# Matching width to horsepower



## JLawrence08648 (Jan 15, 2017)

As most of us are aware, it is always important to match the width of the machine to horsepower.

With more horsepower you be able to purchase a wider machine. 

With more horsepower, the ground speed will be faster, and the snow will be thrown further with less struggle.

Then with more horsepower the blower becomes heavier, bigger, bulkier, which some of us don't need. We want to buy the right size machine for our application.

If on occasion we have a deep 24" snow and we do it slower, no big deal. If on occasion we have a town EOD plowing issue and it takes us longer, not a big deal, though that to me is the most frustrating situation.

If you want to extend the width then you need to know the type of snow you are dealing with (wet or dry), the most common depths, are you dealing with plows at the end of the driveway EOD and how often such as being on a State road, how often are you using your machine to clear snow (several times a week or 5 times a year), and how much surface area are you clearing.

I find the most important thing for the EOD is not only horsepower but weight of the machine, both on the wheels and on the front auger housing. With a lightweight machine the wheels will slip as it's trying to push into the hard packed town plowed snow. A heavier machine, or with chains, will have more pushing power. A light front end will climb the EOD forcing the operator to lift the handlebars to keep the front down, a futile effort. Best to back up and go in with a heavier wheel weighted machine slowly.

However if speed is important, you may be able to clear faster with the next size smaller width snowblower as the machine will go through the snow faster with less struggle with more horsepower going to the wheels. More horsepower will also have less clogging issues though clogging issues are varied and can be reduced.

A 5hp 26" may be able to go through a 24" dry snow but not a 12" wet snow.

Even a 5hp 22" snowblower will have trouble with the EOD after it has sat overnight. It seems most times my town plows the neighborhood streets in the middle of the night thus leaving a pile that by morning has HARDEN! There has been many a time even with my narrow 22" 5hp Ariens with a clean carb, the engine running at 3,600 rpms, I had to shovel the EOD to break it up to allow the snowblower to do the cleanup after sitting overnight. I have fun snowblowing, I don't have fun doing that!

Then you have to take into account newer engines versus older engines, loss of compression and now the power the older engines had when new. Also better designed engines will have more power, more torque, which is more important than horsepower. Think of torque as being strength, power, the ability to push through an obstacle, the pushing power.

Below I listed my opinions for an average snowblower. I've never used a Yamaha or a Honda but it seems those snowblowers can do a decent snow with a lower horsepower machine?

If you had to buy one snowblower, you wanted to deal with all types of conditions on a 3-10 times a year usage, what hp would you get to match the width.

5hp 22" is a good match, 24" is a great machine for light snows but not for the EOD or heavy snows, not enough horsepower. It will do the heavier wet snows it but you will have to go slower, creep along. 26" is way too wide for a 5hp unless it's only light snows. You'll be disappointed with heavy snows and clogging issues. I have a 5hp 22" Ariens and a 5hp 24" Noma and just sold a 5hp 24" MTD.

8hp is a good match for a 26" wide machine, NEVER any wider. A great size for a 24" width machine. 8hp is also good for the EOD. I have a 8hp 26" Dynamark and a 8hp 24" MTD.

9hp a great size for a 26" machine, even good for 28"-29", no problem with EOD.

10hp is good for 28"-30", 32" may be pushing it in wet heavy deep snows, no problem with lighter snows and EOD. I have a 10hp 32" real John Deere that is heavy both on the wheels, and it has chains! and it has a very heavy front end. It's a beast and a beast to handle and steer. I also have a 10hp Murray Craftsman with a 29" width. A very well balanced machine and strong but a light front.

With 12hp-15hp, most of us don't have and never will, can do 32"-36" without a problem, even up to 42" with a 15hp and lighter snows. I have a 12hp Gravely Convertible, 25" width, with a cast iron Kohler engine, chains, that weighs about 300 lbs and will blow snow hitting the houses across the street. Nothing stops it, never clogs, will burrow a tunnel into a 12 foot high pile that State plows have pushed at the end of a T intersection at a traffic light.


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## drmerdp (Feb 9, 2014)

Sounds about right. In cars its power to weight, with snowblowers its power to width.

