Snowblower Forum banner

21 - 37 of 37 Posts

·
Super Moderator
Joined
·
10,821 Posts
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 :eek: 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.
 

·
Registered
Joined
·
1,503 Posts
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.
 

·
Registered
Joined
·
84 Posts
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
 

·
Registered
Joined
·
303 Posts
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.
 

·
Registered
Joined
·
4,020 Posts
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 :eek:

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.
 

·
Registered
Joined
·
1,503 Posts
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 :eek:

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.
 

·
Registered
Joined
·
279 Posts
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.
 

·
Super Moderator
Joined
·
10,821 Posts
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. :)
 

·
Registered
Joined
·
84 Posts
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
 

·
Registered
Joined
·
4,020 Posts
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.
 

·
Registered
Joined
·
279 Posts
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.
 

·
Registered
Joined
·
4,020 Posts
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 ::D

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.
 

·
Registered
Joined
·
1,503 Posts
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.
 

·
Registered
Joined
·
279 Posts

·
Registered
Joined
·
307 Posts
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.
 
  • Like
Reactions: Ziggy65

·
Registered
Joined
·
307 Posts
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.
 
21 - 37 of 37 Posts
Top