Lightweight Flywheels?

[madkaw]

I’m running this - https://zcardepot.com/products/flywheel-lightweight-competition-clutch-240z-260z-280z?_pos=1&_sid=356fe798b&_ss=r

It was more being able to machine it for my CAS . The cool part about this flywheel is that it can be used for 225 or 240 clutch . It is also 13lbs, so a little more mass 

[Diseazd]

As I understand it, a light flywheel is harder to drive in stop and go situations (in town), but I’ve never installed a light flywheel, so can’t speak from experience. I run the stock 23lb. flywheel and love the driveability of those flywheels. However, I did want to try a somewhat lighter flywheel on my last build and searched everywhere for an 18 to 20 lb. flywheel to no avail. You can get yours cut down, but you can’t get a new flywheel in those weights. I would think that a flywheel in that weight range would be a nice compromise and would sell a ton, but no one makes one........I wonder why?

[grannyknot]

10 hours ago, adivin said:

Why is MSA strongly advising against the stock clutch?

Ask them, years ago I had a worked on L28 in my 240z, 188 hp at the rear wheels, a lightened flywheel (I think it was 13lbs) and a regular Datsun clutch kit with close ratio 5 spd transmission.  I never raced it but drove it hard on the highway and it was great fun and worked just fine, well mannered in town or at least I didn't have any problem adapting to the way it drove.

A lightened flywheel has less mass to spin up and helps with acceleration and that lack of mass also means the engine can slowdown quicker when you're off the gas so can lead to some jerkiness I guess.  I've always thought a stronger clutch was needed for a more powerful engine, I'm not sure how a lightened flywheel would affect the clutch in anyway as long as the surface area of the flywheel were the same.

[siteunseen]

I have a Tilton aluminum flywheel, it's 11 or 13 lbs can't really remember but I did have it resurfaced so maybe it's 11? Anyway I run the $100 Exedy clutch from amazon.com with great results. Stock motor with better exhaust and it it's a fun car to drive. Getting out of my driveway is the hardest part but once I'm out I am used to the difference so no stalling.

If I remember right the high performance pressure plates are heavier, giving more clamping force, so that would negate the lighter flywheel in my head. 

[chaseincats]

I actually have the perfect solution for you guys.  This is what I did and it is a very happy medium between a zippier car but without the issues of driving a super light flywheel: https://www.californiadatsun.com/flywheel/lightened-resurfaced-balanced-steel-non-turbo-225mm-flywheel.html

The car definitely is quicker but not a pain to drive at all.  I paired that with the 2+2's 240mm clutch kit for extra grip (the owner of that site can find you a 240mm flywheel if you call and ask).

It was professionally lightened/balanced from a 23/24lb flywheel (the 2+2's is heavier of course) to around I think 17-18lb (I don't remember).

[munters]

It can be to snappy(10.5lbs)... I used the 240 clutch and pressure plate. It was drivable but to sensitive in traffic I find.

After 50miles I burnt the clutch with the power and went with the 280 clutch and heavier 280 pressure plate and this made the difference in traffic.

[Jeff G 78]

I had Top End Performance take mine down to about 15 lbs. in my race car.  Since it's a race car, I can't say how it is in traffic, but I can't feel any difference in the pits or loading/unloading.  You still have a stock flywheel, but without the extra inertia.  It's cheaper than buying a new one too.

[siteunseen]

Yep, a good machinest can lighten it locally. $50-$100 with your flywheel? Having the pressure plate attached and balanced is a good choice for not much $$$. Also having them press the throwout bearing onto the collar.

I don't understand a 240mm clutch on a 225mm flywheel?

I read a 610 or 910 maxima flywheel will work on our cars, 17lbs. if you can find one.

[Namerow]

I remember my experiences with my 240Z in the 1970's as my daily driver in a high-density NA city (Toronto).  That flywheel was definitely designed by Nissan engineers from a 'mass marketing' perspective.   That is, enough mass/momentum to save buyers who were new to the game of low-torque cars with manual transmissions.  I hated it and, IMO, they over-did it.  However, the sales numbers speak for themselves, don't they?

[Jeff G 78]

19 hours ago, siteunseen said:

Yep, a good machinest can lighten it locally. $50-$100 with your flywheel? Having the pressure plate attached and balanced is a good choice for not much $$$. Also having them press the throwout bearing onto the collar.

I don't understand a 240mm clutch on a 225mm flywheel?

I read a 610 or 910 maxima flywheel will work on our cars, 17lbs. if you can find one.

The flywheels are all the same size with different dowel locations for 225mm and 240mm clutches, but the larger OD clutch for the Turbos and 2+2 give you more surface area and clamping load, though they are heavier and have more inertia.  It's a way to get OE pedal feel and disc material, yet support more HP.  A smaller, high performance clutch also works, but at the cost of heavier feel and less progressive take-up.

[adivin]

I think I have decided on the RB26 flywheel 13bs (chrome moly) with a South Bend stage 2 clutch.  Shout out to Godzilla Raceworks.  Still don't know the answer to the MSA recommendation against stock clutch with a light flywheel.

[Yarb]

 I have that same flywheel. Did they they mention the circular shim that’s required to take up the diameter difference between the RB and L series crankshaft. You will need that. The bolt pattern is identical of course but I think you will want the shim to fill the gap difference on the crank. It’s a well made flywheel.