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Diesel Conversions - the numbers!

Discussion in 'Diesel Tech / 24 volts' started by Slow N Steady, Aug 25, 2006.

  1. Slow N Steady

    Slow N Steady

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    Guess I'll jump off the deep end on this one and give everybody some insight on just what goes on in my head ..............

    Last night I was riding the bus home from the airport after a long day a flights and I was thinking about things to do on my cruiser (I'm sure most can appreciate this!). Anyway, my thoughts wandered off to the many, many posts on the subect of diesel conversions. Most of those who have done it say it's about $10k to do the conversion properly. And most who reply say you'll never really recover the costs. You have to do it because you really want an oil burner, etc. etc. This lead me to start crunching the numbers. As I figure very few of us have less than 200k miles on our 60's, I'll use this number as the number of miles we expect to keep our cruiser! $10k will be the cost to convert.

    2F Gas
    200,000 miles at an average of 12mpg (what most of us get - give or take) =
    16,666 gallons of GAS. At current prices ($2.80/gal) that equals a whopping $46,666 to run it for 200,000 miles!!!!!!

    Diesel
    200,000 miles at an average of 25mpg (a good estimate) = 8,000 gallons of DIESEL. At current prices ($2.80/gal) that equals a still whopping $22,000 to run it for 200,000 miles!!!!!! A difference of $24,666!

    If we take this further, when do we recover the cost of this conversion? This will be determined by the difference in fuel economy of the two engines - namely 13mpg. Therefore, with the conversion costing $10k and dividing that by the cost of fuel ($2.80/gal) we have 3571 gallons of diesel. Multiply this by the diference in fuel economy (13mpg) and we have 46,423 miles!

    Net result - drive your newly minted diesel 46,423 niles and consider it paid for! Not bad.

    So, that's what I was thinking last night! Food for thought giving quite a few of us are thinking of going this route!
     
  2. roscoFJ73

    roscoFJ73

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    There is certainly method in your madness;) Of course you havent factored in the low maintenace costs of a diesel.
    Once they are set up correctly they only need a regular oil/filter change which anyone can do in half an hour:D
    No more having the car sitting at a mechanics having it plugged into some machine,getting a big bill and not knowing what they have done to the engine,if anything:mad:
     
  3. ChuckB

    ChuckB SILVER Star

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    I don't know where you live but gas is $3.15 here :flipoff2: But I'm totally onboard with what your saying!!! :beer: :beer:
     
  4. Fourrunner

    Fourrunner SILVER Star

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    Anywhere but California is gas around 2.80/gal and by his signiture it looks like he lives in New Hampshire...
     
  5. Ryan S.

    Ryan S.

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    Thanks for that info, I've been wondering that for some time. I've thought to myself and heard others say that you can buy alot of gas for the price of a diesel conversion, so it's good to know about where the payoff is.
     
  6. freeamerica

    freeamerica

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    I'll play along just to be the Devil's Advocate:

    ASSUME:
    Maintenance costs not factored into this exercise
    Diesel conversion includes full rebuild/0-mile engine (not likely for $10K!!!)
    2F has just had a full rebuild/0-mile engine (add $4000 without)
    No "coolness" factor for diesel conversion
    No accounting for "alternative" diesel fuels and their costs
    ___________
    My real-world mileage for my FJ60 = 14 mpg AVE
    My real-world gasoline cost = $3.00/gal (Low-end of Seattle area prices)
    Gallons consumed in 200,000 miles = 14285 gallons
    Cost at a fixed current gas price = $42855.00

    Most of the numbers I've seen/heard on diesel mileage are in the 25 mpg (Imperial) as most diesels are obviously non-US, so multiply by 0.83 to get US mpg.

    Converted diesel mileage to USGal = 20.75 mpg
    My real-world diesel cost = $3.50/gal (Low-end of Seattle area prices)
    Gallons consumed in 200,000 miles = 9640 gallons
    Cost at a fixed current diesel price = $33740.00

    Difference in fuel expense over 200,000 miles = $9115.00

    So over the course of 200,000 miles you do not fully recover the cost of your $10K conversion.

    Bored yet...

    Slow N Steady: Your "break even" math needs a little help. If you figure out the cost/mile of the gas vs the cost/mile of the diesel, using your figures you get:
    $0.233/mile - gas
    $0.112/mile - diesel FUEL ONLY
    $0.173/mile - diesel FUEL+CONV
    For a difference of 48%
    Multiply 200,000 by 48% = 96,000 miles which is the break even point for FUEL ONLY. You still need to pay for the conversion.

    To figure in the conversion, add the $10,000 to the cost/mile diesel above for $0.173/mile diesel.
    Post-conversion difference = 74%
    Multiply 200,000 by 74% = 148,000 miles for FULL BREAK EVEN mileage


    Still with me...

    Using my figures for mileage and cost/gallon:
    $0.214/mile - gas
    $0.169/mile - diesel FUEL ONLY
    $0.219/mile - diesel FUEL+CONV
    For a difference of 74% - Fuel Only
    Multiply 200,000 by 74% = 148,000 miles Fuel Only
    The break even point for fuel + conversion cost is 204000 miles!

