Abby’s Guide > Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) > Discussions > Does HP Matter?

Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

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bus708

Location: Maryland
Joined: Jul 24, 2010
Points: 321

Does HP Matter?
Original Message Nov 7, 2011 7:02 pm

I have a 15 year old Ariens . ST 924. It came with a 8 hp Techumseh. I'm planning to retiring the engine . Which is better a Subaru Robin sx30 with 9.5 hp 4000 rpm max , a Honda GX 390. or a 305 Briggs? The Subaru does not give me as much HP as the Honda, but I get more rpm. If i put Clarences kit on my unit then is will be even better. The Briggs is the cheapest , but I do not really know its power output They only tell me 305 cc and 13.5 lbs of torque. My Techunseh is a 318 cc so I guess the 305 Briggs is close to 8 HP. I prefer 12 volt electric start. The biggest Briggs is there 342 16.5 I was considering that one too.

This message was modified Nov 7, 2011 by bus708

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manjestic

Location: North Shore, MA
Joined: Oct 31, 2011
Points: 87

Re: Does HP Matter?
Reply #5 Nov 7, 2011 11:32 pm

Bill_H

Torque does the work.

aa335

Joined: Nov 29, 2008
Points: 2434

Re: Does HP Matter?
Reply #6 Nov 8, 2011 10:30 am

Without horsepower, torque will just sit around unmotivated and does nothing. :)

You need both to do the work. The Indians aren't going to do anything without a chief.

This message was modified Nov 8, 2011 by aa335

stresst

Location: The Village in the Middle of New York
Joined: Dec 11, 2010
Points: 213

Re: Does HP Matter?
Reply #7 Nov 8, 2011 8:26 pm

Bill_H wrote:

"Does HP Matter?" no. No. NO. NO.
Ignore HP, it is nothing but a number made up by a salesman to compare steam engines to horses. Torque is what you want. Torque does the work. Snowblowers only perform under load and how much load the engine can handle is determined by torque, not by horsepower.
If you're trying to decide which engine will give your blower the most power, compare them by looking at the torque curves. The highest number between approx 3200 RPM and 3600 RPM wins. Your engine will run at close to 3600 RPM most of the time, but as soon as it hits some heavy/deep stuff and starts to bog down, that when you need torque. Don't be surprised if the engine that has the most torque in that band is not the engine with the highest HP rating. It can happen.
Too many manufacturers played the numbers game to get the highest HP rating possible, they got caught, now they can't do it anymore. Ft-lbs @ RPM is all that matters.

I hear you about the hp numbers! Technically you are 100% correct but for a newbie its gets too complicated imo. Much easier to say yes you need HP!

TORO 826OXE

Steve_Cebu

Joined: Dec 17, 2009
Points: 888

Re: Does HP Matter?
Reply #8 Nov 8, 2011 8:53 pm

You could just paraphrase Carrol Shelby and say " HP sells snowblowers, Torque throws snow."

"If you have more miles on your snow blower than your car, you live in New England." "If you can drive 75 mph through 2 feet of snow during a raging blizzard without flinching, you live in New England."

Bill_H

Location: Maine
Joined: Jan 12, 2008
Points: 354

Re: Does HP Matter?
Reply #9 Nov 8, 2011 10:02 pm

stresst wrote:

I hear you about the hp numbers! Technically you are 100% correct but for a newbie its gets too complicated imo. Much easier to say yes you need HP!

As Steve pointed out (great post, BTW

), HP is (was) a sales gimmick. And newbies better learn fast because since they lost that court case the manufacturers aren't spouting horsepower numbers anymore. Now it seems like they are advertising displacement, as if more displacement means you'll get more power - you might, but it's not directly related.

