Reducing rotating mass/weight
Thread Starter
On The Tree
iTrader: (4)
Joined: Dec 2002
Posts: 149
Likes: 0
From: Sleepy Hollow, NY
Reducing rotating mass/weight I am starting to work on reducing rotating mass
in our 2000 SS (M6). I saw several ads on light weight flywheels (11 vs 24lbs) and also aluminum
driveshafts (any weight reduction there?). These flywheels
are offered by SLP, RK Sport and others - are they
strong enough. My car has around 380..400rwtq.
Any other sugestions?
Thanks for your help,
Gert
in our 2000 SS (M6). I saw several ads on light weight flywheels (11 vs 24lbs) and also aluminum
driveshafts (any weight reduction there?). These flywheels
are offered by SLP, RK Sport and others - are they
strong enough. My car has around 380..400rwtq.
Any other sugestions?
Thanks for your help,
Gert
Re: Reducing rotating mass/weight If your primary intentions are to drag race the car, leave the steel flywheel in. I would concentrate on lighter rims and tires and put a spool it the rear. That gets rid of mucho rotating mass!!!!
Re: Reducing rotating mass/weight It's not just the mass of what's rotating,
what you're looking to get rid of is
angular momentum (to be spun up by the
engine's output). This is mass * radius
(integral of the whole object from its
center of mass).
Flywheel? Designed to apply angular momentum
smoothing to the crankshaft, smooth out the
torque pulses and drag you past the next
compression cycle. You can lighten it but
will want a higher idle, and more finesse
in the clutch foot. No dump & jump when you
don't have that flywheel energy in the bank.
Like a charge card, you pay for that little
impulse purchase cushion all the way down
the track, but doing without it is tougher.
Drivshaft? 2" radius. Forget about it,
other than as a raw weight reduction.
Differential? Kinda chubby, 4" radius,
but a good portion of the mass is concentrated
in the center. So although it's heavy, it's
not as big on angular momentum.
Wheels/tires? 13" radius. Heavy. Mass at the
periphery for the most part. Four of 'em.
Now we're getting somewhere.
what you're looking to get rid of is
angular momentum (to be spun up by the
engine's output). This is mass * radius
(integral of the whole object from its
center of mass).
Flywheel? Designed to apply angular momentum
smoothing to the crankshaft, smooth out the
torque pulses and drag you past the next
compression cycle. You can lighten it but
will want a higher idle, and more finesse
in the clutch foot. No dump & jump when you
don't have that flywheel energy in the bank.
Like a charge card, you pay for that little
impulse purchase cushion all the way down
the track, but doing without it is tougher.
Drivshaft? 2" radius. Forget about it,
other than as a raw weight reduction.
Differential? Kinda chubby, 4" radius,
but a good portion of the mass is concentrated
in the center. So although it's heavy, it's
not as big on angular momentum.
Wheels/tires? 13" radius. Heavy. Mass at the
periphery for the most part. Four of 'em.
Now we're getting somewhere.
On The Tree
Joined: Jan 2003
Posts: 172
Likes: 0
From: Central MD
Re: Reducing rotating mass/weight </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by jimmyblue:
<strong> It's not just the mass of what's rotating,
what you're looking to get rid of is
angular momentum </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Ahh, someone who knows their physics!
He is absolutely correct. The biggest rotating mass problems come from the parts that are big diameter like wheels and flywheel. Aluminum flywheels will have to be replaced very often. If you like dropping the transmission all the time, enjoy. Draglite wheels are your best option.
Your crank and pistons are also a form of rotating mass (it is worse in fact, because you need energy to speed them up, then slow them down, then speed them up in the other direction again). When you measure out the length to the pistons, you can see that the overall leverage on the crank is large. Lightweight pistons are a minor plus as well.
<small>[ February 15, 2003, 10:23 AM: Message edited by: 2000WhiteZ28 ]</small>
<strong> It's not just the mass of what's rotating,
what you're looking to get rid of is
angular momentum </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Ahh, someone who knows their physics!
He is absolutely correct. The biggest rotating mass problems come from the parts that are big diameter like wheels and flywheel. Aluminum flywheels will have to be replaced very often. If you like dropping the transmission all the time, enjoy. Draglite wheels are your best option.
Your crank and pistons are also a form of rotating mass (it is worse in fact, because you need energy to speed them up, then slow them down, then speed them up in the other direction again). When you measure out the length to the pistons, you can see that the overall leverage on the crank is large. Lightweight pistons are a minor plus as well.
<small>[ February 15, 2003, 10:23 AM: Message edited by: 2000WhiteZ28 ]</small>
Re: Reducing rotating mass/weight Skinnies and lightweight front and rear wheels make noticeable improvements in 1/4 mi. times w/LS-1 F-bodies. Even a completely stock car w/light whls and sticky rear tires make a considerable difference. Just make sure they're balanced right on the money, and stay away from rough roads, potholes. They're very fragile. WJ. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Teching In
Joined: May 2002
Posts: 41
Likes: 0
From: NorCal
Re: Reducing rotating mass/weight If you're concerned with rotating mass, you're probably racing. If you're drag racing, that's just fine. But if you're road racing, you'll also need to think about unsprung weight...
Unsprung weight is anything with mass that is not supported by the suspension of the car. The drivers seat is NOT unsprung weight. But the wheel/tire IS unsprung weight. Make sense?
You can reduce weight by running a lighter brake system, lighter suspension pieces, etc.
Overall, by reducting the unsprung weight, you will make the suspension more effective over rough surfaces.
Hope this helps!
-Brad
Unsprung weight is anything with mass that is not supported by the suspension of the car. The drivers seat is NOT unsprung weight. But the wheel/tire IS unsprung weight. Make sense?
You can reduce weight by running a lighter brake system, lighter suspension pieces, etc.
Overall, by reducting the unsprung weight, you will make the suspension more effective over rough surfaces.
Hope this helps!
-Brad
Trending Topics
Re: Reducing rotating mass/weight SLP does offer a billet steel flywheel that weighs 8 lbs less than stock. It's about $380.
I personally wouldn't use it without some significant weight reduction on the car...you need a heavy flywheel to get a heavy car moving.
I personally wouldn't use it without some significant weight reduction on the car...you need a heavy flywheel to get a heavy car moving.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
