Which harmonic damper diameter?
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
I've heared that 1 lbs of rotating mass is worth about 5 lbs of static weight at the track... For example. If you reduce your weight of your rear wheels/tires by going with lightweight wheels and wrinkle wall tires, you can save over 15 lbs each side which is a total saving of 30 lbs. Those 30 lbs are worth about 150 lbs because its rotating mass. 150 lbs is about .1 to .15 at the track.
If you are not racing, it really doesn't matter too much..
If you are not racing, it really doesn't matter too much..
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From: eville in
Originally Posted by GrandSportC3
I've heared that 1 lbs of rotating mass is worth about 5 lbs of static weight at the track... For example. If you reduce your weight of your rear wheels/tires by going with lightweight wheels and wrinkle wall tires, you can save over 15 lbs each side which is a total saving of 30 lbs. Those 30 lbs are worth about 150 lbs because its rotating mass. 150 lbs is about .1 to .15 at the track.
If you are not racing, it really doesn't matter too much..
If you are not racing, it really doesn't matter too much..
C6 the C5 of tomorrow
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From: Twin Cities Minnesota
Originally Posted by gkull
snip--
GS - Dampner weight only has additional friction losses and they are much harder on bearings and the crank shaft. Just think about a 10 pound damper spinning 7000 rpm and you shift gears in nearly an instant with auto trannies and now your spinning 4500 rpm. That is allot of twist on the crank shaft.
snip---
GS - Dampner weight only has additional friction losses and they are much harder on bearings and the crank shaft. Just think about a 10 pound damper spinning 7000 rpm and you shift gears in nearly an instant with auto trannies and now your spinning 4500 rpm. That is allot of twist on the crank shaft.
snip---
Think about the load changes during a shift. 500 ft/lbs...0 ftlbs ( clutch in)...500 ft/lbs all within what 1/2 second???
As far as friction losses, What friction??? Are you talking about air friction or what?
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Just put a 500 lbs weight on a stick on bearings and see how much force it takes to turn it.
Then put a 5 lbs weight and try the same....and you'll feel less resistence with the 5 lbs weight...
Then put a 5 lbs weight and try the same....and you'll feel less resistence with the 5 lbs weight...
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
bearing friction - - however minute. It's just like which is better internal balanced or externally. Internal has a 6 pound damper, 42 pound crank, and 11 pound aluminum flywheel = 59 pounds. external has 10 pound damper, 52 pound crank, and 30 pound steel flywheel = 92 pounds. They might make the about same power if built the same, but frictional losses and the ability to accelerate are massively different. I would not also be spinning 92 pounds to 7500 rpm in a 383 stroker two bolt small block.
Melting Slicks
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From: New Cumberland PA
Originally Posted by GrandSportC3
Just put a 500 lbs weight on a stick on bearings and see how much force it takes to turn it.
Then put a 5 lbs weight and try the same....and you'll feel less resistence with the 5 lbs weight...
Then put a 5 lbs weight and try the same....and you'll feel less resistence with the 5 lbs weight...
It would take longer to get the 500 lb weight up to the same rpm as the smaller weight. The larger weight would also spin for a longer time if at the same speed when the force spinning it is removed/
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From: eville in
Originally Posted by mandm1200
You're going backwards in trying to show an example. They would be identical for all intents and purposes for this discussion. The force you would be looking to overcome is the friction of the bearing(s), same bearings= same friction. The other thing in this example is inertia which you are trying to explain as resistence.
It would take longer to get the 500 lb weight up to the same rpm as the smaller weight. The larger weight would also spin for a longer time if at the same speed when the force spinning it is removed/
It would take longer to get the 500 lb weight up to the same rpm as the smaller weight. The larger weight would also spin for a longer time if at the same speed when the force spinning it is removed/
heck that's why the make "low mass" cranksisn't it
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Melting Slicks
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From: New Cumberland PA
How's this for an example. Let's say your engine is at 450 horsepower. You run the 1/4 mile in 11 seconds. You now hook up a hitch and pull a trailer behind it the weighs 5000lbs. Your ET is now 19 seconds. Did the horsepower of the engine change?
