I need some clarification. Why does Jeg's advertise heavier flywheels to promote an increase in acceleration? Wouldn't a flywheel lighter than stock require less force to turn (thus "spooling" the engine to higher rpms more quickly)?

Also, shouldn't a lighter flyhweel would be easier to slow down (from the same rpm level) than a heavier flywheel due to less inertia?

 

Milt,

I'm with you. That MUST be a typo, or there's a new theory that I'm not understanding here...

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

I haven't seen that ad, but I've heard that the advantage in a heavier flywheel is in a harder launch. The same motor at the same rpm will launch harder with a heavier flywheel because there is more rotating inertia. After launch, you have to drag that heavy flywheel down the track, but that's the trade-off.

 

I'm betting that they assume that the engine rpms will be spooled up in preparation for a launch. Once the clutch drops onto the flywheel, the added inertial energy of the heavy flywheel will be transferred to the rear wheels, resulting in more rapid acceleration.

 

Just a hypothesis:
The heavier flywheel stores more energy before launch, and so doesn't lose as many RPMs when the load is applied at takeoff. It takes more energy (and time) to bring the flywheel up to speed, but this is done before launch when time isn't at a premium. Once its spinning you have more energy available to throw at the wheels.

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1984 Silver Z28, 383 cid long-rod SBC, ARP Bolts, 2 1/2" Cowl w/ Cold Air Induction, 600 cfm Performer Carburetor, Torker II Intake, Performer RPM Heads, XE268H Cam, Roller Tip Rockers, MSD6A Ignition, Blaster2 Coil, HEI Distributor w/ Adjustable Advance, 700R4, TransGo SK, 2.73:1 Limited Slip Dana 44, Terminator Headers, Custom 3" TIG Welded Stainless Exhaust, Flowmaster Muffler, 4 Wheel Disc Brakes, Oil Cooler

 

Yeah, what you said We posted at the same time.

 

yeah the heavy flywheel will launch quicker, i had the lightweight and the heavy weight on mine, heavy weight better

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86 Camaro with 88 305 LB9 converted to carb, edelbrock performer manifold, S/R Torquer Heads, Hedman Headers, Crane Compucam 2032 edelbrock cat-back, gutted cat, slp underdrive pulley, mallory ignition, 305 h.o dual snorkel air cleaner, hypertech thermomaster chip,160 degree thermo, and fan switch, 5-speed, 3.23 posi

95 Beretta Z26, 3100 V6, 4 Speed auto, stock

 

In general, the heavier your car, the heavier you want the flywheel to be. The other posts are right about what it does, which is store up energy for launching the car, so that when everything hooks up and settles down by the 60' point, the car is moving fast enough that the motor won't bog. One of the penalties is that the motor revs up slower (since it has this extra load of flywheel mass) so a close-ratio transmission becomes more important in a car set up this way, so that the engine RPM doesn't hace to vary much.

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"So many Mustangs, so little time..."

 

Okay, so what is best for a "street" car? Stoplight launches would be done at low rpms, but lots of race occur @ 10, 20, 30mph "launch" as well.

From personal experiences it sounds like a havier one is the way to go now, huh?

 

That's a question about tuning your specific combo, not an absolute where one is always better than the other... what motor? cam? heads? how heavy is your car? what trans? what rear gear? any suspension work? does the car hook up now with what it aready has? Another issue with the heavier flywheel is that it shocks the driveline that much harder if the tires hook up when you dump the clutch; that means more broken parts.

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"So many Mustangs, so little time..."

 

The main reason I have the light weight 16lb flywheel was to reduce the shock load as RB83L69 mentioned on the T5, since everyone was debating about the trans durability.

With the light weight flywheel you do not get that really intense "neck snap" like with the heavier 30lb flywheel. ALso the 30lb flywheel dampens engine vibrations and transmission noise at idle much better than the 16lb flywheel. I do get a chattering noise from the trans when it is cold, but when the trans is warm the chattering immediatly goes away after 2-3 minutes.

Also the 30lb flywheel is more durable in terms of abuse and getting it frequently cut when you change the clutch. Also if you like to dump the clutch frequently do no get the 16lb light weight flywheel. I'm on my second light weight.