flywheel questions performancewise

[h22sparkle]

OKay uhhm with my allmotor set-up whats the preludes stock flywheel weight. And what would be best for a lightweight flywheel for everyday driving. And what about a catylic converter from ebay like this cause i have no cat http://cgi.ebay.com/ebaymotors/ws/eB...hippingPayment

[Maple50175]

Hey i like that Converter its sweet too bad it gets durty i like shiney thingss wow i cant spell

[phatdoughnut]

just go straight pipe!

[deevergote]

Just get a stock Prelude cat. Honda cats flow just fine.

As for the flywheel weight, I don't know... Hopefully someone does! I wanna learn too!

I think lightest is best for all motor. You should go with an 8lb flywheel (fidanza makes em, I believe). 8.5 seems most common, but I think that is more suited for FI. You're gonna want a high-, fast-revving engine for all motor!

I'm only going on what I think is best though, since I have absolutely nothing to back it up.

[Andrew]

If you're going to drag(race), I know that Sparkle does, there's a big debate about whether or not lighter is the way to go. It basically hinges around the heavier flywheels "maintaining" power through their greater rotational mass and whether or not this is necessary for winning a race.
Fidanza, which is the brand that I would reccomend because they use replaceable inserts (instead of needing to be resurfaced) and are SFI certified, sends an article with their flywheels that disects the matter, if somebody else remembers the name/title or has a link to the article, as I've lost my copy, please - post up! I think it would be a good, educational read for everybody here.

*Edit* The stock Prelude flywheel weight is most likely around 20 pounds.

[Fearit22]

The term is rotational inertia actually. Force = mass * acceleration... so with the same force coming from your engine and a decreased mass there is more acceleration. The problem people see with it is that whenever you let off the gas it decelerates quicker too. So your revs drop faster between shifts... This can easily be taken care of with a short shifter and some quicker shifts just so long as it doesn't drop fast enough to put you out of your powerband when you shift to the next gear. I just got my 9 lb aluminum flywheel and stage 2 clutch from clutchmasters installed about a week ago and I love it. I have heard lots of good stuff about Fidanza and they are a little cheaper than clutchmasters I think. Overall it's definitely worth getting it, but you will have to completely relearn how to drive/launch your car.

[Andrew]

The way I understood it, and I could very well be wrong, was that the extra mass of the heavier flywheel "stores" more energy when the engine is not applying force to it - the same reason heavier wheels are harder to stop... and the same reason as lighter flywheel drops rev's faster than a heavier one.
Yes, decreasing the mass of the flywheel, when it's connected to the engine, is just less weight for the engine to spin and thus, increased acceleration.

This is from Advanced Composites Product & Technology:

"In some applications, the side effects of an ultra-light flywheel negate the benefits. For example, drag-racing vehicles depend on a near-stock-weight or heavier flywheel to store the necessary amount of energy for an explosive launch. Since the launch is the most critical aspect of a drag race, most racers can’t afford to give up launch quality by using a lightened flywheel to pick up a slight improvement in acceleration"

When the clutch is engaged at, for example, a launch a heavier flywheel will have more force stored to transfer to the wheels thanks to it's increased mass while a lighter flywheel will have less (but increased acceleration once the clutch is fuly engaged) and lose it more quickly than a heavier one.

[Fearit22]

Originally posted by Andrew
The way I understood it, and I could very well be wrong, was that the extra mass of the heavier flywheel "stores" more energy when the engine is not applying force to it - the same reason heavier wheels are harder to stop... and the same reason as lighter flywheel drops rev's faster than a heavier one.
Yes, decreasing the mass of the flywheel, when it's connected to the engine, is just less weight for the engine to spin and thus, increased acceleration.

This is from Advanced Composites Product & Technology:

"In some applications, the side effects of an ultra-light flywheel negate the benefits. For example, drag-racing vehicles depend on a near-stock-weight or heavier flywheel to store the necessary amount of energy for an explosive launch. Since the launch is the most critical aspect of a drag race, most racers can’t afford to give up launch quality by using a lightened flywheel to pick up a slight improvement in acceleration"

When the clutch is engaged at, for example, a launch a heavier flywheel will have more force stored to transfer to the wheels thanks to it's increased mass while a lighter flywheel will have less (but increased acceleration once the clutch is fuly engaged) and lose it more quickly than a heavier one.