Who the hell let all the morning people run things?

niper99

Location: London Ont
Joined: Dec 2, 2007
Points: 354

Re: Does HP Matter?
Reply #10 Nov 9, 2011 2:53 am

IMO.... if money wasnt a consideration id go with the Honda 100%...if u wanna save some coin go with B/S the 305 is a good engine but id go with the 342 if possible...either way u cant go wrong..if it was me l would get the briggs 342

This message was modified Nov 9, 2011 by niper99

manjestic

Location: North Shore, MA
Joined: Oct 31, 2011
Points: 87

Re: Does HP Matter?
Reply #11 Nov 10, 2011 1:26 pm

Just to pile it on...that's one reason why Diesels are popular to do serious work. High torque compared to the HP figures.

royster

" It is the use of power tools that separates man from animals"

Location: New Brunswick, Canada
Joined: Feb 11, 2011
Points: 284

Re: Does HP Matter?
Reply #12 Nov 10, 2011 4:06 pm

I believe that the Briggs engines are an excellent choice. The 305 with 14.5 torque for blowers up to 27 inches.

and the 342 with 16.5 torque for blowers over 27 inches. I am referring to the engines built in the USA and they are stamped as built in the USA.

But it seems that the 305 and 342 engines (and other sizes) labelled "Polar Force engines By Briggs " are manufactured in China.

If anyone has other information on these Polar Force engines., please reply. Thankyou

coasteray

El Toro! 1028 LXE
Tecumseh 358cc
10hp

Location: NE Washington State
Joined: Mar 3, 2008
Points: 142

Re: Does HP Matter?
Reply #13 Nov 11, 2011 1:42 am

Well, there's the formula most of us know about:

Horsepower = torque (in ft-lbs.) x rpm (typically 3600)
                                                5252

Thus, if you have a 305cc engine with a 14.50 torque figure, it comes out: HP = 14.5 x 3600   =   9.94
                                                                                                                                             5252

The 5252 is a real figure, not just something made up to make us happy: http://www.epi-eng.com/piston_engine_technology/power_and_torque.htm

See the end section of the article entitled "Derivation of the Power Equation (for anyone interested)". It explains how the number 5252 is arrived at. Very interesting.

Rearranging the formula gives us :

Torque = Horsepower x 5252
                rpm (typically 3600)

So, if you have an engine like the 10HP Tecumseh 358cc on my El Toro! 1028LXE, it looks like this:     Torque = 10.0 x 5252 =   14.58
                                                                                                                                                                                          3600

Do these figures seem good, realistic? I think so.   The only thing I'm not sure about is that I've read that torque is supposedly measured at 3060rpm instead of 3600rpm. Assuming that's the case, then how could we plug in a torque figure based on 3060rpm into a formula assuming 3600rpm, and expect a decent result? That would change the above horsepower formula to a higher final result, assuming the torque keeps climbing all the way to 3600rpm. Doesn't it peak out before that on these engines?   The torque formula is based on 3600 since we didn't start with a torque figure to begin with, so my result of 14.58 ft-lbs for my Tecumseh engine is based on the horsepower figure and 3600rpm. And we assume horsepower is calculated on 3600rpm, anyway, so that 14.58 torque number seems to be right. Also, assuming that a 358cc L-Head is equal in torque/horsepower to a 305cc OHV, that 14.58 is mighty close to the 14.50 figure we get from today's Briggs 305cc engines. After all, the Briggs 305cc replaced the Tecumseh 358cc on the Toro 1028 (LXE going to OXE). I hope I'm not losing anyone on this. I find it interesting.

This message was modified Nov 18, 2011 by coasteray

El Toro! 1028 LXE - Tecumseh 358cc 10hp Let it snow! Let it snow! Let it snow!

Shryp

Location: Cleveland, OH
Joined: Jul 26, 2010
Points: 532

Re: Does HP Matter?
Reply #14 Nov 11, 2011 5:22 am

Here is an 11 HP Honda GX 340
Peak HP at 3600 RPM, Peak Torque at ~2400 RPM.
Most engines have similar torque curves.

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