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Consider This Build

Discussion in 'Engine Building' started by 22crazy, Feb 21, 2003.

  1. 22crazy

    22crazy Senior Member

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    i was reading an article on the net about an engine build...i thought i might as well share it because its suppose to be the ls/vtec cure.

    the motor consists of this:

    b16a1
    b17a crank
    12.5:1 compression pistons
    here comes the fun part....86mm bore (reseleeved)
    forged connection rods
    and a crazy valve train (u guys can use ur imagine on what that can be made up of)

    basically i wanted ur input on this build.

    the author of the article believes this motor should be able to rev to 12k no problem making 210(i think whp) with ease

    another thing was that u need to machine the head to accomonate the 86mm bore.

    whats ur take?
     
  2. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    It could work- but your pistons may not clear the head after you throw in the longer stroke crank. You're right though- you'd want to deshroud the head some anyway (don't HAVE to), and you'll probably want to use custom pistons, so you'd probably be able to make it all work. Using B16 rods, you would have a rod/stroke ratio of 1.65, and I don't know how long the B17 rods are, so I can't give you that number. The 1.54 of the LS and the 1.58 of the GSR block really aren't bad either, and all you need to rev those up high is a good crank girdle and decent rods/pistons and ARP fasteners (or equivalent) to hold it all together.

    I would personally build a longer stroke engine for less money, and still make the same amount of power (if not more) with fewer revs. Your engine will last longer, and you'll have more torque too.
     
  3. B16

    B16 Super Moderator VIP

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    i dont know how that would be considered an ls/vtec cure, the two motors are completely different, the ls/vtec has an under-square design, while the b16 with a b17 crank would be almost a perfect square (81mm bore x 81.4mm stroke) i've thought of putting a b17 crank in my b16, it would be a nice setup, basically makes it a b17 the blocks are the same. that motor would be great at the high revs like you said, being an 85x81.4 (b16 being 81x77.4) which would actually be pretty much the same geometry as the b16 :)
     
  4. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    You're right... to expand a little more (might as well write it down since I was thinking it), I did some quick math:

    LS/VTEC = 81 bore x 89 stroke = 0.9101 bore/stroke ratio = 1834.47 cc
    His = 86 bore x 81.4 stroke = 1.0565 bore/stroke ratio = 1891.35 cc
    B16 = 81 bore x 77 stroke = 1.0519 bore/stroke ratio = 1587.12 cc

    The 86 x 81.4 would be 1891.35 cc vs the 1834.47 of the LS/VTEC, so it would gain some torque through the extra displacement, but then lose a lot more with the large decrease in stroke. You could also see it as a slightly longer stroke B16 with the same bore/stroke ratio, and extrapolate a torque curve based on the 1.9L vs 1.6L comparison.

    How long are the rods in the B17?

    If we assume that this setup uses the B16 rods, you get rod/stroke ratios of:

    LS/VTEC = 1.5393
    His = 1.6506
    B16 = 1.7449

    So you would have a very rev happy engine that was just a hair under 1.9 liters. If you want a really rough guess for power curves, assuming all factors equal except the bore/stroke (same compression, etc), you could add 19% to the B16's torque curve and estimate from there. Backsolving from the B16A2's peak power of 160hp @ 7600rpm gives you 110.56842 lbft @ 7600rpm, add 19% and calculate power again- then you get 190hp at the crank. (Thinking about it now, you could just add 19% to the peak power and get your rough estimate, since horsepower is calculated on a linear scale from torque and the two will vary according to the same constant whoops.) Add in the longer stroke for more torque, higher compression for more torque, and you have yourself a pretty sweet setup. Headwork, cams, etc- it all adds up.

    Here's how I got my 19%, by the way: (1891.35 - 1587.12) / 1587.12 = 304.23 / 1587.12 = 19.16868%

    Of course, this is REALLY rough guessing, just using some easy math to estimate what could be made with this setup, assuming ideal conditions, and assuming that an engine operating under violent combustion and a dynamic environment really conforms to pure math.

    :lol:

    Now a Golden Eagle sleeve in a B block can actually handle an 87mm bore, so while we're dreaming, try this:

    87 bore x 81.4 stroke = 1.0688 bore/stroke ratio = 1935.59 cc, same rod/stroke of 1.6506

    You now have a 348.47 difference in displacement, which comes out to a 21.95612% increase, resulting in a guessed 195hp at the crank. If you were able to maintain a flat torque curve all the way to 9000rpm, you would actually be pushing 228hp @ 9000rpm, which isn't too shabby. 10000rpm would get you 253hp, and 11000rpm would get you to 279hp.

