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Discussion in 'Mechanic and Repair' started by mrbobian, Jun 13, 2007.

  1. mrbobian

    mrbobian LawnSite Member
    Messages: 26

    Ok, so i am in the middle of fixing an old BMW at this time and my dad and i were thinking about turbocharging it. This gets me thinking about turbos on lawnmowers. Does anyone do this? It makes perfect sense. In the car world, the down fall of the turbo is the fact that it loses it power at a certain rpm than regains it (usually at the apex of a turn causing a burst in power leading to wheel spin.) Anyways, since a mower is run at full rpm when mowing, it would make sense to get a couple extra hp from something like this. It is small and an intercooler would be easily placed. Any opinions?
  2. tomo

    tomo LawnSite Senior Member
    Messages: 660

    hello a designed engine 4 a turbo would be ok and some mowers in diesel already have them .

    No turbo 4 my kohlers[air cooled] thanks now if i had 6x more head bolts , endless supply of head gaskets , oil cooler the size of a truck radiator ,engine bearings as there r none in a kohler vtwin ,decent con rods ,i am assuming u get the point ..

    intercooler would need a electric fan and large altenator plus typically no room to mount it

    A turbo of quality would probaly be worth more than a kohler 4 eg

  3. nmurph

    nmurph LawnSite Senior Member
    from ga
    Messages: 668

    the reason that turbos are used on cars is primarily to increase power with and eye toward fuel economy and packaging, neither of which is major concern with small engines. besides, they add cost, complexity, maintenance, and reliability issues to engines that are inexpensive, simple and rugged. when a manufacturer wants more power it is relatively easy to bore/stroke an existing design or just change the carburetor. just like what we used to do back in the ol' school days.
    nice to dream, though.
  4. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Messages: 2,613

    Turbocharging a lawnmower would be more trouble than its worth. Mainly because you would have to have a turbo built for you as I strongly doubt theres an abundance of turbos small enough in production for use on a 900cc engine. Wouldnt need an intercooler but these engines are_not designed to be run with boost pressure, they would blow up in your face.
  5. fargoboy

    fargoboy LawnSite Member
    Messages: 69

    good point Nmurph. I am always amazed at how manufactures have increased the hp's on mowers over the last 20 years. Remember Bobcat 48" with 8hp Briggs. Somehow they cut the same grass that you do today with a 32hp Kaw
  6. Daneman

    Daneman LawnSite Member
    Messages: 154

    Couple that with the fact that most guys don't idle down there machines, and let them sit at idle for a period to let the turbo cool down. Expensive part to replace when it gets damaged. And since it is about 100$ per hp to increase the size of a new engine, seems cost prohibitive to me. Just my opinion.
  7. MarcSmith

    MarcSmith LawnSite Fanatic
    Messages: 7,157

  8. Idealtim

    Idealtim LawnSite Senior Member
    Messages: 939

    Aw marc, you beat me to it..... I was thinking of those videos the entire time I was reading the thread.
  9. mrbobian

    mrbobian LawnSite Member
    Messages: 26

    I realize that right now the addition of a turbo to a small engine is way too expensive and impractical, i was just thinking about manufactures building a small engine up to par to the demand of a turbo. Just trying to think outside of the box. One of my freinds made a makeshift turbo for a backpack blower. Plus, to answer the qestion why, in my case, my 19hp kaw is not enough for what i do but at the time i bought the machine, i did not know this. So what am i supposed to do? Pay $2000 to get a bigger engine or $7000 for a new machine...
  10. pugs

    pugs LawnSite Gold Member
    Messages: 3,025


    It would be cost prohibitive on a gas small engine. First you would probably want to step up to liquid cooled for a turbo engine to keep the heat in check. Second you would really want an EFI system to make it run correctly under all loads and conditions.

    Finding a properly sized turbo could be a bit of a problem. They are turbo engines out there in the 500-1000cc range but they are not running at 3600 RPM max. They are probably running up to 6-10k RPM. So they are moving twice as much or more air through them already.

    Pick up the book by Corky Bell if you want to read more about turbos ;)

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