For my winter project I planned on changing my clutch out to a new version. I've been using a Centerforce 2 for several months but its slow to release at redline and I don’t like the slower shifting action (its fine at normal speeds). In the past I used the inexpensive Perfection Zoom clutch with great results so I decided to switch back.

THE PLAN: I have a new stock 240mm (turbo/2+2) flywheel and toyed with the idea of having it lightened by Top End Performance to about 16lbs.

The result is that I would have a 240mm lightened flywheel with the extra holding power of the Nissan turbo clutch/pressureplate. In the past though I noticed the 2+2 pressure plate seemed heavier than the coupes’ when changing the clutch. So I emailed Perfection and asked them the weight of their clutches.


MU47732-1A (turbo 240mm) WEIGHT IS 18.72 LBS
MU47594-1A (coupe 225mm) WEIGHT IS 14.76 LBS


So while the stock flywheels are the same at about 23 lbs, the extra weight of the turbo pressure plate assembly seems to negate using the turbo version if you’re seeking light weight. I didn’t ask them the weight of the 2+2 clutch but I would expect a similar weight increase. Interesting.

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Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

In 1969 I lightened the flywheel on my BMW R-60 motorcycle, a lot. The BMW was silky-smooth with the heavy steel flywheel, but accelerated slowly. With the lightweight aluminum flywheel, it revved up like a Limey bike and tore away like a rocket (the entire engine got significantly enhanced at the same time).

But idle suffered noticeably. Instead of the smooth "tick-tick-tick" idle the BMWs were known for, it became a "rump-rump-rump" thumper, which required a higher idle rpm to remain running. Expect both changes if you lighten your Z flywheel significantly. Sort of like a racecar at idle, but instant 'right-side-of-the-tach' rpm at every throttle tap, and rapid rpm drop-off btwn shifts.

So having the smaller flywheel from an N/A, with a center force 2 for extra force sounds like a better option than the bigger turbo flywheel. This is what I have in my 83t, and I like it. Now I need to do this to the 240, and remove the turbo set up. I'm thinkin aluminum flywheel with CF2.

just got my flywheel back from Top End Performance last week. Machining is excellent and it is significantly lightened (28>18 lbs IIRC).
This is a Z31 flywheel, I also presently have a Fidanza in my 86T and will be installing an SBC steel one in a customers car over the winter. Lightened flyhweels on our cars have such a positive effect on the driving experience that it is one of the first mods I do. That and a short shifter are easily one of the best bang-for-buck-mods. They do not alter the idle or drivability as drastically as on Frank's BMW due to the amount of rotational mass in the entire rotating assembly keeps things moving. You may have to add a bit more throttle input to get things going smoothly from a dead stop, after a week you alter your driving style and it will feel "normal".

I used the Fidanza aluminium flywheel to get around this issue. Never did the math in-depth, but I think it evens out the weight problem a bit similar to the "coupe" flywheel while retaining the surface area.

I've tried using the coupe pressure plate / 225mm flywheel combo on my L28ET before, and I don't recommend it at all. Anything past half throttle slips all over the place and burns up the friction disc QUICK.

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-Chris

Gregmatic has it right. I had Top End do my coupe flywheel a couple of years ago and the results were great. The weight went down to about 16 lbs...with no loss in strength and they rebalanced it. Much snappier on the road, revs about 20% quicker.

HINT: Advance Auto sells new coupe and 2+2 flywheels for under $60.

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Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

Was that original Phrog, because I 'm having no issues with center force 2 set up, resurfaced flywheel 225 set up. So it appears they just machine some metal off the back?

It was, both OEM or OEM replacements as far as I knew. I've heard to same story from others with the L28ET conversion slipping their (aftermarket) 225mm assemblies though, which is why I didn't buy an "upgraded" 225. In order to get them to clamp with enough force, you run the risk (with a stiffer clutch) of putting an excessive amount of pressure/load to disengage, which can affect the service life of your engine bearings.

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-Chris

With a strong L28ET and a 225mm clutch, you need really high pressures, or multi-puck discs. I have seen S30 clutch forks snap. The Z32 Clutch fork is a nice upgrade for an S30. It's fits, and is slightly heavier gauge. My left leg made me upgrade to a 240mm clutch, which turns out to be more bearable on the street.

FYI the S30 Fidanza flywheel can accept both 225mm and 240mm clutches.

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-Dave
76Z Turbo'd
72 In Progress---DONE!

I'm guessing THAT'S why it has those unused misaligned holes. Never thought that would be the case.

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-Chris