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Crank Question ls or type r??

Discussion in 'Engine Building' started by younglord94, Oct 14, 2006.

  1. younglord94

    younglord94 Member

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    Ok i have a jdm type r motor that i'm trying to build up.

    Which crank is better an ls crank or a jdm type r crank?

    One other thing can you put a b18b1 ls crank in a jdm type r motor?
     
  2. AHHVTEC

    AHHVTEC Well-Known Member VIP

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    yea it will fit in there but just put the type r in there
     
  3. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    why do you say that? the type r crank is an 87.2 mm stroke, the ls has an 89mm stroke. So between the two, you have to ask yourself, do i want better top end horse power or low end torque. since this isnt your engine, you cant make that determination. and since you didnt give a reason for your answer you took the power out of the builder's hands.

    Also, if hes building for a turbo application youll want as much stroke as possible. High revs + turbo = bad. It can be done dont get me wrong, but the higher the revs go the more likely it is youre going to break something.

    I (and most of the experienced members on this forum) am going to need more information on what youre plans are for this engine.
     
  4. younglord94

    younglord94 Member

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    the motor is going to be high compression all motor. no turbo. i would like more top end.
     
  5. klyph

    klyph Dismember VIP

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    then go with the shorter stroke (type r)
     
  6. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    :werd:
     
  7. klyph

    klyph Dismember VIP

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    long stroke and large bore FTW!
     
  8. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    welcome to general motors theory on how to build an engine for a sports car.
     
  9. klyph

    klyph Dismember VIP

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    Yeah, sorry honda dudes, I'm helpin my brother build his 454 merlin big block el camino this weekend. I rode in it when the engine was in a beat up shell, fastest beater I've ever ridden in. Now he's got a super clean white camino we're swappin the motor into. It's his redneck supercar. sorry for the thread jack. carry on.
     
  10. AHHVTEC

    AHHVTEC Well-Known Member VIP

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    i was asuming he was going all motor, in this case i was right lol.but i agree with what you said
     
  11. LateApex31

    LateApex31 New Member

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    A longer stroke will make more power everywhere in the rev range when compared to a shorter stroked engine with the same revving capability. You need to think about piston speed and acceleration with a longer stroke but realisitcally you will be able to rev either to 9k+ just fine if built properly. This gives the advantage to the longer stroke motor.
     
  12. klyph

    klyph Dismember VIP

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    umm. i think the point we're making is that a shorter stroke will rev more quickly with less chance of throwing a rod than a longer stroke. with a turbo application, you want ur engine to rev as quickly as possible to get ur boost flowin sooner. And i dont think what u said about a longer stroke motor being able to rev to the same rpm's is true. I was under the impression that a shorter stroke motor will be able to rev higher. I could be wrong, though, there's a reason my rep power is so low...
     
  13. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    There's so little difference between the strokes on the two crankshafts. I would just for the longer 89mm stroke crank. LateApex31 is right- either crankshaft will run up to 9k just fine given the correct build.
     
  14. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    i will admit, lateapex does know his stuff, but a longer stroke does not make more power everywhere in the rev range. Lets put it this way. I have 2 friends with El caminos. One has a big block 460, N/A (HUGE FREAKIN STROKE engine 12:1 compression) and the other one has a 396 (bored 350 unknown compression). And the 396 wins the fight every time. They both have 4.10 gears and both have turbo trannies (turbo 400 and turbo 350 respectively). Neither is running nitrous or turbo.

    Explain that to me? I dont have information on the cams, but i will say that both of em lope like a biatch. The 460 just feels like a dog while its running. the 396 feels good all the time. and constantly win by over .5 seconds.
     
    Last edited: Oct 15, 2006
  15. klyph

    klyph Dismember VIP

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    Have you considered the fact that one is a BB and the other is a SB? It ALL comes down to power/weight ratio. The BB in my Bro's camino is HUGE. I mean that is one giant chunk of iron.
     
  16. klyph

    klyph Dismember VIP

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    Also, with a stroker BB like that, your torque will be killer, but ur top end wont be that much higher than ur lower RPM's. The power curves on those things are flat as a pancake, so i can see why the SB wins - they got the same gears. I think if the BB put in some taller gears, he could walk the other guy. IMHO.
     
  17. LateApex31

    LateApex31 New Member

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    You are correct, ultimately the short stroke motor will hold together at a bit higher RPMs. But we are talking 10,569 RPMs vs 10,256 RPMs (not any exact figures here, simply for demonstrational purposes). Ultimately, for a street motor, the longer stroke motor makes more power and torque at a lower RPM with zero sacrifice of top end power.

    Take a B16A vs a B18C1 for example. Same bore, similar compression, 10 more HP and 20 more ft lb of torque for a very small increase in stroke and exact same revability.
     
  18. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    BUUUT...

    the b18c has a 9.14mm taller deck and a 9.8mm longer stroke. I dont know how to do the math on rod length, but i have a feeling that the stroke isnt the only thing allowing the revs and the power.

    ive gotta end the arguement here though due to lack of information.
     
  19. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    The GSR actually has longer rods than the B16, but only by a few mm. The 89m stroke block has rods that are only .9mm shorter than the GSR and ITR. If your argument is between the 87.2mm stroke and the 89mm stroke, you're really just splitting hairs. The difference in rod/stroke ratio is less than .04- just under 1.58:1 for the GSR/ITR and just over 1.54 for the non-VTEC B18.

    Shorter stroke engines will generally have flatter torque curves, but the flow of the B18 engines are such that you can still have a really awesome pancake like torque curve and still rev/breathe to the limits of a worked head.

    Now comparing the B18C to the B18A/B in terms of stroke... just pick the B18A/B crank if you have the option.
     
  20. alterdcreations

    alterdcreations Member

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    i know you see ls/vtec's and b20/vtec's revving to 9,000 + rpms with very simple builds.
    if you have the time to take apart your engine and plastigue everything then while your at it then put it in their. if you dont have plans on tearing it apart unless somthings wrong then keep the
    type-r crank. also type-r stock bottoms and putting 200+ whp to the ground. so i would work on the head unless it is a all out build
    either way your good to go and rev has high as you can make power
     
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