    Again, this is all just educated guessing- you probably won't gain like that, given this build. These are assuming ideal conditions, and a perfectly flat torque curve.

    Confuzzled yet? :lol: :p :lol:
     
  5. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Oh yeah- while I'm at it, let me throw this one at you...

    87mm bore x 95mm stroke, 1.75 rod/stroke ratio in a B block. You get 2259cc out of it, then make the head breathe all the way up to 10k (who knows if it can), and you get boatloads of power without resorting to boost or juice. It's feasible.

    :lol: :lol: :lol:
     
  6. SixtySecondAssassin

    SixtySecondAssassin Senior Member

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    with that r/s ratio the pistons would smash the valves
     
  7. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Maybe, if you use stock pistons. Like I said- you would need custom pistons no matter what. Rod/stroke ratio has nothing to do with smashing valves though... but if you're referring to the rod length that would be required to have 1.75 R/S ratio in a 95mm stroke block, yes they would hit- if you didn't modify the block to suit the application.
     
  8. 22crazy

    22crazy Senior Member

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    wow calesta, ur a geneus....guy i love math, but man u took it extreme...i guess thats why ur en engineer eh ;) but ya this is the article i found...i thought it would be better if u actually read it

    http://www.hondastyle.com/news/wmview.php?ArtID=33
     
  9. SixtySecondAssassin

    SixtySecondAssassin Senior Member

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    i was :D
     
  10. lsvtec

    lsvtec GNU/Linux Evangelist

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    That guy really needs to quit writing "articles". First, his R/S article was complete bullshit and showed that he didn't really understand what he was talking about. Now with this proposed build he neglects to say that the decreased stroke leads to decreased torque. His power numbers are off for a "stock" LSVTEC (what is stock??? if you were dumb enough to build an LSVTEC with all the parts he has listed, you deserve the blown engine). Now for the real :bs: meter. His pricing is lame. For the B16 with B17 crank bored to 86mm:
    Assume you found a 1st gen B16 for cheap like I did: $650 no tranny, $950 with tranny
    Sleeves + install approx. $1000
    Rods $350 (eagle forged)
    Endyn pistons $550
    That comes to $2850
    I did my first LSVTEC with LS rods and B16 pistons, ITR cams, ITR water & oil pump, + a host of other goodies for right around $2500 and had more power than this thing using B16A1 cams will.
     
  11. 22crazy

    22crazy Senior Member

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    lol, yeah i knew something was up wit that build....can u have an 86mm bore (reseleeved) with an ls or gsr crank?
     
  12. 22crazy

    22crazy Senior Member

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  13. 22crazy

    22crazy Senior Member

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    i was doing sum calculations for calesta's motor (87mm x 95mm); to get a ratio of 1.75 u would need rods with the length of 6.65", stock rods are 5.394" - difference of 1.256"

    i was just wondering how would u compensate ur block, head, valves, etc for a 1.256" increase in length.
     
  14. K2e2vin

    K2e2vin Senior Member

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    1.25"!!!!!!!! Thats a lot of space.
     
  15. 22crazy

    22crazy Senior Member

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    ya u think....my god ur hood probably wont even close ;) i was looking at sum site, c-speedracing.com and using there compression ratio test....first off i dunno where ur gonna get a head gasket to fill that space...and second...if i did my calculations right...and im still not sure about this so dont quote me on it but i think the compression ratio will be 3:1
     
  16. 22crazy

    22crazy Senior Member

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    "and the 1.58 of the GSR block" ( i dunno how to quote but basically calesta said this)

    i read that the length of gsr rods are 5.43" which is approx 135.75mm, if this is so then the ratio would be approx 1.56.

    Anyways whether is the tru length and ratio....basically my question is whats the longest rods (custom) u could put in a gsr, 87.2mm stroke...without worring too much about the piston hitting the valves.
     
  17. K2e2vin

    K2e2vin Senior Member

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  18. 22crazy

    22crazy Senior Member

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  19. SolReaver

    SolReaver Senior Member

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    this is the most retarded thing i have ever read -



    so turbos arent good cause honda didnt put them stock on all their cars?

    :bash:
     
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