DOES ALUMINUM FLYWHEELS KILL TQ?
- Thread starter STUGOTS
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GTS Bruce
Enthusiast
No.No affect.No more shouting now and try the search function at the top of the page.It works wonders. Bruce
2002_Viper_GTS_ACR
Enthusiast
I found that I lost TQ and gained a little HP on the dyno. and I KNOW its supposed to have no difference, but it made like 5hp and lost 3TQ. I know thats minimal, and could be based on external conditions. Just telling you what I saw between dyno pulls with that as a change !!
Jon
Jon
2002_Viper_GTS_ACR
Enthusiast
it hurts "take off" because you dont have the "torque" of the heavy flywheel to PUSH you ahead. You can see the "gain" of the alum flywheel in 3rd gear ROLLS.. aka, 80-90 mph and UP accelerations. But off the line.. sorry, steal is better..
So if your going to "street light" race (zero to 60) its not worth it. But if your TRUELY goign to Road Course Race.. its a great investment...
PS !! IF YOU WANT ONE .. I have mine that I had to take out because I like to drag race. I dont have but maybe 2,000 miles on it, and its in perfect shape. Send me a PM if your interested.
So if your going to "street light" race (zero to 60) its not worth it. But if your TRUELY goign to Road Course Race.. its a great investment...
PS !! IF YOU WANT ONE .. I have mine that I had to take out because I like to drag race. I dont have but maybe 2,000 miles on it, and its in perfect shape. Send me a PM if your interested.
opnwide
Enthusiast
Guys, get your terminology correct. An aluminum flywheel reduces rotational inertia--it has no effect on torque or horsepower. However, it does effect rotational acceleration on a chassis dynometer. This shows up as increased torque (and horsepower as a function as rpm). An engine dynometer that measures brake hp would show no change.
In the real world, you've got to rev your engine a couple hundred rpm more when leaving from a light. Also, I know someone who had to change his launch technique at the drags. He had to lauch at 3000-3500rpm to get a decent 60' time. This would smoke the tires on my car, but he did fine, running a 1.8 60'. The quicker acceleration helped him run 11.8s in a "stock" viper! I've heard someone say before "less spin off the line, more spin at higher rpms."
In the real world, you've got to rev your engine a couple hundred rpm more when leaving from a light. Also, I know someone who had to change his launch technique at the drags. He had to lauch at 3000-3500rpm to get a decent 60' time. This would smoke the tires on my car, but he did fine, running a 1.8 60'. The quicker acceleration helped him run 11.8s in a "stock" viper! I've heard someone say before "less spin off the line, more spin at higher rpms."
Tom F&L GoR
Enthusiast
opnwide is correct. It's perhaps better to think of a lighter flywheel as removing weight from the engine... times four or five. Besides decreasing the mass by ten pounds as measured by putting the engine on a scale, you don't have to work as hard to spin it, so the whole vehicle accelerates as if it weighed 40 or 50 pounds less.
Here's a link to a rotational inertia calculator that has a free demo showing the effect of a ten pound reduction of flywheel mass.
http://www.performancetrends.com/Inertia_Calculator.htm
In one of the Carroll Smith books I read that reducing rotational mass of objects at engine speeds is worth 8-10 times it's actual mass, and wheel weight being worth 1.75 times it's actual mass reduction - because besides having to move it from start to finish, you also have to spin it.
Here's a link to a rotational inertia calculator that has a free demo showing the effect of a ten pound reduction of flywheel mass.
http://www.performancetrends.com/Inertia_Calculator.htm
In one of the Carroll Smith books I read that reducing rotational mass of objects at engine speeds is worth 8-10 times it's actual mass, and wheel weight being worth 1.75 times it's actual mass reduction - because besides having to move it from start to finish, you also have to spin it.
joe117
Enthusiast
On a circle track or a roadrace track, you will find that the light flywheel will allow you to slow down much faster.
The only kind of racing that I know of that doesn't benefit from a light flywheel is salt flats top speed runs.
I don't know for sure, but I would guess that large power drag racers will gain from a light flywheel after they adjust their launch.
The only kind of racing that I know of that doesn't benefit from a light flywheel is salt flats top speed runs.