I realise that the damper is only a few pounds difference. By lowering the mass, it allows the engine to more quickly come up in rpm's which is something you want if racing. The sooner the rpms come up the more horsepower you are making and the faster you will go.
When I go from 55 to 60 on the highway it doesn't really matter since I am gradually accelerating anyway.
I realise that the damper is only a few pounds difference. By lowering the mass, it allows the engine to more quickly come up in rpm's which is something you want if racing. The sooner the rpms come up the more horsepower you are making and the faster you will go.
When I go from 55 to 60 on the highway it doesn't really matter since I am gradually accelerating anyway.
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From: eville in
Originally Posted by mandm1200
How's this for an example. Let's say your engine is at 450 horsepower. You run the 1/4 mile in 11 seconds. You now hook up a hitch and pull a trailer behind it the weighs 5000lbs. Your ET is now 19 seconds. Did the horsepower of the engine change?
I realise that the damper is only a few pounds difference. By lowering the mass, it allows the engine to more quickly come up in rpm's which is something you want if racing. The sooner the rpms come up the more horsepower you are making and the faster you will go.
When I go from 55 to 60 on the highway it doesn't really matter since I am gradually accelerating anyway.
I realise that the damper is only a few pounds difference. By lowering the mass, it allows the engine to more quickly come up in rpm's which is something you want if racing. The sooner the rpms come up the more horsepower you are making and the faster you will go.
When I go from 55 to 60 on the highway it doesn't really matter since I am gradually accelerating anyway.
it take's power to turn the mass,,,, if not we are all missing the boat on the energy problem
Melting Slicks
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From: New Cumberland PA
The energy consumed would be made up for when letting off the gas, making it a wash.
I'm not a damper engineer. If there was only one size and weight for all applications (grocery getter and drag car), we would not being having this discussion. There is give and take and depending on the specific application one will be better than another.
I'm not a damper engineer. If there was only one size and weight for all applications (grocery getter and drag car), we would not being having this discussion. There is give and take and depending on the specific application one will be better than another.
Team Owner
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From: eville in
Originally Posted by mandm1200
The energy consumed would be made up for when letting off the gas, making it a wash.
I'm not a damper engineer. If there was only one size and weight for all applications (grocery getter and drag car), we would not being having this discussion. There is give and take and depending on the specific application one will be better than another.
I'm not a damper engineer. If there was only one size and weight for all applications (grocery getter and drag car), we would not being having this discussion. There is give and take and depending on the specific application one will be better than another.
if all you do is stay at the same RPM all the time i vote heavy
Safety Car
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From: San Antonio TX
Did y'all know that the early smallblock(265 ci) only used a hub and no damper at all?
Seems once they started raising the output, a damper became a necessary evil to absorb those harmonics.
Seems once they started raising the output, a damper became a necessary evil to absorb those harmonics.
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
On a engine that was internally balanced, you can even drive the car without balancer.. I have actually done that... The only thing that is different is that your idle will be a few 100 RPM higher without the balancer... If the engine is balanced well, you won't even notice that there is no balancer..
It will be more wear on the bearings, so it's not a good idea to drive too far without a balancer at all..
It will be more wear on the bearings, so it's not a good idea to drive too far without a balancer at all..
Instructor
Joined: Apr 2002
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From: Highland MI
Wow, all this over a simple question. I think everyone has a good point about what they believe in. Let me add my two cents.
A larger balancer helps control the harmonics created by the rotating mass and valvetrain better then a small diameter balancer. The better the harmonics are controlled the more power can be produced. Bearing wear is evidence of this. You can have a well balanced rotating assembly but a balancer is still needed for the induced harmonics created by the valvetrain.
NASCAR has no rule on the size of the balancer only that it must be magnetic and SFI 18.1 approved and one of the HP kings Joe Gibbs Racing. They run the GM Performance Parts ATI 7.74” balancer on all their engines. If smaller was better, I would think they would all run a 6.75” balancer.
