Flywheel - lightened or go Aluminum?

[fgc]

Hi

Just wondering which will you choose? Lighten existing flywheel or go aluminum?

This will be for a weekend car with little track work (who knows maybe more in future)

I hear about how lightened flywheel makes car hard to drive, how different is it really? apart from possibly stalling (which is likely if there is little torque) how bad can it be?

Appreciate anyone who has experience this to share... whether you were tempted to give up your lighten flywheel for stock!

Also if to lighten existing flywheel, where to take the material off and still be safe? please help!

Thanks
fgc

[AR8TR4]

What car do you have ? Then we can address your query.

[Gary Williams]

AR8TR4 asks a good question. Assuming, possibly incorrectly, that you have an older Alfa, there are several threads about aluminum flywheels, with plenty of pro and con.

Each time, I write in to say I am perfectly happy with the aluminum flywheel in my GTV and several people write in to explain why aluminum flywheels are problematic. It all boils down to you and your driving style. No one else can decide that for you.

More info about my car here: http://greend.com/Specifications.htm

[George Willet]

For the last time:
!) Aluminum flywheels do not cause driving problems on Alfas!
2) Lightining a cast iron flywheel is DANGEROUS! for the small gain:3 maybe 4 pounds done by a knowledgeable Alfa machinest.
3) An aluminum flywheel gives the most bang for the buck over other modifications in the lower gears, (IE: first through third), short of a full race engine.

So there!

[Gary Williams]

I'm with you, George. This question has been asked and answered many times over, and all the other threads can be found with a simple search: "aluminum flywheel."

Here are just a few:

1. http://alfabb.com/bb/forums/showthre...eel#post278772
2. http://alfabb.com/bb/forums/showthre...minum+flywheel
3. http://alfabb.com/bb/forums/showthre...eel#post195021
4. http://alfabb.com/bb/forums/showthre...minum+flywheel
5. http://alfabb.com/bb/forums/showthre...eel#post179263

The list could go on and on. #4 and 5 are particularly interesting if you're just beginning to do your research.

[genericwood]

I agree with their are no problems with driveability as long as you aren't driving a 1300. But I disagree that an aluminum flywheel is necessary. A decent aluminum flywheel is $500 or so. The last stock flywheel I had lightened (about 5 pounds) was about $70. Of course the aluminum flywheel is lighter, but the $430 you have left over will buy you a great set of cams!

Erik

[fgc]

OPS sorry I should have check the archive first! Thanks for all the leads.

I am driving a 1750 spider Euro version with carbs.

Super tempted to buy that fidanza flywheel for my alfa. Not sure what parts number it is but I remember someone saying that they make them.

As for lightening stock flywheel, yes but any idea how and where to lighten? I dont want to have to put in a scatter shield.

Thanks again. I am more likely to put in one now than before!

fgc
1967 spider veloce

[Chsmadden]

Actually aluminum flywheels are really only necessary if your going to do racing. It's really not that important to have the engine spool up fast as it is to have use of your legs. if that thing flies apart at 4500 rpm, that flywheel will come right through the bell housing, and the center console and wreak horrific damage to your ankles. Besides I have the stock flywheel and mine runs perfectly, and boy does it launch!

[Gary Williams]

Aluminum flywheels aren't prone to flying apart, at least not that I've heard. A light flywheel allows a much more lively engine, especially when coupled with cams, big valves, port matching, higher compression, etc. While my car might annoy some people at very slow-speeds (such as in parking lots and heavy traffic), most Alfisti would be delighted with the engine's responsiveness in every other driving situation. I'm happy to trade driving ease at one end of the speed spectrum to benefit at the other.

It all boils down to budget and personal preferance.

[genericwood]

Quote:

Originally Posted by Chsmadden if that thing flies apart at 4500 rpm, that flywheel will come right through the bell housing, and the center console and wreak horrific damage to your ankles.

[Chsmadden]

Now that you mention it, I do see it is slightly farther forward. But if it does fly apart it could wreak horrific damage to your wallet. -$500(destroyed flywheel)+new flywheel+new bell housing+new clutch+Bondo(to fill any body holes)=one very, very thin wallet. Besides, I didn't say that a lightened flywheel was dangerous, more so than a stock one, but aluminum ones are just more likely to fly apart at high RPM.

[genericwood]

Quote:

Originally Posted by Chsmadden Besides, I didn't say that a lightened flywheel was dangerous, more so than a stock one, but aluminum ones are just more likely to fly apart at high RPM.

[Subtle]

Glad to hear it! 6000 is my shift point anyway so I have not been concerned.

[60sRacer]

The physics agrees too. First, aluminum is ductile, so it flows (bends) a lot before breaking. The cast iron original fractures at failure rather than flowing. Second, because of the light weight, the aluminum flywheel sees less radial force at 10,000 rpm (never get there!) that the cast one does at 7,000. All-in-all, a lighter aluminum flywheel is much stronger than the original, lightened or not.

The only two short comings are the reduced flywheel stability (lighter weight) in exchange for the faster response, and the $$$$$$$$$$.

Robert

[Subtle]

I have a high regard for the laws of physics.