rpm

Brian
Let me make it as clear as I can.
I believe that the engine will accelerate and decelerate much quicker with light rotating parts when it's not in gear. When it's connected to the axle and the tires are not slipping the entire kart becomes the mass that has to be accelerated or decelerated. The kart weighs hundreds of pounds. The weight of the flywheel is miniscule in comparison to the weight of the entire vehicle. If the tires are slipping that is another problem that you should address.
I will try to get a guinea pig to help me test this on the track.

"In theory, theory and practice are the same. In practice, they are not" Albert Einstein

" If the facts don't fit the theory, Change the facts" Albert Einstein
 
For 9 to 10 hp (true hp) motors on 1/5 and 1/4 mile ovals, I gotta go with Carlson on this one.

IMO, I don't think an inertia dyno would show it, since it basically calculates how much hp a motor required to do what it did on the dyno, then mathematically calculates torque from calculated horsepower.

With a 10 hp motor on a tight sprint track, maximum acceleration and deceleration would be the goal, with the added benefit of further deceleration due to lateral g forces (without applying brakes) in the center of the corner.- light flywheel effect
With the same motor on a 1/5th mile oval, the goal would be the opposite. You would want deceleration from lateral g's to be delayed as much as possible in order to keep the average rpm/mph as high as possible while cornering.- heavy flywheel effect

My .02
 
Bob Evans said:
IMO, I don't think an inertia dyno would show it, since it basically calculates how much hp a motor required to do what it did on the dyno, then mathematically calculates torque from calculated horsepower.
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How can that be, when in fact, horsepower is a calculation!! There is no way to measure horsepower, you measure torque and the rpm where you measured it. Multiply the two by each other, divided by 5252.1 and the result is the calculated horsepower. If all you know is the horsepower, and the rpm where that horsepower was achieved, you can back figure the amount of torque required, but the horsepower was first a calculation.
 
alvin l nunley said:
How can that be, when in fact, horsepower is a calculation!! There is no way to measure horsepower, you measure torque and the rpm where you measured it. Multiply the two by each other, divided by 5252.1 and the result is the calculated horsepower. If all you know is the horsepower, and the rpm where that horsepower was achieved, you can back figure the amount of torque required, but the horsepower was first a calculation.
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Right Al, seems bassackwards to me also. :) I could be wrong, but it seems to me that an inertia dyno calculates the time required to accelerate a flywheel to rpm, which is sort of the definition of horsepower.
Then again, I suppose HP and Torque are just different ways of measuring each other, according to Ernie Elliot.

Flash-o-matic said:
Much ado about about nothing.
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:) Seems I recall you saying pretty much the same thing about a ratio being a ratio. How did that work out?
 
It doesn't take a dyno to know that a lighter weight wheel will accelerate faster than a heavy one.
All you need to do is change the worn out grinding wheel on your pedestal grinder to notice it.
You should immediately notice that it takes a lot longer for the grinder to spin up to speed with the new grinding wheel.
The question is, what is the affect the weight the engine flywheel has on the acceleration rate of a 300 to 400 pound go kart.
 
Jimbo said:
The question is, what is the affect the weight the engine flywheel has on the acceleration rate of a 300 to 400 pound go kart.
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Good points, and then factor in the time it takes. If you're going to calculate the horsepower it takes to accelerate a flywheel, the time it takes has to be part of the calculation.
 
Bob Evans said:
which is sort of the definition of horsepower.
Then again, I suppose HP and Torque are just different ways of measuring each other, according to Ernie Elliot.
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RPM x Torque / 5252.1 = HP

You don't/can't measure HP, you calculate it. How much work (torque) you've done in a given amount of time.

People have dyno's, with a computer, that give them a horsepower reading, so they think the dyno is measuring the horsepower, but it's not, it's measuring the torque, and rpm, and calculating the horsepower. One horsepower is defined as 550 pounds feet per second. If I lift 550 pounds, 1 foot in 1 second, I would be working at the rate of one horsepower. Torque is work, horsepower is a calculation of how much work over a given amount of time.