The "9hp" 14.5ft/lbs engine on my 28" Honda is well matched. More power would be enjoyable but by no means nessesary. 

The "8hp" (no idea how much torque) Tecumseh on my 26" MTD is also well matched. (tecumseh is annoying too because their large frame engines are all 318cc but with different compression ratios that make varying power, but I digress) 

The number 1 limiting factor between these machines are their transmissions. HYDRO is king. With the MTD I'm limited by 6 forward speeds and the snow conditions may be best suited to a gear I don't have. I have found myself where 3rd gear is too fast and the machine is really struggling, but second gear is too slow and I feel like I am wasting time. 

With the hydro transmission I can always dial in the right amount of forward speed that feels productive. The engine is heavily loaded but never struggling. Clearly not an apples to apples comparison but you guys get the point I'm making.


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## RIT333 (Feb 6, 2014)

Very well written ! And, good info for everyone, from beginner to seasoned veteran.


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## Dauntae (Nov 10, 2016)

Very good info, Now I am even happier with the ST1027LE. Have not had use other than a test but I think it should do well and the size is good for my situation if not maybe a tad big but I can live with it. But with the 10hp it should get through the heavy EOD I get living on a main road without issue.


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## HCBPH (Mar 8, 2011)

Reasonable selections there. If anything, a little more HP vs width can't hurt over width vs hp. That's how my one keeper started. It was a 10 hp 32" 3 stage but too big to get through the garage door. Swapped a 26" auger housing in place of the 32" - more than enough power to eat up an Illegally parked Honda any day and about the same weight as an 8 HP.


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## Normex (Feb 21, 2014)

JLawrence08648 said:


> As most of us are aware, it is always important to match the width of the machine to horsepower.
> 
> With more horsepower you be able to purchase a wider machine.
> 
> ...


Interesting facts but it seems all your power to width ratios are based on always blowing the full width of the machine which
in most cases a good operator will amend based on the snow conditions and as you mentioned it just takes a bit more time , for instance when tackling the EOD even with a 5hp and 24", one would simply take a width the snowblower can handle as it would just take more time. Lastly I have problem with a 15hp snowblower tunneling through a 12ft snow bank especially being hard packed, it would be nice to see a vid of this in action.
Just saying


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## JLawrence08648 (Jan 15, 2017)

[QUO GVTE=Normex;1216810]Interesting facts but it seems all your power to width ratios are based on always blowing the full width of the machine which
in most cases a good operator will amend based on the snow conditions and as you mentioned it just takes a bit more time , for instance when tackling the EOD even with a 5hp and 24", one would simply take a width the snowblower can handle as it would just take more time. Lastly I have problem with a 15hp snowblower tunneling through a 12ft snow bank especially being hard packed, it would be nice to see a vid of this in action.
Just saying[/QUOTE]

The first pass is always at the full width. The more suited the size blower and other factors is to the snow the wider width blower you can use. Why take a small partial width when you can take a full width or larger partial width.

Why struggle with the EOD taking partial bites not knowing if you are going to have to shovel or not rather matching the right blower to your expectations. Too many undersize looking at the money rather than the capabilities.

I use to do commercial snow removal, had 5 trucks including flatbed dump, 4 wheel dump, loaders, had all the bank branches for 3 banks, 5 hotel motels, state buildings, office buildings, supermarkets. My main snownblower was, and still have it, Gravely Convertible, 12 HP Kohler cast iron engine, 26" width, 2 speed impeller with 4 ground speeds, chains, weighed 600 lbs. All gear driven, no belts, the internal gearing was such you could get speed or power. With the weight and chains, this was not going anywhere. It was non stoppable, neither the movement forward nor the auger and impeller. It blew the snow across a four lane road and hit the buildings if I wanted. I had a commercial account along US Hwy 1 that was at the edge of both a "T" intersection and a turnaround that was constantly being traveled by the huge State dump trucks. I had to clear the public sidewalk. I discovered the Gravely would burrow a tunnel in the pile then it had no place to blow it. The Gravely was entombed. The best way to clear the sidewalk was to stand on the pile and throw, shovel, push, the snow into the auger of the snownblower of the Gravely while it was operating so the snow can be thrown out. You can do a search for Gravely Convertible to see what the machine looks like. Though I no longer do snow removal, the only thing I can do, next year in a heavy snow, video hitting my EOD pile or maybe a higher residential street corner pile. The Gravely had various attachments, brush broom, dozer blade, stump grinder, generator, brush hog, several mowers, rototiller, water pump, others, and also had a 26" snowblower attachment or a 34" snowblower attachment.