    When it comes right down to the economics of it, the few dollars saved over 200,000 MIGHT, just might convince your wife to let you do the swap, but in the long run really won't make a hill of beans difference.

    If you want the swap because you like diesels then great, do it.
    If you want the swap because you need diesel performance, great do it.
    If you want the swap because you want to run biodiesel and save the world, great do it.
    But it all comes down to because you WANT to do it!

    (Obviously, I don't have enough to do at work today)
     
  7. Jan-78FJ40

    Jan-78FJ40

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    too bad you invented both, mileage and cost per gallon.

    diesel is not 50cents more expensive than gas, here in san diego it is cheaper.
    a 3B gets 26 miles per US gallon in the city.
    a 2H gets 24 miles per US gallon in the city.
    a 1HZ will return more like 27, so does a 1HDT.

    the average 60 with a 2F will not do 14 mpg.

    of course you can send the calculation into any direction you desire if you make up the numbers.

    and if you don't see the coolness of a diesel conversion, there is something wrong with you in the first place :D
     
  8. bigbrown

    bigbrown

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    don't forget increased resale value, and the benefits of more power.
     
  9. PVCruiser

    PVCruiser

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    One thing you folks are forgetting is the cost of money... Yeah I know it's a bit nit-picky, but it is a factor.

    Ask yourself what else you could do with $10k today (in terms of invesments).

    Let's say it takes you 10 years to reach 200,000 miles.

    Assume you can make 7% compounded return on your investment for the next 10 years you'll hit $19.8k with your money.


    All assumptions of course.

    Personally I think Diesels are cool, but I wouldn't do it to save money. More for coolness, Torque, and alternate fuel...

    Oh, FYI, I think $10k might be on the light side for conversion cost unless you do it yourself.
     
  10. 45Kevin

    45Kevin

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    What if ... you made bio-diesel at less that a dollar/gal.
     
  11. 60wag

    60wag SILVER Star

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    I'll bet a 0 mile/freshly rebuilt 60 will do 14mpg.

    What is also left out of the calculations is the new low sulfur diesel fuel standards that will kick in soon. Anyone want to guess what diesel will cost when it becomes harder to refine?
     
  12. fe sus

    fe sus

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    Dude-
    The most important thing that you've neglected to take into account (probably because it's somewhat hard to quantify) is that CHICKS DIG DIESEL CRUISERS! Really. Especially the 60's cause you can fit a queen-sized inflatable matress in there for those cold nights up in the hills... But hang on! I did a diesel conversion this spring and I can tell you EXACTLY what it cost me:

    first I bought an 84 FJ60 in Oregon for $3350 (no, rust... 200k/miles)
    then I bought a rusty ass BJ60 in British Columbia for $2000 (250k/miles)
    then I tore the mofo's apart and put one together from the pieces!!!!

    so... $5350+ $300 (garage rent) +$1000 worth of tools and random junk at the auto parts store = $6650
    then I sold all the stuff I didn't need/want and made $2940!!!!! so...

    $3710... now I can't say I haven't bought a new (used) alternator and a turbo and some nice leather seats and... that aren't really factored in there... but it can be done fairly cheaply if you're willing to do it on your own.
     
  13. Jan-78FJ40

    Jan-78FJ40

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    what about the word AVERAGE is so hard to understand? and AVERAGE 2F is not a 0 mile freshly rebuilt 2F :rolleyes:
     
  14. freeamerica

    freeamerica

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    Yes, you can change any of the variables to make the math look different. I'm not trying to dissuade anyone from doing the swap. Hell, I want a diesel as well, but the math doesn't make sense to me. IF all of the cards fell right, I'd gladly do the swap, but I don't see it.

    The mileage I used is based on what I've seen/heard. If you get better GREAT! All the more motivation for me down the road. As for my 2F or most 2F 60's I've had experience with 12 mpg is HORRIBLE, not average. If you are SOA, 37's, gears, bumpers, etc, then yeah, ok, but any 60 that we are talking about mpg on isn't going to be a "trail rig", I hope.

    An finally, the gas/diesel prices are from Chevron, 76, and Shell, in Monroe, WA as of about 4:00 PM PST yesterday. Monroe generally is on the less "expensive" end of fuel prices in the Puget Sound. I haven't seen diesel under $3.00/gal in over a year. Obviously, local economies play a big part of this as well.
     
  15. 60wag

    60wag SILVER Star

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    Oh, ok... So you want to compare an "average 60" to a diesel with 185,000 miles on it. You're not likely to get another 200k out of either one without putting some money into it. The analysis tried to amortize the conversion cost over the life of the vehicle - 200k.
     
