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itr pistons in grs block

Discussion in 'Engine Building' started by ferrarikiller, Feb 4, 2004.

  1. ferrarikiller

    ferrarikiller Senior Member

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    So who knows the compression ratio of a gsr block and head with itr pistons? I heard its different with usdm than jdm.
     
  2. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    assuming you have stock bore and stroke, and stock sized headgasket......

    with USDM ITR pistons, you are looking at 10.836:1 compression

    with JDM ITR pistons, you are looking at about 11.362:1 compression.

    if it were me, i would get the CTR pistons. with the GSR head and block, everything else stock specs it gets you a nice 12.042:1 compression ratio. but thats just me.
     
  3. Teambypass

    Teambypass Senior Member

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    There are no dumb guestions. Im curious why would a CTR has more compression than an ITR???? I am headed that route on my set up too. I either want type r piston or after market pistons? thanks for your help.
     
  4. B16

    B16 Super Moderator VIP

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    CTR pistons in a GSR/ITR block (and crank) will give you higher CR. the CTR piston comes out of the B16B block, which is identical to the GSR/ITR block. however, the b16b has a shorter stroke, but longer rods. what all this means is the CTR pistons in the b16b with b16b stroke do not get as close to the head (piston - deck clearance) when at TDC. however, if you put these pistons in the gsr/itr (with their stroke and rods) the piston to deck clearance is smaller, thus the piston gets closer to the head, and then you get your higher compression ratio.

    and this would be better suited in engine building. :moved:
     
  5. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    The B16B also has a larger combustion chamber than the GSR- that's the main reason why the B16B pistons have larger domes- to make up the compression difference.
     
  6. B16

    B16 Super Moderator VIP

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    but, the majority of that compression difference comes from piston-deck height and not from the chambers. the chambers account for maybe 0.2 points in CR.
     
  7. B18C_NA

    B18C_NA Banned

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    CTR pistons in GSR block and head to equal 12.042:1? wrong, do your math GSRCRX, 12.487:1. I know
     
  8. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    i used the c-speedracing comp calculator. thats what it gave me. if you have an issue with it take it up with them not me.
     
  9. B16

    B16 Super Moderator VIP

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    he was probably using the c-speed comp. calculator which is incorrect.

    EDIT:
    :doh:
    you beat me too it
    :)
     
  10. B18C_NA

    B18C_NA Banned

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    that's some funny shiet B16, HA! talking bout homer, i'm gonna get me a beer.
     
  11. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Hmm ok- I'll have to do the math again. ;)
     
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