# Discussion on engine size



## Spike60

Would like some opinions from you guys, especially those who've run or have several blowers. With all of this years snow, we've been comparing machines in back of the shop, both new and old. I believe that many of the blowers being sold today are somewhat under powered vs those of a few years ago. And this applies to all brands IMO.

Here in the post-Tecumseh world the narrative has moved from HP to CC's. So it's a little harder to compare things then and now. On most of the recent Tecumseh engines though, the displacement can be found on the serial number tag. Engines that were rated in the 9HP to 11HP range were generally 318cc or 358cc. And they were most often found on 26" to 30" units. 

Seems like today the industry is in love with 205-208 cc engines, and many of them are on blowers that I'm thinking are a bit too big for that size motor. On a compact 24", that may be enough, but beyond that I think you need more displacement. The next size up is around 250cc, which find their way onto many full size machines. My best selling Ariens is the Deluxe 28 with the 254cc AX engine. Yeah, it works. And customers have not complained about power, even in the bigger storms. But it doesn't really compare with my 11HP/318cc Tecumseh OHV 924125. And Ariens sees fit to go with the 414cc Briggs on the Pro 28 and Platinum 30 models. The platinum 24" gets the 291cc AX. In the past, the larger blowers all got a decent sized engine, not just the pro models.

Again, this is going on with all brands. I'm just talking about Ariens as that's what I sell and am most familiar with. Husky, Toro, Simplicity/Snapper, the MTD brands, they all do it. The worst one we tested was a Troy-Bilt 24" with the 179cc MTD engine. That thing was wheezing in 5" of snow. 

I've always been a believer in the old saying "there's no replacement for displacement". And I think a lot of the blowers out there today could use a little more motor. What do you guys think?


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## threeputtpar

My thought was that now that many OPE engines have moved to OHV from the side valves, the same amount of displacement generates a bit more hp than the same sized side valve engine. This may be why smaller displacement engines are being used on larger machines.

My experience is with older snowthrowers, and I've found that it's not always the size of the engine but the size and design of the auger and impeller that makes one machine better than another. I have a 1990 Toro 824 Powershift, and it doesn't even kick in the governor until about 6" of snow. The design of the auger with the drum really helps feed the snow into the impeller efficiently, thus it uses less power to move the snow.


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## UNDERTAKER

the bigger, the machine, the better I will always say.


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## rhenning

Spike the reason HP is not used anymore is not the new engines but because of a law suit. In the early 2000s manufacturers were inflating HP on machines for marketing purposes. They knew it sold mowers, blower etc. The fact was in real life situations the machines didn't produce the HP claimed. Briggs for example made an engine that without changes was rated as 5 to 7 HP depending what the manufacturers wanted it to be. A Federal law suit stopped that and some if not many consumers got a settlement. Looking for marketing the manufacturers changed to engine size which cannot be disputed. It is given in either cubic inches or cubic centimeters. Most of the companies have settled on cubic centimeters or CCs. I suspect because it is a bigger number. It is not a sinister plot but just a fact of life. You may as well get used to seeing CCs as the norm. Roger


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## Sid

*Engine size*

I always felt that the drums would get in the way of large amounts of snow. I have a 66 sears/murray, and I feel i.e. should go a little slower in 1st gear, but the 6 HP engine never bogs down.
Sid


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## mikey517

I've got a '95 Toro 7/24 with the 7hp Tecumseh. It's been a fine machine and has handled all manner and amounts of snow over the years. I don't know what 7hp translates to in cc's, but some of the newer, bigger machines don't seem to carry a big power (hp) advantage.


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## SnowGuy69

To a point, yes. I ran into a big commercial unit, 36 inches wide and 14.5 HP. I realized that was too big for my needs. I need to fit it in the front of my garage and get it into my shed to store in the summer. 

The big units are much heavier to move around and if you have to fit between parked cars while during snow removal, a smaller unit may be more applicable.

