The recent issue of Muscle Mustangs & Fast Fords had a good article on testing the impact of reducing flywheel weight. Yeah...I know it is a Ford magazine, but these Fords guys really do their home work.

They measured the impact of a reducing the flywheel weight by 11 lbs on a 12 sec car. The car had street tires. Interesting points were:

1. The car picked up 4 to 15 RWHP in 2nd gear, 10 - 11 RWHP in third. This was recorded on a chassis dyno.

2. While not recorded, the estimated gain in 1st is 20 RWHP.

3. There was a loss of 22 RWHP between shifts for a tenth of a second...lessed stored energy with the lighter flywheel.

4. Shaved off 1/10th and added .6 MPH to the baseline average of 12.39 @ 109.75.

5. Best lauch RPM went from 3000 to 3500 with lighter flywheel. Before the change, 3000 was used to reduce the risk of lighting up the tires.

6. If you went lighter, like a 22 lbs saving, it is equivalent to reducing car weight by 320 lbs to achieve the same 1st gear accelaration (Their math not mine).

They did the same tests with a blown 10 sec mustang with slicks and the track results were not clear to me.

The article did not say anything about whether the lighter flywheel made it any harder to get consistent 60 ft times with street tires. They left off a lot off 1/4 mile detatils of each run, which makes me suspicious. I would be interested to see the variation in 60 ft times before and after the flywheel change.

They definately proved that there is a very significant in-gear advantage to a lighter flywheel.

To me, the jury is still out. Gut feelings for the 350 are:

road race = light flywheel
drag with slicks and drag radials = go heavier (stock dual mass)
general purpose/drag on street tires = medium weight flywheel.

 

You & they are exactly right....and I see on the Fidanza Flywheel web site my aluminum single mass LT4 model weighs in at a whopping 11.5 Lbs :D
http://www.aluminumflywheels.com/flywheels.html

I can't remember exactly but I do believe my dual mass was around 35Lbs does that sound right? :confused:

:seeya

 

I got something like that too.

 

Thanks for the info, Carl90. Is any member able to provide the tech reasons why the heavy dual mass flywheel is used in our vettes?


[Modified by Oldman, 1:01 PM 1/6/2003]

 

Believe the DMF was use to quiet the noise from the ZF transmission. My stock DMF weighed 38 LBS. The Camaro SMF in my 396 weighs 20 LBS.

 

I guess I can live with my 16lb 4+3 flywheel. :D

 

Thanks for the response, Red Rocket. I guess we are stuck with the DMF.......

 

I'll tell ya' one thing that aluminum Fidanza is noisey as heck, no cast iron to help absorb ANY vibration or noise, looking at those HP numbers makes it more tolerable though.. :D

 

Will the 20 lb rattle the tranny less than the 11 lb flywheel setup?

Sometimes I get some rattling at idle, but it is due to the cam and running the intake cool with no EGR. It is annoying, but not bad. It reminds me of a baracuda fish...it rattles its teeth just before an attack when a threat/opponent pisses him off :lol:

 

I don't think it's the weight difference between the 11 Lb & 20 Lb, that makes the difference in noise. It's my belief the cast iron single mass conversion's cast iron "sucks up" / "dampens" some of the vibration/noise that the aluminum single mass conversion cannot... :)

 

sport compact car did the same test on a civic. and removing 7lbs of mass was equivilent to 200lbs on the car (in first gear).