"No brag, just fact" Walter Brennan, The Guns of Will Sonnett"


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## cranman (Jan 23, 2016)

I have the Gravely 12 hp with snowblower, but I hardly use it for that...over kill for my neck of the woods. I have the chains and four ft blade on it in winter. I use it for tilling and brush hog work in summer. It is the most potent blower ever made that you can walk behind. I buy, refurbish and flip blowers so I'm always looking to try them out before I sell them...same thing with lawn tractors...I never get to use my personal machines! I have several older Gravelys that I've collected years ago...6.6 hp 7.7 hp some with gear reduction wheels The 12 hp Kohler and a 10 hp Kohler...


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## guilateen02 (Nov 23, 2014)

Great write up. But I once had an Ariens 7/32 that when I first purchase was a dog. Full bucket of snow and it would bog down. Seemed liked it was underpowered. I then restored it and thought about throwing an OHV engine but changed my mind for a few reasons. I then started some work on the 7 hp Tec. Cleaned carb, carbon build up, impeller kit and checked rpm. It was running at around 3200 rpm. After that the thing became unstoppable. 
It made me rethink how much horse power is really needed for these machines. I then had a spare gc160 low hour engine rated at 4.5 from a pressure washer. Installed on a dog of an Ariens 824 Tec equipped 924 series. Same results. Checked that Tec out running at 3300 and cleaned up to be a good performance engine afterwards. 
My theory on this is that a snowblower does doesn't require and extreme amount of power. Proven by Honda and Yamaha. But the engine needs to be running properly. Not just by ear, but use a Tach, clean that carbon, make sure the carb is properly tuned and you will be surprised at what small hp and small displacement motor can do. 
I think manufactures have led us to believe we (need) all that hp when we really don't.


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## JLawrence08648 (Jan 15, 2017)

guilateen02 said:


> Great write up. But I once had an Ariens 7/32 that when I first purchase was a dog. Full bucket of snow and it would bog down. Seemed liked it was underpowered. I then restored it and thought about throwing an OHV engine but changed my mind for a few reasons. I then started some work on the 7 hp Tec. Cleaned carb, carbon build up, impeller kit and checked rpm. It was running at around 3200 rpm. After that the thing became unstoppable.
> It made me rethink how much horse power is really needed for these machines. I then had a spare gc160 low hour engine rated at 4.5 from a pressure washer. Installed on a dog of an Ariens 824 Tec equipped 924 series. Same results. Checked that Tec out running at 3300 and cleaned up to be a good performance engine afterwards.
> My theory on this is that a snowblower does doesn't require and extreme amount of power. Proven by Honda and Yamaha. But the engine needs to be running properly. Not just by ear, but use a Tach, clean that carbon, make sure the carb is properly tuned and you will be surprised at what small hp and small displacement motor can do.
> I think manufactures have led us to believe we (need) all that hp when we really don't.


Good post and response to mine. I was thinking of Honda when I wrote "better designed engines" seemingly has more power for the same rated horsepower. Also a "clean carburetor" meant the engine was running properly. Amazing how just a few hundred rpms make such a difference throwing snow and making it unstoppable almost substituting for increased horsepower.


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## tpenfield (Feb 24, 2015)

Great subject and something folks should keep in mind as they consider future purchases.

I think that looking at "horsepower per inch of width" is probably a good factor to go by.

So taking a few examples . . .

a 22" machine w/ 5 HP is 0.227 HP/Inch

a 24" machine w/ 7 HP is 0.292 HP/Inch

a 30" machine w/ 10 HP is 0.333 HP/Inch

Whereas a 30" machine w/ only 8 HP is only 0.266 HP/Inch

My Troy-Bilt 2410 w/ OEM 179cc engine (estimated 5.5 HP) would be about 0.229 HP/Inch

In general, I have considered a 24" machine with 5 HP to be adequately powered, but a bit on the lighter side, and a 24" machine w/ 7 HP to be well powered.

