02-05 Subaru WRX Lightenend Flywheels

[LaszloT]

Are these claims about lightened flywheels accurate, and who in the SPDA club might be running one in their performance auto:

"A lightweight flywheel is a great addition to any car, especially turbocharged vehicles. A lighter flywheel drastically reduces the rotating mass attached to your crankshaft, allowing your car to rev and accelerate faster. Turbocharged cars will benefit from a quicker spool as well."

What items have good value and should they be aluminum or steel; ACT, ClutchMasters, Exedy, Fidanza, etc?

[STeveD]

I like a light weight flywheel on my cars, but I don't drive daily in stop and go traffic. It is honestly more for the feel of downshifts (the revs drop faster than with an OE full mass flywheel) than it is for acceleration from my part. I find it odd that none of these clutch companies post before and after dyno plots... if there was noticeable HP or spool improvement... why don't they show it? It's mostly a butt dyno thing, though the NASCAR style clutches that Scott uses for racing made a noticeable lap time improvement on his low HP naturally aspirated 240sx.

Best to get a flywheel that is all one material type so that you don't have different rates of heat expansion. E.g.: Clutch friction section in aluminum, outer teeth in steel. You're not racing, so I really don't see a reason to drop down to aluminum weight.

I currently use an Exedy from JRP in Pugsy and it's just right at 14 lbs for the 5mt on a car that still sees street driving, and starts on hills. Surge is no worse than stock IMHO. My stock STi flywheel was lightened from 22lbs to 17lbs and that felt fine in most conditions but had significant surge in stop-and-go traffic when combined with a light four-puck Bully stage four clutch.

So consider the total weight of the pressure plate, clutch disc, and flywheel in your modification. Joe prefers stock weight flywheel with very light clutch plate and pressure plate. Look for SFI certification for safety.

Coles notes: Go with a Chromoly flywheel for your application and wait for your clutch to wear out before changing it for minimal install cost. Or at least change the clutch at the same time as the flywheel.

[JoeT]

Yup... What he said.. LOL

Yeah I prefer the full mass flywheel, since the car is also driven daily, my 4 puck clutch with less than 3mm engagement point likes it better too, just blip the throttle to build up energy in the flywheel and let the clutch out slowly and off you go. For launches, you can store more energy in a higher mass flywheel to get you out of the hole quicker without trickery of building boost through launch control. There are drawbacks though, in the form of axles.. LOL But that's another story.