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.... and now, for something completely different.... ADDED LINK

Discussion in 'Center Of Gravity' started by marv_springer, Jul 23, 2004.

  1. marv_springer

    marv_springer 1/2 ton status

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    So.... wouldn't it be great if you could build a drivetrain for a lightweight buggy that had the following features:

    1) 200+ :1 gearing w/ double gear reduction
    2) lightweight
    3) FI
    4) Cheap.....

    Well here's my best shot at it..... (Sorry about the photo quality... /forums/images/graemlins/frown.gif but I just fired my photographer /forums/images/graemlins/grin.gif) What you see here is a Mazda 1.6l FI 4 cyl. mated to an auto transaxle. From there power is shafted to a bass-ackwards mounted 208, then piped into another 208. Front and rear outputs will be totally conventional from the 2nd 208. The whole thing is built onto a "cradle" that is similar to the drive train mounting of most FWD cars. But this cradle will reside smack dab in the middle of the frame.

    This is from the front looking back.
    [​IMG]


    This is from the passenger side.
    [​IMG]

    Crazy huh.... /forums/images/graemlins/screwy.gif Some may ask why? /forums/images/graemlins/dunno.gif
    Here's my reasons:
    1) Final drive in "Hi" range will have an effective gear ratio of 5.54 - but using 3.73 geared axles./forums/images/graemlins/waytogo.gif
    2) ...did I mention it's cheap?
    3) Mid engine layout will keep the Cg low and in the center of the vehicle
    4) It will have 2 - 2.62 gear reductions, much like a Doubler, but lower ratios. /forums/images/graemlins/thumb.gif

    Won't be too powerful, but it should crawl well.... I hope!

    Marv
     
  2. sled_dog

    sled_dog 1 ton status

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    Re: .... and now, for something completely different....

    you building this? Won't be long till you have a moon buggy huh? it is... interesting.
     
  3. gzzgfw

    gzzgfw 1/2 ton status

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    Re: .... and now, for something completely different....

    That's pretty cool Marv,

    Light, Traction, Gearing all in one.

    Here in Indiana, a little weight and wheel spin helps on our terrain of wet hills with tree roots and rocks. Out West it's all about the 'Crawl'.

    I'm heading to the Badlands for UROC tomorrow (sat.) just to get some more ideas for my buggy thing I am working on.

    Biggest thing I see when people build stuff is durability. Good luck.
     
  4. yunit

    yunit 1/2 ton status

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    Re: .... and now, for something completely different....

    Keep us informed of the progress Marv! /forums/images/graemlins/thumb.gif /forums/images/graemlins/hack.gif /forums/images/graemlins/grind.gif /forums/images/graemlins/weld.gif
     
  5. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Re: .... and now, for something completely different....

    Definetly awesome . Can't wait for the other ideas of yours to show up /forums/images/graemlins/thumb.gif What are you going to do with the unused output of the first np208 to hold in the ATF , some kind of cap fastened to tailshaft ? Or maybe some kind of PTO ?
     
  6. sled_dog

    sled_dog 1 ton status

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    Re: .... and now, for something completely different....

    could just drill and bolt a yoke into the output.
     
  7. jac6695

    jac6695 1/2 ton status

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    Re: .... and now, for something completely different....

    I knew it had something to do with a front drive transaxle. /forums/images/graemlins/thinking.gif
     
  8. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    Re: .... and now, for something completely different....

    there goes Marv. always thinking.
    cool sh!t bro. it will ROCK when its done. glad to see you have taken your fun buggy and learned from it in good bad and fun ways, then set out to better it. the problem is you are bettering it in like 100 ways.
    ok, so thats a good thing. and dont get me wrong, i would take the fun buggy in a hearbeat.

    after my blazer is done, some day.. in 2057 or so, i plan on building a single seater mid engine buggy. here is what i want to do.

    3 link with panhard bars, front and rear. D44's front and rear, 40 inch tires, Mazda Wankle, 5.13 gears, t-5 tranny with a 241 t-case. 109 inch wheelbase.

    light, HIGH RPM band, 10k RPMif ya didnt already know, and did i mention lightweight? mostly aluminum drivetrain with an engine that you can pick up fully assembled let alone it would be turbo OR twin turbo....

    anywho, keep up the good work Marv. i look FWD to comming and helping ya with the body panels on that one so i can Sign it as well. :P
    Grant
     
  9. sled_dog

    sled_dog 1 ton status

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    Re: .... and now, for something completely different....

    why a wankle engine? I don't believe they have a whole lot of low end torque like you would still want a little of for crawling and they weigh almost as much as a small block.
     
  10. justhorsinaround

    justhorsinaround 3/4 ton status

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    Re: .... and now, for something completely different....

    no Wankle tis a four cylinder
     
  11. sled_dog

    sled_dog 1 ton status

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    Re: .... and now, for something completely different....

    are you saying a wankle is a 4 cylinder?? A wankle is NO cylinder. It is the rotary engines. The inventor of the Rotary engine was named Wankle. As far as I know most stock RX7s have a 2 Rotor (13B if I remember right) engine in them. Could get a 20B 3 rotor with some turbos but I have no idea why that would be a good offroading engine.

    I'm guessing the idea is to use a low ass crawl ratio to make up for bottom end but be able to wind it out to get some wheel speed or something??
     
