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Thread: Cranking compression
          
   
   

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  1. 01-11-2004 09:38 AM #1
    TyphoonZR's Avatar
    TyphoonZR
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    Cranking compression

     



    I am just wondering, I am working on a 400 block and with my current calculations, 12:1 compression with aluminum heads. We are installing a large cam,
    http://www.compcams.com/Technical/Se...umber=12-225-4
    and I am wondering if anyone could tell me what the true compression would be when taking into consideration the over lap bleed-off.
    Or, if we end up with 200 psi cranking compression, would 94 octane be adequate to avoid detonation?
    Objects in my rear view mirror are a good thing unless,.... they have red and blue lights flashing.
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  3. 01-11-2004 09:14 PM #2
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    I was running a big block dodge 440 magnum with 12:1 compression and It would start but It run like crap till I added some octane booster. about 108 octane is what I ran in it.


    Vegas
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  4. 01-11-2004 10:14 PM #3
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    Thanks Richard for that lengthy post. I too believe that this is a significant topic. Two things which cause pistons to fall apart are heat and detonation. I think it is the hyperutictic pistons which can handle the heat better, but forged take the detonation more readily.

    Vegas, how did you come up with 108 octane?
    Last edited by TyphoonZR; 01-15-2004 at 05:23 PM.
    Objects in my rear view mirror are a good thing unless,.... they have red and blue lights flashing.
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  5. 01-15-2004 02:10 PM #4
    budlight
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    You need to look at the dynamic compression ratio!

    I have a e-mailable DRC calculator.

    I am running 11.2 with a SR cam and thermal coated pistons on our 91 octane unleaded without a problem
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  6. 01-16-2004 01:47 AM #5
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    Typhoonzr ; It was not any thing specific with the 108 oct. when I first tryed to start that old charger after I rebuilt it with 12 to 1 It didn't want to start. that was with 92 oct, so I went down to the old union 76 and got 102 oct the car started then but got some pingin so I added oct booster and the car ran great. So that's what I used in that old 440 magnum. Now in this car you didn't watch the speedometer you watched the gas gage because you were not sure if you could make the next gas station.HE!HE!HE!


    Vegas
    I would send a picture but I have not figured out how to send it with out the site timmin me out. How do I make the picture have less lines so it will send? thanks
    Last edited by vara4; 01-16-2004 at 01:57 AM.
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  7. 01-16-2004 08:17 AM #6
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    Originally posted by budlight
    I have a e-mailable DRC calculator.
    Please!!! ima@dowco.com
    Objects in my rear view mirror are a good thing unless,.... they have red and blue lights flashing.
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  8. 01-17-2004 10:03 AM #7
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    Originally posted by budlight
    I have a e-mailable DRC calculator.
    Hey budlight, what would I have to do to get me that progrom?
    If I said, "may I have the Octane calculater Please", do you think that I might find one in my e-mail one of these days?
    Objects in my rear view mirror are a good thing unless,.... they have red and blue lights flashing.
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  9. 01-17-2004 10:18 AM #8
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    TypoonZR; If you do get a octane calculator from Bud light please send me a copy I e-mailed him directly but I have not gotten a response yet!!! thanks


    Vegas
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  10. 01-17-2004 11:59 AM #9
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    Will do Vara, I got your e-mail but I didn't understand it. I thought that maybe you were budlight and wanted me to say, "Octane Calulator PLEASE. hahaha! That is why I made my previous post, hahaha!
    Objects in my rear view mirror are a good thing unless,.... they have red and blue lights flashing.
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  11. 01-20-2004 06:32 AM #10
    budlight
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    DCR calculator on the way!

     



    typhoon - it's on the way

    Vara4 - I don't see any e-mail address for you.
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  12. 01-20-2004 03:21 PM #11
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    Bud light or TyphoonZR;
    May I Please have a octane calculater,and I'm sorry TyphoonZR I may have E-mailed you by mistake or instead of Budlight. thanks


    Vegas
    My E-mail address is dkerwood@tampabay.rr.com
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  13. 08-14-2004 02:29 PM #12
    sowardjr
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    NO. 94 along will not work.
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