im looking too get a lightweight flywheel for my h22. ive had one on my d16 and b18 and i miss the acceleration characteristics.

my question what would be an ideal weight too look for? im thinking the ACT street light. ive used act both time with 0 problems. any other suggestions? i dont want a 5lb one, cause i love my torque. chime in guys.

 

Flywheel mass has no effect on engine torque output as far as anyone has proven.

Inertial physics would also indicate that a flywheel of uniform mass and radius would not contribute at all to torque along the axis of rotation. Heavier counterweights on the crank, however, would.

 

So does that mean a heavier fly wheel would give it more torque

 

i just installed a lightweight Fidanza flywheel and Fidanza 2.1 clutch about 5 months ago and i absolutely love how the engine speeds up, it goes from idle to 6k in no-time, its great espically when youre shifting quickly. youll just notice that youre car is much easier to drive hard, and revs MUCH quicker

 

ACT Streetlite ~12lb'er......
Matched rev downshifts are night and day compared to stock.....Which leads me to believe that the engine will rev faster. If you go too light, you will loses rpms too fast during shifting.

Something weird I have to mention though about my Civic. When I swapped the broken d15b for a fresh one, I installed an ACT SL FW. With the identical mods, the setup made 2-4whp more from 3000-7500rpms and 5-6wtq from 4-6000rpms. I can't say it was pure Flywheel but kind of weird nonetheless......Still freakishly high #'s for a 1.5 liter with stock internals.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Acidcrakker &raquo;</TD></TR><TR><TD CLASS="quote">So does that mean a heavier fly wheel would give it more torque</TD></TR></TABLE>

Not according to what I said. If there was a big counterweight, it would add torque on its downstroke, and steal some on its upstroke. A heavy flywheel, however, wouldn't do anything to torque output, because it is uniform around all 360* of rotation. It simply stores inertia, so a heavier one will take longer to rev up because it is storing more energy as inertia, but will stay spinning longer if you let it go (which is why rpms drop more slowly with heavy flywheels).

A light one stores less energy, so it revs up faster, and it has less to keep it spinning, which is why the rpms drop fast with a lighter flywheel.

Personally, I really want to see a back to back dyno proving what happens one way or another, but it is tough to change a flywheel and do back to back dynos like that....lotta work.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">
Personally, I really want to see a back to back dyno proving what happens one way or another, but it is tough to change a flywheel and do back to back dynos like that....lotta work.</TD></TR></TABLE>
Well, it would be one of those time waster dyno tests....I watched 2 Acura techs do a clutch and front brakes in &gt;90min at work! I was amazed!
This is one time where I think the butt dyno works well.....downshifts FEEL so much smoother!

 

I agree, I'd do it anyways just for the improved rpm response

 

in my gutted ef hatch with a b18 the flywheel killed me between shifts. once i started powershifting, it was fine. then i noticed that i could still pull at high speeds. i was pulling on a cobalt ss at 120 when i couldnt before.

i think ima look for arournf a 12 lb.

 

All sounds intresting. So you guys suggest lighter flywheels? Anyone in particualr?

I think that might be my next mod after I do this swap. And then Suspension and Wheels. Then off to nitrous, with a miltary green paint job .

Lol Should be completed by next year this time.

 

8lb nuff said

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Cottonwoodz &raquo;</TD></TR><TR><TD CLASS="quote">8lb nuff said</TD></TR></TABLE>


ACT makes a 12lb Streetlite. If you go TOO light your car will lose revs very fast. This is something you can see in slow motion when you let off the gas when approaching a light.

 

Has anyone seen, or have a link to a dyno with a heavier flywheel, and a lightened one? I've been dying to see one. I too can't see how lightening it could do anything but help torque. You might not get that tire chirp at first when you shift do to it's ability to converse energy between shifts while it's free of the whole drivetrain, but after that it should help no?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ::NirVTEC:: &raquo;</TD></TR><TR><TD CLASS="quote">


ACT makes a 12lb Streetlite. If you go TOO light your car will lose revs very fast. This is something you can see in slow motion when you let off the gas when approaching a light. </TD></TR></TABLE>

Why is that bad?

I've driven an 8lb flywheel for 3 years now and I have NO complaint WHATSOEVER. I've also driven a 12lb and couldn't tell a difference at all.

 

Not to totally change direction of the thread but I found some nice info on flywheels and it describes what I was trying to say. I believe it's talking about motorcycles, but it's the same concept.

All engines have flywheels or weighted crankshafts that balance out compression and power strokes, maintain idle, aid starting and reduce component wear. If the flywheel is too light the motorcycle requires more effort to start, idles badly, and is prone to stalling. Weight is not the important factor here, but inertia. Inertia is stored energy, and is not directly proportional to flywheel weight. It’s possible to have a light flywheel with much more inertia than a heavier flywheel.

