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woods mower specs! mystert in speed and blade tip speed!

Discussion in 'Lawn Mowing' started by SfTD_service_CENTER, Jun 16, 2009.

  1. SfTD_service_CENTER

    SfTD_service_CENTER LawnSite Senior Member
    Messages: 868

    ok well it is obvious that the generac spec says it is a faster mower than the kawi on the mower but how come it has less blade tip speed than the kawisaki? overall the kawisaki is a faster blade with a slower speed and the opposite is ttrue for the generac equiped mowers. i was interested in woods cuase my dealer can get them if he wanted to for me, i never really new they were the same as the bobcat since there is no dealer near me i just didnt compare them. bobcat must be the same way. i know i am not the only person that wants to know why the generac is faster but i thought i would just bring it up about the different blade tip speed too.

    MZ2652G MZ3361G MZ3372G MZ3761K MZ3772K MZ2661KL
    Engine Make Generac®
    763cc V-Twin Generac®
    992cc V-Twin Generac®
    992cc V-Twin Kawasaki 999cc V-Twin Kawasaki®
    999cc V-Twin Kawasaki®
    675cc V-Twin
    Type / Fuel Air-cooled, OHV, gas
    Liquid-cooled, OHV, gas
    Fuel Capacity 12 gallons 12 gallons 12 gallons 12 gallons 12 gallons 12 gallons
    HP* 26 33 33 37 37 26
    Lubrication Full pressure - spin on filter

    Air Filter System Heavy-duty canister style air filter system with pre-cleaner

    Deck Cutting Width 52" 61" 72" 61" 72" 61"
    Design Fabricated - Welded 10-gauge steel, plus 7-gauge reinforcements

    Skirts 7-gauge skirts with heavy welded steel bumper

    Front Lip Adjustable front lip opening on 52" and 61" decks

    Anti-Scalp Rollers Adjustable - 6 on 52" & 72" (all 4 corners - front & rear center); 7 on 61" (all 4 corners, rear center, 2 on front center);

    Spindle Type Maintenance free with 1" shaft - Double sealed, precision ground ball bearings

    Cutting Height 1.5" - 4.5" 1.5" - 4.5" 1.5" - 4.5" 1.5" - 5" 1.5" - 5" 1.5" - 5"
    Lift Type Spring assisted manual with quick lift foot pedal (electric lift option)

    Blade Tip speed 18,404 fpm 18,315 fpm 18,153 fpm 18,854 fpm 18,153 fpm 18,854 fpm
    Drive Transmission Twin Hydro-Gear® variable displacement pumps with oil cooler and Parker ® wheel motors

    Pump Size 16cc 16cc 16cc 16cc 16cc 16cc

    Dampening Ease of control - smoother operation
    Adjustable - 25% increase or decrease

    Ground Speed mph - Forward/Rev. 13.5 / 4 13.5 / 4 13.5 / 4 12.4 / 4 12.4 / 4 12.4 / 4

    Size Length 80" 80" 80" 80" 80" 80"
    Width - Chute down/up 64.5" / 58.25" 73" / 62" 84" / 72" 73" / 62" 84" / 72" 73" / 62"
    Height 46.5" 46.5" 46.5" 46.5" 46.5" 46.5"
    Product Weight 1,045 lbs. 1,112 lbs. 1,386 lbs. 1,148 lbs. 1,386 lbs. 1,126
  2. SfTD_service_CENTER

    SfTD_service_CENTER LawnSite Senior Member
    Messages: 868

    the only generac and kawi with the same blade speed is on the 72" decks 3372 generac and 3772 kawi 18,153fpm
  3. Richard Martin

    Richard Martin LawnSite Fanatic
    Messages: 14,699

    There are only 2 ways to alter BTS and mower speed given both mowers use the same length of blade and hydro system components. Engine RPM and pulley sizes. I've been reading your posts about the Generac being faster than other engines and it's just not true. If you put 2 engines of the same HP and torque on a given mower there will be no difference in speed unless there are different pullies or RPM used. Manufacturers like to keep costs low. Part of doing that is building everything the same. In other words by using the same pullies on all of the engines they use. The more pullies they buy the cheaper they can get the pullies for. It's called "Economy Of Scale". The only reason I can see for them to use different pullies on different engines is if the output shafts on the 2 different engines is of a different size. In this engine class you generally have 2 diameter sizes of output shafts in a few different lengths. All of the engine manufacturers agree on this so their engines are interchangable.

