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UUC lightweight flywheels on sale today through 6-30-07 normally $429.00 sale price of $395.00 plus shipping. the factory flywheel is 51lb's while the UUC is aprox 18lb's aside from the weight difference here is what this part will do for you as written by the guys at UUC

How a lightweight flywheel works

How does a lightweight flywheel work? Amongst the majority, there are two schools of thought concerning light flywheels. The first is that they do not contribute to power output. The second is that they do. Which thought is correct? In fact both, in a way, are correct.

If we measured the power output of an engine first with light flywheel and then again with the standard part on an engine dyno, no change in power will be seen to occur. At first it appears that the light flywheel has done nothing and was a total waste of cash. This is not the case. A dyno that shows max power at constant revs does not demonstrate what happens to an engine's power output in real life situations - like acceleration. If an engine is accelerated on a dyno (we are talking about a rate of around 2000rpm a second ) it would show a power output of around 20%-25% less than at the constant rev state.

The reason for this is that when accelerating a vehicle the engine not only has to push the total mass of the car but the internal components of the engine need to be accelerated also. This tends to absorb more power as the extra power is used accelerating the internal mass of the engine components and is why a motor accelerating on a dyno will produce less power than at constant revs. Also it must be remembered that the rate of acceleration on the engine internals is much greater that the rest of the car. This would then suggest that by lightening the flywheel, less power would be required to accelerate it and therefore more power would be available to push the car along.

Now, it may seen unbelievable that by removing a few pounds from the flywheel a noticeable difference to a 3000lb+ car’s acceleration will be made. In fact the difference is quite noticeable and the secret behind this is hidden within the gearbox. Everyone knows that cars accelerate at a greater rate in low gears, this is because a car’s gear box basically a mechanical lever and just like when using a leaver to lift a heavy object, the gearbox reduces the mass of the car that the engine sees. For example, in first gear an engine will see the car's mass as only around say 250lbs but the engine internal mass would still remain around 45lbs.

As for the "virtual" weight loss of a typical lightweight flywheel in the 3-series or M3, we've prepared the full mathematical analysis:

Calculations for UUC flywheels showing exact "virtual" weight loss in each gear - click here to download Acrobat .pdf file

It is now easier to see were the extra performance comes from when you lighten a flywheel. You effectively "lighten" a car by more than 10% in first gear just by removing mass from the flywheel. As the gear used increases this "lightening" effect is reduced. This is why car’s acceleration improvement reduces in higher gears, to very effect in top gear. Great for drags and tight race tracks but will not increase a car's top speed.

You will see the calculations include the diameter of the flywheel, weight lost (same overall rotating mass difference in UUC Stage1 or Stage2 due to pressure plate weight differences), gear ratios including 6-speed application, and typical diff ratio.

The effective "virtual" weight losses are:

GEAR "virtual"
weight lost:
1st gear 394.4 lbs.
2nd gear 151.7 lbs.
3rd gear 75.4 lbs.
4th gear 48.5 lbs.
5th gear 37.6 lbs.
6th gear 31.0 lbs.


A general rule of thumb for weight loss equivalence to "gained" power is approximately 10lbs/hp. That is for every 10lbs lost, the car gains the effective performance increase of 1hp.

With that in mind, the effective performance increase expressed in gained power can be expected to be the same as the "virtual" weight lost due to the flywheel in each gear divided by 10:

GEAR "virtual"
performance gain:
1st gear 39.4 hp
2nd gear 15.2 hp
3rd gear 7.5 hp
4th gear 4.9 hp
5th gear 3.8 hp
6th gear 3.1 hp



This gear-dependent gain is also another reason why a typical 4th-gear dyno pull may not show a significant difference - the calculations show that little more than 4hp would be detected, yet a 4th-gear dyno run shows nothing of real-world acceleration through the gears. Improvements in rev-matching and upgraded clutch clamping power remain regardless of gear.

Due to the nature of the "virtual" weight loss, typical 4th-gear dyno runs may show miniscule differences. Real-world acceleration runs will show improvement equivalent to the "virtual" weight loss.

To order, email or call me at the below info. thanks in advance.
 