The bigger units cost a bit more too.

Bigger is better if you have the need.


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## detdrbuzzard

it would be nice to have the engine displacement of the older briggs and tecumseh's as a reference for someone looking at a new machine which. my 521 has an engine displacement of 195cc so looking at a new snowblower i know even with an ohv motor its not going to have much more hp than my old tecumseh so whats the displacement of the 6hp, 7hp, 8hp ect engings of our older engines. most of the new machines with what i think might be an 8hp motor come with a 26" bucket. i want an 824, so what if i have to make an extra pass space in the garage is at a premium and is much more important


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## Roar

It seems that snow blower engines are not that different from generator engines. Those who work on both may have different opinions.
A two pole generator has to run at 3600 RPM to generate 60 cycles per second alternating current, so I am guessing that snow blower engines do also. 
Looking at an Ariens brochure, the 208 cc engine is rated at 9.5 foot pounds of torqe, and the 420 cc engine at 21. Using the formula: HP = Torque x RPM / 5252. 
That gives about 6.5 horsepower for the 208 cc engine and 14,4 hp for the 420.
Specific output then is 31 horsepwer per liter for the smaller engine and 34 for the big one. That falls right in a typical range of 30 to 35 horsepower per liter. The old side valve engines would typically run in the 20 to 25 horsepower per liter range I believe.
For those who are stuck in the world of gallons and cubic inches, one liter is 1000 cubic centimeters.
This could be calculated more accurately if someone knows what RPM the governors are set for on snow blower engines, and likewise if the rated torque is at the running speed, or if it is a peak number at some other speed.


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## InfernoST

What's actually more important than horsepower is the amount of torque the motor can generate at its output shaft.


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## Colored Eggs

It is actually incorrect to say older machines were more powerful than today machine. Here is a good example. Toro make a 3521 421 and 521. They were all identical except for the engine. 3.5 I would have to say was very under powered for that type of snow blower. 

I do like that the machines of today will rate the torque specs though and not just CC as the amount of torque is more important.


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## HJames

I would like to see the industry start using torque as "the" number, it is a much cleaner representation of power. As far as newer machines being under powered...I agree, all manufacturers are producing models that are under powered based on bucket size, but people keep buying them so what incentive do they have to stop. Now I'm not saying that they are all bad machines, but I would take 12.5 ft pounds of torque on a 24" bucket over the same 12.5 ft pounds on a 28" bucket. That being said I really like the size vs. power of Ariens Platinum 30 and Pro 32 with their 20 & 21 ft pounds of torque.


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## Roar

Keith,
I am not trying to start an argument here, just shedding some light.
Torque at the shaft is, of course, important, but "torque" by itself is meaningless. It becomes meaningful when RPM enters the equation, and then it translates into horsepower. Horsepower is a measure of how much work can get done in a given amount of time. You can convert horsepower into torque through gears.
Roar


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## InfernoST

Roar said:


> Keith,
> I am not trying to start an argument here, just shedding some light.
> Torque at the shaft is, of course, important, but "torque" by itself is meaningless. It becomes meaningful when RPM enters the equation, and then it translates into horsepower. Horsepower is a measure of how much work can get done in a given amount of time. You can convert horsepower into torque through gears.
> Roar


Roar
No argument just a discussion. I understand you can convert horsepower into torque through gear ratios (Horsepower is only a factor after the vehicle/engine has overcome the initial load, thereafter is when horsepower matters). Our augers run at one speed (single speed gearbox so to speak), IMO one would be more concerned with higher torque value at a lower HP rating than higher HP with a lower torque value.
A simple example of this is comparing a 600hp engine with 400 lb ft of torque in a sports car to a 400hp engine with 2500 lb ft of torque found in most 18 wheelers. Using each each vehicle to pull a fully loaded 53' trailer which vehicle is going to get the job done with efficiency and not self destruct?