  16. Martin White

    Martin White

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    The fuel economy numbers that have been posted seem quite optimistic for the 1HDT. The best number I've heard of in long term use is 26.5 mpg imperial under ideal driving conditions, using summer fuel. Most are getting more like low 20's imperial. I know, I have one, as do 2 other friends of mine. Also, I think the conversion costs are very optimistic. Diesel is great and I highly recommend going for it, but I'd add 40-50% to your budget and reduce the fuel economy projections about 20% to get a more realistic payback time. I also have a friend who had a 1HZ and got about the same fuel economy. (They now own an 81 with a 1HDT). Just food for thought.
     
  17. Slow N Steady

    Slow N Steady

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    Ok guys - been busy with work and came back to family feud! :)

    My intentions with all of this were to simply to crunch some "average" numbers - whatever those may be and look at the "trends" that resulted. Yes, you can fiddle with the numbers all day long, but the jist of it is if you want to "justify" the outlay - you can. Then again, it's always easier to ask for forgiveness than permission!

    My 60 has a rebuilt 2F gets about 12 in the city and 15 to 16 on the highway. It's in perfect tune. I do live in NH and gas is around $2.79 with diesel at $3.00 or so. I consider the point at which one recovers the cost of outlay when the savings equals the initial outlay for the conversion. That boils down to the fundemental difference (incidental's are nice as well) - which is fuel economy.

    Diesels are cool ! Plain and simple. They fit the cruiser nicely in all respects. As hot of a topic as diesels are today, they make a lot of sense. Think about it - look at the new trucks out there. If you were to buy a new one how much would it cost......$40 to 60k would be my guess. Of those, they ALL have about the same economy (15mpg gas). Diesels are very soon to be a thing of the past. In the USA Uncle Sam is instituting new emissions regs to which no diesel will burn cleanly enough (even the direct injection type). Unless things change, manufacturers are goiing to stop selling them which will be a shame for everybody.

    So, "if you were going to go for something new, what would you get if you spent that money on your 60?" A Diesel Conversion would be on the top of my list. They make sense and compared to anything else out there - New OR Used, it's the type of rig I want. If I were to convert to a diesel with 40 gal long range tank - that's about a 1000 mile range. Bladder busting to say the least!! This would give me plenty of time in the woods or on the road with reliability to boot.

    Utlimately, everybody looks at these things from different perspectives - each being "right" for them and their situation. I think its worthwhile to look at the numbers and ask the question - what's it's really come down to from a dollars and sense perspective At least doing it this way, you make an informed decison. Judging from the responces, everybody does have an opinion and that's what the fun of this is all about!
     
  18. Jan-78FJ40

    Jan-78FJ40

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    I understand your point, and I actually agree with almost everything here. Seth spelled it out-if you do it for the money, it is likely not going to pay off.
    Conversion costs are mostly higher.
    One of my trucks started out as a trashed HJ60, and until it got a new engine, turbo, new H55F, rebuilt transfer, axles, differentials, driveshafts, alternator, steering....whatever you can think of, it was about 30k. that's a LOT of gas :D

    still, it is infinitely cooler than a gasser, and probably won't need much work in the next 20 years :D
     
  19. rick_d

    rick_d

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    lies dam-nit

    first and foremost, no hz or hd-t conversion or factory assembly will get 27mpg , and none will not get 25mpg unless leaned out so bad it barely runs. same holds true for most other higher mileage 3B, 13B-T 2H etc etc.

    expect a modest gain of 10 miles per gallon (with HD-T I get at best 22.5 USmpg in 70 series, worst 17.6 Tucson to Susanville and back)

    the number shall be "23US mpg" hereafter, I want repeatable data and methods for proof of anything greater than this on average basis.

    ....and I hate to tell you, but a vortec will be pushing 17/18 US mpg....

    $10,000 conversion cost is a bit light. You all had better keep better records and what is your time worth calling Australia for parts, or driving Denver to SOR to pick up the engine, or finding a 30002 oil filter in Bangor, Maine.

    oil changes are more $$$ for a diesel than gasser.
    most parts diesel are more $$$ than gasser.

    Without a single calc, 100,000 us miles is a minimum for mileage/fuel consumption recovery. One cannot only use fuel consumption as the sole rational for conversion, period. "100,000 miles" shall be the lowest number used hereafter.

    in the end, it will always ALWAYS be cheaper to stick with the factory product under the hood. fj60 engines are common and it's easier to swap a 2f for (used) 2f than do anything else.

    ...if you want a diesel do it because you want it for many levels not only "fuel gain".

    jeeeze, novices
    rick --hd-t infected since 1998
     
  20. fe sus

    fe sus

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    Fun facts for people who burn dead dinosaurs:
    1. There is only a finite ammount of oil on the planet.
    2. We have used or are about to have used half of it.
    3. We've only been using it for the last 100 years or so.
    4. Demand for this oil rises exponentially each year.
    5. Last May I drove across the US of A and paid and average of $1.85/G.
    6. Today it's about $3.00/G where I live (Seattle).
    7. Next year it will be $4.00/G and so on... until there is none left or some upstart country like say, China? decides they need it all (like we have been doing?)
    SO...

    If gas costs oh say... $5.00/G in 2010 then how do the numbers look? Anyone want to take bets?