Reptoid Overlords

Lightening of the flywheel

Recommended Posts

I'm slowly obtaining parts for my F54/P79 engine build.  The block is all stock, no mods, and the head will be shaved .080 with the appropriate shims/spacers/valves.  Stock cam.   Not in any rush, I'd rather wait and save money for parts I want than rush it into the car.  That being said, I'm beginning to think that my original plan to buy a lightweight flywheel/stage 1 clutch won't be that good of an idea considering the amount of traffic in my area.  I use my Z daily in the summer, and while I take it out regularly for open freeway drives when everyone else is off the roads, It sees work commutes alongside Subaru's and Teslas. 

How light can I have a machine shop make my stock flywheel before I need to go beyond the OEM style clutch?

Share this post


Link to post
Share on other sites

IMO, I would stick with your stock clutch with your build....nothing stronger needed. I installed a Stage I Exedy Racing clutch in one of my Stroker Motors and replaced it with a stock 240mm clutch 1000 miles later (I run stock 240mm flywheels). It was a PITA to drive in town with the Stage I. You probably shouldn’t take your flywheel much below 20 lbs. and make sure you have someone reputable do the cut. I run stock 240mm flywheels (23 lbs.) in both of my Strokers and love em. You’ll get many opinions on flywheel weights and this is my humble opinion.

  • Like 1
  • Thanks 1

Share this post


Link to post
Share on other sites

I use an OEM spec Exedy clutch with a real light aluminum flywheel in my 240.  It was $100 from amazon.com, part number was 066009.  Fun to drive as a weekend car.  The tach needle bounces like a ping-pong ball but it is a pita just getting up and out of my driveway when I first get in it.  After a few restarts I get used to it pretty quick.

Humble opinion #2

  • Like 2

Share this post


Link to post
Share on other sites

I think at the end of the day when I ask myself, why would I want to lighten the flywheel?, The answer is to get quicker revs, and a bit more responsiveness.  But since I drive it pretty regularly, I'll need to strike a balance between stop and go drive ability and quick revs.  it's definitely cheaper to keep it stock.  I'll probably end up having the machine shop take it down to 20lbs and keep an Excedy OEM clutch and spend all my saved money on exhaust. 

  • Like 3

Share this post


Link to post
Share on other sites
4 hours ago, Reptoid Overlords said:

I think at the end of the day when I ask myself, why would I want to lighten the flywheel?, The answer is to get quicker revs, and a bit more responsiveness.  But since I drive it pretty regularly, I'll need to strike a balance between stop and go drive ability and quick revs.  it's definitely cheaper to keep it stock.  I'll probably end up having the machine shop take it down to 20lbs and keep an Excedy OEM clutch and spend all my saved money on exhaust. 

spend it on the new style Fujitsubo one.

  • Like 2

Share this post


Link to post
Share on other sites

I went with Fidanza flywheel and Exedy clutch and pressure plate for a 280zx Turbo 2+2.

 

Great pedal feel, never slipped under hard use and best of all i have a very revvy motor without slow speed driving issues.

 

It took me 4 hours to do a 1:45 journey to Silverstone in stop/start traffic on Friday. No issues at all. You just have to learn to dial in 500 more rpm when pulling out of junctions but you soon get used to it.

 

 

  • Like 2
  • Thanks 1

Share this post


Link to post
Share on other sites

Check msa's ceramic coated header and the 2.5 premium exhaust. Seems like it was around $500 on Black Friday. Take those savings and buy some nice wheels and tires.

  • Like 3

Share this post


Link to post
Share on other sites

I run a 10lb Fidanza flywheel on an OEM clutch. It has stock-like tractability but revs much quicker. The car dynoed at 195whp and 180ftlb, the clutch holds just fine. 

I run an 8lb flywheel with OEM clutch in my S2000 which made a more notable change in tractability as it doesn't have nearly the low-end torque of the Z. Still much better than the 23-pounder it came with.

Both cars are driven in SF Bay Area traffic without issue.

  • Like 4

Share this post


Link to post
Share on other sites
On 7/28/2019 at 7:50 AM, Diseazd said:

IMO, I would stick with your stock clutch with your build....nothing stronger needed. I installed a Stage I Exedy Racing clutch in one of my Stroker Motors and replaced it with a stock 240mm clutch 1000 miles later (I run stock 240mm flywheels). It was a PITA to drive in town with the Stage I. You probably shouldn’t take your flywheel much below 20 lbs. and make sure you have someone reputable do the cut. I run stock 240mm flywheels (23 lbs.) in both of my Strokers and love em. You’ll get many opinions on flywheel weights and this is my humble opinion.