Keith


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## peisnowguy

I purchase a Platinum 30 this year. I had a Craftsman 11Hp (Tecumseh) I had since it was new (16 years) and it had a 30 inch bucket. The Platinum is rated at 14 HP and the Craftsman was rated at 11 HP, but it is night and day difference in power. I cannot load this blower down and if anything I have to slow down because the augers can't keep up. The neighbor across the road has a Cub Cadet 45" with a 13 HP engine and it is night and day difference between the two snowblowers. Even if he takes half the width of the blower I can still blow alot more snow than him. I guess if you want a robust snowblower you have to do your research and buy based on need. I would have to say that our winters have gotten tamer and maybe the need for that extra horsepower is not as necessary as it used to be. Figuring all snowblowers are created equal is not just a calculation of torque or HP divided by the width of the snowblower, but it may be a ball park figure. If I was to judge the snowblowers of today with what you could buy 20 years ago I would say the opposite. When I bought my old Craftsman I bought the biggest baddest Craftsman that was available at the time and finding a 14 HP walk behind snowblower was hard to come by. You can buy powerful blowers now at a reasonable price.

Just my thoughts


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## InfernoST

I hear what you're saying, I too just picked up a 2014 Platinum 30 and had a chance to use it in very heavy snow & large plow piles and the machine didn't even break a sweat.


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## RedOctobyr

Interesting discussion. 

I recently upgraded from an Ariens ST824, to an Ariens 1024 Pro. The ST824 had an 8hp flathead Tecumseh, 318cc. 

The 1024 Pro has a 10hp Tecumseh OHV, also 318cc. The owner's manual spec page says my specific model # is 357cc, but it's apparently wrong (I've measured the bore of my engine). 

My hope is that the 10hp truly is more powerful (not just marketing), due to the OHV vs flathead design. In some quick testing, the 10hp appeared to do a little better in deep snow, both machines have 24" buckets, but it wasn't a huge difference. Some deep wet stuff (if it had been available) might have been a better test. 

If nothing else, the 1024 Pro has 16" augers and a 14" impeller, vs 15" augers and 12" impeller for the ST824. The 1024's impeller RPM is also higher. So even if the engines were the exactly the same, it has a few marks in its favor. It does also throw further than the ST824, though some of that may be due to the new-style, taller chute. 

I wouldn't say no to more displacement, but I'll have to make do. Even the Harbor Freight engines that would be an upgrade are still $300.


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## 94EG8

The old rule of thumb used to be 8/26, 10/28, 12/32

Any time you can get a machine that has a larger engine than the standard for the bucket size is great. IE a 10hp on a 26" machine, those are the machines that all else being equal perform especially well for that particular style of machine.

As someone else mentioned impeller design and speed can dramatically change how a machine works. two machines of the same cutting width with identical engines may perform very differently if they have a different impeller design/speed.

In relation to displacement vs HP as I said in another thread you really can't directly equate the two. An OHV engine of a specific displacement will put out more power than a flathead/L head of the same displacement (it's usually pretty large difference in HP too) The only thing you could do at one time was if you knew the displacement of a B&S engine you could figure out out the HP if you'd worked on enough of them and knew what the numbers translated into from the ones you'd worked on that had HP decals, this really only works for flatheads though. For example 13CI = 5hp. 19CI = 8hp

In relation to RPM, historically most small engines have a top no load speed of 3600RPM (some of the Tecumseh OHV engines are more like 3400RPM) and the HP was rated at that RPM.


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## MnJim

New 28 Deluxe owner and new to cc's and torque vs HP as all my old blowers where rated in HP.
I don't think a little extra power is ever a bad thing and IMHO the 254cc is ok on the 28 Deluxe but would have been better with a 291cc or even slightly larger.
The 254cc almost makes me wish I had purchased the 24 Deluxe instead.

I would tend to agree with 94EG8s rules of thumb but with ccs and torque its harder to compare and makes me wish I had done more research before my purchase.


