theory

iTrader: (5)

Hey all,

I'm thinking abou tpicking up a lightweight steel flywheel. The car will be mostly street driven, spirited driving, and very possibly solo events.

If you have installed one, were you happy with it? What sort of gains did you achieve?

I'm just wondering if it's worth getting.

Thanks.

Attila the Fun

iTrader: (1)

Short answer: Yes, if you're installing a new clutch. In its 2-rotor days, the RXX-7 got a lightweight steel flywheel, and drivability was greatly improved, except when starting from a dead stop on steep hills.

theory

iTrader: (5)

Thanks!

Anyone else have any input?

By the way, it's for a S4 N/A.

I'm just trying to justify the price for my budget...

arghx

iTrader: (3)

Previous owner installed a lightweight steel flywheel in my car. I haven't driven a whole lot of N/A's besides mine, but it definately makes it rev a little faster and feel more responsive. You may notice that starting off is a bit trickier because the revs drop faster, but the lightweight steel flywheel really isn't all that light compared to some of the aluminum ones.

theory

iTrader: (5)

That's the main reason I'd like to go with steel, the car will be street driven, and the alum. won't have the same drivability.

coldfire

iTrader: (1)

my car is basically just street and solo also (and hopefully some track days). i've thought about this a bunch, and from what i've found is you don't want to go TOO light. you need a certain amount of rotational mass otherwise your car will actually drive slower overall (between shifts you need a certain amount of mass, on/off throttle transition, high-load low powerband operation like going up a hill).

the stock flywheel is about 25 lbs i think. it seems heavy because it has a built-in counterweight. all aftermarket flywheels require a seperate counterweight, so you have to take that into account. i forget how much the counterweight weighs...maybe 5 lbs or so?

i've concluded for me, about a 12 lb aftermarket flywheel would be ideal. but i could be wrong, it's just an educated guess. i'm looking at the one on www.tweakit.net

theory

iTrader: (5)

from my info, I've learned that the stock flywheel is ~24 lbs.

A lightweight steel one is ~17 lbs from what products i've.


However i didn't know that the 24 lb original flywheel included the weight of the counterweight.

I guess going to a 12 lb flywheel with a 5lb counterweight would equal the 17lbs i initially thought I was going to receive.

Although at a higher cost....

what to do what to do!

koopz

weight of aftermarket flywheels doesnt mean a whole lot a 12lb flywheel with most of its weight out near the edge of flywheel will feel very similiar to a 17lb flywheel with most of its weight near the cnter. Most people neglect to include this fact and just generaly dont understand flywheels.

coldfire

iTrader: (1)

well if you can show me a way to properly evaluate the weight distribution of a certain flywheel without actually having the flywheel, please do so.
i don't expect the weight distribution to be radically different between the different flywheels out there. plus the fact that you are pretty limited in selection anyways with what is available out there, especially if you are looking at a certain cost range.

Boostmaniac

Yeah, Koopz is correct. The weight doesn't matter as much as where the weight is located. More weight at theo outside of the flywheel means more inertia. If the weight is at the center of the flywheel, less inertia. More inertia means slower revs and more streetability, less inertia means faster revs and less streetability. You are just going to have to shop around and ask different people what they think.

theory

iTrader: (5)

It's exactly why I started this thread.

Just trying to feel out what flywheels people may have used and how much of a difference that flywheel had.

As well to also learn a bit more about them. I knew about inertia and the affect of weight reduction in a flywheel, I did however neglect to think about the factor of where the weight is located on the flywheel... thanks.

beamer242

i have an SR motorsports 11 lbs flywheel. im not sure where the weight is on the flywheel, i didnt think about that when i bought mine, but i also converted my car from auto to manual when i had the conversion done. (Great Job Chris at Banzai Racing) i did drive a 7 with a stock flywheel and i can tell a large difference. my motor revs up alot quicker and drops alot quicker. great response from the flywheel and i love it. i also had an HD ACT clutch installed with it. love my set up and hope i dont get in to much trouble. hope that helps a bit.

www.srmotorsports.com they also i have 9 lbs flywheels also.