    The only reason I can see Gravely using a different shaft from Generac to Kawasaki is because they got a great deal on one of those engines (or both) but they would have different output shafts. Gravely has been known in the past to buy a whole lot of engines and put them into inventory taking years to go through that particular lot. I bought a brand new 1997 Gravely Pro 150 that had a 1995 14 HP Kawasaki engine on it from the factory.
  4. Razorblades

    Razorblades LawnSite Bronze Member
    Messages: 1,161

    I think he's talking about Woods mowers which, in this case, are built by Bobcat for them. I agree, it is probably because of various pulley sizes that they use on the model/engine combination that would cause this. I wonder if that is why the Generac powered models have a higher ground speed (because of pulley size on the Hyd. Pumps or do they use different size wheel motors to acheive the higher speed or maybe it is a typo on the speed difference?
  5. Richard Martin

    Richard Martin LawnSite Fanatic
    Messages: 14,699

    Well, without laying my hands on them and doing some measuring or having the parts manuals it's hard to tell why they're rated differently. It's not simply because a 30 HP Generac makes more power than a 30 HP Kawasaki.
  6. Razorblades

    Razorblades LawnSite Bronze Member
    Messages: 1,161

    I have no idea if that's what was being insinuated by sftd ser. center, but I wasn't implying that the 33 Generac engine makes more power that the 37 Kawasaki, although i will say that a 30 HP generac will make more power than a 30 hp Kohler. Unless someone asks a tech person at that works for the Bobcat division of their corporation, it is pure "speculation" as to why the Bobcat Predator Pro model specs are different for the different powered ones.
  7. SfTD_service_CENTER

    SfTD_service_CENTER LawnSite Senior Member
    Messages: 868

    yeah i jut meant it seems like a mystery, which i spelled wrong on the title as to why they say the generac is over 1mph faster and it is the same mower. i also said why would they say that and have a different blade tip speed at the same time only to have the same rated tip speed on the 72" model between both kawi and generac. i just thought maybe some tech for that company might be able to give a little insight on why they arent all pretty much the same.
    cause in my eyes those mowers are totally different with the different engine options, i can either have one of the fastest there is with a generac or a average speed one with a overly poweful kawi. what seems wier alos is that someon said the generac is as powerfull as the kawi if not more powerfull! i wnt to know why more ztr makers havent been trying to use these motors if they are what people say, good on fuel and powerfull. they have been arround for a while i have seen the 33 on dixie choppers for the last few years.
  8. Razorblades

    Razorblades LawnSite Bronze Member
    Messages: 1,161

    From what i've read, generac parts aren't carried by all that many small engine repair shops, compared to the rest of the brands. Also, I think that there were a few engine issues with the early models and some people became scared of htem after that. I will say that the common perception is that while Generac's make great torque, they are also thirstier on gas than other brands of engines in a comparable size. I have a 32 HP Generac on my Lastec and i avg between 1.55 and 1.8 GPH, depending on mowing conditions and what type of blades I'm running. My GPH avg seems to be close to what most guys with the Vanguard big blocks are getting and less than the 34 and 37 Kawasaki's are getting.
  9. TomberLawn

    TomberLawn LawnSite Bronze Member
    Messages: 1,299

    I've got a MZ3361G and love it. I noticed when looking at the specs on the brochure at the dealer that the Generac-equipped models go faster and I'm not sure why either. I just sent an email to Bobcat to ask why there is a difference.

    I read an article about the Generac engines in which it was stated : Plus, the entire engine line is very conservatively rated. "When we say it's 33 hp, it's a true 33 hp," Sugar said. "We also bring some of the highest displacement air-cooled engines in the industry to the open market." (Sugar is the VP of sales)

    Other manufacturers may label an engine with a rating, but with emissions controls and other things on it, it makes less than the rated power. I don't know if this would account for the difference in the speeds, but the Kawi may have about as much, or even less, usable power as the Generac.

    After posting, I noticed Razorblades' post above this one, and I'll comment on fuel usage. I checked my Woods a couple weeks ago and it is burning 1.3 gph in average mowing, including some steep hills, some flat land, some nice weekly-mowed yards, and some thick bi-weekly yards. Right after I bought it in October, I was mulching leaves with it a lot and got 1.4gph.
    Last edited: Jun 16, 2009
  10. TomberLawn

    TomberLawn LawnSite Bronze Member
    Messages: 1,299

    OK, I just got a reply from Bobcat about the speed difference. Here is what their product manager said:

    "The difference is Engine RPM. The Generac engine was originally designed for generator use. Generators need to run at specific RPM’s so that they maintain the proper cycles (Hz) for electrical generation. What that means is that they have to run at a governed 3800 RPM’s. Most other commercial engines like Kawasaki run at a top speed of 3600 RPM’s. So we pick up the additional speed from the additional engine RPM. This additional RPM would cause blade tip speed to go up also, but we control that using different pulley sizes so that it doesn’t exceed the blade tip speed set by ANSI B71.4. Basically it gives you an extra mile per hour for transport speed. The other benefit of the Generac engine is the governor sensitivity. Since RPM is so important to generating electricity, the governor that is used for the Generac Engine has to react very quickly to be able to pick up load without loosing RPM. This turns out to be a benefit and big bonus when used on a Zero Turn. Since you have very little governor droop (RPM loss) you maintain a very high quality of cut because you don’t loose RPM which relates to blade tip speed and blade tip speed relates to quality of cut. "

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