So perhaps *0.250 HP/Inch (or 1 HP for every 4" of width)* could be a benchmark to go by . . . More than that is well powered and less than that is lightly powered. . . And it seems like the wider machines tend to be more towards the 'well powered' range to handle the more challenging snow conditions.

Of course, with power comes a variety of other factors, as mentioned in this thread, like the weight of the machine, the efficiency of the impeller mechanism, etc.


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## merdody1 (Jan 30, 2017)

Great write up. I like the 1HP for every 4" sounds like a good ratio. I have been tinkering with a few old Tecumseh heads with low compression and I am amazed at how much compression comes back after adjusting the valve clearances and lapping them. I haven't finished them up yet but just putting my thumb over the spark plug hole I get tremendous suck and blow. I think the tiredness of the engine is a big factor in the equation. A freshened up 5HP 24" should still be able to handle most scenarios.


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## JLawrence08648 (Jan 15, 2017)

tpenfield said:


> I think that looking at "horsepower per inch of width" is probably a good factor to go by.
> 
> So taking a few examples . . .
> 
> ...


Got everybody thinking? This post was initially for the newbie and the get ready to purchase.

Looking at tpenfield - the 0.250 HP/inch, 1hp/4" inches is something to start with and as he completely knows, that power factor number gets blown out when using a 8hp on a 30" blower with a power factor of .266, above the .025 which is "acceptable" however is there a person on here that will say a 8hp is adequate on a 30"? In most conditions? And never in all conditions. Put a 8hp with a 30" cut into a EOD and it will be faster to shovel than to go "slow"! Only in light dry snows would an 8hp be able to handle a 30" width snow!

The power factor is an interesting concept. Can we come up with a better name for it?


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## RedOctobyr (Mar 2, 2014)

JLawrence08648 said:


> Put a 8hp with a 30" cut into a EOD and it will be faster to shovel than to go "slow"! Only in light dry snows would an 8hp be able to handle a 30" width snow!


Probably true, but it assumes you're taking a full-width cut. Unavoidable for the first pass, of course, but at least you have options after that. And for overwhelming EOD, you can feather the clutch to inch it forward, and let the engine recover, then do it again, etc. 



> The power factor is an interesting concept. Can we come up with a better name for it?


It is effectively power density. Power-to-weight is a common expression for cars, so power-to-width (PTW) seems fairly reasonable here. 

As has been said, unfortunately the "required" number varies by the type and amount of snow you get. Also by how fast you want to clear, and how much you need to clear. The person with a huge driveway, and deep heavy storms, has different guideline requirements than the person who gets 2" of fluffy stuff, and a small driveway. 

But recommendations based on 8hp/24" (0.333hp/in) seem pretty reasonable for me, here in New England. 

I expect many of us would agree that more is better. I've had 8hp/26" (0.308), 8hp/24" (0.333), and now 10hp/24 (0.417). Not surprisingly, I like the 0.417, and it handled our record-breaking winter, with EOD that was over the top of the bucket. 

When I bought this machine, I wanted a high power-to-width, which it gives me. Since using it, however, I've realized the benefit of maybe 10hp/26, possibly even 10hp/28, since those can clear faster in smaller storms, when taking full-width cuts. And for most EOD work, I could still take narrower cuts, to avoid overwhelming the engine. 

You can usually take narrower cuts with a wide machine (effectively increasing your PTW), but you can't take wider cuts with a narrow machine.


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## Normex (Feb 21, 2014)

RedOctobyr said:


> Probably true, but it assumes you're taking a full-width cut. Unavoidable for the first pass, of course, but at least you have options after that. And for overwhelming EOD, you can feather the clutch to inch it forward, and let the engine recover, then do it again, etc.
> It is effectively power density. Power-to-weight is a common expression for cars, so power-to-width (PTW) seems fairly reasonable here.
> 
> As has been said, unfortunately the "required" number varies by the type and amount of snow you get. Also by how fast you want to clear, and how much you need to clear. The person with a huge driveway, and deep heavy storms, has different guideline requirements than the person who gets 2" of fluffy stuff, and a small driveway.
> ...