Brian

eriksseven

iTrader: (6)

If you search around in some of the old "lightweight flywheel" threads posted in the past couple of years, IIRC it seemed like there were very few people who complained about going too light, but there were a lot of people who said they wished they would've gone lighter.

steve84GS TII

Ive run light steel flywheels on all my engines.Its a great mod with noticable gains in 1st,2nd and 3rd.
The change in startup clutching will be slight and youll forget about it all together in a short time. After almost 10 years of driving rotaries with light steel flywheels,I cant even remember what it was like with a stocker.....the aftermarket one feels stock!Even my super small OS Giken clutch and light steel flywheel never felt too light,although the cluch was a bit grabby.
Basically,theres nothing un-streetable about a light steel flywheel.....

RX_AV8TR

One simple answer.....ABSOLUTELY YES, don't even think about it anymore, I've had one TT and two T II's and I've dumped tons of money on upgrades, by far the best one I've ever spent the money in is the SR Motorsports 11lb flywheel/ACT clutch combo. When I picked up the car I couldn't believe the difference, it was huge.
Don't worry about driveability, I've been an RX-7 owner for 13 years and I think the car drives a lot better, feels torquier, better throttle response. First gear needs a little more gas 'cause if not it stalls very sudden and it tends to jerk a little if you are on gear at low rpms, but that's about it very very small price to pay for such a huge improvement in performamce.

Hope this helps

coldfire

iTrader: (1)

one thing to keep in mind is that the turbo cars have a lot more torque than the non-turbos, so the negative effects of highly reduced rotational mass will be less apparent.

theory

iTrader: (5)

This has been really helpful. Thanks everyone.

Jager

iTrader: (10)

Odd that it feels torqueier since a lighter flywheel doesn't hold interia as well?

RX_AV8TR

You are correct but let me put it this way, don't think about revvin' up then releasing the clutch, think about going in first gear at 2000 RPM the tapping the gas or even flooring it, on a T II with the factory fw it feels like you're pulling a trailer untill it boosts up.

But all in all you are right, the big difference I didn't mention before and you brought it up is that since there's less inertia now you no longer get that big jerk forward when you power shift at high RPM...but you rev up a hell lot quicker with the light one though.

rodney87

I put a 17 lb flywheel in my S4 NA and I love it. I live on an island AKA one big hill and I have no problems getting her going in traffic or on hills. I could have gone lighter but to late for that now.

rotarygod

iTrader: (1)

I've got a Racing Beat steel flywheel for an n/a sitting in storage. I don't have an n/a anymore and can't use it. If anyone is interested in it, let me know. I don't have a counterweight though.

NZConvertible

You're absolutely right BUT, most people don't understand rotational moment of inertia (the correct way to compare flywheels) and no flywheel manufacturers ever supply this info anyway. So the only thing you've got to use to compare flywheels is the weight, because that's all you're ever given.

As mentioned, most light flywheels have the mass distributed in more or less the same way, so weight does provide a rough way to compare them. Extreme ones with big holes in them are obviously not so easily compared.

Personally I had 10lb flywheel in my daily-driven 12AT Cosmo, and loved it sometimes and hated it others. For a street car ~15lb is a good compromise between performance and drivabilty. It's still a huge improvement over stock.

LittleCon

would you guys recomend getting a flywheel/clutch combo, as aposed to one then the other?

i ask because im broke lol i'd rather get what i can, when i can, instead of droping $1000+ all at once

Green_Streak

honestly it's a matter of taste. i got RB's aluminum flywheel and never looked back. i love it

RotaryEvolution

iTrader: (30)

i have installed many different weights of flywheels and in my opinion lighter is better in these engines unless you do alot of high load take offs like clutching on a hill. i have an 11lb flywheel in my car and the throttle response was greatly increased as well as acceleration. remember.... you're taking over 10lbs of rotational mass off the e-shaft.

the higher performance the engine is the more noticable the gains are however.

cheapest would probably be the ACT flywheel(installed 2 of them with no problems), try and find a used counterweight or buy a new one from the dealer, remember most of the time the dealership is actually cheaper for parts so i am going to beat it into you guys... i personally do not like the racing beat flywheel because the spacers for the pressure plate is extremely cheesey in my opinion, i have also heard about some issues with the fidanza flywheels with the ring gear bolts backing out.