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## Roar

Keith, I think we are basically on the same page here.

RJames, We need to keep the terms straight. Torque is a measure of force. Horsepower is power, which is a measure of how much work gets done in a certain amount of time.
For a given amount of power, one can gear that to whatever ratio one needs in order to achieve the torque (force) to get the job done.
Since the quoted torque numbers do not come with an RPM number, one can not really know the power. Steam engines are a good example here. They have max torque at start up (= 0 speed), in other words, max torque but no horsepower, since nothing is moving yet. Remember: power = force x velocity, so it does not matter how high the torque is, if it does not come with some velocity (RPM), the power, or work done, is zero.
May be semantics, but at least it makes it more clear to me.
Roar


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## Kiss4aFrog

Spike60 said:


> The worst one we tested was a Troy-Bilt 24" with the 179cc MTD engine. That thing was wheezing in 5" of snow.


I have that machine  At 5.5hp in my opinion it's just enough to get the job done but isn't really big enough. It works ok but I think the main problem with it is the EPA approved non-adjustable carb. Mine surges and I can't wait for warmer weather to take it off and drill the jets. I don't have anything heated.

I also have a Estate ES825 that's a 8/25 and that is much more reasonable. It doesn't go on it's governor nearly as much.


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## GustoGuy

94EG8 said:


> The old rule of thumb used to be 8/26, 10/28, 12/32
> 
> Any time you can get a machine that has a larger engine than the standard for the bucket size is great. IE a 10hp on a 26" machine, those are the machines that all else being equal perform especially well for that particular style of machine.
> 
> As someone else mentioned impeller design and speed can dramatically change how a machine works. two machines of the same cutting width with identical engines may perform very differently if they have a different impeller design/speed.
> 
> In relation to displacement vs HP as I said in another thread you really can't directly equate the two. An OHV engine of a specific displacement will put out more power than a flathead/L head of the same displacement (it's usually pretty large difference in HP too) The only thing you could do at one time was if you knew the displacement of a B&S engine you could figure out out the HP if you'd worked on enough of them and knew what the numbers translated into from the ones you'd worked on that had HP decals, this really only works for flatheads though. For example 13CI = 5hp. 19CI = 8hp
> 
> In relation to RPM, historically most small engines have a top no load speed of 3600RPM (some of the Tecumseh OHV engines are more like 3400RPM) and the HP was rated at that RPM.



Exactly. An engine is nothing more than an air pump. Big overhead valves which are located directly over the pistons will breath better than valves off in the side of the engine block. The HF Predator at a conservatively rated 6.5hp puts out this much horsepower per cc 6.5hp/212cc=0.03066
My old Flathead Briggs 319cc is rated at 8hp puts out this much power per cc
8hp/319cc=0.02507. So if the Briggs made as much power per cc as the Predator did it would make 319cc X 0.03066=9.7Hp.

Now I know the Horsepower rating on the Predator is quite conservative since NR Racing tested a stock Predator engine minus the stock restrictive air cleaner with bigger jetting and a K&N style filter and it put out just a bit over 9hp stock as tested on their Dynometer. The stage 1 kit is $59.00 or so dollars and says will produce 9 to 10hp on 196cc to 212cc engine. It is just a reduced restriction air filter unit and 140 emulsion tube and a larger than stock jet that is calibrated to run with that air filter. You can also buy a 4 degree timing advance key and it will give it another hp too.


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## rhenning

Gusto Guy you have the decimal point in the wrong place on the Briggs. It should be 0.02507 not .2507. Very big differnce. Roger


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## GustoGuy

rhenning said:


> Gusto Guy you have the decimal point in the wrong place on the Briggs. It should be 0.02507 not .2507. Very big differnce. Roger


Thanks. I was still able to edit it too.