Working at the rate of one horsepower for one minute, I will have done 33,000 pounds feet of work.(pfw) There are 2 x Pi radians (2pR) in a circle, (Carry that out to 16 decimal places) so if I divide that 33,000 pfw by 2pR, I get 5252.1. Look up horsepower, or James Watt, in any encyclopedia and you'll see how he came up with that number. It had to do with him trying to explain to farmers how much work his steam engine could do compared to their horses. Every farmer knew how much work a horse could do, Mr. Watt needed a way to explain to them how much work his steam engine could do.
 
Al, do you really think I don't know the formula for hp? Given either torque or hp at a specific rpm, the other can be calculated.
So Al, why don't you explain to me how an inertia dyno works? Please.

Brian was specifically referring to low hp momentum oval racing. I agree with him.
As far as the clutch goes, the question is not the weight difference between clutches compared to kart weight, it's the amount of stored energy in the clutch at 6000 rpm multiplied by the rear gear ratio. Seems like a half pound difference could be considerable, especially if concentrated towards the outer diameter of the clutch.
 
One thing going on in the 206 Junior classes . Drivers are never lifting off the gas pedal , there riding the brake to slow to a minimal speed . Keeping the engine up on RPM . So in effect never loosing much momentum / RPM. There is little lag between deceleration to acceleration and back again . My observations
 
Elmer Patterson said:
One thing going on in the 206 Junior classes . Drivers are never lifting off the gas pedal , there riding the brake to slow to a minimal speed . Keeping the engine up on RPM . So in effect never loosing much momentum / RPM. There is little lag between deceleration to acceleration and back again . My observations
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Something I found myself doing too. Coming out of a corner with my two cycles, if it looked like I might drop a wheel off the track, I touched the brakes rather than letting off the gas. If you let off the gas, the temperature is going to drop in the engine, and it takes a bit to come back up. A drop in temperature is a drop in horsepower. I don't know if it makes that much difference in a four cycle, but every little bit helps. I never flapped the throttle going into a corner. I figured; if you have time to flap the throttle, you didn't go in deep enough.
 
Gary,
I don't think the intent of Jammer's clutch is what mine is..I believe it was built heavier to better handle the increased torque that the OHV engines like the animal make over the flatheads.

Bob,
I'm glad someone understood what I'm getting at. ;)

Flash,
Very well could be much ado about nothing.
Then again, setting the slide opening a couple thousandths closer to the max legal limit might be much ado about nothing yet we all do that as well.
Racing (more specifically race engine building) is a game of thousandths. I'll take all the thousandths I can get and accumulate a few tenths. ;)
 
CarlsonMotorsports said:
Then again, setting the slide opening a couple thousandths closer to the max legal limit might be much ado about nothing yet we all do that as well.
Racing (more specifically race engine building) is a game of thousandths. I'll take all the thousandths I can get and accumulate a few tenths. ;)
Click to expand...

This is why I ask tech for a courtesy check before last practice session. Just to be sure.;)
 
A Hilliard clutch weighs 2.5 pounds
A Titan clutch weighs almost exactly 2 pounds more.
I will be trying it on the sprint track at Road America next Tue night.

I couldn't test it on my dyno even if I wanted to.
I normally don't take my laptop for my dyno to the track with me but I did last Sat.
Unfortunately, someone dropped a Kart stand on it and now, hopefully, all I need is a new screen.
 
I drove for jammer for a big and I do believe that was the intent of the animal clutch to make up for the light flywheel. Pretty sure my engine builder mentioned the idea to jammer.
 
Gary is correct on both intent and origination.

Several builders caught onto this early. If you recall, when Animal was first introduced to Gold Cup it was a Drum/Shoe clutch only rule.

The original Animal flywheel was very light, and the second one was heavier, but as poorly balanced.

Quite a few people had Premier Titans (heaviest drum clutch for 3/4" shaft) balanced to the engine, to gain an advantage.

Balancing was getting so out of hand, IKF even instituted dimensions on size and shape of starter nut because creative builders were balancing rotating assembly using starter nut as counter balance.

Does Starter nut specs still exist in 2016 IKF Animal rules ??
 
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