Need some math help here...........................

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TwinStick
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Need some math help here...........................

Post by TwinStick » Mon Jan 29, 2018 6:30 pm

Just curious here, so bear with me. Trying to get some more distance from my snowblower. By increasing the engine shaft pulley diameter.

Impeller speed is now between 1010 & 1100 rpms.
Factory pulley looks to be about 2.5"-3" diameter. I want to increase it by 1".
How much more rpm's will a 1" increase give the impeller ?
Is 1" too much ?

It is just like on a dirt bike right ? To increase power but lower top speed, you go with a larger rear sprocket & a smaller front sprocket ?
To increase top speed, you go with a larger front sprocket & a smaller rear sprocket ?

Snowblower is an Ariens 36", 13 hp beast, but everything can be improved. Looking to try this before a V-twin swap.

Thanks for the help
In WNY State. 2008 Red QC PW G56. No lift yet, stock size tires. It pulls an 18' 2016 Starcraft AR One Extreme, 3500 lbs.
Load Pro 35 helper springs. 2015 A.R.E. MX Series custom cap. PCP front diff cover protector. Mag-Hytec 6 qt rear diff cover. K&N replacement air filter only. Dual grounded throttle body. Winch TPC bypass. Fab Four rear bumper. DURA BAK lined rocker protection. And a bunch of new front end stuff.

G-56 Gear ratios: 1st) 6.29:1 2nd) 3.48:1 3rd) 2.10:1 4th) 1.38:1 5th) 1.0:1 6th) 0.79:1 Rev 6.29:1 --- = 78.01613:1 Crawl Ratio
-------------------------5.94:1--------3.28:1-------1.98:1-------1.31:1-------1.0:1-------0.74:1-----5.42:1 ---- = 73.675:1
545RFE----------------3.0:1---------1.67:1--------1.0:1--------0.75:1-------0.67:1------------------3.0:1 -------=37.21:1

2013+ 32.47 crawl ratio...............Can you see the trend ??????????????

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Bill2014
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Re: Need some math help here...........................

Post by Bill2014 » Mon Jan 29, 2018 7:22 pm

Circumference is Pi times diameter.
So your belt speed is directly proportional to your drive pulley diameter.
If your drive pulley goes from 2.5" diameter to 3.5" diameter, then your impeller speed will go from 1100 rpm to 1540 rpm.
If your drive pulley goes from 3" diameter to 4" diameter, then your impeller speed will go from 1100 rpm to 1467 rpm.

A 1" increase in diameter is a pretty big change. Perhaps you may want to try a drive pulley that is only 1/2" bigger in diameter. The stock design was probably already configured to be reasonable for the engine and impeller...
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TwinStick
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Re: Need some math help here...........................

Post by TwinStick » Tue Jan 30, 2018 2:07 pm

Thanks for that info, I appreciate it. So, if it is a V-pulley, I would measure from the bottom of the V, correct ?
Do they even make belts that are a 1/2" longer ?

If we never modified anything, it would be a boring world, lol. :lol:
In WNY State. 2008 Red QC PW G56. No lift yet, stock size tires. It pulls an 18' 2016 Starcraft AR One Extreme, 3500 lbs.
Load Pro 35 helper springs. 2015 A.R.E. MX Series custom cap. PCP front diff cover protector. Mag-Hytec 6 qt rear diff cover. K&N replacement air filter only. Dual grounded throttle body. Winch TPC bypass. Fab Four rear bumper. DURA BAK lined rocker protection. And a bunch of new front end stuff.

G-56 Gear ratios: 1st) 6.29:1 2nd) 3.48:1 3rd) 2.10:1 4th) 1.38:1 5th) 1.0:1 6th) 0.79:1 Rev 6.29:1 --- = 78.01613:1 Crawl Ratio
-------------------------5.94:1--------3.28:1-------1.98:1-------1.31:1-------1.0:1-------0.74:1-----5.42:1 ---- = 73.675:1
545RFE----------------3.0:1---------1.67:1--------1.0:1--------0.75:1-------0.67:1------------------3.0:1 -------=37.21:1

2013+ 32.47 crawl ratio...............Can you see the trend ??????????????

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Bill2014
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Re: Need some math help here...........................