  12. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    Re: .... and now, for something completely different....

    [ QUOTE ]
    I'm guessing the idea is to use a low ass crawl ratio to make up for bottom end but be able to wind it out to get some wheel speed or something?

    [/ QUOTE ]
    BINGO!

    i guess i kinda strayed off of Marvs work here. the only real thing his work, and my idea have in common is they are both going to be light as heck.

    lets try to keep this on topic.
    Grant
     
  13. sled_dog

    sled_dog 1 ton status

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    Re: .... and now, for something completely different....

    well being the CoG I think everything is suppossed to spark discussion so I didn't see a problem.
     
  14. marv_springer

    marv_springer 1/2 ton status

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    Re: .... and now, for something completely different....

    Some decent images here...


    Marv
     
  15. 87GMCJimmy

    87GMCJimmy 1/2 ton status

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    Looks cool!

    Just one questons with driving the output of the 1st t-case and using the input to drive input of the second. Does this mean the the 1st case will get you a 1:1 ratio in Hi but then a 1:2.62 overdrive in lo? Unless you worked some magic on the 1st case wouldn't you total selection of gears for the combined cases be 1:2.62 overdrive, 1:1 and 2.62:1 reduction? I imagine you figure something out and I wouldn't mind knowing how you did it. /forums/images/graemlins/bow.gif

    Either that or I'm totally missing something... /forums/images/graemlins/confused.gif

    Mike
     
  16. marv_springer

    marv_springer 1/2 ton status

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    Mike... /forums/images/graemlins/thinking.gif

    [ QUOTE ]
    driving the output of the 1st t-case and using the input to drive input of the second

    [/ QUOTE ]
    he he ..../forums/images/graemlins/screwy.gif


    [ QUOTE ]
    Does this mean the the 1st case will get you a 1:1 ratio in Hi but then a 1:2.62 overdrive in lo?

    [/ QUOTE ]
    you got it!... So, strangely enough - if you put both cases in their "intended" Lo - there's actually a 1:1 straight drive thru the cases... /forums/images/graemlins/confused.gif But now, the "Hi" will be going thru the planetaries of the first case (which was it's intended Lo) and Lo will be straight thru (which was it's intended Hi /forums/images/graemlins/tongue.gif)


    [ QUOTE ]
    Unless you worked some magic on the 1st case wouldn't you total selection of gears for the combined cases be 1:2.62 overdrive, 1:1 and 2.62:1 reduction?

    [/ QUOTE ]
    No magic.... you got it right. But remember that the intermediate shaft is already going thru a ring gear/pinion reduction of 3.83:1.... So, your gearing "ranges" (downstream of the transmission) are as follows:

    Hi-Range:
    R&P - gear down - 3.83
    bassackwards 208 - gear up - 2.62
    regular 208 - straight thru - 1:1

    So, final drive will be (3.83/2.62)*axle ratio (3.73) = 5.45:1 /forums/images/graemlins/thumb.gif

    1st low range:
    R&P - gear down - 3.83
    bassackwards 208 - straight thru - 1:1
    regular 208 - straight thru - 1:1

    This gear is 2.62 * lower than where we started. /forums/images/graemlins/grin.gif

    2nd Low Range:
    R&P - gear down - 3.83
    bassackwards 208 - straight thru - 1:1
    regular 208 - geared down - 2.62

    And this gear is 2.62 * lower .... AGAIN...

    So... really the only reason for the "bassackwards" 208 is to have a "Hi" range that will allow you to go faster than 20 mph... /forums/images/graemlins/laugh.gif

    Marv
     
  17. CK5

    CK5 In my underwear Administrator Premium Member GMOTM Winner Author

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    How much does that setup weigh? Drop it in the passenger seat for better weight distribution. /forums/images/graemlins/thumb.gif
     
  18. 87GMCJimmy

    87GMCJimmy 1/2 ton status

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    Ahhh....I see, I saw the "double gear reduction" and didn't get how your doing that with the t-cases. But then there's still the axles. /forums/images/graemlins/doah.gif

    So total crawl would be (assume around 3:1 first)

    3 x 3.85 x 1 x 2.62 x 3.73 = 112.9

    What size tire are you planning to run and how do you think the drivetrian going to hold up?
     
  19. marv_springer

    marv_springer 1/2 ton status

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    [ QUOTE ]
    So total crawl would be (assume around 3:1 first)

    3 x 3.85 x 1 x 2.62 x 3.73 = 112.9

    [/ QUOTE ]
    You're forgetting the torque converter... 2:1 ? /forums/images/graemlins/dunno.gif

    [ QUOTE ]
    What size tire are you planning to run and how do you think the drivetrian going to hold up?

    [/ QUOTE ]
    To start w/... prolly 35's. We'll see how it holds up when we get to test it... /forums/images/graemlins/grin.gif Using old beat up Green Blazer axles...

    Marv
     
  20. marv_springer

    marv_springer 1/2 ton status

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    [ QUOTE ]
    How much does that setup weigh?

    [/ QUOTE ]

    I don't really know.... The whole thing can't be more than 600 lb.... and it really feels lighter than that. I can "scoot" it around on the garage floor by myself... and I don't think I could "scoot" a small block Chevy motor.

    Also... prolly got a grand in the whole drivetrain....so far.

    Marv
     

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