# Horsepower



## SnowGuy69 (Feb 12, 2014)

In the good old days, you purchased a snowblower by horsepower. Now I see they sell them by “cc”. Is there a cc to horsepower conversion?

For example, the Ariens Deluxe 28 is 254cc, the Ariens Deluxe 30 in is 291cc. I know they list the power in foot pounds of torque. But HP and torque can vary in engines. 

So how many HP is the 254cc vs the 291cc?


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## rhenning (Sep 19, 2013)

Torque is what does the work and HP was mostly used for advertising and the manufacturers cheated on how they got their HP numbers. The Feds and lawers finally stepped in because of false advertising. At that point companies mostly stopped using HP and went to displacement and torque. At first they used cubic inches but went to CCs when they found CCs were bigger numbers. This was again for advertising reasons. As with HP the bigger number in CCs and torque is the bigger engine. I mostly buy things by torque as that gives me an indication of the work any small engine is capable of doing. Roger


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## motorhead64 (Dec 15, 2013)

Manufacturers began shying away from "hp" ratings several years ago. As with hp, bigger is better. 212 cc is listed as 6.5 hp in some locales. Beyond that is anyone's guess. Mh


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## SnowGuy69 (Feb 12, 2014)

Let’s use car motors as an example. You can have a 350 cubic in motor put out 270 HP and 200 FT/pounds of torque or a 350 cubic in motor put out 350 HP and 370 FT/pounds of torque.

Also, it matters where the HP is measured. At the crank or the rear wheels. 

I was hoping there was a conversion chart. I call one place and they got all excited and mentioned law suits of the HP ratings. But they are fine with Torque? I’m confused.


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## SnowGuy69 (Feb 12, 2014)

I have been finding interesting conversions:

123 cc = 4 hp
179 cc = 5 hp
208 cc = 5.5 to 6 hp
277 cc = 7 to 8 hp
291cc = 9hp
305 cc = 9 to 10 hp
342 cc = 11 to 12 hp
357 cc = 13 hp
420 cc = 13-15 hp 


Read more: http://www.doityourself.com/forum/outdoor-gasoline-electric-powered-equipment-small-engines/410252-cc-horsepower.html#ixzz2tamGzOWl


Also:

Typical new carbureted engine well tuned: 
*1 x HP per each 25 cc*


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## Smolenski7 (Nov 24, 2010)

I found several torque to HP calculators online. The only catch is that you need to know the rpm. From what I've read, manufacturers rate engines anywhere between 3060 rpm to 3600 rpm; I have seen 3600rpm more often though, for what it's worth.

Pop those numbers into the calculator and it will convert it to HP.

Torque to HP - Horsepower Converter, Calculator


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## mkd (Dec 31, 2013)

torque x rpm divided by 5252 is equal to horsepower. 12.5 tq. x 3600 rpm equals 45000. 45000 divided by 5252 (the rpm where torque and horsepower cross) equals 8.568 hp. that being said lct the mfg. of the 254cc ariens engine has the engine serial number rating listed at 7.5 hp.. from left to right the first two numbers are the mfg. year and the next two are the horspower. my 28 deluxe engine serial # is 1375h******** lct explains every digit of the serial number on their website.


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## knutestoner (Feb 10, 2014)

Just to jump in on the fun here is the fact that my MTD 10hp/28" has a displacement of 358cc. This would seem somewhat contrary to some of the conversion charts I've seen.


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## 94EG8 (Feb 13, 2014)

You can't directly relate hp to displacement. I don't have time to dig around for numbers right now, but an old flathead B&S 8hp is 319cc, an overhead valve engine of the same displacement, from the same manufacturer puts out a fair bit more power.


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## HJames (Oct 28, 2013)

Torque numbers as related to maximum rpms can also be deceiving. They are all relative to the engines power curve. The 212 cc predator achieves its maximum 8.1 ft pounds of torque at 2500 rpm although the engine is rated for 3600 max rpm. There is no noticable increase in torque when the rpms are increased unless modifications are made.


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## mkd (Dec 31, 2013)

it all boils down to how it's tuned. cams, ignition timing,carburetor settings, compression and so on all have to do with what you end up with! 94EG8 hit the nail on the head! my old 8 hp tecumseh as he stated was 318 cc but the L head doesn't run quite like the over head valve engines they have today.


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## brickcity (Jan 23, 2014)

i think the whole ft torque standard is confusing to say the least.
conversion charts that rely on rpms when under load or not. the more i research it the more confusing and vague it is to me.
i also believe it is disshonest as they sell engines with a giant number '9' on them and the average joe shmoe like me thinks it's 9 hp.


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## 94EG8 (Feb 13, 2014)

brickcity said:


> i also believe it is disshonest as they sell engines with a giant number '9' on them and the average joe shmoe like me thinks it's 9 hp.


