Hanson

would it be a good idea to switch to a lightweight flywheel on a b18b in a boosted situation, or would that counter the benifits of the long ls gear ratios?

Hanson

anybody???

Hanson

ttt

dustin

Uhh what? Lighter is almost always better.

Dustin

Ray

I just got back my lightened flywheel( 12lbs) cost 110


Let me know what u think.



[Modified by Ray, 6:21 AM 1/20/2002]

Boosting73

Having a lightned flywheel means quicker accleration thus quicker gears. So if you like switching gears numerous times in your daily driver, go for it. I would think it would be better too keep the flywheel as it is. Seems like you get more out of longer gears in a Forced Induction motor rather than in a N/A setup. What do you guys think???

b18bvudoo

well i have a 9lb toda in my car and it was great NA. under boosted conditions for the b18b...well i just wish i had a little higher rev limit cuz the rpms move fast. 1st gear is almost non-existent when i step on it. all other gears are fine tho. just my experience. i wouldnt change my flywheel cuz i've already gotten use to it. i probably need to learn to drive better too.


as a recommendation to you maybe no lighter than ~11lbs.

Lsos

I don't know about that reasoning
I mean, adding 100hp would mean quicker acceleration, thus quicker gears?
Adding 2000lbs of weight would give you slower acceleration, thus less shifting?

Changing the flywheel doesn't actually change the gear ratios.

Smashback

Exactly, and just because you are boosting doesn't mean you're going faster. For instance, I can be pushing 6 PSI at 3500 RPM but it's making WAY more power doing 6 PSI at 6000 RPM. The sooner you can hit your peak the faster you are making more power

1

Now wouldn't too light of a flywheel allow the rpms to drop too quickly between shifts? I would think the centrifugal force gained would be lost with less weight.

bruthaboost

All that rpm dropping stuff is over stated. I have a 9 lb fidanza and if you rev match, the whole rpm thing is not an issue. Even when I don't rev match I can engage the tranny before I drop more than a 1.5k rpms.

Also centrifugal force pretty much only exists in washing machinces, dryers and centerfuges ( personally experienced this myself-9g's is like 1000 lbs on your chest). It's really a "fake force."

93LSivic

Depends what your into. Heavier, or probably stock, flywheel is better for drag racing. Whereas a lightened flywheel is better for road racing.

bigTom

as light a flywheels as u can get is the best for drag racing... y would anyone think anything differant??? lighter=faster in this case... no if ands or buts... and if ur worried about the rpm's falling 2 fast... shift faster!!

93LSivic

No, I dont think so. Im not gonna argue on this, but more weight of the flywheel takes more power to turn, but while it gets up to speed it'll be able to put more power to the ground along with torque.
Lighter is better for roadracing because of the engine speeds constantly changing and allowing the motor to speed up faster.

InfamousRS

Everyone in my area seems to think if you get a lightened Flywheel you will loose all of your torque, is this at all true?

Rain_man

If you do a search on light flywheels you'll find a discussion that pretty much concluded that a lighter flywheel will lower torque when engaging the clutch, but once the clutch is fully engaged, then torque will not be affected.

The reason is because the flywheel stores energy, with a heavier one storing more energy. When you engage the clutch this energy is transferred to the tranny and thus wheels.

For this very same reason some people have said lighter flywheels make it easier to launch turbo cars because you don't get as much wheelspin.

Lsos

A heavier flywheel wil supposedly give you a better launch. I've heard this from a guy who got a lighter flywheel on his Mr2, and was about .5 sec slower on the 1/4 mile, although his mph increased a little.

degradated

Somebody on another board keeps arguing with me that a lighter flywheel will give you more horsepower on a dyno, 10 whp or so.

Can somebody explain why this would be? I am pretty sure it won't affect the maximum power output.

Rain_man

A heavier flywheel will allow you to launch harder, but if you have tons of power like with a turbo or drag car, your problem will not be how hard you can launch but how much you can control your wheelspin.

bigTom

exactly... why are people so worried then about engagement or whatnot... when u race u generally launch anyway... and once ur moving its just more power to u...

and the reason u might make more power on a dyno is because u lightened the rotational mass...

Lsos

That's why I never understood why his times were worse. The only explanation given was that he would bog more. I never thought bogging would be a problem with a 250+hp Mr2.

About the hp gains, I never bought that. However, I heard of a test where the dyno measures how fast the engine accelerates against a load. I could see gains on that test, but not on a steady-state test.

lbz34

Its true EIN is right. lighter is more accleration. heavier stores more energy hence more turque upon shiftng/launching. The nly question relevant is, is this car a daily driver in lots of stop and go traffick. if not then lighter flywheel. my opinion anyway.

Rain_man

He probably needs to launch at a higher rpm because there is no way that he should lose .5 of a second. That is a lot of time to lose.

Actually horsepower is a measure of how fast you can accelerate a load.

X2BOARD

B-Haw haw haw haw haw !! That's a good one... you should do stand up...

A lightened flywheel will have a small negative effect on low end torque AND due to less rotational mass, WILL accelerate and decelerate quicker than a stock weighted flywheel... you cannot argue with simple physics, but you can learn to shift really fast.

Prior to your tranny, your flywheel is the first thing that the engine encounters as far as weight to move and the lighter it is, the more horsepower you can transfer to the ground. On dyno a lightened fly will not create power, but 'free it up'. And yes, you will see an increase.

Turbo cars, in my opinion, have weak low end (pre-boost) torque and with a lighter fly, you will need to launch at higher rpm to get that SOB to move.

It will help you in the higher rpms, but if you're turbo, f*k it, higher rpms is where you'll make the most Hp anyways...

Besides, you have a b18b... it's fly is relatively light anyways... why bust a mission for +/- 5 whp ? That's what boost is for !

Lsos

Horsepower is how fast you can move against a force (load). Acceleration doesn't need to be there. That's how dynos work, right? They see how fast an engine can spin against a load without accelerating.

The thing with a flywheel is that once you get it going you don't really need any power to keep it going, except to cancel whatever friction there is. So I don't see how this would show up on a steady state dyno (no acceleration). Theoretically you could put a million pound flywheel on a car and it shouldn't make a difference in a steady state dyno test (except for friction).

Look at the space shuttle. The thing weights hundreds of thousands of pounds (I don't really know). Once they get it going, they don't need to put any more power into it, except for friciton (of which there is none in space). If there was 20lb of air resistance acting against the space shuttle, they would just need 20lb of thrust to counter that. Doesn't matter if the space shuttle weights a billion pounds or a hundred pounds.




[Modified by Lsos, 6:31 PM 1/20/2002]