Flywheel inertia is stored when you rev the engine slightly before letting the clutch out - this small amount of extra power helps in getting the motorcycle underway with minimal effort. By “borrowing” power for a few seconds, the engine has to develop less to move from a standing start. Once the clutch is completely engaged, inertia can no longer be borrowed - the motorcycle can only use what it produces in “real time”.
In any event, except for when the clutch is slipped all flywheel weight reduces acceleration. There is no engine speed or other condition where extra flywheel weight helps (see note: ).
However, let me clarify something that is frequently mis-stated and/or mis-understood. The amount of power a motor develops is NOT RELATED to flywheel weight. Heavy flywheels do NOT “make more torque”, this is completely fictional. The power is merely stored by the flywheels, and they only have what is diverted from the primary drive.
Obviously, there’s a certain minimum amount of flywheel inertial that should be present for several reasons:


Again this is just more jargon on paper and I would love to see a dyno for real world satisfaction, but what it is however is the physics and I'll take my chances trusting te physics.

http://victorylibrary.com/tech/inertia-c.htm

 

Word.

Thats a good summary of what I was trying to say. They're just a piece of weight on the crank once the clutch is engaged, just like the clutch, and everything in the transmission.

 

If the comparison between the 8 and 12 is AS different as the 12 and stock, I personally would want nothing to do with a 8lb'er....My car is setup more for RR though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">Word.

Thats a good summary of what I was trying to say. They're just a piece of weight on the crank once the clutch is engaged, just like the clutch, and everything in the transmission.</TD></TR></TABLE>

Lets patent and sell a lightened flywheel with all the weight at the leading edge of it. This way it would have the benefits of a lightened flywheel, yet maintain the intertial benefits of a heavier one.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ::NirVTEC:: &raquo;</TD></TR><TR><TD CLASS="quote">If the comparison between the 8 and 12 is AS different as the 12 and stock, I personally would want nothing to do with a 8lb'er....My car is setup more for RR though.
</TD></TR></TABLE>

I have never used a 12lb, but i doubt that your statement is true.

I have daily driven an 8lb for 2 years and have no complaints what so ever.

Really the only thing to look at on flywheels is the material......steel/aluminum/cromoly........everything else is a cookie cutter copy of the next guy.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94Vtecluder &raquo;</TD></TR><TR><TD CLASS="quote">

Lets patent and sell a lightened flywheel with all the weight at the leading edge of it. This way it would have the benefits of a lightened flywheel, yet maintain the intertial benefits of a heavier one. </TD></TR></TABLE>

If I was gonna make any kinda flywheel, it would be 8" in diameter and I'd design a 6" twin-disk clutch setup to go along with it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ::NirVTEC:: &raquo;</TD></TR><TR><TD CLASS="quote">If the comparison between the 8 and 12 is AS different as the 12 and stock, I personally would want nothing to do with a 8lb'er....My car is setup more for RR though.
</TD></TR></TABLE>

Why is losing rpm fast between shifts so bad for RR? Shift faster.

I disagree in my experience, being able to rev match so you can downshift into a turn very fast is very worth it, those that know how to downshift quickly and correctly can carry a lot more speed than people who just slam the brakes last minute.

 

Can't call yourself a man 'till you learn to rev match! VTECluder, that was good piece of reading right there. So anyway, a lighter flywheel has no effect on overall power output....how about acceleration/power delivery? That's what I'd like to know.

Edit: The "leading edge" on a flywheel...that's what I was thinking about cranks. If it worked out like that, then it should give it a little push on the upstroke? I'm sure Honda would have thought of that...there must be a reason. Maybe, it doesn't work in practice?



Modified by Televator at 2:03 PM 11/2/2007

 

like stated before i had a pretty light flywheel in my hatch and i loved it. i lost a bunch of races untill i started powershifting again.

i learned quickly too rev match, lol. my friends all laughed at me. it took me about a week too get use too my hatch. it took me a month too get use too this damn accord!! lol.

the flywheel question i guess can be answered with "preference"

some like stock, some like lightweight. cant hate on anyone for their opinions.

as of now im not going too worrry about it. if i come across a good deal, i might just take it.

94Vtecluder, ******* awesome on backing your statement with facts. kudos bruh.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Televator &raquo;</TD></TR><TR><TD CLASS="quote">Can't call yourself a man 'till you learn to rev match! VTECluder, that was good piece of reading right there. So anyway, a lighter flywheel has no effect on overall power output....how about acceleration/power delivery? That's what I'd like to know.

Edit: The "leading edge" on a flywheel...that's what I was thinking about cranks. If it worked out like that, then it should give it a little push on the upstroke? I'm sure Honda would have thought of that...there must be a reason. Maybe, it doesn't work in practice?

Modified by Televator at 2:03 PM 11/2/2007</TD></TR></TABLE>

What do you mean by "leading edge"?

The flywheel is there to keep the engine turning in between combustion events, it needs to be uniform so that it can do so for all 360* of crank rotation.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">

What do you mean by "leading edge"?

The flywheel is there to keep the engine turning in between combustion events, it needs to be uniform so that it can do so for all 360* of crank rotation.</TD></TR></TABLE>

What I meant was disperesed on the outside ring of the flywheel equally 360 degrees.


Also about rev matching, just because you have a lighter flywheel doesn't mean your rev matching any better. All that means is that a lighter flywheel is more forgiving during the rev match because it's lighter and has less intertia. Therefore it will sync up faster and smoother than a heavier one. If anything it's harder, and takes more skill/precision to rev match a heavier flywheel.

 

Well, I'm not sure exactly how it applies to a flywheel either. That's why I was thinking more about the crank. As it was revealed to me in another thread though, It seem Honda took care of that.