I don't know for sure, but I would guess that large power drag racers will gain from a light flywheel after they adjust their launch.
joe117
Enthusiast
The aluminum flywheels have steel inserts at the wear point. Don't worry about it, it will last a long time.
joe117
Enthusiast
A rotating flywheel stores energy. Watching the lights come down, spinning up the flywheel with the clutch held down, stores energy that get's released to the wheels when you dump the clutch.
That's good.
But now the flywheel is along for the remainder of the run and the engine must spin it up again at each gear change. As it spins up, it's storing energy again.
That's bad.
This time you use up the stored energy heating up the brakes at the end.
I don't believe a lighter flywheel in a Viper will make you take off slower from a dead stop.
Vipers have plenty of power. They don't need the stored energy in a rotating flywheel to get off the line. The Viper's problem is traction, not power.
You need to learn how to do it. If you are used to a stock wheel you will have to re-learn with a light one.
I believe a light flywheel will always accelerate the car faster at any speed.
It's just like taking weight out of the car. Of course the weight removed from the flywheel is worth more than just removing the same weight from the car body.
That's good.
But now the flywheel is along for the remainder of the run and the engine must spin it up again at each gear change. As it spins up, it's storing energy again.
That's bad.
This time you use up the stored energy heating up the brakes at the end.
I don't believe a lighter flywheel in a Viper will make you take off slower from a dead stop.
Vipers have plenty of power. They don't need the stored energy in a rotating flywheel to get off the line. The Viper's problem is traction, not power.
You need to learn how to do it. If you are used to a stock wheel you will have to re-learn with a light one.
I believe a light flywheel will always accelerate the car faster at any speed.
It's just like taking weight out of the car. Of course the weight removed from the flywheel is worth more than just removing the same weight from the car body.
The only experience I have with this kind of thing is on a single cyl four stroke bike on the streets at home, and at the drags.. I tried pulling the flywheel off and using total loss ignition, and see what happened. It's been too long ago to remember the ETs, but the difference in the time it took to rev in each gear was huge. It definitely revved alot quicker.
Whoever Wrote The Above deserves a merit badge for an informative, accurate, and succinct analysis. You could say more...you could say less. But this post just about says it all..........
DEVILDOG
VCA Member North TX
I wouldn't be without an alum flywheel....revs like crazy...combined with a short shifter it doesn't take long to get through the gears. 
VANTA'SVIPER
Enthusiast
I HAD AN ALLUMINUM FLYWHEEL PUT IN AMONTH AGO AND IT WORKS FOR ME.BEFORE THE ALLUMINUM FLYWHEEL I RAN CONSISTANT 13.5S IN THE QUARTER,NOW AFTER BREAK IN PERIOD OF MY ALUMINUM FLYWHEEL I RUN CONSISTANT 12.7
HOPEFULLY THAT HELPS.
GOD BLESS
HOPEFULLY THAT HELPS.
GOD BLESS
99 R/T 10
Enthusiast
Dude, stop yellin
, are these times in your viper? Seems slow if so. I had my Gen I in the high 11's with simple exhaust and gears.joe117
Enthusiast
He's not yelling, he's using caps. If you don't go around telling people that using caps is yelling, they will never know.
Why don't we start telling people that using caps is really speaking in Dogpatch?
I don't write in all caps, you don't write in all caps, who cares if he writes in all caps.
Why don't we start telling people that using caps is really speaking in Dogpatch?
I don't write in all caps, you don't write in all caps, who cares if he writes in all caps.
Jerry Dobson
Enthusiast
aluminum flywheel is NO good for drag racing.
You get way too much tire spin. Then between shifts you loose RPMs.
None of the big boy pro drivers use them.
They are only good for Road Racing.
You get way too much tire spin. Then between shifts you loose RPMs.
None of the big boy pro drivers use them.
They are only good for Road Racing.
joe117
Enthusiast
Jerry,
If a light flywheel is no good for drag racing,
do you know of any testing that has been done to determine if a heavier flywheel would improve 1/4 mile times?
Or is the stock wheel exactly right for street use and pro drag cars?
Wow! What a great coincidence.
Please go over the points you made as to why the light wheel isn't good for drags.
If a light flywheel is no good for drag racing,
do you know of any testing that has been done to determine if a heavier flywheel would improve 1/4 mile times?
Or is the stock wheel exactly right for street use and pro drag cars?
Wow! What a great coincidence.
Please go over the points you made as to why the light wheel isn't good for drags.
