Lightweight Flywheels?

[pacotaco345]

Can you guys convince me either way on lightweight flywheels? I just blew my 2nd SR and I figured go big or go home this time. Its getting eagle rods & arias pistons, the head is already built and I have an exedy stage clutch in it. The machine shop told me they need a flywheel to balance the rotating assembly as best they can but I'm still driving the car around on 3 cylinders so pulling the stock one isn't really an option. I'm gonna buy a second flywheel anyways to reduce downtime but I need to justify the extra 2-300 for a nice lightweight one.

Personal experiences etc, I drive my friends car all the time which has a ka and a comp clutch steel flywheel but that still weighs around 16 pounds, if I do this it will be some kind of billet < 10 lb flywheel plus the lighter internals I have. Is it worth it/will I hate my life daily driving this thing? Thanks

[economix]

Fidanza Flywheel is 11# and around $350 or so (Enjuku). I picked one up, no complaints.

[derass]

If you are drifting, IMO a stock or steel lightened flywheel, would be preferred over an ultra light aluminum one. A heavier flywheel will help keep the revs up when you are using the ebrake. For all other types of performance driving, as light as you can go is ideal for increased response, but I'm sure there are downsides.

[pacotaco345]

Originally Posted by economix

Fidanza Flywheel is 11# and around $350 or so (Enjuku). I picked one up, no complaints.

Awesome, fidenza was actually what I was looking into. Are you running the one with the replaceable friction plate?

Originally Posted by derass

If you are drifting, IMO a stock or steel lightened flywheel, would be preferred over an ultra light aluminum one. A heavier flywheel will help keep the revs up when you are using the ebrake. For all other types of performance driving, as light as you can go is ideal for increased response, but I'm sure there are downsides.

That used to be my opinion on them as well. I did however have the pleasure of Yokoi driving my car and it is now my personal opinion that the sound/feel/look of constantly hammering the gas pedal & clutch when using ebrake or footbrake and quick revs is much cooler lol.

[ManoNegra]

~15lbs is a good compromise between streetability and performance from experience.

[pg240]

I have been running the 10.6lb Toda Chrome-molly Flywheel for about a year now and the engine is much more responsive over the dual mass flywheel that comes with the S15 SR.

[economix]

Originally Posted by pacotaco345

Awesome, fidenza was actually what I was looking into. Are you running the one with the replaceable friction plate?

I do indeed run the replaceable friction plate unit, however, I've never had to do that yet so I can't offer you reliable or decent feedback there. I can tell you that it makes it more responsive and depending on your power output can create some adverse streetability - can be jarring at times, quick engagement.

[curo72]

http://www.w8ji.com/rotating_mass_acceleration.htm
I'm not going to say this is correct, but it's convincing and he uses maths.

[SilviaSR20DET]

I daily a Blitz active clutch or aka ogura clutch that comes with a lightweight flywheel i tell you it rocks. Daily driving it is not bad at all very streetable yet grabs very hard. Easy to adapt to for sure.

[aga]

if you can choose, take one that is not too light. it can be a pain in the ass when starting from a stop. also when the flywheel is too light, when you switch gears in normal driving, the revs drop too much and jump up again when the clutch is engaged.

the factory knows what it's doing :P

[Wookie384]

My NA SR20DE in my S13 loves to rev thanks to the Toda flywheel I have, the ACT clutch on the other hand is a piece of shit but that's a whole different topic, just stay the fuck away from ACT like it's Miley Cyrus infected with Ebola on a Malaysian Airlines flight flying over Crimea.

[OBEEWON]

Do not like light flywheels for the cost. I like the rpm's to hang a little. In my M3 they drop so fast I have to really time my footwork. Plus I get that light flywheel chatter. Ugh.

[Dboyizmlg]

I have the Fidanza 11lbs flywheel, been running that for about 2 1/2 years now.
I love it, response is good also my motor dyno at 332wtq with and exedy stage 2 clutch.
I have no complaints at all!!

[didderson]

Been running the ACT xtss clutch kit with their chromoly flywheel for a few years & haven't had any problems. Perfect compromise in weight so I don't run into nuances that Obee does with his m3. Awesome organic disc can take a lot of drift sessions, feels like stock from a dig other than the beefy pedal feel on the 3/4 slave. /nerdout

[eek]

I would stay away from anything that is not chromoly.

Anyhow, I found this older thread, http://zilvia.net/f/showthread.php?t=187760

Check out post #25...

[az_240]

^yep... good advice from shadows. Can't go wrong with the ACT streetlite.

[Matej]

If you use your car for drifting at all, you should not use an aluminum flywheel.

Drifting is quite hard on the clutch and flywheel assembly and creates a lot of heat. Aluminum has different thermal expansion properties than steel, so when you have an aluminum flywheel bolted between a steel crank and pressure plate expanding at a different rate, it can end badly.
There have also been instances of the starter ring gears separating from aluminum flywheels due to heat.

[Dboyizmlg]

Originally Posted by Matej

If you use your car for drifting at all, you should not use an aluminum flywheel.

Drifting is quite hard on the clutch and flywheel assembly and creates a lot of heat. Aluminum has different thermal expansion properties than steel, so when you have an aluminum flywheel bolted between a steel crank and pressure plate expanding at a different rate, it can end badly.
There have also been instances of the starter ring gears separating from aluminum flywheels due to heat.

