mac11

I'm putting together a rx8 into a club racer for now and before I put the motor back in I would like to see if I can find a small diameter clutch and flywheel to toss on there. I am assuming the bolt pattern and offset for the flywheel and the output shaft for the clutch is the same between 7's and 8's? There is no information about this on 8club so I thought I would try over here.

I see this pic on Pettit's page which looks to be the type of setup I am after, except I don't really need the multi-disk clutch right now. Anyone know anything about this setup or something similar?

Black91n/a

I *think* that the RX-8 uses an RX-7 turbo (FC TII or FD) sized flywheel, so one made for one of those may well work for you. Guru Racing makes such a clutch/flywheel. You can get the clutch disks in any number of splines, so you should be able to get one that works for you.

http://www.rotorsportsracing.com/per...drivetrain.htm

mac11

I also see that the motorsports program offers some stuff from tilton and quarter master 5.5" setups.

Anyone ever used these?

jgrewe

iTrader: (1)

I have two cars that run 7.25" set ups in the shop. We have to run stock diameter flywheels though.

The biggest issue with going to a smaller flywheel is the starter location. I'll bet the engine in the picture sits in front of a very expensive transaxle!

mac11

Yes, I suppose the thread would more aptly be titled small diameter clutch.

I had come to the conclusion to use the OE trans, and henceforth starter, I would be going with a stock sized flywheel with a small clutch package much like what was posted earlier in this thread. Thanks for that link!

What setup do the cars you have in the shop run? Are there any considerations you can point out that I may be overlooking as this is my first time building a dedicated track only car? Or any more information you may be able to point me at? I still need to get some pics sent over to the motorsports office to get the pricing from them but there is only so much information that I have seen about small clutch setups on their site so far.


thanks


mac

jgrewe

iTrader: (1)

We have QuarterMasters, one is a dual disc, one is a single disc.

The dual disc uses a regular aluminum flywheel that has had the quartermaster clutch bolt pattern drilled into it. With the single disc(mine) I made a spacer to put behind a stock flexplate from an automatic to hold a button type flywheel that I had custom drilled to fit the 13B. It was an expensive way to go but its is the lightest way I could come up with. The other issue with my set-up was the ring gear dia that is smaller on the manual and spacing the clutch fork piot point to only move the quartermaster clutch the required distance.

My way was a royal PITA but I ended up with an assembly that fit the rules and only weighs 15 lbs. That is everything from the counter balance to clutch and most of the weight is near the center of rotation.

With out a bunch of fabrication tools and experience it would be best just to spend the $500 for the right flywheel to fit the clutch you want.

With the smaller clutches you have to be careful. You can't use a 5.5" clutch to load the car on a trailer, you will burn it out slipping it. They aren't really good for road use either because they are on/off switches.

mac11

Thanks for that info jgrewe

ccanepa50

iTrader: (1)

yep, know that on/off feeling well, you can look into "rally" clutches as opposed to "road race" if you use her on the street at all, the rally rated clutches have a slight bit more drive-ability.......
tilton had a 5.5" and a 7.25", the 7.25 being more drivable, the 5.5 was better on the track (lighter and weight was closer in), dont know what is offered now.....the number of clutch plates is directly related to HP/torque.......was using 1 clutch plate at 150 hp (for 1200lb car)

mac11

car won't see street time.

TrentO

I run the old Racing Beat Turbo II 7.25" steel flywheel and the tilton 7.25" dual disk setup. 400 rwhp and three years of abuse with no issues.

The Guru setup looks awesome.

-Trent

thetech

iTrader: (1)

What's the benefit of running the 7.25" disc instead of the 5.5" (for a dedicated track car)?

Black91n/a

More torque capacity, more durable and better drivability as far as I know. The last point would probably be more of an issue if standing starts are used.

jgrewe

iTrader: (1)

I would say the main thing would be cost. I have a friend that has a 5.5" triple in his FP Miata and has over a $1000 in it

TrentO

The 7.25" is cheap. Holds a lot of torque and racing beat used to sell it as an assembly with flywheel for $1000.

-Trent