Race Car Tech Discuss anything related to road racing and auto X.

Small Diameter Flywheel

Old 10-29-08, 10:15 PM
  #1  
Junior Member
Thread Starter
 
Join Date: Feb 2008
Location: Outside Chicago
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Question Small Diameter Flywheel

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?

mac11 is offline  
Old 10-29-08, 11:33 PM
  #2  
Lives on the Forum
10 Year Member
 
Black91n/a's Avatar
 
Join Date: Sep 2003
Location: BC, Canada
Posts: 5,707
Likes: 0
Received 1 Like on 1 Post
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
Black91n/a is offline  
Old 10-30-08, 09:20 AM
  #3  
Junior Member
Thread Starter
 
Join Date: Feb 2008
Location: Outside Chicago
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
I also see that the motorsports program offers some stuff from tilton and quarter master 5.5" setups.

Anyone ever used these?
mac11 is offline  
Old 10-30-08, 10:22 AM
  #4  
GET OFF MY LAWN
10 Year Member
iTrader: (1)
 
jgrewe's Avatar
 
Join Date: Feb 2005
Location: Fla.
Posts: 2,838
Likes: 0
Received 0 Likes on 0 Posts
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!
jgrewe is offline  
Old 10-30-08, 10:36 AM
  #5  
Junior Member
Thread Starter
 
Join Date: Feb 2008
Location: Outside Chicago
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by jgrewe View Post
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!
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
mac11 is offline  
Old 10-30-08, 06:33 PM
  #6  
GET OFF MY LAWN
10 Year Member
iTrader: (1)
 
jgrewe's Avatar
 
Join Date: Feb 2005
Location: Fla.
Posts: 2,838
Likes: 0
Received 0 Likes on 0 Posts
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.
jgrewe is offline  
Old 10-30-08, 06:42 PM
  #7  
Junior Member
Thread Starter
 
Join Date: Feb 2008
Location: Outside Chicago
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Thanks for that info jgrewe
mac11 is offline  
Old 10-30-08, 08:32 PM
  #8  
Full Member
5 Year Member
iTrader: (1)
 
ccanepa50's Avatar
 
Join Date: Apr 2006
Location: san francisco
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
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)
ccanepa50 is offline  
Old 10-31-08, 03:43 PM
  #9  
Junior Member
Thread Starter
 
Join Date: Feb 2008
Location: Outside Chicago
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
car won't see street time.
mac11 is offline  
Old 10-31-08, 05:16 PM
  #10  
Senior Member
 
TrentO's Avatar
 
Join Date: Jul 2003
Location: Edmonton, AB, Canada
Posts: 408
Likes: 0
Received 0 Likes on 0 Posts
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
TrentO is offline  
Old 10-31-08, 06:38 PM
  #11  
****** of disaster
10 Year Member
iTrader: (1)
 
thetech's Avatar
 
Join Date: Aug 2001
Location: Santa Monica, CA
Posts: 1,115
Likes: 0
Received 0 Likes on 0 Posts
What's the benefit of running the 7.25" disc instead of the 5.5" (for a dedicated track car)?

Last edited by thetech; 10-31-08 at 06:45 PM.
thetech is offline  
Old 10-31-08, 07:18 PM
  #12  
Lives on the Forum
10 Year Member
 
Black91n/a's Avatar
 
Join Date: Sep 2003
Location: BC, Canada
Posts: 5,707
Likes: 0
Received 1 Like on 1 Post
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.
Black91n/a is offline  
Old 10-31-08, 08:51 PM
  #13  
GET OFF MY LAWN
10 Year Member
iTrader: (1)
 
jgrewe's Avatar
 
Join Date: Feb 2005
Location: Fla.
Posts: 2,838
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by thetech View Post
What's the benefit of running the 7.25" disc instead of the 5.5" (for a dedicated track car)?
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
jgrewe is offline  
Old 11-03-08, 11:22 AM
  #14  
Senior Member
 
TrentO's Avatar
 
Join Date: Jul 2003
Location: Edmonton, AB, Canada
Posts: 408
Likes: 0
Received 0 Likes on 0 Posts
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
TrentO is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Jeff20B
1st Generation Specific (1979-1985)
73
09-16-18 07:16 PM
risingsunroof82
1st Generation Specific (1979-1985)
2
09-09-15 08:06 PM
Enzo1944
New Member RX-7 Technical
2
09-06-15 08:57 AM


Thread Tools
Search this Thread
Quick Reply: Small Diameter Flywheel


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: