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EFI/DFI fuel consumption vs diesel

Discussion in 'Mechanic and Repair' started by nosparkplugs, Jul 13, 2008.

  1. nosparkplugs

    nosparkplugs LawnSite Gold Member
    Messages: 3,444

    I have noticed that when someone purchase's a EFI/DFI engine one of the responses is "it gets the same or better fuel consumption than the diesel option?????"

    While the EFI/DFI engine option is the cheaper option, and lighter;however we are now stuck with $4.00 87 octane gasoline. Premium gasoline is .40 cents less than diesel. If you run off road diesel you can get diesel for the same or less than gasoline,depending on area.

    Heck, I might end up with a new ZTR gasoline powered EFI/DFI:cry:; there are many factors that are troubling with a EFI/DFI gas unit; while many report excellent power, fuel consumption, and reliability. These are low hours of use reports. I have yet to wear out a mower deck, crack a frame, have a drive wheel motor fail. I just tear the air cooled engines up before 800hours, and that is unacceptable.

    This is a tough years for us; because I am contemplating supplementing our 1 Walker MT20, with 1 Walker MT26 EFI with 2 large SD decks or 1 BB AOS 35HP diesel 72" to handle the wide area's & rough cutting.

    Many of the On-road diesel power advantages apply to the new diesel powered ZTR's; however their weight penalty & high cost in the Walker line are serious enough to avoid the diesel option their.

    Sticker shock need not only apply to the Walker diesel, Scag TT 28Hp Cat diesel is very expensive, but has many features the BB AOS diesel line does not, and the BB AOS diesel line has features that Scag should have?

  2. jkason

    jkason LawnSite Senior Member
    Messages: 546

    Why do you wear them out with such low hours? Are you operating them consistently on a greater than 25 degree angle?

    If you are, just buy a "cheapo" commercial unit like a Red Hawk or a Bad Boy. If you are going to destroy engines, may as well not pay top price for good units.

    As to the EFI/DFI vs. Diesel question - No idea. I do know that EFI/DFI vs carburetor saves about 1 gallon of fuel every 4 hours. (Kohler 25hp carb engine vs Kohler 26hp EFI engine) Study done (by Kohler - independently verified) when the EFI system for kohler first came out. fuel economy has probably gotten even better now.
  3. Ridin' Around

    Ridin' Around LawnSite Senior Member
    Messages: 266

    Both leading systems, the DFI kaw and the EFI Koh are both now liquid cooled. Liquid cooling will typically lead to doubling your hours versus an air cooled. I have been to both Service/Sales updates for Kohler and Kawi within the past year. I am leaning toward the Kohler based on how the fuel injection works. The DFI has less sensors to go bad but does not provide the accuracy for changing Injector impulses as often as the Kohler system. More engine sampling and changes to the way it is giving the engine fuel leads to more efficiency. Plus the latest versions of both give a 2 HP advantge to the Kohler.
    On a side note, I have a close friend, who also mows commercially, with a 2001 Toro 286E that has 2600+ hours on the air cooled Kohler. It is an EFI 26hp. He does run Synthetic fluids in it, and it a nut about maint.
    He also has purchased 2 diesel machines and has not went back to FI gas. His problem with gas FI has been that he only runs 72" decks and has not found a FI unit that he feels has enough power to turn 72" worth of blades, like his "old" Toro still does. We have run Scag, new Toros, etc. Both diesels and gas. His purchases have been Kubota ZD's. The new Scag we ran early this spring was a brand new machine, and needed a few hours of break-in time. It seemed a little short on power to both of us. The rep said he will bring it back with 100+ hours on it to try again!

    TOOMUCHWALKING LawnSite Member
    Messages: 167

    When I was shopping for a ZTR ( 2001 ), I considered the diesel version of the Exmark and chose the FI because it was 300 lbs lighter and $3K cheaper. I also didn't care for the diesel fumes following me around
  5. jkilov

    jkilov LawnSite Bronze Member
    from MS
    Messages: 1,415

    When I was looking at a new ZTR, I took some time to get the figures:

    Specific fuel consumtion (may wary upun manufacturer) :
    - L-head : 300+ g/hph
    - carb/air cooled : 250-270 g/hph
    - carb/LC or FI/air : 230g/hph
    - FI/LC : 200-230g/hph
    - diesel 170-200g/hph

    But these are minimum consumption figures rated by manufacturers, so who knows what you get in reality. Diesel fuel has about a 15% higher density which translates to less gallons needed. Also diesels don't suffer from low-load inefficiency as bad as gassers do.

    I have a 26hp LC/carb Kawi that gets 1.1gph, my friend has a similar power diesel and he claims .75gph which sounds reasonable. The idea of an FI matching a diesel sounds stupid to me. But it comes with it's own problems. If you have a strong desire for one of those Perkypillars, why not just get one.

    As for 800hrs out of your engine that's way too low. More like a handheld. If nothing breaks this is what you should expect out of a ZTR engine:
    - air cooled : 2500+hrs
    - LC : up to 4000hrs
    - diesel : 6000+hrs
  6. genesis215

    genesis215 LawnSite Senior Member
    Messages: 795

    Today I just ordered a 26HP Kohler Command PRO air-cooled vertical v-twin. Would this be the EFI model? Every source I can find is saying that the only 26HP vertical v-twin is an EFI unit (which I did NOT expect when I ordered it earlier today). I got it nearly new from an engine rebuilder out of Des Moines IA for $800. Is this a great deal, or did I make a mistake? It will be used on a 52" Exmark Turf Tracer HP.
  7. djagusch

    djagusch LawnSite Platinum Member
    from MN
    Messages: 4,350

    I think 26HP engine is a bit of overkill for a w/b. Didn't it have a 15hp or 18hp engine.
  8. tomo

    tomo LawnSite Senior Member
    Messages: 660

    hi ,
    Your suggestion of supplementing the MT20 hp walker with a 26efi to run larger decks .
    If u need speed walker to slow
    If u need long life ,cutting rough areas will most definitely shorten life of a walker chassis components

    Engines in a walker do suffer alot compared to a mid mount and therefore have a shorter life
    The most reliable engines are the gaser 20hp ,diesel
    The 25hp is good/reliable if cylinder head is updated
    The most economical and the most expensive are the diesel and 26efi

    The larger walker decks are not of the best design and cannot pass the volume of clippings others can = slow mowing

    I agree there are not many gaser packages available for 72 inch
    Deck design for 72 is critical for high volume hard work .Some makers offer a tunnel deck on the 72 version

    At least 28hp 1.1litre diesel for a 72 inch


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