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ITR head vs. b18c head w/ITR cams vs. aftermarket

Discussion in 'Engine Building' started by CRXSI91, Apr 18, 2005.

  1. CRXSI91

    CRXSI91 Senior Member

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    ok...all i want to know is what is the difference??

    i mean i know your block,and the compression has a lot to do with the power output..but i mean what seperates..getting a geniune ITR head that puts out 200hp...as opposed to getting a b16 head or b18c head..and putting ITR cams in it?? the numbers or power arent gonna match up right? or are they?

    and then what about aftermarket cams...what about putting aftermarket cams in a gsr head...would the numbers match up to a type r head? im trying to figure out the differences,and why people take these three different routes.
     
  2. pissedoffsol

    pissedoffsol RETIRED

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    an itr head is a pr3 casting- same as a b16a and b16b.
    it does, however, have different valve train to accept the higher revs, different cams, different LMA's and a mild port/polish job from the factory.

    it gets most of its additional power from the cams and the compression.

    the GSR head is vastly different from the b16 and itr heads. total different casting, different combustiuon chamber shape, even a different intake manifold bolt pattern...


    once you get into some serious head work, it really doesn't matter which casting you use.

    if you plan to port with a good shop like RLZ or portflow, get a b16 or gsr head. the ITR head sucks, really, if you want to take it out some more. the OEM P&P is a crappy job, really, and its better to start off with nothing.
     
  3. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    the itr has a factory mild port job done to it. but ive heard from many people that the factory port job is shit and that your better off starting with an untouched head and getting the port work done by a pro.

    the gsr head will yeild higer compression. and if you have a gsr head and an itr head with the same internals, the gsr head will make more power. most people choose a b16 head because its cheaper but IMO the gsr head is the best head to use. some people will try to argue flow differencens between gsr and itr/b16 but for one its so neglagable that it doesnt even matter, and two once you do port work the comparison is obsolete and soley dependednt on the port job.
     
  4. formby

    formby learning in progress

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    i think that if you change your cams you should buy pistons to match the compresion wanted by the cam..aftermarket or OEM

    ..if you put itr or ctr cams on a stock b series engine; the motor will gain hp, but not as much as if you also changed to the same pistons from the same engine as the cams...


    if you put itr cam in a gsr, and leave the gsr pistons...it will be less hp than if you used itr or ctr pistons with the ctr/itr cams
     
  5. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    its not like gsr;s have super low compression. its a solid 10:1. 00itr/ctr cams make a nice upgrade top a gsr. you will get some more power with more compression true but its not a bad choise to do just the cams.

    also if you put ctr pistons in an gsr you get like 12.4:1 compression and with only ctr cams you will be starving the engine for more air. that combo is entirely mismatched.

    itr pistons or b16 pistons with ctr cams would be a nice mild build in a gsr. and is probably what im gonna do eventually, but i may opt for the skunk2 satge 1's since they are slightly more agressive.
     
  6. pissedoffsol

    pissedoffsol RETIRED

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    ctr pistons in an otherwise stock gsr yeilds 13.0-13.1 compression.
     
  7. SixtySecondAssassin

    SixtySecondAssassin Senior Member

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    i thought it was a little above 12:1, are you taking into account the different piston to deck heights between the b16/b18c?
     
  8. adnoh

    adnoh Senior Member

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    Christ....how would that translate into HP/TQ #'s? Much of an increase?
     
  9. formby

    formby learning in progress

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    i only used a gsr as an example......just letting him know that sometimes just changing the cams wont do....
     
  10. pissedoffsol

    pissedoffsol RETIRED

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    according to c-speed racing or any other calculators, yes.

    problem is, they don't consider the fact that the ctr piston actually sits ABOVE the deck... and that's where the extra point comes from. Power? its compression, not power. it doesn't coorrelate at all by itself.


    these are correct figures, at most off by .1 or .2 dure to vairances in gaskets, and so forth..

    PR3 head/B16 Block

    STD = 11.643438609136867
    .25 OS = 11.703231023151065

    PR3 head/B17 Block

    STD = 12.193487116069006
    .25 OS = 12.256369577319077

    PR3 head/B18C Block

    STD = 12.58636786521145
    .25 OS = 12.649248792586258

    P72 head/B18C Block

    STD = 12.924594026551906
    .25 OS = 12.989047869209281

    PR3 head/B18A/B Block

    STD = 12.825536009218106
    .25 OS = 12.88971493738735

    P72 head/B18A/B Block

    STD = 13.170743903246784
    .25 OS = 13.236528215133324

    but this is getting off topic.
     
  11. dc boy

    dc boy New Member

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    im building a ls vtec...i was wondering ctr pistons with stage 3 cams be safe to do?do i need to shortened the ls rods and what would the compression be?
     
  12. |Chaz|

    |Chaz| Well-Known Member VIP

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    Congrats on bumping a 3 year old thread. :thumbsup:
     
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  13. CleanEKHatch

    CleanEKHatch New Member

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    Why not?
     
  14. CAFROG

    CAFROG Honda Minion VIP

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    Because it is a question with little to no reference to this specific (and old) thread.
     
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