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Retro Z

Lightweight flywheel question. How light should i go?

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Hi Guys. Im ordering a bunch of stuff for my new engine setup/build and want some help.

 

Im looking to buy a new flywheel (dont currently have one).

And instead of trying to source a 2nd unit to machine and lightened i am looking at lightweight aftermarket ones.

 

In particular i am interested in a 12lbs chromoly steel one.  Is 12lbs too light for a street car?. Stock i believe is 23lbs. My machinest is only happy to take stock ones to 17-18lbs. Would aluminium be better than chromoly?

 

My car won't see a track, nor will it see city traffic. It will be a 1-2 day a week toy to thrash around the suburbs. I know the pro's and con's but wondering more about how an L28 idles or if its hard to launch etc.

 

Engine will be a mild L28 with 2mm overbore, extractors, triple dellortos, p&p head, (possibly a mild cam in future).

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Your intentions for your zed sounds the same as mine and my engine guy told me not to go too light and waste money on a performance lightened flywheel for the street. So I had a stock 240z lightened, balanced and IIRC it was under $100 exchange. I am running mild cam with triple carbs. Feels good.

 

When I was at the workshop he showed me a performance flywheel like the one pictured below. It came out of a track car because the owner deemed it too light even for the track and went back to a lightened stock flywheel. Here's some more info:

 

http://www.infinitegarage.com/light-flywheels-pros-and-cons/

 

m51mgHEfgWzOQVWXYWA5HMA.jpg

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Get a stock one, machine the backside, to the 17-18 lbs.

A 200B/Bluebird off a L20B will give you a smaller diam clutch cover, reducing the rotational mass, and getting it closer to centre

You can buy a Daiken clutch assy that will clamp to approx 750 lbs.

They are 200mm diam clutches

 

Or if you want more clamp, and a better quality clutch plate is to be used, get the cover re-levered.

Mine clamps at 1350 kgs, that one has 280hp at flywheel.

 

A Datsun Spirts 2000 clutch assy bolts on i put 245 hp at fly through these

 

The alloy with steel insert units have been known to warp, and your ability to hold torque is a lot less.

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Thanks Sydney mike. That one pictured was the very exact one i wanted to get. Quick question how light was your flywheel after lightening? As im quite sure 240z ones are already under 20lbs stock.

 

Thanks Dat2kman for the help aswell.

 

As its been 2 weeks and i can't find a stock flywheel anywhere im thinking this one is a good buy considered the maching has already been done. Its also 17lbs.

 

post-2348-144023760696_thumb.png

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My 240z flywheel was lightened in the red car, I can't say how much as I didn't weigh it but for a street car it's as light as I'd want to go really. It made a difference in the way the motor revved and responded. For the cost of machining I'd just do that and likely will do that with my current L28 build.

 

It's the harmonic balancer I'm not sure what to do about yet.

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I always go as light as i can with flywheels. Anything that isn't custom built is not going to be too crazy. Even the one on my stroker which is a custom built thing is fine on the street, twin plate clutch not so much.

 

 

There was a place in Japan that was selling on AU ebay was the lightest i could find and a good price. You will know which one i am talking about when they pop up.

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Hydraulic power steering will be installed in the coming weeks and possibly A/C one day will these 2 items justify me getting a light flywheel? Still tempted getting the 12lbs chromoly from positive reviews that i've read on Hybridz forums.

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Yeah it really livens the engine up. Don't forget there are two different size clutches and flywheels.

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Yeah i am looking to go with the larger 240mm flywheel as clutch choice seems more plentiful. Thanks for your help Jake, much appreciated.

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to revive this.

 

I recently sat in DAT240 that has an OS Giken twinplate clutch and flywheel. The clutch pedal feel is great and would be comfortable to drive on the street, but the flywheel is extremely light and would take some getting use to. But if you drive a regular manual street car then get into this and vice versa, it would be hard to get use to. For a street car I'd prefer some mass.

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There's this old thread. http://www.viczcar.com/forum/topic/6688-light-weight-flywheel/

 

It's been great on my car, really changed the throttle response.

 

I got it from eBay for about $300 quite a few years ago, I have seen them on yahoo Japan still. Datsun Spirit also sell them too

https://datsunspirit.com/shop/lightweight-cromoley-flywheel/

 

And a few pics

post-101023-0-38704700-1450411097_thumb.jpg

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to revive this.

 

I recently sat in DAT240 that has an OS Giken twinplate clutch and flywheel. The clutch pedal feel is great and would be comfortable to drive on the street, but the flywheel is extremely light and would take some getting use to. But if you drive a regular manual street car then get into this and vice versa, it would be hard to get use to. For a street car I'd prefer some mass.

 

The problem with twin plates isnt the pedal weight, it's the off on nature of the take up. As i said previously i dont think you will be able to go too light with a standard configuration single plate. How much torque are you pushing anyway? A twin plate is a waste unless its on a race engine or a turbo that pushing big numbers.

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The problem with twin plates isnt the pedal weight, it's the off on nature of the take up. As i said previously i dont think you will be able to go too light with a standard configuration single plate. How much torque are you pushing anyway? A twin plate is a waste unless its on a race engine or a turbo that pushing big numbers.

DAT240 (BenZed) has some big power and torque and because of this I imagined I'd need both feet to push the clutch pedal down. Was surprised how soft it was.  I wouldn't get one if I didn't need it and particularly because of the extremely light flywheel and cost. We went for a spin around the block, I wasn't driving, the clutch seemed well behaved

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You can get a regular run of the mill clutch cover re-levered for higher clamp ressure.

The ones i use are for 200mm single clutch plate, and cover ( lass rotational inertia) and mass is closer to centre.

They clamp at 1320 kg

Pedal effort is only marginally increased.

 

No need for bling and fancy costly temermental twin/triple stuff.

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This is my new 8.5kg billet flywheel, designed to accept a 240Z pressure plate.
The pressure plate is being upgraded by Jim Berry to 2000kg clamping force with a Sachs organic friction plate. Will only have a marginal increase in pedal pressure.
It will be going behind my new engine.

12322501_1731383230429452_16855603568629

I never even considered a twin plate - a cheap one will shit itself pretty quickly & the proper AP/Tilton items are too exxy and are a PITA on the street.

Edited by Lurch ™

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This is my new 8.5kg billet flywheel, designed to accept a 240Z pressure plate.

The pressure plate is being upgraded by Jim Berry to 2000kg clamping force with a Sachs organic friction plate. Will only have a marginal increase in pedal pressure.

It will be going behind my new engine.

 

12322501_1731383230429452_16855603568629

 

I never even considered a twin plate - a cheap one will shit itself pretty quickly & the proper AP/Tilton items are too exxy and are a PITA on the street.

Hi, Where did you get this one from?

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