Steel vs aluminium flywheel - what do you run?

[Chris]

Ok can’t seem to find anything on this here so I’m after real world opinions on steel vs aluminium flywheels in a GT40.

How do you find the light flywheels on the street? I understand the car being so light could remove some of the downsides of pulling away with a light flywheel etc.

Trying to work out which is the best way to go for my build, engines going to be a neutral balance 347 mated to an 01e 6 speed. Will be 95% street driven.

 

[DaveM]

No problem with aluminum flywheel on my 427 Windsor/RBT street driven.

 

[Doug Dyar]

Steel comes in lighter weight than stock, too. You don't necessarily have to go alum to lighten the flywheel. Shoot for 1% of the car's weight. Somewhere around 20-25 lbs for a '40.

 

[Bill Kearley]

Cost benefit for the street, steel.

 

[Jim Craik]

If it’s going to be a street driver, I strongly recommend a steel flywheel, you won’t go through as many clutch’s and with everyone watching stalling is quite embarrassing.

 

[Chris]

If it’s going to be a street driver, I strongly recommend a steel flywheel, you won’t go through as many clutch’s and with everyone watching stalling is quite embarrassing.

it is going to be a primarily street driven car. my last road toy had a triple plate carbon clutch and dogbox so im used to tricky drivetrains but indeed it still caught me out sometimes at my expense.
However the car was 600kg heavier than the 40 will be.

The kennedy gearbox adaptor kit is a reasonable price but then only offer it with a billet steel flywheel which is 30lbs.

 

[Mike Pass]

It's not the weight that matters for flywheel effect. It is the way the mass is distributed. Mass further from the centre has a larger effect on the rotational inertia. Many race flywheels have a skeletonised outer part of the flywheel which is only there to carry the starter ring. A well designed steel flywheel can have less inertia than an aluminium one.
Mike

 

[H.J.Bayer]

Steel in my little Alfa

 

[Chris Kouba]

Mine is alu on a ~350h/~350tq SBF road car with EFI. It's been over a decade since I put it in but I believe the flywheel itself was 11.5 pounds. The motor is extremely tractable and I have no issues driving it on the street. Before I had the shifter properly adjusted, I would occasionally select third gear from a stop and it required no excessive slipping when compared to what a heavier steel one would. I went with it on the recommendation of Dennis Quella at Pantera Performance and have yet to be disappointed by it.

Mike's comment is spot on though. It's the rotational inertia which truly matters so it's possible to have an equally effective steel one as an aluminum one (as in the work of art shown above).

I can tell you, my motor revs quicker than I can sneeze though! I love it.

 

[Chris]

Steel in my little AlfaView attachment 111853

I mean now that is a flywheel! #porn

 

[Skip Markley]

Ok can’t seem to find anything on this here so I’m after real world opinions on steel vs aluminium flywheels in a GT40.

How do you find the light flywheels on the street? I understand the car being so light could remove some of the downsides of pulling away with a light flywheel etc.

Trying to work out which is the best way to go for my build, engines going to be a neutral balance 347 mated to an 01e 6 speed. Will be 95% street driven.

I have a 427 FE in my GT40 Mk II. I purchased the Tilton triple disc carbon fiber clutch and when it came in I just couldn't bolt it to just any modified flywheel. So we made a chrome-moly spoked flywheel. Now the total assembly, clutch flywheel and hardware weigh in at just under 20 pounds. The clutch is a little touchy but very drivable on the street. And wow does the engine spin up quickly.

 

[Skip Markley]

 

[Chris]

Anyone know a company who manufactures a lightweight flywheel for the 01e SBF conversion? Ideally 20lbs or less.

 

[Skip Markley]

Can you provide a sample that I can reverse engineer? It can be a heavy one - I just need the geometry.

 

[Chris]

Can you provide a sample that I can reverse engineer? It can be a heavy one - I just need the geometry.

Not as it stands at the moment unfortunately.
I’m now unsure as to whether I’m going to run the 01e or go for the Quaife whenever it

 

[Mike Pass]

GTRacing in Exeter UK do conversion parts for Audi to SBF and GT40 stuff. They should be able to sort a flywheel etc.

GT Racing mid engine vehicle design and specialist services. Vehicle parts manufacturer, body design, V8 engine translaxles MK1-UN1 race-car conversion kits suppliers, parts, chassies, Detomason Pantera VW Voltswagen van, Lola, Lamborghini, replica c

gtracingonline.co.uk

Cheers
Mike