I think they started doing that in an effort to give the customer a number that lines up with what the hp would have been without actually putting hp on it since that's what got them in trouble in the first place. HP was the only number the meant anything to most consumers and now a lot of them are confused as to what CC and CI translates into.


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## Jackmels (Feb 18, 2013)

This explains why There's No Horsepower Numbers...

Mowers: Horsepower goes the way of the buggy - Houston Chronicle


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## brickcity (Jan 23, 2014)

94EG8 said:


> I think they started doing that in an effort to give the customer a number that lines up with what the hp would have been without actually putting hp on it since that's what got them in trouble in the first place. HP was the only number the meant anything to most consumers and now a lot of them are confused as to what CC and CI translates into.


i agree.
funny how ft torque number is always higher than the old hp rateings.
sounds like they are still being deceptive. it's really not a big deal if you know they went to ft torque ratings but the vast majority of consumers never heard of it.


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## detdrbuzzard (Jan 20, 2012)

i still don't see why the makers of small engines couldn't say with the hp rating. lets say that tecumseh is correct, that the engine on my 521 puts out 5hp. at what rpm does it make 5hp? at the governed speed of 3600rpm. ok 5hp at 3600rpm on my 521 toro. as we all know if the motor is governed at 3000 rpm it will not make 5hp so maybe briggs and all other manufactures of small engines should state the rpm the engine make the clamed hp


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## SnowGuy69 (Feb 12, 2014)

OK, let me ask this...
Is there a functional difference that you would notice in deep heavy snow between 250cc motor with 12.5ft/toqure and a 291cc with 14.5 ft/torque? Motors almost the same size. But big difference in torque.


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## db9938 (Nov 17, 2013)

detdrbuzzard said:


> i still don't see why the makers of small engines couldn't say with the hp rating. lets say that tecumseh is correct, that the engine on my 521 puts out 5hp. at what rpm does it make 5hp? at the governed speed of 3600rpm. ok 5hp at 3600rpm on my 521 toro. as we all know if the motor is governed at 3000 rpm it will not make 5hp so maybe briggs and all other manufactures of small engines should state the rpm the engine make the clamed hp


I agree, hp rating is the number that most have grown to know. Make the claims universal, and transparent as to how measured.


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## 94EG8 (Feb 13, 2014)

Jackmels said:


> This explains why There's No Horsepower Numbers...
> 
> Mowers: Horsepower goes the way of the buggy - Houston Chronicle


In regards to that article, it mentions that sometimes the same engine is sold under multiple hp ratings, that's true. Take a look at the newer B&S single cylinder lawn tractor engines. The ~17hp - 21hp engines are all the same. I can't remember if anything under 17hp uses the same block but I remember some of them had an intake gasket that was half blocked off, that was the difference, as far as I know carb jetting was the same, and I defy you to find someone that can tell the difference between an 8hp and 10hp Tecumseh Snow King.


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## detdrbuzzard (Jan 20, 2012)

SnowGuy69 said:


> OK, let me ask this...
> Is there a functional difference that you would notice in deep heavy snow between 250cc motor with 12.5ft/toqure and a 291cc with 14.5 ft/torque? Motors almost the same size. But big difference in torque.


 having the toro 521 and 826, the 826 doesn't weem to be working as hard as the 521. where the 521 revs up cause of deep or wet snow the 826 just cruises through without reving up so i would say yes to your question


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## SnowGuy69 (Feb 12, 2014)

Jackmels said:


> This explains why There's No Horsepower Numbers...
> 
> Mowers: Horsepower goes the way of the buggy - Houston Chronicle


 
That was an interesting article. I guess there is no easy solution. They mention block size, which as others stated, may have little to do with a HP rating. Depends on the crank, valve size, carb size, etc.

I do see the issue. They need to standardize where and how to measure the HP. Using a snow blower, If you measure a motor, not on any device and measure it at the crankshaft, you will get a number. Take the same motor, throw it on a snow blower, and now it has to move the unit, spin the auger and impeller (2 stage). I am sure it you now measured it at the auger, it would be less than at the crank


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## SnowGuy69 (Feb 12, 2014)

detdrbuzzard said:


> having the toro 521 and 826, the 826 doesn't weem to be working as hard as the 521. where the 521 revs up cause of deep or wet snow the 826 just cruises through without reving up so i would say yes to your question


Thanks. I was originally looking at the Ariens Deluxe 28 with the 12.5 Ft-lbs (254cc) motor. 

But I am now considering either the Ariens Deluxe 30 or Platinum 24 to get the 14.5 Ft-lbs (291cc) motor. Actually the 24 Platinum is a bit narrow, and the 30 may be too wide to fit between cars parked in the driveway. The Yardman Snowbird was 26 inches wide and thought 28 would be perfect.

From what detdrbuzzard mentioned, I would notice the difference in motors in deep, wet snow.


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