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2004 CTS-V
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Care to comment on potential drive train warranty implications:bigroll:

I would like to do this but fear losing warranty coverage on the trans and or diff that are both known to have potential issues:tisk:
 

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2004 BLK Cadillac CTS-V
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Care to comment on potential drive train warranty implications:bigroll:

I would like to do this but fear losing warranty coverage on the trans and or diff that are both known to have potential issues:tisk:
My guess on this is that it might actually help the abuse recieved by the diff. With less spinning weight when the clutch is dumped the torque delivered to the drivetrain should also be less. So initial launch with these would probably be slightly less extreme with the real acceleration gains coming once the engine is locked in with the rest of the drive train and not having to keep spinning up all that weight.
 

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If a lightweight flywheel delivers these benefits, why did the V come with the heavier version? The V is pretty well designed (aside from the diff as we all know.) Can't see GM beancounters entering into this equation. Curious mind wants to know.....
 
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Discussion Starter #7
Our shop gets 5 hours to install the flywheel which translates to about $520.00. As far as warranty issues go that is as with any other mod a grey area. dealerships are legally responsible (moss magnuson act) to show proof the the modification in question was directly responsible for what ever failed on the car. with that said some dealerships will go out of there way to not honor warrantys the minute you upgrade somthing, especialy if they didnt sell it to you. as stated in a post above this flywheel is designed to help take stress off of the driveline.
 
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If a lightweight flywheel delivers these benefits, why did the V come with the heavier version? The V is pretty well designed (aside from the diff as we all know.) Can't see GM beancounters entering into this equation. Curious mind wants to know.....

anything can be improved upon!!! look at the shifter :bouncy:
 

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anything can be improved upon!!! look at the shifter
Still.... a lightweight flywheel is not a new idea and the designers must have thought about that when designing the drivetrain. I would think there has to be an integral design thought process in choosing the stock version. I don't consider bushings and shifter to be in the same league as a flywheel.
 

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If a lightweight flywheel delivers these benefits, why did the V come with the heavier version? The V is pretty well designed (aside from the diff as we all know.) Can't see GM beancounters entering into this equation. Curious mind wants to know.....
You must not be in the industry. The bean counters make ALL of the decisions. There is no way they would let the engineers spend $300 more on the flywheel if the current one works.

Sad but true..............
 

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2005 CTS-V
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You must not be in the industry. The bean counters make ALL of the decisions. There is no way they would let the engineers spend $300 more on the flywheel if the current one works.

Sad but true..............
The production cost of lightweight flywheels is not necessarily more than that of heavy flywheels when produced in comparable numbers. For example, CTS-V heavy flywheels cost more than Corvette lighter flywheels.
 

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They did it so that the shifts are smoother. No performance in mind. The engagement of the clutch to the flywheel is much smoother than that of a corvette. It is also more forgiving.
 

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So the heavier flywheel allows for continued rotation at a higher RPM when shifting, thus allowing for a smoother shift. With a lighter flywheel the RPM's drop quicker leading to a noticable engagement when shifting.... So faster acceleration is sacrificed for a smoother ride in a V with the heavier flywheel, keeping with the idealogy of a Caddi. I get it now.
Still a steep price to pay for quicker acceleration with the lighter flywheel including installation. Wheel hop and diff issues are still there.
 

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Still a steep price to pay for quicker acceleration with the lighter flywheel including installation. Wheel hop and diff issues are still there.

Price seems reasonable for those that track their cars. Rev-matching properly is very important and is sometimes difficult to do perfectly with the stock flywheel. It just doesn't "blip" fast enough. If you're just driving your V from work and back (not that there's anything technically wrong with that) then you probably won't be able to see past the cost of the modification...
 

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The heavy flywheel is for easy drivability. Any idiot can pretty much let the clutch out and begin rolling with the 51lb flywheel and can easily start out in second if desired. Try this with the 19lb flywheel! Heavier flywheel makes it more tame which would lead to more buyers! Remember, we are the extreme people for these cars. The light flywheel will help it rev faster and I do have one but have not installed it yet...still!
 

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Hmmm looks like you need to sell it to me then.... Of course even though it hasn't been installed I'll have to get it for a used price.... $200 sound good? :highfive:
 

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I've so been wanting a lighter flywheel. The car should rev easier & I've been convinced that was the issue. How much for the part+install if I bring my V to you guys?
 
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