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## Smolenski7

MnJim said:


> New 28 Deluxe owner and new to cc's and torque vs HP as all my old blowers where rated in HP.
> I don't think a little extra power is ever a bad thing and IMHO the 254cc is ok on the 28 Deluxe but would have been better with a 291cc or even slightly larger.
> The 254cc almost makes me wish I had purchased the 24 Deluxe instead.
> 
> I would tend to agree with 94EG8s rules of thumb but with ccs and torque its harder to compare and makes me wish I had done more research before my purchase.



Couldn't agree more. When I was in the market a few years ago, I believe the 24" Deluxe and the 28" Deluxe both came with the same B&S 250cc 11.5 engine. There was no question in my mind which one to choose, I went with the smaller bucket so that I had more relative power per square inch with respect to the bucket. So far, after 3 full winters and several historical blizzards, it hasn't hesitated.


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## RedOctobyr

Before I start- I made the same decision. I waited for a 10hp, 24" blower to come on Craigslist. A 10hp 28", etc, would have been easier to find. 

But I wanted high-power, narrow-cut. My driveway isn't enormous anyhow, so it's not like I need 32". And with New England winters, we can get wet, heavy stuff, plus I can end up with quite an EOD mess to deal with (we're on the outside of where our street turns, so the plows sometimes leave a big area to clear in front of the driveway). 

I also have storage constraints; a previous 26" blower was a tighter fit in the garage. 

But it did occur to me after buying the 24" machine that the same power, but a wider bucket, isn't all-bad. Yes, the first pass might require going slower, if the snow is deep (less hp per inch of bucket width). But after that, you could take narrower cuts, and manage the power requirements that way. And in a smaller storm, you have an extra few inches of width available, when taking full cuts. Granted, maybe I could just use a higher gear, for more ground speed. 

I don't regret going 24", but it was an aspect I admittedly hadn't really considered before buying the machine 

GustoGuy, cool info on the engine upgrades! It sounds like they plan on spinning the engine faster, as well (stiffer valve springs, and suggestions to use better-quality flywheels due to risk of breakage). I did see they also sell some upgrades for the larger engines as well, beyond the 212cc. I wonder at what speed valve float, etc, becomes a problem, without the upgrade. Additional RPM (just a governor adjustment) would provide higher impeller & auger speeds, for better throwing distance, if the engine could handle it.


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## GustoGuy

RedOctobyr said:


> Before I start- I made the same decision. I waited for a 10hp, 24" blower to come on Craigslist. A 10hp 28", etc, would have been easier to find.
> 
> But I wanted high-power, narrow-cut. My driveway isn't enormous anyhow, so it's not like I need 32". And with New England winters, we can get wet, heavy stuff, plus I can end up with quite an EOD mess to deal with (we're on the outside of where our street turns, so the plows sometimes leave a big area to clear in front of the driveway).
> 
> I also have storage constraints; a previous 26" blower was a tighter fit in the garage.
> 
> But it did occur to me after buying the 24" machine that the same power, but a wider bucket, isn't all-bad. Yes, the first pass might require going slower, if the snow is deep (less hp per inch of bucket width). But after that, you could take narrower cuts, and manage the power requirements that way. And in a smaller storm, you have an extra few inches of width available, when taking full cuts. Granted, maybe I could just use a higher gear, for more ground speed.
> 
> I don't regret going 24", but it was an aspect I admittedly hadn't really considered before buying the machine
> 
> GustoGuy, cool info on the engine upgrades! It sounds like they plan on spinning the engine faster, as well (stiffer valve springs, and suggestions to use better-quality flywheels due to risk of breakage). I did see they also sell some upgrades for the larger engines as well, beyond the 212cc. I wonder at what speed valve float, etc, becomes a problem, without the upgrade. Additional RPM (just a governor adjustment) would provide higher impeller & auger speeds, for better throwing distance, if the engine could handle it.


