[Mk2] [Turbo] Lightweight flywheel

[pbmr2]

So got to make a choice very soon before installing the engine. Is it worth going for a light weight flywheel or will it ruin the daily drive-ness of the engine?

Never had one other than paired with an OS Giken double plate clutch, but that was on a 4wd 411hp monster. Boost was so violent and the clutch so heavy that it didn't matter. Every pullaway was a rally launch.

Going to be running about 300hp (crank) from a gen4 engine, stage 1 clutch, turbo gearbox and driving it every day.

Looking at a genuine Fidanza, not the ultra light, just the light.
How are these lightweight flywheels on the MR2?

[Bear87]

From personal experience my old gen 3 tubby had a lightened flywheel and I hated it. It was already installed when I purchased the car and it was a pain pulling away. When I blew my gear box I replace with a oem fly wheel and for me was a great improvement in driving but very little difference in how free or fast the revs were.
Don't hold me to it but I'm sure the mechanic also said it can decrease spool rate and a hevier fly wheel can increase it???
For your power goals the money may be better spent elsewhere.
Again I stress I didn't build my last tubby and I don't even know the weight of the fly wheel that was removed but it was a much improved driving experience after!

[pbmr2]

Thanks for the input!

[mr2magic]

A lw flywheel is always a trade off. Reducing the mass of the flywheel increases the rate of increase in revs but decreases momentum when rolling out. It also reduces rate of spool if you still rev at the same rate because the load on the engine and therefore the amount of exhaust being produced is less. This is compensated by the faster rise in revs which produces more exhaust gas.

[gavsdavs]

If you have a light fly, it helps if you have a 'slippy' clutch, as opposed to a grabby clutch. I had a fidanza and an ACT clutch, didn't like it. Needed lots of revs or the grab could stall the engine, and if it bit too hard you launch scarily quickly.

I use a helix clutch now which is more like OEM and the effect of the lightweight fly isn't as noticeable.

If you plan on quarter mile i'd probably opt for a stock fly, not a light one.

[shinny]

My 2p (copied from parallel topic on MR2OC), having fitted a Fidanza on a standard clutch:

I love the lightened flywheel on my turbo. Revs rise and fall quicker, allowing quicker (smooth) upshifts and heal and toe downshifts are a joy. It's slightly easier to stall when pulling away, but I'd still recommend it.

[Martin F]

I have had many standard ones and many lightweight ones, I have never really noticed any difference between them

[CalMac]

I run ligtened flywheels on my MR2 and MX5, love them

Haven't experienced any problems pulling away, or found it a pain to drive etc. Just makes the car feel even quicker really

Definitely worth pairing with a grabby/aftermarket clutch though as otherwise the clutch just seems to 'absorb' the new reviness and basically you won't notice a difference

[pbmr2]

Thank you all for your views.

So far I've had very conflicting reviews with everything from excellent to it's ok and don't do it to yourself best stay stock. And even one it'll ruin your engine and snap a crank.

TBH I have no idea how grabby or not the clutch is going to be.

Have never driven a 3sgte with a light flywheel so can't gauge if slightly easier to stall is a huge hurdle to live with or a minor adjustment to pulling away.

If I stick with the stock flywheel then it's roughly a known thing, but if it feels a little held back then it's too late as taking the box off again is a pain in the neck.

Might sit it out till after the weekend, possibly make it down to the Kent run for some food and a catch up. See if anyone there has a light FW to compare.

[Martin F]

Thank you all for your views.

So far I've had very conflicting reviews with everything from excellent to it's ok and don't do it to yourself best stay stock. And even one it'll ruin your engine and snap a crank.

TBH I have no idea how grabby or not the clutch is going to be.

Have never driven a 3sgte with a light flywheel so can't gauge if slightly easier to stall is a huge hurdle to live with or a minor adjustment to pulling away.

If I stick with the stock flywheel then it's roughly a known thing, but if it feels a little held back then it's too late as taking the box off again is a pain in the neck.

Might sit it out till after the weekend, possibly make it down to the Kent run for some food and a catch up. See if anyone there has a light FW to compare.

You will be hard pushed to notice any difference beyween a lightened one and a standard one Imo, if you are going to be running around 300 bhp then personally i wouldn't bother unless i had a few spare £££ and was changing the clutch.

[pbmr2]

Well did have a few quid spare but it was mainly trying to choose whether to stick a stock gen3 flywheel on the new gen 4 engine or go with the lighter one before it's installed in the car.

Thing being it's all in bits at the minute and easy to work on. Once it's installed then the gearbox can stay in there until the clutch dies, hopefully many years down the line.

In the end got a Fidanza flywheel, not the ultra light just the light. Hoping it's the right compromise. Other gen 4 owners have said it works well with the early spooling ct15b, hope they are right.