Pettit              8.50   700          N/A

*Before I start getting replies on who does and doesn't include the counterweight, let me just say this is from the information I gleamed off of the websites and I do not attest being the absolute final word. This is just an FYI of my cursory findings and is no way an endorsement.

Brian sent the f/w UPS 3 day ground and I received it as promised. Total with shipping $445. The f/w looked so sharp, I almost didn't want to install it. Almost. I did notice a stamping on the engine side of an eagle and MI Clutches and Flywheels. It is all aluminum except for the ring gear which is bolted on in three parts and the friction surface which is riveted on. If anyone can remember or notices, it would be interesting to see what other companies manufacture these.

Well, a few weeks later, Rick was able to fit me in and the clutch and f/w were installed yesterday. Kudos to Justin for a job well done and next time we'll get the Jack in the Box order right(inside joke). Justin was almost able to lift the tranny back into place w/o assistance. Almost. :)

First impressions. After backing out of the driveway, I almost stalled the car in 1st. Almost. I'm not so sure that it's due to the f/w so much as the grippier clutch. Since then, I've only come close on two other occasions and am getting quite acclimated to the new setup. The contact point is much lower on the pedal now. Again, I'm not sure whether it's lower than stock or that my original was just so worn. Car definitely seems 'alive' now. Revs are quick, very quick. It also seems smoother going into the gears, I've heard lightweight f/w's were easier on the synchros. Freeway speeds are a lot of fun! Just in 5th the revs climb ever so easily. Another observation. I usually engine brake(I know, I know, please no flames, we've had this thread before). When I downshift now and release the clutch, engine speed doesn't seem to fall at all making engine braking very ineffectual(maybe I can break the habit now although it sure does sound cool).

Anyway, just my observations for the curious and for any others thinking about making the plunge. For everyday driving I wouldn't fear the lightweight f/w. I'm sure there may be a few things I've missed. I welcome any and all comments/questions.


Date: Fri, 8 Oct 1999 18:02:57 -0700
From: "SR Motorsports" (

Actually we use light weight flywheel in our race cars. We have used the aluminum 9.5 pound and light steel for years. The stock heavy flywheel would also work in our cars but it _tears_ up our transmission by not allowing the Rpm's to fall fast enough( broken gears and dogs ) Our 60 foot times are no different with the 24 pound heavy stock or with the 9.5 aluminum. The car builds boost and doesn't care about the rotational mass/force .

Throw-out Bearing

Date: Thu, 14 May 1998 15:57:32 -0400
From: Demetrios Karagiannis (

Actually according to Peter Farrell the sign of a worn throw out bearing is when foot is off the clutch you will hear the bearing noise or whining or spinning sound when it is pushed in you will not hear it.

Clutch Master Cylinder

Date: Fri, 6 Apr 2001 06:19:11 -0700 (PDT)
From: Chuck Westbrook (

Mazdatrix lists two different clutch master cylinders for the FD.

    FD01-41-990B for 93 only
    F100-41-990B FOR 95-95

Does anyone know if there is a real difference and are they interchangeable?

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