The stock connecting rod and flywheel are unsafe for high performance upgrades. ARC Makes a Billet forged connecting rod which is over twice as strong as the original and you can also Buy an ARC forged billet flyweel that is rated to over 8000rpms. With stock valve springs you will get valve float at about 5000rpms. With 18lb springs will allow up to 8000rpms. You can also buy a billit 3 to 1 rocker arms that will allow for more valve lift as well as a more radical cam shaft that will allow for bigger valve duration for better breating. NR racing has souped these engines up to 14hp out of 212cc

I am also a member on Oldminibike.com and over there they build these engines up like mad and some even race them.


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## HJames

Roar said:


> Keith, I think we are basically on the same page here.
> 
> RJames, We need to keep the terms straight. Torque is a measure of force. Horsepower is power, which is a measure of how much work gets done in a certain amount of time.
> For a given amount of power, one can gear that to whatever ratio one needs in order to achieve the torque (force) to get the job done.
> Since the quoted torque numbers do not come with an RPM number, one can not really know the power. Steam engines are a good example here. They have max torque at start up (= 0 speed), in other words, max torque but no horsepower, since nothing is moving yet. Remember: power = force x velocity, so it does not matter how high the torque is, if it does not come with some velocity (RPM), the power, or work done, is zero.
> May be semantics, but at least it makes it more clear to me.
> Roar


 
I agree we should keep the terms straight, but I stand by what I said in regards to torque being a better measurement as it pertains to snowblowers, in other applications such as cars, motorbikes, gocarts, etc.,when gearing is used, horsepower is the better measure of what the motor can accomplish. For the purpose of a snowblower, most engine manufacturers set the max rpm at or around 3600, and most of these engines reach their torque rating between 2500-3600 rpm. The auger gear boxes are then designed to work under these load conditions, and spin the impeller between 1000-1200 rpm at max load. The only gearing, so to speak, is the pulley that spins the auger. You can increase or decrease the diameter to some degree but doing so will directly affect the engines ability to operate at max load. IMO, the force applied by the engine under max load is the best measurement of what it can do when it is mounted on a snowblower.


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## Kiss4aFrog

Like cars the engine manufacturer should supply the horsepower and torque and the RPMs that each max is reached at. That would give a level playing field to compare them.

But the engineer who chooses the diameter of the sheave or pulleys can help that engine overcome a limitation or create one.

It's all just information that works as a guide but I wish they would just settle on something so we have a standard going forward.


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## rhenning

Kissafrog the feds stated in a court settlement that manufactiurers must use displacement in their advertising because they cannot lie about what that number is. I will grant you that doesn't give a true number for horse power but that is what we have so you may as well get used to to it. I used to have a twin stroke Bridgestone motorcycle that was 180 ccs and put out just under 20 HP. The Predator which is 212 cc is only rated at 6.5 HP is just one example of what can be done playing with numbers. I suspect the torque on the Predator is better than what the Bridgestone had and the powerband is also much better on a Predator. Roger


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## RedOctobyr

But, alluding to what GustoGuy linked to, small engines typically run at 3600 RPM. 

With a certain displacement, there is a practical limit to how much torque you can generate. And because your RPM is effectively fixed, so too is your power. 

Now, if you help the engine breathe better, and spin it faster, and you can produce more power, assuming it can maintain decent torque as the RPMs climb. Like your 180cc 20hp example. 

A simple example- small inverter generators tend to be lighter and more fuel-efficient (not to mention quieter) than their "contractor" generator counterparts. Contractor generators have to turn at 3600 RPM to generate 60 Hz. Inverter generators can still generate 60 Hz no matter how fast they're turning, so they slow down with no load, and speed up to produce more power, as required. 

My EU2000i (98cc 4-stroke) runs at 3000 RPM to produce 0-400W, ramps up to 4300 RPM for 1600W, and will go up to 5000 RPM for 2000W (temporarily). If it had to produce enough power to make 2000W, while running at just 3600 RPM, the engine would likely have to be bigger. It would need more torque to make that power at the lower RPM. 

