You can use this relation to estimate gains in each gear from the change in rotating mass at the engine:



nfd is the final drive ratio (3.538 for 6MT)
ngear is the gear ratio (3.794, 2.324, 1.624, 1.271, 1.000, 0.794)
r0 is the flywheel radius
rtire is the tire radius (~13.4 inches)
dm is the mass change for the flywheel (negative for lightened flywheel)
Mv is the mass of the vehicle (3524 pounds + driver)

Just make sure that r0 and rtire are in the same units, and dm and Mv are in the same units. Here are some sample calculations for all 6 gears for a mass change of 1 pound, assuming a 6.125" flywheel radius and 160 pound driver:

0.445%, 0.192%, 0.093%, 0.057%, 0.036%, 0.022%

Since the gain in each gear is proportional to the mass change, multiply these numbers by 5 for a 5 pound mass decrease, 10 for a 10 pount decrease, etc.

So for a lightened flywheel 13.7 pounds lighter than stock, assuming a car putting out 235 whp, the flywheel is responsible for the following peak gains in each gear:

16.6 whp, 6.2 whp, 3.0 whp, 1.9 whp, 1.1 whp, 0.7 whp

So you can certainly feel the gains in 1st, maybe in 2nd, but problably not in the higher gears.

 

Did you get a chance to measure the outer diameter?

 

yup, 12.25 in

 

i have the jwt clutch and flywheel, it ****n rocks. i dont mind the chatter, it actually sounds pretty cool. most improvements are in first in second, you dont wanna see me off my launch. highly recommended, the stock dual mass sucks, i burnt out stock in about 8 months.

 

haha i am going to have to disagree with the cool chatter part, but yeah it rocksss

 

Did you consider the Nismo flywheel? I wonder if it would have even less chatter?

 

i heard the nismo one rattles a lot too. from what i have heard the ur rattles least, then jwt, then nismo. this is based off of what people i know have said after they have heard all three.

 

Ah, I must increase all my calculated gains by 24% then. I've edited my post to indicate the more accurate numbers. The gains in 1st must feel pretty good!

 

haha nice nice! i think already getting used to it though : ( must have more power!

 

I just picked up the G from the dealer today...installed NISMO pressure plate, clutch and flywheel...the chatter at idle isn't very noticable but in every gear (except 1st) running LESS THAN 2k rpm the throwout chatters a lot...I wasn't ready for the chatter when i first drove the car and so I returned to the dealer complaining and they said thats what it is supposed to sound like...I LOVE the NISMO parts and I would do it over again but the sound is the ONLY drawback. After 2k rpm it's fine...

 

The chatter with the stock setup is already horrible, I'd hate to make it worse.

 

The obvious solution is to make your induction and exhaust noise louder so you can't hear it. Yes! I have the JWT flywheel sitting at home right now, trying to decide a clutch to go with it. Glad to hear the good words about the flywheel.

 

Mine was only bad when A) - Pressure plate shattered at 11K and B) Tranny replaced at 18K

Each time when car was new and tranny was new, it was whisper quiet for a few thousand miles. I just put the JWT combo in and I will say that it's the exact same as when my stock would chatter so you probably wouldn't notice a difference at all.

 

It's not a noise, it's a feeling through the pedal and a rough start unless you're really careful when starting at low RPM.

 

honestly, engaging first doesnt feel all that different. shifts between gears is a lot smoother. during normal driving, these are the only effects that the fw has, but under spirited its a blast!

as for the chatter, mine seems to have died down a bit, but i attribute that to the colder weather.