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8lb flywheel

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Old 11-28-06, 05:37 PM
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8lb flywheel

I have heard many different opinions on flywheels on different cars. My question is, for the FC, what are the advantages and disadvantages of having a light flywheel (the one i have is 8lbs)? I plan to have a 60-1 turbo set up for about 400whp by this time next year idk if that makes a difference in opinion. Thanx
Old 11-28-06, 05:56 PM
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basically...
advantage: revs up quicker
disadvantages: revs fall quicker
EDIT: and the lighter weight may make the front end a little lighter too...

Last edited by swbooking; 11-28-06 at 06:04 PM.
Old 11-28-06, 06:00 PM
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I have an 8lb flywheel, too. I'm excited to use it.
Old 11-28-06, 06:56 PM
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lighter flywheels are good for autoX and spirited drivings in that it is quicker to bring/keep the revs up

But with 400whp, I take it that you tend to drag this car? If you do straight line runs, the light flywheel will bog up your launches
Old 11-28-06, 07:14 PM
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i personally am not a fan of super liteweight flywheels in high hp turbo cars. it does depend on the main purpose for the car, but as said it seems you probably want to drag or highway pull with the car. if you have it just throw it in and see for yourself. what clutch are you using?
Old 11-28-06, 08:08 PM
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less torque off the line but quicker acceleration, it also helps with shifting since the RPMs drop quicker so you can mash through gears easier.
Old 11-28-06, 08:24 PM
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Light flywheels will give you MORE wheel hp and torque EVERYWHERE. What people sense as less low down torque is the fact that a light flywheel stores less energy, so it requires slightly more throttle and slightly better coordinated clutch disengagement and throttle application.
Old 11-28-06, 08:26 PM
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overall it's a sound performance upgrade.

however, the reduction in mass does have some negative impact, some internal engine stresses and vibrations will increase as a result of losing that damping mass of iron mazda called a flywheel. See page 25 of the Kenichi Amamoto book. Figure 3.19 and accompanying text.
Old 11-29-06, 01:10 AM
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what brand is this 8-pound flywheel?
Old 11-29-06, 02:37 AM
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Definitely a livelier feel to the car with the light flywheel. One annoying downside I've experienced is a tendency to stall when the a/c is running in stop/go traffic -- that the one time I miss the extra inertial mass of the OEM flywheel. The problem could be tune or vacuum leak related, so I can't be sure I can blame the light flywheel for the problem. All around, the light flywheel is an excellent mod. There are several brands. Racing Beat is a sure bet.
Old 11-29-06, 04:39 AM
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i have been thinking of a light weight flywheel as well this link has some good info http://www.rotaryresurrection.com/2n...vs_aftfly.html
Old 11-29-06, 04:49 AM
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just to reply for him if im correct its an ACT 8lb flywheel with counterweight i told him for 400hp and drag racing mainly i would stay with stock flywheel...
TwEaK
Old 11-29-06, 06:45 AM
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Originally Posted by swbooking
disadvantages: revs fall quicker
+ Doing reverse on a steep hill is a BITCH!!
Old 11-29-06, 07:22 AM
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Originally Posted by pengarufoo
overall it's a sound performance upgrade.

however, the reduction in mass does have some negative impact, some internal engine stresses and vibrations will increase as a result of losing that damping mass of iron mazda called a flywheel. See page 25 of the Kenichi Amamoto book. Figure 3.19 and accompanying text.
He meant Yamamoto if anyone's interested in the book.
Old 11-29-06, 07:42 AM
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So if driveability for the 8lb is in question why dont you consider something that is in between the 8lbs and the stock 24lbs flywheel? How about the racingbeat 17lb flywheel?

For S4: Part Number: 11444
Retail Price: $372.00

For S5: Part Number: 11447
Retail Price: $390.00

HEre is another option 12lb Flywheel

S4: Part Number: 11464
Retail Price: $455.00

S5: Part Number: 11465
Retail Price: $455.00

hOPE THAT helps.