The Honda S2000 sports car is a related example. They got 240 hp from a 2.0L 4-cylinder, by running it up to something like 8000 RPM. F1 cars, etc, also get a lot of power from small-displacement, high-RPM engines. 

But most things for OPE run around 3600 RPM, so we tend to get used to power #'s that you can get from a given-displacement engine.


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## HJames

RedOctobyr said:


> But, alluding to what GustoGuy linked to, small engines typically run at 3600 RPM.
> 
> *With a certain displacement, there is a practical limit to how much torque you can generate. And because your RPM is effectively fixed, so too is your power. *
> 
> *Now, if you help the engine breathe better, and spin it faster, and you can produce more power, assuming it can maintain decent torque as the RPMs climb. Like your 180cc 20hp example.*
> 
> A simple example- small inverter generators tend to be lighter and more fuel-efficient (not to mention quieter) than their "contractor" generator counterparts. Contractor generators have to turn at 3600 RPM to generate 60 Hz. Inverter generators can still generate 60 Hz no matter how fast they're turning, so they slow down with no load, and speed up to produce more power, as required.
> 
> My EU2000i (98cc 4-stroke) runs at 3000 RPM to produce 0-400W, ramps up to 4300 RPM for 1600W, and will go up to 5000 RPM for 2000W (temporarily). If it had to produce enough power to make 2000W, while running at just 3600 RPM, the engine would likely have to be bigger. It would need more torque to make that power at the lower RPM.
> 
> The Honda S2000 sports car is a related example. They got 240 hp from a 2.0L 4-cylinder, by running it up to something like 8000 RPM. F1 cars, etc, also get a lot of power from small-displacement, high-RPM engines.
> 
> But most things for OPE run around 3600 RPM, so we tend to get used to power #'s that you can get from a given-displacement engine.


 
The results that I have seen on the 212cc predator indicate that a max torque or 14.10 ft lb. occurs between 2200-2400 and a Max of 9.83 hp is achieved at 4700 rpm with simple rejetting, open air flow filter and open exhaust. Now that is a 2400 rpm gap between max torque and max hp. The engine actually put out 9hp at 3600 rpm so the over reving isn't needed to give it a little more punch. Further mods follow the same pattern and the gap only gets wider, so they aren't continuing to produce more torque at higher rpms, just more torque at the same rpm. Which follows the idea that it is a motor built for torque and the horsepower takes care of itself. Reving up to 8000 rpm to get to 15-20 hp is great for the racers who can use the higher hp, but without the torque at those higher rpms it isn't very useful to go beyond 3600 rpm on a snowblower.


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## RedOctobyr

It sounds like you have a dyno? That's awesome, that sure would shed a lot of light on this stuff, and would allow checking the advertised numbers  

I guess we'd agree to disagree on the power. Give me 15-20hp instead of 9hp (or 6.5 or whatever), at higher RPM, and I'd argue you should simply re-gear it accordingly. With the extra power, you'll get more effective torque at your load, after you factor in the gearing. 

Get twice the power at twice the RPM (just hypothetical #'s), and if you gear it down by half, it would seem like win-win to me, no? Granted, it would be more wear on the engine, more gas, noise, etc. But we're talking about power, not efficiency : 

It may be overly-simplistic. But let's say you could safely run an engine at 4500, vs 3600, with no hardware changes. Let's also assume you don't get any additional power from the extra speed. Adjust the governor to 4500, and you'd get better snow-throwing distance with light loads, due to the higher impeller speed. But load the blower up with deep stuff, and you'd simply slow back down to more-normal speeds. You'd get some benefit in light stuff, and would be no worse off when it got heavy. 

Some guys on another forum do this to 2-stroke engines in single-stage snowthrowers, just cranking the governor up (some 3-5hp Tecumseh engines apparently are popular candidates). They seem happy with the results.