Post by Bill2014 » Tue Jan 30, 2018 4:34 pm

Increasing your drive pulley diameter by 1/2" will require a belt that's about 8/10th of an inch longer. So get one that's an inch longer and use the belt tensioning adjustment to take up the slack.
2014 Power Wagon Laramie
Titan V5 2.5" Receiver Pintle Hook
Warn wireless winch controller
.188" DOM White Knuckle Rock Sliders
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TwinStick
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Re: Need some math help here...........................

Post by TwinStick » Tue Jan 30, 2018 5:09 pm

Cool. Thanks for the info Bill2014. :rockon:
In WNY State. 2008 Red QC PW G56. No lift yet, stock size tires. It pulls an 18' 2016 Starcraft AR One Extreme, 3500 lbs.
Load Pro 35 helper springs. 2015 A.R.E. MX Series custom cap. PCP front diff cover protector. Mag-Hytec 6 qt rear diff cover. K&N replacement air filter only. Dual grounded throttle body. Winch TPC bypass. Fab Four rear bumper. DURA BAK lined rocker protection. And a bunch of new front end stuff.

G-56 Gear ratios: 1st) 6.29:1 2nd) 3.48:1 3rd) 2.10:1 4th) 1.38:1 5th) 1.0:1 6th) 0.79:1 Rev 6.29:1 --- = 78.01613:1 Crawl Ratio
-------------------------5.94:1--------3.28:1-------1.98:1-------1.31:1-------1.0:1-------0.74:1-----5.42:1 ---- = 73.675:1
545RFE----------------3.0:1---------1.67:1--------1.0:1--------0.75:1-------0.67:1------------------3.0:1 -------=37.21:1

2013+ 32.47 crawl ratio...............Can you see the trend ??????????????

TwinStick
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Re: Need some math help here...........................

Post by TwinStick » Tue Jan 30, 2018 5:12 pm

Bill2014 wrote:
Mon Jan 29, 2018 7:22 pm
Circumference is Pi times diameter.
So your belt speed is directly proportional to your drive pulley diameter.
If your drive pulley goes from 2.5" diameter to 3.5" diameter, then your impeller speed will go from 1100 rpm to 1540 rpm.
If your drive pulley goes from 3" diameter to 4" diameter, then your impeller speed will go from 1100 rpm to 1467 rpm.

A 1" increase in diameter is a pretty big change. Perhaps you may want to try a drive pulley that is only 1/2" bigger in diameter. The stock design was probably already configured to be reasonable for the engine and impeller...

I am curious though how going from a 2.5" to a 3.5" will give me 1540 rpms but going from a 3" to a 4" will be less rpm increase, @ 1467 ?
In WNY State. 2008 Red QC PW G56. No lift yet, stock size tires. It pulls an 18' 2016 Starcraft AR One Extreme, 3500 lbs.
Load Pro 35 helper springs. 2015 A.R.E. MX Series custom cap. PCP front diff cover protector. Mag-Hytec 6 qt rear diff cover. K&N replacement air filter only. Dual grounded throttle body. Winch TPC bypass. Fab Four rear bumper. DURA BAK lined rocker protection. And a bunch of new front end stuff.

G-56 Gear ratios: 1st) 6.29:1 2nd) 3.48:1 3rd) 2.10:1 4th) 1.38:1 5th) 1.0:1 6th) 0.79:1 Rev 6.29:1 --- = 78.01613:1 Crawl Ratio
-------------------------5.94:1--------3.28:1-------1.98:1-------1.31:1-------1.0:1-------0.74:1-----5.42:1 ---- = 73.675:1
545RFE----------------3.0:1---------1.67:1--------1.0:1--------0.75:1-------0.67:1------------------3.0:1 -------=37.21:1

2013+ 32.47 crawl ratio...............Can you see the trend ??????????????

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olyelr
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Re: Need some math help here...........................

Post by olyelr » Tue Jan 30, 2018 5:47 pm

Less percentage of increase.
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TwinStick
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Re: Need some math help here...........................

Post by TwinStick » Tue Jan 30, 2018 11:18 pm

But both are 1" increase ?
In WNY State. 2008 Red QC PW G56. No lift yet, stock size tires. It pulls an 18' 2016 Starcraft AR One Extreme, 3500 lbs.
Load Pro 35 helper springs. 2015 A.R.E. MX Series custom cap. PCP front diff cover protector. Mag-Hytec 6 qt rear diff cover. K&N replacement air filter only. Dual grounded throttle body. Winch TPC bypass. Fab Four rear bumper. DURA BAK lined rocker protection. And a bunch of new front end stuff.

