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i'm looking get Mazdatrix aluminum flywheel and quartermaster 5.5" twin disk clutch. please give some feedback if you have used this setup or similar setup for road course. thanks
You might get more info on it over at RX7Club. Pretty sure you can’t go wrong, but there’s some variation in performance vs cost depending on what friction discs are used. I went with the Tilton clutch and put it on their flywheel. Still sitting on jackstands though so no feedback yet.
Well I decided to pull the trigger on the Mazdatrix 5.5" setup. The whole assembly is crazy lite. Less than 11 lbs with hardware. Definitely not going to be street friendly or easy to get car on trailer. Will try to get it in next week.
Does this use a stock slave cylinder and throw out bearing? I was under impression all the multi-disc setups used hydraulic TO bearings... if not then that is awesome and I may look into this setup closer if you have good luck with it!
Interesting, I guess if they make a TO bearing that interfaces it then that works.
It's only about $80 more to go with the hydraulic setup though, which may prove to be a better long term solution in race applications. I wonder if you could take measurements off of that one Mazdatrix sold and find a cheaper interchange part though... looks like a pretty standard assembly.
I contact them and confirmed that the setup is designed for the stock hydraulic system.
Also the TB is a custom piece. It's as small as possible to get the most leverage on the diaphragm. The retaining clip in the back is custom laser cut and fabricated to the bearjbe. You won't find and off the shelf unit that will work. Im hesitant to use hydraulic TB because if there's any issues with it you gotta drop the tranny.
Ah okay, I didn't realize it was custom made. Let us know when you get it all together, I'm curious how that setup works. I'm looking at making the jump sometime in the next few months... gotta get the diff back in the car and make sure it isn't going to explode first though.
I got the new clutch in over the weekend. It's the easiest tranny i ever had to remove. Took about an hour to remove it and I was taking my time since it was my first time on this car. Getting it back on is a different story. Took about half an hour just to fight it to line up both disk. Had to pull the tranny out a couple times to make sure both disk were still lined up.
Didn't drive it the road yet because we're working on a new muffler. I did drive it back and forth in the shop. It's noisy with the clutch disengage and it chatter like a **** on take off, as expected with any multi disks race clutch. Rpm drops crazy quick. The clutch pedal is significantly more heavy. I haven't try to adjust the pedal travel yet. But initially, the pedal went to the floor. I and to hand pump it several times for the pedal to come back up.
Last edited by trackjunkie; 01-14-2019 at 02:29 PM.
Looks good! Think you could still drive a car up onto a trailer with it?
i'm going to try to drive it on the trailer. slipping the clutch a little while its cooled shouldn't hurt it too back. a few guys ive talked to that use this clutch on different cars said they drive it on the trailer, but their engines also have lot more torque at low rpm. i'm prepare to get an electric winch if i have to tho.
Mazda just lists it as "Dynamic Damper" on the parts listings... I'd guess it's safe to pull off. I'm curious how much it actually weighs, I've never given the thing two thoughts.
This setup revs super fast. With a stock 1st gear, it should not be too bad. Plan on using the starter a few more times until you are used to it. Heel toe downshifting will take some getting used to but it's nice once you are there.
I drove my 2nd gen with this setup on to the trailer for years, that had a tall 1st gear. I ended up getting an electric winch, but waited 3 years to install it so it couldn't have been that bad!
This is awesome on the track, but would be a PITA on the street.
nice thanks for some feedback. i'm also installing 5.1 FD also, so 1st gear should be pretty short. how did heel/toe change? need to rev engine more and shift quicker?
We used the 7.25" version of this for a bit before switching to Tilton, while using the same style flywheel you have. We had significant issues with the QM unit that they could not diagnose. Especially when hot, it would drag like crazy, to the point it would nearly stall the car trying to put it into gear with the clutch in. Lots of 2nd gear grinding issues too, for the same clutch drag reason. We ended up replacing everything in our clutch system including the transmission, and went through multiple QM clutches trying to figure it out... before finally pulling the clutch out.
Ultimately we figured out that Mazda's input shaft is slightly over industry standard (not QMs fault, aside from not being able to give us the specs to check if that was the problem). We had to lap the clutch splines to give it a little more clearance, so it wouldn't bind up, and also used a very small amount of lube despite the instructions saying it must be totally dry. I would suggest you check yours for any bind before installation... but looks like I arrived a little late to the thread.
