I have heard so many different things related to flywheel weight and straight line performance Im not sure what to believe. Im thinking of getting a new flywheel but Ive heard heavier is better for straight line performance and ive heard the same about lighter. Just wondering if anyone has run at the track before and after putting in just a lighter flywheel. I have a 92GSR and think that with my low torque a lighter flywheel would benefit my car quite a bit. Any opinions?

 

There are a lot of opinions going around about this subject.

Basically a lighter flywheel will allow your motor to rev up easier. The motor doesn't have to work as hard to spin the flywheel.....spin the pressure plate.....transmission.....and finally to the wheels.

You are increasing your "mechanical advantage" when you get a lighter flywheel. I guess you could say it's good, but you do also have to shift faster since the rev's drop quickly when you press the clutch (due to you having less momentum). If you have a turbo setup (or any forced induction setup), it's also a bit harder to drive since the revs will shoot up so quick. You also lose some "cruising" ability since the car will slow down faster in gear (also because of the momentum loss).

Remember momentum = mass x velocity. Your flywheel will slow down faster than a stock/heavier one.

All in all, there are advantages and disadvantages to it.

 

so whats the advantage of a heavier flywheel

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bay_707 &raquo;</TD></TR><TR><TD CLASS="quote">so whats the advantage of a heavier flywheel</TD></TR></TABLE>

Heavier? Most, if not all flywheel "upgrades" are lighter.

There are advantages for both heavier and lighter ones. These are the ones off the top of my head:

Lighter:
1) Rev up easier
2) More mechanical advantage for the motor

Heavier flywheel:
1) You can cruise longer without the car slowing down
2) Easier shifting (you don't have to shift too fast to make it "smooth")

I guess, if you are a "hardcore" drag racer , the light flywheel will be better. But remember that unless the flywheel is dramatically lighter, it won't make TOO much of a difference.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bay_707 &raquo;</TD></TR><TR><TD CLASS="quote">so whats the advantage of a heavier flywheel</TD></TR></TABLE>

Less torque loss(?). Slack on the shift speed?

Ok, Shamoo hit some points. I went from stock to 12 lb in my old hatch, and it was a great upgrade. The driving was more fun...I like rev matching, and feeling the 'free-ness' of the throttle.

 

I heard the differences you choose for you flywheel depend on the car setup you have. I heard its better to have a lighter flywheel if you want to run a N/A setup with low HP. I heard if you are boosting and you go with the lighter flywheel it will have problems boosting prolly! Im not to sure...but I would think lightest and strongest are you two keys for a flywheel...

 

that less torque loss is nonsense. Just as what was said before, it's momentum and inirtia that makes the "sense" of having more or less torque. with a heavier flywheel, more rotational inirtia can be stored = more tire spinning action when the clutch is dropped. however, with more weight = more effort getting the flywheel spinning and slowing it down, so the engine has to work more. The lighter flywheels don't have that inirtia-storing capability that the heavier ones do. This means that the engine can rev faster, but it feels as if there is less torque, but in fact, there was no loss, just a loss in momentum and inirtia. Hope that makes sense. If not, go get a physics book and read up on moments of inirtia and momentum.

 

There's a good thread on here...search for it...explains the whole flywheel concept. Garados tapped it with his explanation...directional, inertia, etc.

 

on the explanation. It gets no easier than that. I opted to run an 11 lb flywheel over some of the more popular 7 and 8 lb ones. Road racers/ Autocrossers would probably see more benefit in the 7 and 8's. But drag racers and heavy footers, ya dont need them to be suuuuper light. But the lighter they get, the trickier you have to be with your foot play.

 

DB2GSR: I've driven a b17a w/ oem flywheel lightened to 13lbs (my car), and a b17a with the act 8 or 9lb flywheel(friend's car). IMO both are still very easy to drive and it made a very big difference in how the car feels. Revs don't go up or down as fast as some may lead on. There is no feeling that you have to "shift faster" or that the car slows down abruptly when you're cruising and then let off the throttle. IMO the downsides to a lighter flywheel are blown out of proportion when talked about online.

I don't have any timeslips to show any sort of performance difference.... but I can say I definitely prefer the lighter flywheel. Just makes the car more fun to drive, more sporty. IMO the stock flywheel is WAY too heavy. Our cars should come from the factory with a 13-14lb flywheel. I saw a big difference in how much more fun the car was to drive, and zero drawbacks (wasn't any harder to drive....for me at least).

After feeling the difference it made on my car and my friend's car I now think that a good clutch and light flywheel setup is one of the very best initial mods you can do to your gsr. I'd put it on the list before i/h/e (since the benefit, imo, is much greater, and cost is comparable). Only problem is its more difficult to install and sometimes more costly to install....

All of this of course is my opinion.... If possible try to get a chance to drive someone else's car that has a light flywheel if you're at all worried about it causing a drop in drivability. That way you'll know before you commit to it.

 

insightful.

yet subjective.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91IntegGS &raquo;</TD></TR><TR><TD CLASS="quote">DB2GSR: I've driven a b17a w/ oem flywheel lightened to 13lbs (my car), and a b17a with the act 8 or 9lb flywheel(friend's car). IMO both are still very easy to drive and it made a very big difference in how the car feels. Revs don't go up or down as fast as some may lead on. There is no feeling that you have to "shift faster" or that the car slows down abruptly when you're cruising and then let off the throttle. IMO the downsides to a lighter flywheel are blown out of proportion when talked about online.

I don't have any timeslips to show any sort of performance difference.... but I can say I definitely prefer the lighter flywheel. Just makes the car more fun to drive, more sporty. IMO the stock flywheel is WAY too heavy. Our cars should come from the factory with a 13-14lb flywheel. I saw a big difference in how much more fun the car was to drive, and zero drawbacks (wasn't any harder to drive....for me at least).

After feeling the difference it made on my car and my friend's car I now think that a good clutch and light flywheel setup is one of the very best initial mods you can do to your gsr. I'd put it on the list before i/h/e (since the benefit, imo, is much greater, and cost is comparable). Only problem is its more difficult to install and sometimes more costly to install....

All of this of course is my opinion.... If possible try to get a chance to drive someone else's car that has a light flywheel if you're at all worried about it causing a drop in drivability. That way you'll know before you commit to it.</TD></TR></TABLE>