I'm getting ready to purchase a flywheel for my 69 Caprice. I plan on getting a SFI approved one but am having a hard time deciding on the heavy steel one or a lighter aluminum one. Any suggestions or experience with this???

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1969 Caprice (It's not an Impala darnit!)
427/TH-400 (Soon to be M-20)
12-bolt 4.10 Posi
13.45 @ 105

1966 Caprice
396/325 TH-400
15.38 @ 97.4

Andy and Nick's Highway to Hell (http://www.public.iastate.edu/~amcarthu)

Y e a r s ago when I had my first 67 SS (maybe 69/70) I bought a Schiefer alum flywheel and loved it. Didn't race the car but it sure did spin over easy on cold mornings!



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Dale McIntosh
Team Chevelle Gold #92
ACES #1709

1974 454 Corvette for sale (http://www.dalesplace.com/htm/corvette/corvette.htm)
www.dalesplace.com (http://www.dalesplace.com)

Andy,

While there are horsepower advantages to a lighter flywheel, there are drivability disadvantages as well.

True, you will pick up some extra ponies to the rear wheels because the engine uses fewer trying to spin the flywheel.

However, in a street car - particuarly a heavy one, you need the extra mass of a heavy flywheel to get the car moving.

In a very light car you can get by with a lighter wheel - less mass to get moving.

Let me know what you end up doing.....

Regards,

Dan

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Awww, fer cyrin out loud, there's that IMPALA guy again.

http://photos.yahoo.com/bc/ss3964spd?d&.flabel=fld1&.src=ph

Take it from Dan the Impala man... http://www.chevelles.com/forum/wink.gif

427, I wouldn't run an alum unless I had a light, sub-3000 lbs car.

Friends car is a 3200Lbs 92ish Eclpipse. Manual tranny. AWD. Turbo charged. When getting into performance clutches and bigger turbos, ONE most always get's a lightened fly wheel.

They take 4 cylinder cars and put them into the 11 second range, which is very impressive.

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BB414, TH400, 3.73 posi,
13.1sec @ 105 MPH (TH400 needs clutch pack, Radial T/As = zero traction)
"I've seen sunny days that I thought would never end " J.T.
Picture of me roasting the tires and other guy stuff (http://www.auburnextremeracing.org/drivers/mike/)
Video of me staging (smoke of course) (http://www.notabusinessracing.org/videos/mike_chevelle_burnout.avi)

Try common sense:
The only time it makes a difference is when it is speeding up or slowing down.A heavier flywheel takes more energy to accelerate it and decelerate it. At steady speed it matters not what it is made of, NO horses used.
IF THIS IS NOT A FULL RACE CAR THEN:
Start your engine, warm it up, now let it idle. Next slam the padal to the floor and time how long it takes to hit 5000 RPM. Now decide if aluminum will make a serious difference in a street car.
It matters in extremely high rpm motors on the track. I vote NO for the street.

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Make it the way you like it, forget what the other guys say!

If you do decide to go with the alum. flywheel, do not install it without a explosion proof bellhousing. At high rpm if the flywheel breaksup at the attaching bolts, the pieces are like a gernade. They will comeup thru the floorboard and even up thru the roof of the car. Have been known to takeoff parts of the right foot. Not the best for a heavy street driven car.

65Camino
Team member #74

I've wondered this as well and unfortunately never seen any documentation or testing published.

I have heard that less flywheel weight lets the engine rpm quicker(thus improve acceleration-slightly?)and easier on synchros.

Also heard it can cause drivability problems due to insufficient weight and poor idle with larger cams. I've seen the driveability problem on two occasions although possibly not entirely the flywheels fault-clutch set up, etc.

One situation was an older Trans Am type car(road racing) using a flywheel similar to flex plate-individual could not leave from a standstill with out tremendous rpm. The clutch seemed either in or out with engine either spinning 5000 or near zero. Other occasion was similar except autocross car with twin disc type clutch and again flexplate type flywheel.

No way on a big car! Like Gene said, only on a sub-3000lb high-revver. Big cars need all the inertia that a heavy flywheel has. There's a hell of a lot of resistance on the pressure plate side when trying to accelerate our 2-ton bricks. What you don't have in inertia must be made up in revs and clutch-frying. Stick with the ol' reliable heavy sucker.

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Tony Nausieda
1970 SS 396-350hp
Frame-off Resto: Just Say No! 4 years and counting...