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flywheel
- Thread starter healeyboz
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kcbugeye1275
Jedi Knight
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The aluminum flywheel might be great for racing, but for street use a lightened flywheel is the only way to go. Spend that money someplace else. A lightened FW really gives you the best of both worlds.
Hap Waldrop
Yoda
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Aluminum flywheels work just fine on street engines, not the nightmare you often hear about, although as explained above you can benefit from lightening a stock unit as well.
Lessening rotating mass does not create more horsepower, it will however allow to get to what you already have quicker. In racing we lighten stock rods and cranks as well, in the SCCA full prep rules you can do this by buying a billet crank and Carrillo rods, in limited prep you have to use stock rods and cranks, but you can lighten them. here's a picture of a 1275 crank that I wedged lightened (about 3 pound reduction), and then a before and after look at a 1275 rod I lightened (about a 100 gram per rod reduction), plus the polishing of the rod help to strengthen it.
Lessening rotating mass does not create more horsepower, it will however allow to get to what you already have quicker. In racing we lighten stock rods and cranks as well, in the SCCA full prep rules you can do this by buying a billet crank and Carrillo rods, in limited prep you have to use stock rods and cranks, but you can lighten them. here's a picture of a 1275 crank that I wedged lightened (about 3 pound reduction), and then a before and after look at a 1275 rod I lightened (about a 100 gram per rod reduction), plus the polishing of the rod help to strengthen it.
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Hap Waldrop
Yoda
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SilentUnicorn
Yoda
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Hap,
not to sound like an idiot, but can you define "wedge" as it refers to a crank and/or rods?
thanx
mark
not to sound like an idiot, but can you define "wedge" as it refers to a crank and/or rods?
thanx
mark
regularman
Yoda
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God that stuff looks expensive Hap. I guess it the universal truth though that I heard when I was a kid hanging around over at Banjo Mathews(bout a mile from here) shop when I was a kid. A whole lot of money buys you a little bit of speed /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
kcbugeye1275
Jedi Knight
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I like shiney motor internals. I really don't care that anybody else sees them, it is just nice to know that you took the time and effort to make it perfect on the inside. Less rotating mass does make it easier for the motor to spin up, but these cars need some rotating to be drivable on the street. Life is full of compromises.
Jayrz
Jedi Trainee
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Wedging a crank is the process of removing excessive material from the "pin" side of each counterweight. The A series cranks do not have enough counterweight but it would be silly to add weight to one side when you can remove it from the other...
Kind of a statice vs dynamic balance thing, little bit pricey but depends what you want out of your motor, probably not worth doing unless you rev it to above 6 or so on a regular basis.
Hap please correct me if I am in error.
Kind of a statice vs dynamic balance thing, little bit pricey but depends what you want out of your motor, probably not worth doing unless you rev it to above 6 or so on a regular basis.
Hap please correct me if I am in error.
SilentUnicorn
Yoda
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umm...ok...what is the "pin" side of each counterweight ?
do you mean (and i reference hap's pic above of the crank) the areas opposite the rod journals where there is a large chamfer?
mark
do you mean (and i reference hap's pic above of the crank) the areas opposite the rod journals where there is a large chamfer?
mark
racingenglishcars
Darth Vader
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The pin side is the connecting rod pin. The journal. These cranks were under-counter balanced. That is to say that the counter balance on the crank has much less mass than the crank web, journal and connecting rod sitting directly opposite it. By reducing the web closest to the journal, this helps bring the crank back into a better balance. This trick is not noticable on either a static or a standard dynamic balance machine.
Generally on a crank, static balance is nearly useless. And stnadard two point dynamic balance will only keep each end of the crank balanced. The deal here is to help, especially the center main bearing, where it has two "heavy" journals and connecting rods on one side counter two not-so-heavy counterbalance weights on the other side. Same deal with journals 1 & 4.
Generally on a crank, static balance is nearly useless. And stnadard two point dynamic balance will only keep each end of the crank balanced. The deal here is to help, especially the center main bearing, where it has two "heavy" journals and connecting rods on one side counter two not-so-heavy counterbalance weights on the other side. Same deal with journals 1 & 4.
racingenglishcars
Darth Vader
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Reducing rotating mass (actually mass mooment of inertia) of the engine is directly comparable to reducing the weight of the car during acceleration. Except the advantage of reducing the inertia of the engine gets multiplied by the gear-ratio-squared to the rear wheels. In first gear with a 3.9 rear, this is equivelant to 156 times the reduction of inertia of the rear wheels gained by using lightweight wheels and tires.
The important part about lightening the flywheel, isn't in reducing the weight of it. It's about lightening the OUTTERMOST portion of the flywheel.
If you want the math, just ask.
The important part about lightening the flywheel, isn't in reducing the weight of it. It's about lightening the OUTTERMOST portion of the flywheel.
If you want the math, just ask.
From the seat of MY pants, I have had a lightened flywheel and now I run an aluminum flywheel.
I'll never lighten one again, the aluminum ones winds up beautifully. I love it!
And mine is a street car, no problem at all.
My wife, daughter, and even my niece who is learning to drive have no problem. Well the niece is still a bit jerky with the clutch /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
I'll never lighten one again, the aluminum ones winds up beautifully. I love it!
And mine is a street car, no problem at all.
My wife, daughter, and even my niece who is learning to drive have no problem. Well the niece is still a bit jerky with the clutch /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
racingenglishcars
Darth Vader
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As long a lightened steel flywheel has the same moment of inertia as the aluminium flywheel, they will behave exactly the same. Except that steel wears less. They don't have to weigh the same to have the same moment of inertia.