Lightening of the flywheel

[Reptoid Overlords]

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?

[Diseazd]

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.

[siteunseen]

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

[Reptoid Overlords]

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. 

[Diseazd]

Well played......

[Jason240z]

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.

[AK260]

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.

 

 

[siteunseen]

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.

[LeonV]

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.

[SoCalJim]

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!

[siteunseen]

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.

[Reptoid Overlords]

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

 

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