Hello All,

Has anyone ever used a lightened flywheel from QSC? I have been unable to reach them on the phone or via email. Considering dipping my toe in the water and purchasing this forged chrome moly 15 lb. flywheel(approximately 3 lbs. lighter than stock) for my 2056 L-jet street car. If I purchase it, I will have it balanced with my new stock pressure plate.

I have read every thread on this site regarding lightened flywheels and thanks for all who have contributed to them...very helpful.

https://www.qscusa.com/collections/flywheel...-flywheel-215mm

There is a link on their website that takes you to the same part on their eBay store for $30 less.

Just be sure it’s forged (914) not cast (bus)

Buy an original and lighten it. I have yet to see one of these other flywheels that is actually round. They have internal and external runout, and the sealing surface isn't even round. They don't match the crank surface flat either.

I recently tried a new 914 flywheel from Sebro. It said all over it "Made in Germany". The material was so soft that I was able to cut .300" off in my lathe with a single pass. Thats about 8X more than I can cut from an original 50 year old flywheel. My Hendey lathe is a beast, but I've never been able to even cut .100 from a flywheel at a single pass.
Straight to the scrap pile it went..

So Jake to what weight do you (typically) take your FW's to? Or is it variable dependent on the build?

I had my stock FW cut to 13.5 lbs.

Can you provide more info on this? Why can't a bus one be used?

Bus flywheel fits the motor, but won't work with the 901 transmission.

Clay

My engines make so much power that they don't need a lightweight flywheel to feel fast.Due to this I prefer to keep them stock weight, to add drivability. The issue with a LWFW is the engine revs down just as fast as it revs up. I don't like this for cars that see any street time at all.
I take flywheels to around 14# when I do lighten them, but with the 901 gearbox I seldom offer it.

The bus flywheel is not 901 compatible, either with the starter ring gear, or the 901 specific pressure plate. These only match the 002 and T1-T3 transaxles, and in the case of the 228mm, only the 091 gearbox.

How do you distinguish a bus FW from a 914 FW? Any P/N's on the FW?

The 914 flywheel has 3 dowels that index the pressure plate, the 210 and 215mm bus flywheel does not have this.

If Sebro quality is going down hill what is our source for flywheels?

The scrap pile.

Do you think cryo treatment might bring these to an acceptable hardness?

I agree with Jake.
If this is a street car, don’t lighten it.
Btdt, flipped it back

I knew there was a reason I was rat-holing all these used FW's

This has been covered before.
Jake opened the door so I thought it was worth the ask.
I dont agree.
Sure you can go crazy and driveability will suffer but in my experience a slight lightening has NO detrimental effect for street driving
& in the case of an L-jet equipped car can offset the somewhat sluggish nature of the AFM system

Cryo doesn’t increase hardness. It realigns the molecular structure of the material.
It may decrease wear, but it won’t fix poor quality.

I can see why people think it does harden the metal with claims like this:

"Cryogenic hardening is able to make metal objects and workpieces more resistance to wear and tear. Metal doesn’t just become harder through cryogenic hardening; it becomes tougher and more resistant to wear. As a result, cryogenic hardening is performed to increase the usable life of metal objects and workpieces."

https://monroeengineering.com/blog/an-overv...ning-for-metal/

Lightened flywheels are very popular with type 1 vw's. My dad had a lightened flywheel on his bug. It was fun on flat ground, but on hills the flywheel would spin down to fast and you would lose a lot of momentum and have to downshift more. The engine was a 1641 with dual weber's and 3/4 cam. It would rev up very fast and sounded awesome.

That was why I did it, it is almost like a Jake Brake, the compression of the engine would slow me down with out hitting the center pedal. Maybe I'm alone here but I really like it for Fundays. Maybe I got used to it and that is why I do not notice any negatives.

I agree with Rich. A lightened flywheel on Betty's 914 made the low end performance much better, but it doesn't help any above about 2K RPM.

Clay

Mine was not as light as I thought … after lightening it weighed in at 15.75?
What do they start at? I hav a zero balance and dynamic balance with assembly .. so its moot now

I believe the flywheel is 18 lbs.