a few important things: For general guidance on the HP needed, you can just look at blowers that have engines on them-to find out the HP you need. Walk behind kind. Example: is my older Toro model 724 (7HP and 24inch). I'm going to build an engine powered (my 443B doesn't have enough aux hyd power) blower attachment myself. I've got a 48" single stage blower - so, I figure I'll need about double the HP for double the width. One of my friends engr. at Toro told me you need a tad bit more HP for a single stage than for two stage of same width. makes sense because there is friction load on a lot of auger surface. Already have a 2cyl Onan (cast iron) 16 hp. I may be about 3-4 HP underpowered. I'll compensate to avoid clogging - by slowing down my forward drive speed. Once you have your HP figured out - now you need to find out if you've got enough HP in your aux hyd. You know your flow rate, but you need to find out the pressure delivered to your fittings. Flow times pressure equals HP (or watts or other POWER value expressions) If you've got enough HORSEPOWER at your front hyd, then you need to source pump, and chain / sprocket or whatever it's going to take to "connect" pump output shaft to input drive shaft on blower. Very important to calculate these speeds / ratios so that augers on single stage blowers spin the correct speed because that's how the snow gets flung. I'm pleased to tell you all that - (more research with engineers at OEMs I've done) the TIP SPEED of the O.D. of the auger must "fly" at about 3000 feet per minute. Spinning it too fast risks tearing blower apart AND MOST OF ALL requires A LOT MORE HORSEPOWER. An auger like this is essentially a centrifugal pump - and (this is kind of a mindblower) if you DOUBLE the speed of a centrifugal pump - it TAKES THREE TIMES THE HORSEPOWER to turn it. Another "design point tip" for systems like we deal with.......... just because an engine driving a hyd system is 15, or 25, or 40 HP - that doesn't mean we can do 15, 25, or 40 HP of work at the wheels or the bucket lift, etc. Hydraulic systems are EXTREMELY INEFFICIENT - nominally, 1/3 HP loss in the hydraulics (that's why the pumps, motors and hoses are so hot - it's heat loss from the friction inside the hydraulics). So - my little 443B with 15HP Kubota is only putting about 10 HP into wheel drive and bucket/arm mechanisms. Sorry if that's more than you wanted - but - if you spend a lot of time looking up energy units conversions and careful calculating - you'll save yourself OODLES of money and frustration.
