EFI vs Carb

Discussion in 'Lawn Mowing' started by tacoma200, Sep 30, 2007.

  1. tacoma200

    tacoma200 LawnSite Fanatic
    Posts: 5,426

    Just read an interesting article by a company with a good reputation about comparing their efi models to the carb models. I thought it was very interesting. Its not that the efi saves approximately 20% in fuel and would take about 2 years to pay for the additional cost at 800 hrs a year that surprised me most. It is the fact that carb or efi, the larger engines used less fuel than the smaller one. Which leads me to believe that having more power works the engine less and doesn't necessarily mean the fuel economy will suffer. I realize this is just a comparison of 4 engines by one company but it's still interesting. I like efi but I still think it takes too long to pay for the extra cost and if you have a repair out of warranty it may never pay for the additional cost. Heres the chart based on saving at 800 hrs per year. If everything goes well you will put some money in your pocket but if if the efi needs out of warranty repair you could end up in the red. I'm an efi fan but still think it cost too much as an option on "most" ZTR's.

    Of course it's all just a matter of time till we are all running efi (due to the epa) and that may not be a bad thing.

    EFI.jpg
     
  2. MOturkey

    MOturkey LawnSite Silver Member
    Posts: 2,761

    Interesting stats, but about what I expected. I agree that going EFI for the sole purpose of saving money is, perhaps, a crap shoot.

    I also, however, think there is a bigger issue here. Multiply an approximate fuel savings of 20% by hundreds of thousands of ZTR's, mowing millions of hours a year, and you are talking lots of barrels of oil. Just makes sense, to me, that we reduce consumption where we can. I'm not a "green" nut, but oil, in spite of thoughts to the contrary, is a finite resource.
     
  3. tacoma200

    tacoma200 LawnSite Fanatic
    Posts: 5,426

    I agree and everything will be going to the efi. I would just like to see the cost come down some and the reliability go up. I have heard that most on Lawnsite have good luck with efi engines but if you go to a dealer with in 100 miles of me and mention you want an efi they are quick to tell you tales of all the problems they have had tracking down efi problems. If this was just one dealer I would blow it off but I've heard it 6 or 7 times about different brands. It very well could be they are not trained well enough. And I see your point about savings in a fleet of ZTR's.

    But the main point I was making is that the lower hp engines use just as much fuel as the higher ones on this test. The 23 carb used more fuel than the 25 carb while the 31 efi bested the 26 efi in fuel economy. I'm not knocking efi, I like it.

    My Hustler dealer didn't want to sell and efi, the largest shop in Lexington didn't recomend them, and the list goes on. I haven't heard any bad about the Kawasaki 29 yet though.
     
  4. MOW ED

    MOW ED LawnSite Fanatic
    Posts: 5,028

    I own 2 26 EFI's and one carburated 20hp. All Kohler. Hands down the 20 hp uses much more gas so I am gonna say the chart is true.
    One efi has 1600 hours the other 450 hours and are trouble free. The problems were with the design of the first generation fuel pumps. That is solved and I will try and never buy a carb job again.
     
  5. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    Yes, it's a crap shoot and too expensive of an option still in my opinion.
    Too expensive because for the money you can look around and have a liquid cooled 3 cylinder Kubota diesel engine on a mower for around the same cost. Even more fuel efficent, cheaper off-road fuel, more reliable, longer living, more torque, better suited to a commercial environment.... and the exhaust just plain smells better in the morning.

    Oh, and yes, having a larger engine does work it less, and usually results in less fuel usage. The reason is that the govenor seldom engages to open the fuel/air flow to keep the engine RPM's up.

    I agree... I think EFI needs to become a normal standard, like on everything else... but not at a $1,000 - $1,200 premium.

    That's the trouble with being "green" today...
    There is a punishing premium to pay for something that is more efficent and cleaner.

    Instead, I think there ought to be incentives for such things...
    Both for MFG's to produce better stuff, and for those that choose to use it.

    Yes... cost down... reliability up... I think we all want that.

    In their defense though, the early EFI's did have a lot of issues in some applications. Over time, I have come to understand it was mostly the "application".... in other words, how the mower MFG chose to install everything. They did little R&D before sticking the engine on production models. This resulted in EFI bugs. Lots of them had hard issues to track down... like they would vapor lock from overheating of the fuel delivery, etc...

    Most of the bugs seem to be worked out now... either that or these mower MFG's no longer offer EFI.
     
  6. barnard

    barnard LawnSite Senior Member
    Posts: 618

    Wouldn't you need some deck sizes and total acreage cut to really have useful info here. Or is that info in the article.If two engines run the same hours one burns 20% more fuel but mows 40% more area..... see what I mean.
     
  7. lawnMaster5000

    lawnMaster5000 LawnSite Senior Member
    Posts: 589

    barnard,

    They are comparing 4 engines to each other independent of what the engines are being used for. so to answer your question, no in the charts it doesn't matter.

    But I do understand your point, but that is your decision to make when picking the engine / deck combo you want. Take the chart's gal/hr rate and divide it by the mower manufacturer's acres/hr rate. You will get your gallons per acre that you are looking for.
     
  8. tacoma200

    tacoma200 LawnSite Fanatic
    Posts: 5,426

    This was a study by a manufacturer "Walker". It didn't say but I assume they were testing the carb against the efi with the same mower. I'm sure different manufacturers would come up with slightly different figures. I'm not anti efi or pro carburetor. I just thought it was interesting. Read the entire article in this months Walker magazine. Any time I find something interesting that seems to be from a reliable source (which Walker no doubt is) I like to post it for others. No they're not paying me to say this, I just read whatever I can get my hands on about the turf industy.

    In a different article this month one large LCO out of Maine figured the cost per hr to run and maintain his Walkers. It turned out to be $ 9-10 per hour including fuel. Lot's of useful info in this magazine, it called Walker Talk and I think its free.
     
  9. Eric D

    Eric D LawnSite Senior Member
    Posts: 295

    Tacoma,

    Thanks for posting the info. I too find it interesting to read about where the manufacturers are headed.

    If I had the choice between carb or efi, I would choose efi for a number of reasons. Just a one includes engine starting. With efi no need for a choke. This alone accounts for some of the fuel savings and lower emissions. As many have already pointed out, with time it will become cheaper to make efi units and I believe the fuel usage will continue to go down as the control of the efi system improves.

    Thanks again for posting.
     
  10. Keith

    Keith LawnSite Gold Member
    Posts: 3,977

    Here are my thoughts on the carb vs. EFI debate.

    I own a 26 EFI 60" Lazer and a 27 Carbed 60" Hustler Super Z. Definitely nothing scientific here, but I saw similar numbers. Over the six months that I checked regularly, the carbed engine used an average of 1.18 gallons an hour vs. .91 gallons an hour for the 26 EFI engine.

    I bought the 27 carbed Super Z just five months after the EFI Lazer because the Lazer was about to give me a nervous breakdown, if not risk a good deal of my business. In the shop for two weeks. Out, but never running right. Back in again. Not fixed. Back in again and finally resolved. But it has had a couple of EFI issues since then and currently appears to have something going on with it again. My fuel savings was not worth the cost on this one. And by cost, I'm not talking dollars.

    But I still can't say that I would not look at another EFI tomorrow if I was shopping for a new mower. When they are running right, they're great. I guess I will just say that no matter what I have, I'll keep a carbureted mower to back it up :D
     

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