guido944

i was just checking the catalog of performance of automotion.com and i saw this lightwheight aluminum by fidanza for 379.95 they said is 61% less weight the stock iron and said will performance better the car is it true or lie!!!!!!!! have one of my 944na 1987 changing clutch at this moment was thinking will be good idea change flywheel for one on this if will be better and more realiable and will perform better my car what can i get with ths change , please some help here?.thanks guys !!!!!

L8 APEKS

In my opinion, good. I've used them on a few cars.

The car will rev up faster.

It will also rev down faster when you let off the gas because there is less inertia from the lighter flywheel.

Some people will tell you it makes the car harder to drive, especially in hilly terrain. I have never experienced this and I would disagree. You may have to adjust your gas/clutch timing a little, but nothing more.

Geo

Amen. Anybody who can't drive with a low mass flywheel needs to take off their skirt. Shoot, my wife (a non-enthusiast) drove our turbo G20 every day with a low mass flywheel with zero complaints.

IMHO most people who put them down are people who have never used one and want to convince others not too because they need to convince themselves.

bleucamaro

less inertia = less paracitic power loss = more power to the wheels.

you will have to practice being smoother on your downshifts though.

guido944

so that mean car will be easy to drive or not?? what about in highways 4th or sth gears !!!!!!and what about accelaration???please som hel somebody that had used one or had one in his car what it makes for you????guido

IMB951

Correct me if I'm wrong, but the lightened flywheel won't necessarily make a noticeable change in your car's acceleration once the clutch is engaged and power is being delivered to the driveshaft. It will, however make the car REV faster with the clutch disengaged and you are pressing the gas say during a downshift when you are trying to rev match. This is from less rotational mass. I understand that the power is technically increased from the lower mass, but is it enough to feel? All this talk of lightened underdrive pulleys and such has got me intrigued.

bleucamaro

depending on how much inertia is reduced, not mass, there will be a gain of power at the wheels. The same will happen if you use lighter weight pulleys, axels and wheels. A college dynamics and physics text will give you all the theory behind it, but in laymens terms, a merry-go-round with 15 kids all around the outside circumfrance of it is alot harder to turn accelerate than a merry-go-round with 5 kids around the circumfrance of it. ALSO, the merry-go-round with 5 kids all around the circumfrance will be harder to accelerate than if there were 15 kids all piled on top of each other in the very center. So all that extra energy that you didn't waste trying to spin the drivetrain will go towards accerating you down the road.

guido- 4th and 5th will drive about the same, starting on a hill will cause you to abuse the clutch a bit more.

guido944

so is not that benefit ??have lighter flywheel ???if you have the car just to cruse arround 2 a month on sundays will not be that improvement have it install!!guido

Dmitry S.

[QUOTE=bleucamaro]depending on how much inertia is reduced, not mass, there will be a gain of power at the wheels. The same will happen if you use lighter weight pulleys, axels and wheels. A college dynamics and physics text will give you all the theory behind it, but in laymens terms, a merry-go-round with 15 kids all around the outside circumfrance of it is alot harder to turn accelerate than a merry-go-round with 5 kids around the circumfrance of it. ALSO, the merry-go-round with 5 kids all around the circumfrance will be harder to accelerate than if there were 15 kids all piled on top of each other in the very center. So all that extra energy that you didn't waste trying to spin the drivetrain will go towards accerating you down the road.
QUOTE]

When the clutch is engaged, it is now turning much more than the 30 or so pounds that the flywheel weighs. Depending on the gear, the engine is attempting to spin upwards of 1000 lbs. A 10 lb lighter flywheel will not make any difference in acceleration once the motor is in gear. It will however allow you to shift faster. On a street car, it makes little sense, but on a track car, it is advantageous.

Geo

Actually, a low mass flywheel or pulleys will NOT add power or free up power. BTW, simple high school physics will tell you that inertia is dependent upon mass. "Inertia is that quantity which is solely dependent upon mass."

Go here for more information about mass and inertia:

http://www.glenbrook.k12.il.us/gbssc...aws/u2l1b.html

OK, back to cases... Low mass components will NOT add horsepower. They WILL accelerate more quickly (with the clutch engaged) allowing the car to accelerate more quickly. On an inertial dyno this will show up as a hp gain, but it's a false gain. If you take 100 lbs out of your car and it accelerates more quickly, did it gain hp? Of course not. Same with rotating components. Run an engine on a brake dyno and then install a low mass flywheel and low mass pulleys and you will find zero gain. You see a brake dyno does not measure hp through acceleration.

Oh, now underdrive pulleys will produce a gain due to making it easier to turn the accessories. But the lower mass and lower rotational inertia will not produce hp (there are two gains from underdrive pulleys, lower mass [no hp gain, but improved acceleration] and lower loses turning accesories [true hp gain]).

bleucamaro

It certainly wouldn't be my first mod, but lighter wheels, flywheel, and pullys will show you about a 10hp gain on a dyno. If you've ever seen Sports Car Revolution on Speedvision, they put a big brake kit on an integra or RSX and lost 12 hp.

Mike C.

Faster acceleration off the line is what most of us NA people are after. I'd like to see before and after data. Would it not be possible to measure this on a roller dyno?

Geo

Then they selected poorly. I'll bet they selected a thick rotor set-up that is far too much for that car. A well designed racing brake set-up (which is what these kits are) shouldn't be much heavier than stock (and perhaps even lighter). I know the common set-up for a Sentra SE-R is lighter weight than the stock brakes with a little more rotaional inertia due to the mass being a bit more concentrated at the outer edge.

Geo

Yes, this shows up as a hp gain on an inertia dyno such as the ever popular Dynojet.

L8 APEKS

You WILL feel a difference in acceleration, period. The car will pull harder.