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What is pefect comp. for turbo?

Discussion in 'Forced Induction' started by CRseX84, Jan 3, 2004.

  1. CRseX84

    CRseX84 Senior Member

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    hey guys my 91 siR is gona be at my house in 4 days, im doin a full rebuild to it, for turbo. im planing on running like 13boost. im getin new rods, pistons, and getin the head and block squared and milled, now when i give it to the machine shop to square the block and stuff i can tell him i want a exact comp and he will mill my head to give me the comp i want. what is the perfact comp for my JDM siR with 13boost? iv heard 9.5:1 is real good. but wut do u guys think? thanks for the help.
    Tyler
     
  2. swanny

    swanny Senior Member

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    9 to 9.5 is ideal.
    Edit: what turbo are you running?
     
  3. mwvnos

    mwvnos Senior Member

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    :ditto: althought type R's react well to turbos...id still go 9ish for a built turbo motor....
     
  4. CRseX84

    CRseX84 Senior Member

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    i wil be getin a T3 most likly... so low 9's?? or mid??
     
  5. pissedoffsol

    pissedoffsol RETIRED

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    what are you going to tune with?

    for a low boost setting (IMO, 13 psi is low), i'd go with 10:1. the in-vacuum power difference will be quite consideredable. lots of street cars run this CR.

    keep in mind that 13 psi will most likely need a hondata unit or better. the vafc hack tops out around 10, fmu's just below, and you're going to need a 3-bar map sensor to go above 11, neither of which an fmu or vafc support.
     
  6. pissedoffsol

    pissedoffsol RETIRED

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  7. NotUrAverage_Si

    NotUrAverage_Si Senior Member

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    milling the head will raise the compression ratio. if I were you instead of milling the head I'd get a 2mm cometic head gasket to lower the c/r.

    also I would check your compression per cylinder. if your it's no more than 185-190psi per cylinder then it should be ok to turbo. anymore though and you'll probably be seeing detonation, especially on 13 lbs. of boost. which pistons/rods were you planning on using? 9.5:1 is good.
     
  8. CRseX84

    CRseX84 Senior Member

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    eagle rods and JE pistons, i might change my mind on the pistions to some other brand, and i was plaing on getin the hondada setup
     
  9. pissedoffsol

    pissedoffsol RETIRED

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    is that the baby version? :lol:
     
  10. KFBhonda

    KFBhonda Junior Member

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    i followed the link and all i found was a debate - no deabte in the entire post. :unsure:
     
  11. kyleirwin

    kyleirwin Retired OG

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    well, if you only read one post it would be kinda hard to find any debate or deabte.

    now if you actually read the thread... that would be a different story.
     
  12. KFBhonda

    KFBhonda Junior Member

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    oh yeah
    mistakes all around
     
  13. lude68

    lude68 Senior Member

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    Personally i dont think there is a "Perfect" Comp. for turbo. Rely on power goals to get you there and compensate P.S.I. for compresstion to get you to your power goals. Lower Comp. will hold boost better and longer.. but the higher it is the better throttle response you will have...Just like NotUrAverage_Si said, I think 9.5:1 is a 'good but not perfect' CR. You have to decide that for yourself when you determine your power goals!
     
  14. CRseX84

    CRseX84 Senior Member

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    yea wit the 13boost i wana get near 300hp, somthing like 175+ would be good enough. im dropin $7k into the rebuild so im hoping i can get the hp that high. wuts some other bad ass turbo pistion brands that are respectabel?
    Thanks
    Tyler
     
  15. NotUrAverage_Si

    NotUrAverage_Si Senior Member

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    Arias
    JE
    SRP
    CP
    Endyn
    Wiseco
     
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