The QM units were also never well balanced and always had a strange resonance around 3500rpm for us. The Tilton is balanced (has specific markings to indicate which order and clocking direction to install the floaters based on their in-house balancing) and thus our resonance issues went away, and their engineering team was better at helping us diagnose and solve the clutch drag problem. It also has smoother engagement for driving around paddock. It's been a great unit and I would highly recommend them for both the quality product and their engineering team.
We use a winch. These clutches don't like slipping and will wear out much faster if you load onto a trailer without a winch.
yeah unfortunately i already have everything back together. the spline issue is probably what i was experiencing when i had trouble putting the tranny back in. it slid on the first disk fine but seemed to get hung up on the second disk. i guess i'll pull the tranny out again to check the clearance and lap the input shaft if needs to. thanks for the feedback.
There is very little rotating mass with this set up. On your down shifts, the throttle blips will be almost instantaneous and RPM will be higher than needed until you adjust. At Road America, I would come into T 5 in 5th gear, blip and go right to 2nd every lap. Like butter. Once you get used to it, you will love it.
I've run the Quarter Master 5 1/2" for 10 years and never had any issues. I use a "sawn off" input shaft as a clutch disk alignment tool so maybe that has something to do with it never hanging up when I pull/reinstall a tranny.
Don't forget about the angle of the tranny compared to the engine when installing. That inch or so between the clutch disks means it has to be dead nuts straight to go in. A little wiggle to get it to slide in is common. If you have the tranny/input shaft installed, why take it apart? Maybe I am wrong, but I believe a spline shaft is not supposed to move. Too much wiggle bad, too little is a pass/fail matter of getting it to slide in.
i used a plastic clutch alignment tool, they aren't the highest tolerance. Tamra gave a good suggestion, insert the tool and turn the disk to make sure both disks are lined up on one side of the tool. did you have issues with the oem input shaft being slightly over sized and bind up on the disks like Tamra did?
I've never had a problem but there is little if any tolerance using the steel input shaft I have a Team Support number with Mazda and get the clutches through them, not that it should matter. I have never heard any complaints about Quartermaster and that's what Mazda Motorsports stocks and sells. Not saying is did not happen, just news to me.
Making sure both disks are lined up on one side of the tool makes sense if you are stuck with that alignment tool. I assume you are torquing the bolts partially, then fully in a proper patter while the tool is still installed.
wow i didnt know that you can get QM through Mazdamotorsport. I have a support number and could have gotten it for cheaper. how long does a set of disks last you.
Mine last several seasons even driving it on to the trailer but it depends on a lot of factors. I trashed one on a chassis dyno that bolts to the rear hubs, never ever happened on a roller type. I just went to a PBS dog ring box so I only use the clutch to get out of the pits so I'm starting over.
Do you lube them (despite the instructions specifically saying not to)?
We tested with three input shafts (two transmissions and our cut off input shaft for installation) and multiple QM units and had consistent results.... clutch drag due to insufficient clearance between the splines and the input shaft. The first clutch worked the best because we had some lube left from removing the stock clutch. All of them had a weird resonance around 3500rpm from not being balanced.
Good to know some people have had a positive experience while using a stock, synchronized transmission. Wish we had had that luck!
We are much happier with the well balanced Tilton unit combined with light lapping. Their customer service is also amazing.
I've never lubed an input shaft. As a disclaimer, I had been running a 13b in a 2nd gen RX-7 in SCCA E Production. I bought the RX-8 in October and am replacing the Renesis and Mk II box with the RX 7 drive train. I believe I'm the first person in SCCA taking advantage of the new rules allowing a ported 13b in the R-8 chassis.
That being said, I'm not using a stock synchro box. When I went from ITS to E Prod, I started with a dog ring box built by Ron Olsen that fits inside the stock gearbox, then went to the stock synchro setup with close ratio Emco gears. After that I ran a close ratio box built by Jesse Prather with synchros and straight cut Houseman gears. Now I'm using a PBS dog ring box.
My new RX-8 has the 5 1/2" quartermaster and lightweight flywheel, stock gearbox and 5.12 rear diff. It's fast, and smooth through the rev band.
I'm glad you got it worked out. Where do you race? I'll be at VIR in April then again in the fall for the Runoffs.
12-11-2018, 06:57 AM
