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Compression Ratio

Discussion in 'Engine Building' started by T0mMuNi$m, Jan 30, 2003.

  1. T0mMuNi$m

    T0mMuNi$m Senior Member

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    I am building my H23 for a 100 shot of nitrous and was wondering what any of you guys thought would be a good c/r for this setup. I am still going to need to run on pump gas since this is a daily driver. Someone im gonna buy JE pistons from (www.autoraceparts.com) told me 11 1/2:1, yet i think this is a little high, i could be wrong though.
     
  2. hcivic.com

    hcivic.com Senior Member

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    11:1 is the highest you can run on 93 octane without retarding the timing so much you lose the benifets of the extra comp
     
  3. 2 litre EG

    2 litre EG Senior Member

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    11.5:1 c/r should be fine for a daily driver then squeeze a lil here and there... i dont see why that should be too high... but if you wannabe more cautious then just stick with 11:1 i guess... its completely up to you
     
  4. T0mMuNi$m

    T0mMuNi$m Senior Member

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    I want to be completely safe.....would it be perfect with 11:1 or should i go lower, i know nothing about nitrous compression ratios.
     
  5. 2 litre EG

    2 litre EG Senior Member

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    are you sure about that? i run 11.8:1 c/r on my ls/vtec and im running fine on 91 pump gas here in cali
     
  6. lsvtec

    lsvtec GNU/Linux Evangelist

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    I was running around 11.2:1 on 91 as well, no problems.
    Calesta is running something like 12.6:1 in Houston on pump gas. It's all in the tuning.
     
  7. T0mMuNi$m

    T0mMuNi$m Senior Member

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    Im just cautios....because ill probly have a 75 shot for the street and 100 shot for weekends and track....with that much nitrous i wanna be safe.
     
  8. T0mMuNi$m

    T0mMuNi$m Senior Member

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    Will nitrous do anything to compression when you spray? i also will be running na until i get my head and fuel system done, so i want a good cr for a lil extra power.....just not overkill so i blow it up.
     
  9. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Uhhhhhhhhh no.

    Take this into account:

    Honda S2000 - 11.0:1 from factory, has to run on 91 octane
    Toyota Celica GT-S - 11.5:1 from factory, has to run on 91 octane

    Consider that the factory has to turn these things out with some headroom, since normal people who don't give a damn about daily maintenance will be driving these things, and they will get bad tanks of gas every now and then. Manufacturing tolerances and mass production tolerances have to be allowed for also.

    The factory is mass producing cars that run 11.5:1 on 91 octane, so why can't you go higher on 93 with even more careful tuning? I could probably go higher than 12.6:1 on pump gas if I really wanted to.
     
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