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Thread: compression ratio

  1. #1
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    Default compression ratio

    Anybody here tried to push the limits of compression ratio? Trying to get around 11.2-11.4:1 static compression. .04" quench height, 82 cc chambers via early 5.7 heads milled .02". At sea level with 93 octane pump gas. I know it will depend on the dynamic really, but I just want to see what others have had in a heavy truck.

    let me try, im a genius

  2. #2
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    I was going to do it but I found F/I. If you do it I'm sure it will run badass
    2005 DAYTONA - 468 Aluminum HEMI, 4l80, FTI converter, 4.56 🌽

  3. #3
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    He said quench!
    2014 RAM 1500 Express QC 2wd Hemi

    5.7 Stock Block
    1/4 - 12.18 @ 110.15 NA
    1/8 - 7.74 @ 89.06 NA

    426 Stroker
    1/8 - 7.16 @ 95.79 NA

    2000 GMC Sierra 1500 RCSB 2wd - ERL 454 LS2 Dry-Sleeve powered drag truck...

    SOLD - 2007 Dodge Ram 1500 QC 2wd Hemi
    1/4: 12.63 @ 104.92 NA
    1/8: 7.98 @ 84.83 NA

    Quote Originally Posted by DaKing View Post
    "It rubs the oil on its piston.."

  4. #4
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    What are your plans about getting .040" quench with 5.7 heads? I know there's a couple ways to do it, just wondering which route your going with.
    Built, Not bought.

  5. #5
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    Quote Originally Posted by Hemidup View Post
    What are your plans about getting .040" quench with 5.7 heads? I know there's a couple ways to do it, just wondering which route your going with.
    I was under the impression the stock deck height was .012" in the hole, give or take, plus the factory .028" gasket thickness. Obviously that's just a target, and until shortblock is assembled I won't know for sure exactly where it will be, but for all intents and purposes. My current calculations with rod and piston combo, along with what deck height "should" be, comes out to a .04" quench.

    let me try, im a genius

  6. #6
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    Quote Originally Posted by sldhemi View Post
    I was under the impression the stock deck height was .012" in the hole, give or take, plus the factory .028" gasket thickness. Obviously that's just a target, and until shortblock is assembled I won't know for sure exactly where it will be, but for all intents and purposes. My current calculations with rod and piston combo, along with what deck height "should" be, comes out to a .04" quench.
    You must also take into consideration there's about .052" from the head deck surface to the quench pad. After you mill the head .020" that leaves .032" plus your .012" piston deck height plus .028" gasket = .072" quench. Being close to sea level you may want to take some more off the head. IDK, your call.
    Built, Not bought.

  7. #7
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    What is ideal quench? If I recall My strocker had originally .035 quench with 6.1 heads. But I have 5.7 heads, and plan on eventually running eagle heads Good topic.
    2005 QC 2wd 5.7 HEMI
    392 stroker
    Fastman ported TB
    Frank Racing custom stroker cam, 231/235
    Superchips 3815 Stacked with SCT
    Motive 4.56's
    Summit underdrive pulley
    Pacesetter longtube headers
    Awaiting Circle D 3400 T

  8. #8
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    Quench, squish, piston to head clearance means all the same. Most say .040" is ideal for a N/A build when using steel connecting rods. A tighter quench is more prone to detonation, piston to head contact and visa versa with more quench.
    Built, Not bought.

  9. #9
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    Quote Originally Posted by Hemidup View Post
    You must also take into consideration there's about .052" from the head deck surface to the quench pad. After you mill the head .020" that leaves .032" plus your .012" piston deck height plus .028" gasket = .072" quench. Being close to sea level you may want to take some more off the head. IDK, your call.
    I didn't know that about the quench pad. Well dang. That just throws a stick in the spokes. I can take .01" off the block and .01" more off the heads, but that bumps the calculated static CR to around 11.8:1. Which I wouldn't be worried about if it wasn't such a heavy vehicle.

    let me try, im a genius

  10. #10
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    My stroker was 11.25 i barely got by on pump gas, but it sure loved it too
    04 Silverado 4x4 & 11 Charger R/T

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