Stock Flywheel vs. Fidanza Aluminum for Turbo L20B

[510rob]

...the younger you are the more you put up with irritation, discomfort and doing things the hard way. If older this shit get old really fast.

+1

[qwik510]

A lot of 'racing' things just don't work on daily driven street cars.... I'm older and like to enjoy driving.

Mike - I would agree with you much of the time on this statement. It boils down to preference, really.
David, I would also agree that Keith has the right balance at a 17 lbs - it's right in the middle of what you have got on hand.
10 lbs is pretty light, and you'd be shifting fast to keep the RPM's before they drop. At 28 lbs, the synchros will be getting a workout when driven in a spirited way. It really comes down to what you want as a driver.

BTW - cool vintage turbo kit - what's this going into?

Byron

It’s going in my 2 door.

[qwik510]

Preference, yup you can never say for sure what someone else will prefer. This is why I mentioned age as a rule for selecting just how much you might be comfortable with. It's a sliding scale and the younger you are the more you put up with irritation, discomfort and doing things the hard way. If older this shit get old really fast.

At 60 years old, I don’t want to have to put up with much of anything. Lol. So I hear you loud and clear. Thanks Mike.

[qwik510]

Thanks to everyone for their input.

I think I will start out with the stock flywheel and see how I like it. If I later decide I want it to rev faster, I can buy a clutch kit and change out the flywheel.

[bertvorgon]

I'm 72 and I must admit, that last 400 mile drive we did, me in my G35........Quiet, music, air if needed..power steering...... I must be getting older....

I did miss that rush of pure visceral experience though....!!!!

[iceman510]

Mike - I would agree with you much of the time on this statement. It boils down to preference, really.
David, I would also agree that Keith has the right balance at a 17 lbs - it's right in the middle of what you have got on hand.
10 lbs is pretty light, and you'd be shifting fast to keep the RPM's before they drop. At 28 lbs, the synchros will be getting a workout when driven in a spirited way. It really comes down to what you want as a driver.

BTW - cool vintage turbo kit - what's this going into?

Byron

Seeing the numbers I have to agree with Byron and others. I think 10 lbs. is really quite light for a street car, even one as light as a 510. 28 on the other hand is pretty heavy. Is that stock L16 or L20B weight? I will have to weigh my various flywheels. I probably have six different flywheels here somewhere.

I use a lighter flywheel on my Galant VR4, but I don't remember the exact reduction from stock. It was noticeable at first, but didn't cause too much issue. Clutch was same as stock in weight. That car though weighs more than 50% more than a 510, probably 75% more.

[icehouse]

I would agree with iceman on this. My race car has an Fidamza aluminum 200mm clutch running a roadster PP which is lighter than my 14lm steel 200 mm flywheel combo and it’s still no issue for lack of inertia.
In the end the clutches are so heavy, I’d think going with the lightest flywheel possible is still a solid choice.
Byron

We just put a heavier flywheel in our Racecar. We had the stock SR20DE flywheel but we swapped to the 6 speed transmission that requires the S15 SR20DET flywheel which is dual mass and heavier. I didn't mind the old stock DE flywheel so I'm sure I won't mind this one. I can see in a spec class where every ounce of weight matters and every HP. But for us the lower gears will be nice but we don't want to spend 400 bucks on the Jim Wolf conversion flywheel or machine a bunch of parts. The Juice wouldn't be worth the squeeze. I remember reading a SR forum where a guy worked at a shop. He dynoed his car before and after a lighten flywheel he did 3 pulls and averaged them. He said maybe it gained 1 HP. Not worth it for power that's for sure. Maybe to be easier on the trans but I think that's more driver.

[datzenmike]

All the L flywheels I have are either 29 or 21 pounds. Lighter for larger displacement or cars and heavy for smaller displacement and trucks... generally.

You can lighten other things in the drive train.... aluminum drive shafts, 'mag' rims, tires. Rear disc might be lighter than drums. All this reduces the inertia of the drive line.

[qwik510]

When I bought this motor, the guy I got it from said that it came from a 1980 Datsun 720 pickup which belonged to a guy who was a sales rep for CarTech. This was a demo truck that was used to show performance shops their turbo setups. So the flywheel is likely a stock 720 pickup L20B flywheel.

[bertvorgon]

That is EXACTLY what my flywheel came from at the time. It has been in service since 1978.

[qwik510]

That is EXACTLY what my flywheel came from at the time. It has been in service since 1978.

So you had a stock L20B truck flywheel lightened to 17lbs?

[bertvorgon]

Yup. to the best of my memory

[Three B's Racing]

I've had a Fidanza 10lb flywheel behind my SR20DE S14 for 10/12 years now and to date drivability is awesome. It takes off nice and smooth, great on the hiway, no surging and it made quite a difference in acceleration hell I drove it to Oregon in 2017 and been driving to West Virginia Summit Point since. Ya, ok it isn't a Turbo, but I don't believe that has any relevance because exhaust pressure is still being created but maybe a bit quicker with a lighter rotating mass. Also, a lighter flywheel doesn't make horsepower, it simply creates better acceleration, the HP is already there. Either wheel will work fine David and you won't know the difference until you've ran both.

[Pjackb]

Not an L20B but still relevant to your question I believe ,
In one of my roadsters, I have a modified U20 that puts about 160bhp , I run thishttps://www.datsunrestorationproducts.c ... l-flywheel 10lbs billet FW paired with an Exedy 225mm 240Z clutch and PP .
It’s very smooth and driveability is not an issue also there’s no need to slip the clutch or anything.
This is a quick video with the car after cold start as you can hear very smooth

https://imgur.com/3Z7GZyv

The Fidenza Lseries FW will accept both a 225mm and 240mm clutch , I run it with a 240mm Luk clutch in my slightly modified L28 and same as the roadster very easy engagement and smooth shifting . ( I probably have a video of that also
If I were you I would not hesitate to run a 225mm Clutch and the Fidenza that was original my plan for my L/Z22 but I decided to stay automatic

[datzenmike]

The Roadster weighs about 2,000 pounds, so that helps a lot.