What should I look for and/or what questions should I ask a machine shop to gain confidence that they’re the right shop to lighten a flywheel for me?  I’ve never gone to a machine shop for work before, and if I can find a good shop in my area (south Orange County, CA), I’m going to get the flywheel lightened when I pull out my 4-speed and install my 5-speed tranny.  Thanks!

Share this post


Link to post
Share on other sites

They resurface the flywheel to get the hot spots out where they're slick. Instead of doing a light cut they go a little deeper until it's the weight you want. I've seen the machine they use. It's a horizontal milling machine. Most shops have one I would think. The small town shop here has one so I bet you'll have no problem finding one.

It left a circular cut on mine and it seems like he said they use cutting stones? Anyway it's like a floor polisher on top of your flywheel.

Share this post


Link to post
Share on other sites

I know some people who have sent their flywheels off to this place and have good results. A 1st Gen RX-7 w/ 17 b motor and a MK 2 Cressida with a supra 7M-GTE drivetrain swap.

 

They are in Chatsworth.

 

https://www.racetep.com/engine-building/flywheel-lightening.html

 

Sent from my Coolpad 3310A using Tapatalk

 

 

 

 

Share this post


Link to post
Share on other sites
1 hour ago, Reptoid Overlords said:

I know some people who have sent their flywheels off to this place and have good results. A 1st Gen RX-7 w/ 17 b motor and a MK 2 Cressida with a supra 7M-GTE drivetrain swap.

 

They are in Chatsworth.

 

https://www.racetep.com/engine-building/flywheel-lightening.html

 

Sent from my Coolpad 3310A using Tapatalk

 

 

 

 

I run a TEP flywheel in my racecar.  They took 10 lbs. off and it works great.  They must have started lightening them again.  For quite a while, they had to stop after the one guy who did their machin work died and apparently was the only one who knew the cut plans for all the various make and model flywheels they lightened.

Share this post


Link to post
Share on other sites

Thanks for the advice, guys.  I'm only thinking of reducing the weight to 18-20 lbs.  I'll ask TEP if they would do that for me.

Share this post


Link to post
Share on other sites

I was thinking more about this, which I guess is a dangerous thing. Anyway, I live in a pretty hilly area and I wonder if I’m asking for trouble by having my flywheel machined down to 18-20 lbs.  At the time I would have this done, I’d install the close-ratio 5-speed & 3.90 diff that are sitting in my garage.  Do any of you have any thoughts about, or experience with how drivable a Z would be in a hilly environment with a moderately lightened flywheel?

Share this post


Link to post
Share on other sites

My aluminum one is 11lbs.  No problems driving my end of the Appalachian Mountains.  I stall it a couple of times backing up my driveway but that because I'm trying not to disturb my neighbors.  It's kind of loud and raspy when you get the RPMs up.

  • Like 1

Share this post


Link to post
Share on other sites

Thanks guys.  I’m probably overthinking this.  We have San Francisco-type hills around here and I guess I can adjust my use of the pedals to avoid stalling with a bit lighter flywheel.

  • Like 1

Share this post


Link to post
Share on other sites

My Top End Performance 18 lb. flywheel is on my racecar, so I can't say how it is on hills, but I have never had any issues with loading the car on a trailer or driving it around the pits at low speeds.

Share this post


Link to post
Share on other sites

I don't have any issues in the hills of San Francisco with a 10lb flywheel. The stock pressure plate and disk allow for easy engagement and an L28 with a 3.9 is plenty torquey. You're overthinking it.

  • Like 4

Share this post


Link to post
Share on other sites

Leon V suggested the cheap stock oem clutch and pressure plate was fine, and it was/is. Exedy 6009 I think from amazon, $100. Works great. Thanks again @LeonV

Saved me some $. I was about to go with a $300 stage 3 kit from Center Force.

  • Like 2

Share this post


Link to post
Share on other sites
5 minutes ago, siteunseen said:

I was about to go with a $300 stage 3 kit from Center Force.

I did go with the stage 3 Center Force unit and it was complete overkill, the stock clutch would have been more than adequate, I know now.

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now