....is this true?
Hmm, more info por favor..

[pacotaco345]

Thanks for all the input guys! I think I'm going to go with a comp clutch 10.2 lb chromoly flywheel. After what I read on here about aluminum ones and the fact I can get it new at cost from one of my friends so I don't feel like I'm overpaying for whatever marginal performance gain I get. On top of that I don't think I'll ever use it enough to the point where a simple resurface won't fix any imperfections.

I'm not sure if I stated it before but I'm not too concerned with how it affects my driving style as I'm a ricer inside and post this build I should have a straight piped, high comp, cammed SR that will be my daily for at least a few months. I want the car to sound cool and snappy when I'm at events, I'm sure I can adapt my driving style to suit.

[dorkidori_s13]

ive been running an ACT prolite flywheel for the better part of 4 years now on my SR (and for about 2 years on my previous SR)... all round i have zero complaints, though on a stock ECU, the car gets a little fickle when it cant go into idle loop (put car in gear, let clutch out a bit to drop RPMs, take car out of gear when this happens). in my last 240, i beat the crap out of my ACT clutch setup and found no real ill effect. but just throwing in my 2 cents is all.

honestly, for just an all around great clutch/flywheel combo... acts sprung 6 puck, Prolite flywheel and heavy duty pressure plate are VERY VERY streetable (and hold good power as well)

[jrmto]

Originally Posted by Dboyizmlg

I have the Fidanza 11lbs flywheel, been running that for about 2 1/2 years now.
I love it, response is good also my motor dyno at 332wtq with and exedy stage 2 clutch.
I have no complaints at all!!

did you do your own work on car with the fidanza flywheel and exedy clutch?

[2plus4plus0eq6]

I've got a lightweight ACT one I paid big bucks for back in the day. I also have an aluminum driveshaft. Guys will say it doesn't increase horsepower, but the less weight in the car, better throttle response, and quicker acceleration is worth the money. Do it now while you have access to the tranny.

[Dboyizmlg]

Originally Posted by jrmto

did you do your own work on car with the fidanza flywheel and exedy clutch?

Yes I did, why do you ask?

[Kingtal0n]

imagine you had a flywheel that weighs 100lbs. You think that when you let out the clutch it will slow down much? No. It will rip the tires off the car and propel the vehicle forward as the rpms drop slightly.

Imagine you had a flywheel that weighs 0.01lbs. You think that when you let out the clutch it wont come to a complete stop, stalling the engine?

On the other hand, getting that 100lb flywheel moving will be costly. And carrying that thing around, spinning all the time, will also be costly. Also, when sudden changed in RPM are required, such as between shifts, it will be more difficult to slow down because of all that spinning mass, the clutch will work harder and get hotter.


These two extremes should give you an idea why people tend to go only slightly less weight than stock, and why many will say do not go too light. It gives a slight performance increase without being so light that driving the car becomes a chore.

Note that vehicle weight also factors in. the heavier the vehicle the heavier you want the flywheel. It should become obvious why if you consider back to the 0.01lbs flywheel example. Imagine if your car also weighed 0.01lbs. You could let out the clutch and not stall the engine, because the car is so light it would move as easily as the flywheel did, and just a couple horsepower would get you moving pretty fast. Big heavy trucks with big heavy engines that carry heavy loads should have big heavy flywheels.

[Matej]

Why would a 0.01lbs. flywheel stall the engine? An engine can run without a flywheel.

Theoretically, there really is no mechanical disadvantage to a lightweight flywheel in a vehicle. The only reason stock flywheels weigh as much as they do is because the manufacturer decided that is the weight that would provide the optimal balance between efficiency and ease of shifting for the average driver.

[l adam l]

Originally Posted by Matej

Why would a 0.01lbs. flywheel stall the engine? An engine can run without a flywheel.

Theoretically, there really is no mechanical disadvantage to a lightweight flywheel in a vehicle. The only reason stock flywheels weigh as much as they do is because the manufacturer decided that is the weight that would provide the optimal balance between efficiency and ease of shifting for the average driver.

he's meaning if you were to let off of the clutch slowly it wouldn't have enough rotational force, so the engine would die instead of pulling the car...like a stock one does.

the whole rotational force thing is what comes into play. im sure on throttle response you'd feel it right off, but inbetween shifting i bet your car would quickly drop as it doesn't have that extra weight to keep it spinning.

try thinking of it like this, hang a paper plate up on the wall by its center with a bolt and spin it, then hang your flywheel on the wall in spin it. one is going to stay spinning longer than the other, but one will take more force to move initially.

also there have been horror stories of aluminum flywheels cutting people's feet off, probably because of the whole heating up and cooling down at different temperatures.

[pacotaco345]

Anyways... I bought a comp clutch lightweight one, and it weighs 10 lbs, not .01.. I love it, car revs fast, heel & toe is much more crisp, I can be more of a ricer.

[jrmto]

Originally Posted by Dboyizmlg

Yes I did, why do you ask?

I have some questions on fidanza flywheel regarding upon installation

[Dboyizmlg]

Originally Posted by jrmto

I have some questions on fidanza flywheel regarding upon installation

Ask away... Might be a little off topic for this thread though.
But just ask, what would you like to know?

[jrmto]

I have new fidanza flywheel and new exedy stage 1 clutch was wondering if it would all line up perfectly.