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## GustoGuy

> just cranking the governor up (some Tecumseh engines apparently are popular candidates). They seem happy with the results.


I would not run a Tecumseh 7 to 10hp engine faster than stock rpm *ever* since they have been known to blow connecting rods at rpms faster than 3600rpms or if oil level gets low. Predator 212cc are unlikely to blow rods as discovered during torture testing done by Cart racing part suppliers and cart engine builders.


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## HJames

Unfortunatly I don't have a dyno, just referencing what this guy did.

https://www.google.com/url?sa=t&rct...DV_MzGo-l-FmdZrlnvnIyLA&bvm=bv.62577051,d.eW0


Agree to disagree is ok with me, builing for torque or building for horsepower is a discussion that professional engine builders have had for years, nobody's wrong it's all about application.


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## Dusty

mikey517 said:


> I've got a '95 Toro 7/24 with the 7hp Tecumseh. It's been a fine machine and has handled all manner and amounts of snow over the years. I don't know what 7hp translates to in cc's, but some of the newer, bigger machines don't seem to carry a big power (hp) advantage.


The H70 is 246cc for those who wanted to know. They are most commonly found on 24 and 26 snowblowers, by todays standards, still bigger than most of the engines their sticking on blowers that size.
For those who wanted to know, because the information is not that widely published, the displacements for the older H blocks are as follows, 
H50 200cc
H60 221cc
H70 246cc
The older H40 180cc
These engines all shared the same or similar blocks. These were the first line of Tecumseh horizontal engines to come out, they were out before the medium frame hm80-100 8 and 10hp engines.
The 4 and 5 horse were later replaced with the smaller HS40 and 50 which is 195cc, for the h40 its more powerful, for the h50, it was a step down. The h40 and h50 have bigger blocks than the hs blocks. The old h50 is a very popular minibike engine now. Small but still more power than the HS50.
They are indeed putting smaller less powerful lower cc engines on many snowblowers now, that would never have gone that low during the Tecumseh era. A lot of it, most of it, is due to environmental and fuel consumption saving. All of the blowers I've had weather a Toro with an H60 6hp or a Snapper with a HM100 10hp were all more powerful than any of the new blowers out now. Only a few are bigger than what was available during the Tecumseh era, like the machines offering the 420cc. That started post Tecumseh, that machine has a bigger more powerful engine. However Toro and others did use the 11hp 399-400cc Briggs flathead at one time which isn't far behind that 420cc unit. In general snowblowers had more power and bigger engines back in the day. Many of them are under powered now, a lot of them with 300cc and up engines are fine, have plenty of power, but its the ones their putting 161cc and 208cc, those are less powerful, than the Tecumseh powered oned were. I was looking into this while looking up the displacement for the H60, 6hp on my Toro 6/24. If anyone ever wants spec info on any Tecumseh engine. Its in the technician handbook, towards the back. The L head book covers all the L heads obviously, the OHV book will cover all the OHV's. I know this is an old post, nut felt the need to update the information. That Toro 6/24 with its H60 has some balls. My father also had a Jacobsen 626, that had balls, those classic H block engines had great power and are reliable, those blowers moved snow well.


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## Dusty

GustoGuy said:


> I would not run a Tecumseh 7 to 10hp engine faster than stock rpm *ever* since they have been known to blow connecting rods at rpms faster than 3600rpms or if oil level gets low. Predator 212cc are unlikely to blow rods as discovered during torture testing done by Cart racing part suppliers and cart engine builders.


Predators throw rods too, but at much higher rpms, 5000 range. Tecumseh's are not to be set over 3600, any of them, 3-13hp, it says it on all of them, thats nothing new. It doesn't mention it on the Predator because you can safely go higher. I go as high as 4500 rpm on the Predators, no problem have for ahwile. Tecumseh's are great too, just dont go over 3600.


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