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high c/r with turbo

Discussion in 'Forced Induction' started by civicious, Oct 17, 2003.

  1. civicious

    civicious FüK-VTEC VIP

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    before anyone flames me, we were talkin about this in chat tonite before hardly anyone was in there

    i dont know shit about turbos, so i could be completely wrong.


    im tryin to figure out if it's good or bad to have a high c/r with a turbo setup. i've heard some people say its bad...my question is why

    the way i look at it, and this is purely from my perspective, having a low c/r and pushing a lot of boost would get the same effect as having a high c/r and pushing not so much boost.

    say for instance you make 200whp at 9:1 c/r, and 8 lbs of boost
    to make the same whp at 11:1 c/r, wouldnt it make sense that you wouldn't need to boost as much?
    (those numbers are just numbers i pulled off the top of my head)


    it seems like with a higher c/r to start with, you wouldn't need to push as much boost to achieve the same effect as boosting a lot with a lower c/r.

    anyone?


    like i said, i dont konw shit about that kinda stuff, so dont flame me.
     
  2. pissedoffsol

    pissedoffsol RETIRED

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  3. 1fastcrx

    1fastcrx Junior Member

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    Good article. Only thing missing that I can tell is that the article doesn't go into detail about what range is good or safe effective compression versus what would be bad effective compression. Thanks for the clarification.
     
  4. saturn_boy96

    saturn_boy96 88 C1V1C 53D4N DR1V3R

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    i think the reason B left it that way is because you can't really say. i mean it all really depends on tuning, and engine management.

    either way :thumbsup: article.

    "Long enough to cover the subject and short enough the keep it interesting".
    the way i like essays and skirts :) .
     
  5. 1fastcrx

    1fastcrx Junior Member

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    Yeah I figured as much, too many variables....how about in a normal situation where everything is done right, meaning fuel, timing, and everything else...I guess what I am searching for is an understanding of what the numbers mean. In the article Brian wrote that an effective compression of 15.3 was fine for a b16a with a 10.4 compression and 7psi of boost. There should be at least a guideline where in the same situation a number of lets say 20 would be bad for a high compression engine.....Thanks again for your help.

    EDIT: Just realized, maybe this will help me out more....Let use the same example of the B16a, what would be a bad effective compression for the same example, stock internals but everything else done right.
     
  6. 92civicb18b1

    92civicb18b1 The Trisexual

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    Im gonna threadjack a minute. Let say I put a turbo on my Ls at around 8 psi, and had effective compression ration of around 15:1. isn't that too high for pump gas. I'm not familiar with compression vs fuel so somebody please enlighten me on the subject.
     
  7. 1fastcrx

    1fastcrx Junior Member

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    Maybe Pissed would shed some light on the subject ;)
     
  8. pissedoffsol

    pissedoffsol RETIRED

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    effective is NOT static. 15:1 on a turbo is NOT 15:1 from a super domed High compression piston.

    its hard to explain....
     
  9. 1fastcrx

    1fastcrx Junior Member

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    Yep I understood that one, effective doesnt equal static. I was trying to get a better understanding of the effective compression in the article. I was just shooting for a number or an approximate value that would be bad for effective compression. But if its hard to explain thats cool, I've gotten more from you guys than anyone else....keep up the good posts.
     
  10. t3t4si

    t3t4si Member

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    High compression on a turbo can be a good thing and it could be a bad thing. It honestly just depends on how much money you want to spend. On pump octane it would be wise to go low compression. But you can fine tune your timing and fuel along with extremely high octane (105) to (110) to make it work. And yes it will be faster than a low compression turbo. But you will have to get everything precise or bye bye engine.
     
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