G-56 Gear ratios: 1st) 6.29:1 2nd) 3.48:1 3rd) 2.10:1 4th) 1.38:1 5th) 1.0:1 6th) 0.79:1 Rev 6.29:1 --- = 78.01613:1 Crawl Ratio
-------------------------5.94:1--------3.28:1-------1.98:1-------1.31:1-------1.0:1-------0.74:1-----5.42:1 ---- = 73.675:1
545RFE----------------3.0:1---------1.67:1--------1.0:1--------0.75:1-------0.67:1------------------3.0:1 -------=37.21:1

2013+ 32.47 crawl ratio...............Can you see the trend ??????????????

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olyelr
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Re: Need some math help here...........................

Post by olyelr » Wed Jan 31, 2018 6:26 am

TwinStick wrote:
Tue Jan 30, 2018 11:18 pm
But both are 1" increase ?
But the 1” change is at different sizes, so it is a different percentage of change. 1” at the smaller pulleys is more drastic than 1” at the larger pulleys.

New pulley size divided by old pulley size multiplied by original impeller speed yields new impeller speed.
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- A virgin, other than White Knuckle sliders... and lots of Fluid Film -

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Re: Need some math help here...........................

Post by 13BlkPowerWagon » Wed Jan 31, 2018 7:52 am

Have you tried the impeller mod yet? You'll get more throw with that than you will from upping the impeller speed. Take some rubber pieces, and self tapping screws with some big washers, and screw the rubber pieces to the impeller so that they contact the housing very lightly. It'll give you a tighter seal between the impeller and the housing. It also effectively gives you a longer impeller, which gives you a higher velocity at the end of the impeller (same angular speed, but longer distance).

I put a 13hp Honda motor on my Husqvarna snowblower when the original engine threw the rod (actually, I bought it with the blown engine). It has a 1" crank, so I couldn't use the 3/4" shaft pulleys from the old engine. I had to step up in pulley diameter a bunch, and didn't really notice much better throw (compared to my previous blower), and was pretty disappointed. I did the impeller mod, and now it will throw snow 100' if I want (and if there's enough snow). The more snow there is, the farther it'll throw it, and the 28" width with 13hp doesn't ever bog down.

I still got sick of using it, and ended up putting a plow on the PW. They both have some benefits, and some drawbacks. I still use the blower for sidewalks and walkways, and my back patio where I can't get the plow, so having some extra nut behind it does make things easier.

TwinStick
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Re: Need some math help here...........................

Post by TwinStick » Wed Jan 31, 2018 3:32 pm

The impellers on my Ariens are curved, so it would be difficult i think. Plus, the steel is very thick, compared to others I have seen. You aint gonna use self tappers on that i don't think ? I'd say I have 1/4" at least, all the way around, between the impellers & housing. I may try that first, idk. Definitely have to disassemble & separate the housing & totally remove the impeller to do it right. Maybe a summer job, lol.

Thanks for all the help everyone.
In WNY State. 2008 Red QC PW G56. No lift yet, stock size tires. It pulls an 18' 2016 Starcraft AR One Extreme, 3500 lbs.
Load Pro 35 helper springs. 2015 A.R.E. MX Series custom cap. PCP front diff cover protector. Mag-Hytec 6 qt rear diff cover. K&N replacement air filter only. Dual grounded throttle body. Winch TPC bypass. Fab Four rear bumper. DURA BAK lined rocker protection. And a bunch of new front end stuff.

G-56 Gear ratios: 1st) 6.29:1 2nd) 3.48:1 3rd) 2.10:1 4th) 1.38:1 5th) 1.0:1 6th) 0.79:1 Rev 6.29:1 --- = 78.01613:1 Crawl Ratio
-------------------------5.94:1--------3.28:1-------1.98:1-------1.31:1-------1.0:1-------0.74:1-----5.42:1 ---- = 73.675:1
545RFE----------------3.0:1---------1.67:1--------1.0:1--------0.75:1-------0.67:1------------------3.0:1 -------=37.21:1

2013+ 32.47 crawl ratio...............Can you see the trend ??????????????

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