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

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.

"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.

Bill_H 
+1

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. 

Bill_H 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!

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

stresst wrote:
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.

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

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

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

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.