Lightened Flywheel Thread

[Alchemist]

Guys my experience with a lightened flywheel isn't too great. It rattled excessively at 3/4 throttle and low rpm(I know they rattle abit, but this was bad), didn't seem to make the car rev any more freely. I found moving back to the stock dual-mass number I saw performance gains, and a much quieter transmission.

Noise alone wouldn't stop me looking at a lightened flywheel in the future, I feel I may have had a crap cheapie flywheel installed by previous owner, but the stockie seems better so far...

[Rex_Kelway]

Phsyco,

Rex too is looking at the XTreme Aluminium One for the 4AGZE as they dont do a Chromolly steel one.

After talking to the lads there they get them out of the US, and after some hefty research and comparison, He believes there is a great possibility they are Fidanza manufactured items branded for XTreme. Which holds true given they also do a few cam-gears and shifters, just like Fidanza.

If this is the case, the materials are a very high grade making them a suitable competitor to the typical Chromolly steel ones in terms of strength and lightness. The ring-gears and friction surfaces are also servicable/replaceable.

He also has a low 3Kg TODA wheel to suit a 200mm clutch in the Rally Car so it will be intersting to see the results of similar weights on SC and NA 20V engines. But who knows how long rex will take...


Rex

[psychofox]

Mick, I feel so ashamed about admitting this, but no I haven't installed it yet I have got an LSD and 4.3:1 CWP for it though...It's just another thing for me to do to the car...I also ended up using the discs on the front of the car (with s5 RX7 calipers).

I think I'll go out an get one of the cro moly flywheels, I'll post up my experiences here....

Rex I think you're right about the fidanza supply, they look identical. I also think they probably got them from Fidanza as they already are SFI compliant. Here's a pic of the Xtreme aluminium one....

[kingmick]

Mick, I feel so ashamed about admitting this, but no I haven't installed it yet I have got an LSD and 4.3:1 CWP for it though...It's just another thing for me to do to the car...I also ended up using the discs on the front of the car (with s5 RX7 calipers).

I think I'll go out an get one of the cro moly flywheels, I'll post up my experiences here....

Rex I think you're right about the fidanza supply, they look identical. I also think they probably got them from Fidanza as they already are SFI compliant. Here's a pic of the Xtreme aluminium one....

dont worry! things take time for the best of us!lol
very cool about the disc's now just get another set of them for the rear and the thing will brake with the best of them!

[oldcorollas]

light flywheel will also be noticable with GZE... but maybe a little less so because the SC also has extra inertia... but for all cars, you are effectively reducing the cars effective weight (once clutch is slipped) so it all helps. perhaps with turbo it would be harder to use in terms of slip points etc... but... dunno


so... just to add to this (and hopefully not drag off topic)

with twin plates (like i think Alchemist had??) you get a lighter overall mass for clutch and flywheel, but....

what about small diameter clutches? like Tilton etc... a twin plate or triple plate 5"??
the reduction in inertia would be greater than just going to a light flywheel with normal 8" or 9" clutch... and if the material is still slippable, ... all better? (apart from wallet)

Bill or MIck (or others ) opinions on smaller diameter multi plate clutches?

[Billzilla]

Bill or MIck (or others ) opinions on smaller diameter multi plate clutches?

Good for racing, pointless for anything on the road. And I guess debateable for a lot of race engines - You lose the larger diameter that helps hold the clutch plate against the torque of the engine but pick up with a reduction of rotational inertia. And also perhaps a lower engine in the chassis, etc.
It's a lot of money for little gain, I suspect.

[WindeX]

I have a group a lightened flywheel in my 3sge, the main difference will be that you cant spin your wheels easily, so burnouts become harder, but other than that all positives, mine is still a bit jerky when taking off, but thats cause I am used to the falcons pull at low revs.

[oldcorollas]

the main difference will be that you cant spin your wheels easily, so burnouts become harder, but other than that all positives,.

i would still count that as a positive


Bill, my thinking was to have heavier rated clutch with lighter pedal pressure...... but with lower rotating mass than standard twinplate....
i guess "ideally" it is good... but in practice... not so good thanks for the reply.

[roadsailing]

OK, i'll try not to sound too much liek a smart ass engineer (i am both unfortunately)

when people say "light flywheel" what the mean, weather they know it or not is "low inertia flywheel" it's almost akin to saying "lightweight" car, the correct term is "low mass"

anyway, you can/could get lightweight flywheels for drag racing that had the equivalent inertia to a standard flywheel for reasons i have mentioned before without the wright penalty.

and small diameter clutches/flywheels have a number of advantages (all things being equal a twinplate clutch has twice the torque capacity than a single due to the extra friction surfaces)

one advantage is reduced flywheel inertia, but another big one is the fact that used in conjunction with drysump, custom bellhousing and other mods, you can lower the engine a good few inches and improve cornering.

HTH

[kingmick]

lol pretty much answered with bits from each post!lol

[TooF]

just to throw this in there.

ive hear of people having stalling issues with very light flywheels on gze's due to the fly not holding enough intertia to keep the SC spinning when you snap off the throttle and the SC is still enguaged ? it makes sense.. the SC spinning at 10k takes what 30-40hp ? without the interia the engine would struggle to keep spining it for the few moments that the factory comp keeps it on.. (and depending on your tune you make keep the SC on with an aftermarket)

i havent experienced this just going off what ive heard so i dont know its legitimacy although it sounds plausable..

discuss...

[oldcorollas]

not if you still have the ABV (or a version thereof) on. when manifold goes vacuum, the ABV should open, reducing load on the engine from the SC??
or do i have that arse about?

[TooF]

no you dont have it arse about it seems plausable but apparently it dosent work spot on with the lightened fly.

same as having the charger fixed (no clutch) in *theory* if the abv is open there is an equalisation of pressure and hence there shouldnt be a temp[erature build up.. no pressure no heat (especially as there is no internal compression in a roots unlike a twinscrew) but i can quite comfortably say this isnt quite correct as when i ran a fixed pulley i had quite the heat build up..

[takai]

Ok, just to confirm a few things, the Xtreme lightened flywheels are most certainly made by Fidanza and then rebadged. The Fidanza flywheel which i have in the race car is supported and exactly the same as the Xtreme ones, and when i purchased my replacement friction plate it even came with the Fidanza instructions despite being an "Xtreme" product.

Anyway, i love mine, but hillstarts were certainly a pain in the butt.
I have heard some people have issues with the alloy/steel two part designs on the road as the metal expands at different rates, and therefore warps the plate, although i think this has been fixed more recently.
I also believe that Fidanza dont do a GZE clutch specifically, but rather that the one which Xtreme list as GZE is actually a 212mm smallport GE flywheel, rather than the larger 224mm GZE fly, not 100% on that one though.

[Rodger]

A couple of interesting numbers from a book I am reading.

Taking 1kg from a part rotating at engine speed is 15 times more effective than if taken from static parts and 5 times more effective than from parts rotating at road speed.

So taking 1kg off the flywheel is like taking 15kg of tar matting and carpet from the interior.

My 74rwKw 2T has a lightened OEM flywheel, don't know the weight but it made a big difference in the way it accelerates.

Any competant engine shop can lighten them when they do the balancing of the internals.

Regards

Rodger