Also, we "GM Racing" has done studies in the past and have found the ATI balancer perform the best due to thier ability to be tuned to a specific RPM range
The
A larger balancer helps control the harmonics created by the rotating mass and valvetrain better then a small diameter balancer. The better the harmonics are controlled the more power can be produced. Bearing wear is evidence of this. You can have a well balanced rotating assembly but a balancer is still needed for the induced harmonics created by the valvetrain.
NASCAR has no rule on the size of the balancer only that it must be magnetic and SFI 18.1 approved and one of the HP kings Joe Gibbs Racing. They run the GM Performance Parts ATI 7.74” balancer on all their engines. If smaller was better, I would think they would all run a 6.75” balancer.
Also, we "GM Racing" has done studies in the past and have found the ATI balancer perform the best due to thier ability to be tuned to a specific RPM range
The
Melting Slicks
Joined: Apr 1999
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From: Moon Twp. PA USA
Originally Posted by 69schemers
Wow, all this over a simple question. I think everyone has a good point about what they believe in. Let me add my two cents.
A larger balancer helps control the harmonics created by the rotating mass and valvetrain better then a small diameter balancer. The better the harmonics are controlled the more power can be produced. Bearing wear is evidence of this. You can have a well balanced rotating assembly but a balancer is still needed for the induced harmonics created by the valvetrain.
NASCAR has no rule on the size of the balancer only that it must be magnetic and SFI 18.1 approved and one of the HP kings Joe Gibbs Racing. They run the GM Performance Parts ATI 7.74” balancer on all their engines. If smaller was better, I would think they would all run a 6.75” balancer.
Also, we "GM Racing" has done studies in the past and have found the ATI balancer perform the best due to thier ability to be tuned to a specific RPM range
The
A larger balancer helps control the harmonics created by the rotating mass and valvetrain better then a small diameter balancer. The better the harmonics are controlled the more power can be produced. Bearing wear is evidence of this. You can have a well balanced rotating assembly but a balancer is still needed for the induced harmonics created by the valvetrain.
NASCAR has no rule on the size of the balancer only that it must be magnetic and SFI 18.1 approved and one of the HP kings Joe Gibbs Racing. They run the GM Performance Parts ATI 7.74” balancer on all their engines. If smaller was better, I would think they would all run a 6.75” balancer.
Also, we "GM Racing" has done studies in the past and have found the ATI balancer perform the best due to thier ability to be tuned to a specific RPM range
The
NASCAR is a different ballgame. I really doubt an engine from a NASCAR racer would live well on the street.
Yes, bragging rights mean a lot. I GOT NASCAR PARTS UNDER THE HOOD. I must got lots of Horsepower!!
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The deed is done! I went with a standard replacement Summit branded damper.. For some odd reason, this damper wasn't as wide as the one I replaced. Didn't need to use any shims at the water pump to get the pulleys in line.
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From: eville in
Originally Posted by ddecart
The deed is done! I went with a standard replacement Summit branded damper.. For some odd reason, this damper wasn't as wide as the one I replaced. Didn't need to use any shims at the water pump to get the pulleys in line.
did you weigh them to see if there is a difference
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From: eville in
Originally Posted by glen242
NASCAR is a whole other thing. Are you turning, constantly, over 7000RPM? From what I understand, NASCAR limits carbs to 390 CFM. Would you run a 390 CFM carb on your engine?
NASCAR is a different ballgame. I really doubt an engine from a NASCAR racer would live well on the street.
Yes, bragging rights mean a lot. I GOT NASCAR PARTS UNDER THE HOOD. I must got lots of Horsepower!!
NASCAR is a different ballgame. I really doubt an engine from a NASCAR racer would live well on the street.
Yes, bragging rights mean a lot. I GOT NASCAR PARTS UNDER THE HOOD. I must got lots of Horsepower!!
Nextel Cup engine's can't run a roller cam
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