EDIT: I have a s4 na with K&N intake, and soon to complete my RB complete exhaust. I am considering the 17lb flywheel, since it still contains a closer mass to the original and will increase acceleration and release some of my HP quicker. What do you guys think?

Last edited by ROTARYROCKET7; 11-29-06 at 07:53 AM.
Old 11-29-06, 10:12 AM
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Originally Posted by My5ABaby
He meant Yamamoto if anyone's interested in the book.
Thanks for the correction.
Old 11-29-06, 05:24 PM
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Originally Posted by fcfdfan
One annoying downside I've experienced is a tendency to stall when the a/c is running in stop/go traffic -- that the one time I miss the extra inertial mass of the OEM flywheel. The problem could be tune or vacuum leak related, ...
yeah, that's weird. usually, i read where people use the A/C to counteract the tendency to stall on deceleration. i've read where a Porsche tuner actually tuned a customer's standalone to idle as if the A/C was always on to keep the car from stalling on deceleration. i'd look into trying to tweak the tune at idle a bit.
Old 11-29-06, 08:06 PM
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First of all thanx for all the input! Like Tweak said its an 8lb ACT. As of right now i'm using an ACT street/strip heavy pressure plate combo. I had and 8lb on my H22 prelude and it was AMAZING, gobs of power freed up everywhere. The car will be mostly tamed for the street but with easily acessible big power for 1/4 mile days. I wan't the car to be all around its not like i will be running 400+ hp every day. The one thing i need to look into is the engine wear i can understand how that would work as the stock flywheel is the weight of a small pig. I plan on upgrading to a 4 puck sprung clutch to handle the power and to also leave it street freindly.
Old 11-30-06, 01:08 AM
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with the 8lb ACT flywheel do you use your existing counter weight or does/should the kit come with an additional counter weight?...
Old 11-30-06, 01:19 AM
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It really depends sometimes the flywheel doesnt come with a counterweight, check with the seller/dealer if it is included.

You won't have a counterweight to use if you had a stock flywheel, because the counterweight is integrated into the stock flywheel.

If the kit doesnt come with a counterweight it likely bolts to the stock counterweight of an *automatic* setup for your generation car, and you will have to include the cost of this counterweight in the cost of completing the upgrade.

stock rear automatic counterweight courtesy of mazdatrix:
Old 11-30-06, 05:31 PM
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No it didnt come with a counterweight i had to buy one. Also, i guess the engine stress wouldnt be a huge deal because when its done it wont be a DD anymore mostly a garage queen seeing no more than 2.5k a year
Old 11-30-06, 06:10 PM
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whats this talk about engine stress with an aftermarket flywheel?...
Old 11-30-06, 06:30 PM
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Originally Posted by Archangels
whats this talk about engine stress with an aftermarket flywheel?...
Old 11-30-06, 10:23 PM
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ok so what precautions should i be taking and what exactly can this do to my vehicle?...
Old 11-30-06, 11:17 PM
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stock flywheel is the biggest heap of poop for the t2
28lbs
TWENTY EIGHT!!!!!!!! Thats 20 over what you guys ar etalking about. HUUUUUUUUUUUUUUUUUUUGE loss of rotating mass, and also a decent loss of weight from the car itself, although very low and centered so not as good as other spots. The rotating mass weight loss is well worth it though.

At least do a steel flywheel (14lb area)

I personally went w/ a SR Motorsports 11lb aluminum flywheel. Felt it was a nice medium between the 9lb alum and 14lb steel.

Stock FD is aorund 20lbs to 18lbs, s4 n/a is 24lb, s4 t2 is 28lbs, s5 n/a is 22lbs or maybe 20lbs, s5 t2 is 24lbs i think.
these are from memory but i tried to give best i could remember

unless you're a little girl, or a drag racer. get at least a lightweight steel flywheel if you feel an aluminum is too much.

Can't wait to try mine out.


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