Gear ratio between engine and transfer case?

ElectroTV said:

Hi Everyone,
I am trying to mod a Sportsman (most likely 500) to drive off of an electric system. However, I am hovering above a few options of motors. I just wanted to know, what is the approximate gear ratio between shaft that exits the engine to the shaft that enters the transfer case? Is it a larger gear on the transfer case and a smaller one on the engine, or vice versa, or are they the same? Also, when they say for example, the engine has a power of 44 horsepower, is that coming directly out of the engine or at the wheels?

Thanks,
ElectroTV

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The ratio between the crankshaft of the engine to the transmission is a constantly variable belt drive - the actual ratio is not published but in therory it is 0 at idle and 1:1 at full throttle and at maximum speed. The 'transfer case', is a transmission and there is a fixed gear reduction with the choice being low range, high range and reverse and I do not know the overall reduction of the gear box to the final drive or what the reduction to the tire surface would be.

The power is typically BHP at the rear wheels the engine probably has appx 15 to 20 crankshaft HP, but that depends on RPM.

The primary clutch mounts directly to the engine output shaft.

Engine speed varies from about 1000 to 7500 RPM.

The sportsman 570 is rated at 44HP at the crankshaft. Recent dyno testing by a forum member has shown approx 33HP to the rear wheels.



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Mike_B said:

The primary clutch mounts directly to the engine output shaft.

Engine speed varies from about 1000 to 7500 RPM.

The sportsman 570 is rated at 44HP at the crankshaft. Recent dyno testing by a forum member has shown approx 33HP to the rear wheels.

2019 Sportsman 570 hits the DYNO!!!

I finally got to the dyno Dec. 2nd. The sportsman 570 rated at 44 crank horsepower puts down 33 wheel horse power. My only mods are snorkel kit and QSC clutch kit. I tried a K&N air filter first, it made less than 1 horsepower difference. I also tried a iridium spark plug(found the part...

www.polarisatvforums.com

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I challenge that dyno test!

Crank HP is always less than wheel braking horse power because or the power multiplication of the transmission and final drive. When the Honda 750 Four came out it was rated 24 HP at the crank and over 80 HP at the rear wheel. My Honda 79 CBX 6 cylinder was the highest HP rated motorcycle on the market at the time at 103 rear wheel while the engine dyno'ed at about 30 HP. We never dyno'ed the engine because we knew the wheel HP would be higher and we wanted to know how much power we were getting to the ground. We adjusted that number with gear changes while the engine HP remained the same.

What is the front differential gear ratio on the sportsman 570?

And does anyone know the weight or have the cad of this differential? I'm still going to make the purchase for an alternative engineering vehicle project, and I can't physically gauge that. However, I can't find the weight and cad (or at least the dimensions and attachment points) anywhere

ennzo_patrus said:

And does anyone know the weight or have the cad of this differential? I'm still going to make the purchase for an alternative engineering vehicle project, and I can't physically gauge that. However, I can't find the weight and cad (or at least the dimensions and attachment points) anywhere

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I have a Sportsman XP1000 front gear case, I have to look at it tomorrow.
I think the ratio is the same.
What year and model you have?

crazyflyboy30 said:

I have a Sportsman XP1000 front gear case, I have to look at it tomorrow.
I think the ratio is the same.
What year and model you have?

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I don't have the sportsman yet, but I need this information to buy just the differential and apply it to my engineering project. But I believe I will buy the 570

ennzo_patrus said:

I don't have the sportsman yet, but I need this information to buy just the differential and apply it to my engineering project. But I believe I will buy the 570

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I thought about adding a electric motor to my Sportsman XP1000 so could move it in s steath mode.
I looked up the ratio of the Sportsman XP1000 I think it's the same even though it shows 3.818 on the 1000 and 3.82 on the 570 .
I don't see how that they could have a different number of teeth because if had 1 more or
1 less it would make more difference and .002 they must have rounded up on the 570.