= rotational inertia = exactly what I just said. The quote you have shown is somewhat misleading. You can still get the same launch you just have to rev higher to have the same momentum whenever you launch. So like I said you have to learn how to drive/launch your car all over again.

[BustedLX]

Originally posted by Fearit22
= rotational inertia = exactly what I just said. The quote you have shown is somewhat misleading. You can still get the same launch you just have to rev higher to have the same momentum whenever you launch. So like I said you have to learn how to drive/launch your car all over again.

That's not exactly true. It may hold true with vehicles such as ours but to the majority of the racing world it's not. The Article that is quoted is dead on.

Our cars can just make up for the negatives by reving higher and the fact that they are lighter but with heavier cars like Mustangs lightening the flywheel can actually make you slower.

Lightening the flywheel takes allot of the comfort out of the ride and makes you work harder at driving the car, now granted once you learn how to deal with it it's no big deal but is it really worth it for the added acceleration?

I'm keeping my stock flywheel. I just don't see the point on spending money on something that could make me slower and makes my car harder to drive.

[Fearit22]

It's not really harder it's just different. The only thing that could be seen as making it harder to drive is you can't shift slow when you are racing but who would do that anyway. Like I said I just got mine put in and if I didn't like it I would be the first to bitch about it. What kind of comforts do you think it takes out of the ride? My car is a lot faster than it was before . I'm really happy with it, and I would definitely recommend it.

[MRX]

did u install it urself or have someone do it for u?

[Andrew]

It's funny that you'd mention shifting slow... road racers, real, honest-to-god HC, WC and SCCA RR guys don't generally need really fast shifting - which, I believe, is where the light weight flywheel made it's debut and continues to be a pretty popular item (for those guys that can afford to race AND run not stock setups)... I remember the SHO Shop (as in Taurus SHO) building an '89 for IT racing and leaving in the stock cable shifter which had a tendancy to bind when shifted fast. They reasoned that converting to the technically better rod shifted model was just a waste of money, as shifting super-fast wasn't exactly high on the list.

As far as power gains go, to really sort out what the situation is on our cars a dyno is something I'd want to see. No attack on you, Fearit22, it is quite realistic for the flywheel to free up some ponies, but also possibly at the sacrifice of a bit of torque. From what I can gather, though, each car seems to respond different to this kind of modification.

[Fearit22]

I paid to have it done. $250 for installation of the clutch and flywheel. I see no reason why it would make you lose any torque. The torque is only dependent on the force coming from the engine and the radius of the flywheel. Don't forget most of the rally racing sort of people also have a very wide powerband because they have limited maximum power outputs. For them it wouldn't matter as much if they dropped down to 2k during a shift, but for me that is a different story. I agree it isn't for every car, but I see that as being irrelevant since this is a vehicle specific forum.

[deevergote]

I never thought about the possible torque loss involved... That sucks. I like my torque!

Are there any midrange flywheels out there? If the stock Prelude one weights about 20lbs, and the lightened ones are 8-9 on average, are there some around 13-14lbs maybe? I would think those would give the faster revs of the lightened ones (if not as fast) and some of the power and inertial force of the heavier ones.

[Andrew]

Honestly, I lack the math to quantify *why* a lighter flywheel could contribute to a loss of torque, however I have seen it happen. I am also not making the claim that it WILL happen, only that I have seen it happen and wonder what the effect is on the F22.

Also, note that H(onda) C(hallenge), W(orld) C(hallenge) and SCCA club racing is not rally. They are track-specific events that very commonly see competitors searching for peak power outputs.

Finally, you're right, we don't want to know about how well a 9 pound flywheel serves an LT1 owner, we want to know about our power plants. But, well, we still aren't sure of what the quantifiable effects are in our cases.