Super Chevy lightweight flywheel test
 

Super Chevy did an engine dyno test with a 31lb flywheel vs a 14lb aluminum. They found about a 10hp increase and about the same for torque.....peak hp/Torque also climbed 500rpm. They also saw gains from 3K-6.5K RPM

Re: Super Chevy lightweight flywheel test
 

how much is a fidanza flywheel and how hard is it to install?? How much would be the average price to install one in a zr1?

ed ramos #3028

Re: Super Chevy lightweight flywheel test
 

Ed -

Replacing a flywheel is:

- remove the exahust
- remove the drive shaft
- remove the C-beam (drive beam)
- remove the transmission
- remove the clutch housing
- remove the clutch

You now get to the flywheel - it's 8 bolts off, and then 8 bolts on.

You'll need to check the flywheel specification with your clutch application, but I'd advise (in any case) that if you're at the flywheel, you may as well replace the clutch while at it too - and you can get good clutch and flywheel kits from many suppliers. I recommend Jerry at Jerry's gaskets, who recently helped me out with a new flywheel and RAM dual disc setup.

I did this work myself, on SUV stands and under the car - took about 12 hours of my own time end-end, i.e. a long day or a few hours on each day of a weekend.

For a shop to do the same work, I used Vette Doctors to replace a clutch (which is about the same work as getting to the flywheel), and you're looking at around $800-$1000.

HTH

Steve

Re: Super Chevy lightweight flywheel test
 

I believe Marc Haibeck measured nearly the same difference for the LT5 with the stock (41#) dual mass FW vs. the 12# aluminum Fidanza FW.

I installed the Fidanza with a new pressure plate and clutch disc. It requires longer threaded shanks on the pressure plate bolts, thus the PP holes are drilled and tapped to accept the longer bolts. (Not a big dea, but important).

Jerry has what ya need.

As for drivability, launching at the drag strip is somewhat easier with the heavier FW, compared to the Fidanza, due to the amount of energy stored in the FW at launch. Perhaps true. But, once the tires hook, the rpms wind up quicker, especially in the lower gears. And, for about a half hour of first driving with the light weight FW, I noticed it took a weee bit more throttle, coming from a dead stop. But, after that, I never noticed it again.

Marc Haibeck uses the stock dual mass FW with a 410 diff. His motor mods compare with mine. He's a better driver, to be sure, but his trap speeds with the dual mass vs. mine with the lighter Fidanza are very close; with his ETs usually beating mine by a couple tenths.

But, factoring out the FW, Bob Banks' Z and mine are comparable except for the rear gear. Once again, the 410 combination in the half mile contest gets there quicker, leaving a clear indication that the differential - the 410 ratio to be specific - is the overwhelming factor - at LEAST where ET is concerned at that distance. (Note: my mph was 144.xx in 4th gear whereas Bob's was 138.xx mph in 5th. FWIW)

Me? I like the snappy throttle response the Fidanza allows!! And, if you have the 410 ring gear instead of the stock 3.45, you'll like it even better as the "effective" hp is advanced with the rate of rpm change.:dancing

Re: Super Chevy lightweight flywheel test
 

If cost is a factor, and you are not upgrading the clutch to a dual disc, consider retaining the stock clutch if it's got less than 20K mi. on it. But the disc is relatively cheap, so I'd replace that.
Also consider getting a "sprung disc" if you're using a single mass light weight flywheel. That might help reduce vibration which causes the dreaded trans rattle common to the LT5 without a dual mass unit.

Re: Super Chevy lightweight flywheel test
 

In my engine's defense, I was short shifting in the half mile, probably around 6800 or so. Also the 4.10 gears required an extra shift as Paul noted. I suspect with a better driver like Paul or Marc H my speeds would have been in the low 140s. But I do like the dual mass for around town driving and no trans noise. --Bob

Re: Super Chevy lightweight flywheel test
 

If you're thinking of doing this, think about a short throw shifter too. Whether ZFDoc or Hurst. I love the mechanical feel of my shifter.

Re: Super Chevy lightweight flywheel test
 

Not a big Fidanza fan based on that company's crappy quality control observed on a C5 flywheel/clutch assy in installed back in 2009. That was my one time to use their stuff and, three months later, I had to replace it all with McLeod parts to get my C5 Z06 clutch to drive properly.

I have had a McLeod aluminum wheel in my LT5 since the early 90s along with their clutch. The original McLeod disc is still in service, too.

I did not test before and after, mainly because done right that testing requires and engine dyno capable of doing "sweep tests". This is because any torque difference between different weight flywheels will only occur as the engine accelerates or decelerates not in any steady state operation. The 10-hp difference Super Chevy magazine saw is the same number I've seen from several sources over the years.

That said, torque/power changes aside, if you put in an aluminum wheel instead of the DMF and you'll right away notice an improvements in throttle response and ease in shifting.

Re: Super Chevy lightweight flywheel test
 

There are many options available that cover the full spectrum of flywheel weight ranges, that allow the use of the stock, pull-release clutch.

Here's what we carry in single mass flywheels that can be used with the stock ZR-1 clutch.

RAM 13.17lb
http://www.jerrysgaskets.com/flywhee...let-89-95-0c7/
http://cdn3.bigcommerce.com/s-nkg90o...0.1280.jpg?c=2

Jerry's Gaskets custom 18lb
http://www.jerrysgaskets.com/flywhee...let-90-95-0b3/
http://cdn3.bigcommerce.com/s-nkg90o...0.1280.jpg?c=2

Jerry's Gaskets custom 22lb
http://www.jerrysgaskets.com/flywhee...let-90-95-0b1/
http://cdn3.bigcommerce.com/s-nkg90o...0.1280.jpg?c=2


We also carry clutch discs, compatible with the stock, pull-release system.

Sprung Hub, Organic Facing
http://cdn3.bigcommerce.com/s-nkg90o...0.1280.jpg?c=2
http://cdn3.bigcommerce.com/s-nkg90o...0.1280.jpg?c=2

Sprung Hub, Metallic Facing
http://www.jerrysgaskets.com/clutch-...909-89-95-0c3/
http://cdn3.bigcommerce.com/s-nkg90o...0.1280.jpg?c=2

Re: Super Chevy lightweight flywheel test
 

I couldn't be happier with the lightweight flywheel upgrade that Marc H. did as part of the engine package in my yellow '95. I think he did a very good job tuning it.

(Fidanza, but I am sure others are just as great)

Idling at neutral there is barely any rattling noise, - only slightly more when the car is warm. Really, the more "observable" noise comes from accelerating lightly or lugging away under lighter load at lower RPMs. This is easily remedied by accelerating harder or holding your gear a little longer in the rpm range.

One of my Z's I would not think of modifying. The other...well, I wanted to see what all the fuss is about. I am glad I did the flywheel mod on this car, because together with the other mod's as part of Marc's 500hp engine package, this car accelerates like a rocket and has the feel of a race car! Thanks again Marc!