Agreed but as many a time on this site it was mentioned that more power is better and it should be said that power is now expressed as torque ft. pd. This thread does not help a newbie when expressed in hp.


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## JLawrence08648 (Jan 15, 2017)

RedOctobyr said:


> I expect many of us would agree that more is better. I've had 8hp/26" (0.308), 8hp/24" (0.333), and now 10hp/24 (0.417). Not surprisingly, I like the 0.417, and it handled our record-breaking winter, with EOD that was over the top of the bucket.
> 
> When I bought this machine, I wanted a high power-to-width, which it gives me. Since using it, however, I've realized the benefit of maybe 10hp/26, possibly even 10hp/28, since those can clear faster in smaller storms, when taking full-width cuts. And for most EOD work, I could still take narrower cuts, to avoid overwhelming the engine.
> 
> You can usually take narrower cuts with a wide machine (effectively increasing your PTW), but you can't take wider cuts with a narrow machine.


I have a 10hp with a 29" cut and a 32" cut. The 29" is a better combination for all snow, the 32" with a 10hp for the EOD if too deep or too hard I have to creep and feather, or take partial cuts. One of the problems is the 32" has a short chute and not throwing it far enough so I'm redoing what I've already done, besides it's too wide if the snow is too high and hard.


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## sscotsman (Dec 8, 2010)

These are fine guidelines, and if you follow them you will end up with a machine that has enough power..so following them can be a good thing.

but..

be aware that many of the guidelines are also just informed opinions, but they are not necessarily indisputable facts. 
for example:



> 8hp is a good match for a 26" wide machine, NEVER any wider.


you cant use the word NEVER in a case like this..
You could say "8hp is a good match for a 26" wide machine, but its probably not a good idea to go any wider than that with 8HP"

My 1971 Ariens 732 proves the word NEVER does not apply..it has no problems at all.
As others have stated in this thread, engine health is also a major factor.

Scot


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## tpenfield (Feb 24, 2015)

EOD can be challenging and why you would want to be on the high side, like in the 0.30 - 0.35+ range. Although I will say that my slightly powered Troy-Bilt could still get the job done on the frozen snow banks.

With my current re-power of my TB 2410, I'll be up in the 0.38 - 0.40 range, which should be pretty exciting to see.


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## drmerdp (Feb 9, 2014)

I feel the old machines due well regardless of a low power to width ratio because of their "gear ratios."

I've noticed they have speed ranging from slow to really slow. 

Most vintage snowblowers don't throw snow very far. Is it daring to infer that the impellers are "geared" lower then most newer machines? Handles a lot of snow at the expense of throwing distance. Kinda thinking out loud. 

I'm planning on uping my one machine from a .321 to a .464 ratio. We may need to come up with more elegant number method. 

It all comes down to being able to do more work in less time.


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## tpenfield (Feb 24, 2015)

I think JLawrence makes a good point about the wider machines needing more HP/Inch. I see that there is probably a 'sliding scale' of power 'adequacy' based on the width of machine for EOD and other reasons. The manufacturer's engine choices on the larger machines tend to indicate this as well.

Sort of a chart that looks like this based on size of the machine . . .


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## JLawrence08648 (Jan 15, 2017)

Let's add another thought to the equation!

Of course we all agree on the variables play a roll; dry wet snow, soft hard ice snow, ground speed of machine, engine speed, impeller speed, the efficiency of the auger, the auger speed as the amount of snow being drawn in, the size and efficiency of the spacing of the impeller blades, size of the impeller housing, the discharge chute opening, size shape and length of the chute.

I don't think you can use a inch per horsepower as a linear line. A square inch formula of width and height would be more accurate. The wider the snownblower is, the greater the horsepower needed, not more horsepower, greater horsepower, more power, because HP per inch is a linear, what I'm talking about here is that the linear line can't be a straight progression, it has to turn upwards, curve, as the width of the snownblower is wider it does not take a linear progression of power to adequately move the snow but an increasing amount of power.


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## Bob z (Apr 5, 2015)

You cant beat cc's and Hp and torque. My Ariens 28 in 414cc is a beast, no regrets what so ever. Its probably 13-14 hp.


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