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who's got the highest compression?

Discussion in 'The Distillery' started by IUP99snake, Apr 18, 2011.

  1. IUP99snake

    IUP99snake The Shocker Established Member

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    We all know the octane ratings of E-85 and its benefits for performance applications.

    Just checking in to see if anyone's building a purpose-built E-85 motor with high compression (and perhaps even boost). If so, what ratio?

    For N/A, what's the highest compression ratio you should go with running E-85 compared to 93 octane?

    What about for a centri car running 11-12LBS of boost on the street (which is a bit more forgiving when it comes to boost and compression)

    Or what about an all-out twin screw 4.0 whipple with the most boost you can throw in it? Still safe to run a high(er) compression ratio?

    I know there's a guy in this board who bought the "N/A" aluminator longblock simply because it had higher compression, even though he was going to boost it and run it with E-85.

    I'm running 10.3:1 on 93 octane... and with 12 LBS of boost, and no problems yet.

    If there were more E-85 stations in my area, I'd take the compression ratio into consideration and pump it up! Since compression is the one "constant" in the motor once you've built it, you'd think that you'd go as high of a compression ratio as you could possibly get, and then manage detonation with all the other variables, such as fuel, timing, intercooling, meth injection, etc. etc and most importantly, a good tune. (Engine tuners: I'm sure there's MUCH more to that, but that's just my .02). Even ford is raising compression ratios on the 5.0 motors and even the ecoboost motors to 11:1!!

    But it would be awesome to see some wild high compression motors. 11:1? 12:1? 13:1????

    Compared to my low compression 8.5:1 motor I previously had in my car, my 10.3:1 motor definitely has a more aggressive "cackling" idle. And definitely has better throttle response for around town driving.

    Interesting.
     
  2. AntiHeightPunk

    AntiHeightPunk New Member Established Member

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    agree 10:1 is the lowest i would go on an e85 motor
     
  3. GodStang

    GodStang Well-Known Member Established Member

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    There is a couple Twin Screw guys that are at least 13:1 but they are on race fuel and not E85.
     
  4. Derek@Amazon

    [email protected] RTCTTFMF!!! Established Member

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    the race car is 13.8:1 last motor was 14:1 but we are on C23
     
    Last edited: Apr 18, 2011
  5. SSeatr

    SSeatr Active Member Established Member

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    9.98:1 twin turbo going to be running E85

    i wish i planned all this before i started building i would have went 10.5:1 area
     
  6. 04sleeper

    04sleeper Runs On "Liquid Gold" Staff Member Super Moderator

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    I have seen as high as 15.9:1 compression on a N/A motor.
     
  7. IUP99snake

    IUP99snake The Shocker Established Member

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    Haha that's crazy! You could probably run diesel in that thing. I wonder what that sounds like.

    Anyone have any videos of a really high compression modular motor?

    Here's a video of my car with the procharger, it's got 10.3:1. Oh and the white smoke is because it was cold and rainy that day, not because it was burning any coolant. [nomedia="http://www.youtube.com/watch?v=4S6DZOQAjSo&feature=youtube_gdata_player"]YouTube - 99 cobra procharger aviator swap idle[/nomedia]
     
  8. pacific4v

    pacific4v New Member Established Member

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    I'm in the process of putting an intercooled vortech s-trim on my 11:1 cr 5.0 stroker. I'm not for sure how much boost I'm going to run, probably 10-12psi. Should be interesting to see what it makes in about another month.
     
  9. SSeatr

    SSeatr Active Member Established Member

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    should be bad ass, what fuel? go E85 and tear it up!!!

    let me know how it goes, if i mess up my pistons im going higher CR
     
  10. Chris _Scott

    Chris _Scott NA FTW Established Member

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    Engine I'm building will be a 4.6 w/ a CR ~11:1

    Will be pushing 35-40# of boost through my ProCharger F2

    E85, blow-through, non-intercooled
     
  11. fst86410

    fst86410 Member Established Member

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    I'm going to get mine tuned may 13. It's a 10:1 motor with a f1a should be around 18lbs. Ill post back what it makes.
     
  12. blowngt

    blowngt Active Member Established Member

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    Flat Top pistons and 01 4v heads here (just under 11:1)

    Same combination now runs faster (both dyno and track) at 11#s of boost as it did previously on 17#s of boost.

    I'm using E85 now and had run 110 previously.

    Compression and E85 is definately the way to go.......
     
  13. ZOSO

    ZOSO colorados baddest eaton Established Member

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    Even tho its a DSM a local guy here is running 10.5:1 and 45psi on E85. Car is stupid fast. He keeps pushing it harder to try and find the limits of E85. Has yet to find it.
     
  14. SSeatr

    SSeatr Active Member Established Member

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    stock stroke?

    cuz i went with flattops notched, with my 99 heads, and stroked i got 9.98:1cr so the builder says
     
    Last edited: Apr 24, 2011
  15. blowngt

    blowngt Active Member Established Member

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    Yeah, stock stroke.

    The heads have been milled down a bit, and it's also a .020.

    I would check with the piston manufacture and see what they say, but I'll bet it's at least 10.5:1
     
  16. 01bluesnake

    01bluesnake Authorized Vendor Authorized Vendor Established Member

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    I just placed my order on pistons, should be sitting around 10.8-9 with 03/04 heads. This also be .030" over and 3.75" crank, cant wait to get it all together.

    Forgot to mention this is a boosted enigne
     
    Last edited: Apr 24, 2011
  17. pacific4v

    pacific4v New Member Established Member

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    It'll def be fueled by E85. I just decided to sump my tank and run an A1000 pump and probably 72# injectors. It's gonna be blow thru s-trim with a procharger 3 core intercooler. The head unit has a gt impeller, which should start making boost a little lower in the rpms. I'm really curious as to how much hp and even more so how much tq it makes. I figure with 11.1 cr, longer stroke, long tube headers, the blower making boost fairly low, and being able to get aggressive with timing down low thanks to the E85 should make some great tq numbers for a centri, and still pack a punch up top like the centris are known for.
     
  18. Tampa03cobra

    Tampa03cobra Frivolous Lawsuiter Established Member

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    Just a quick side note sir,


    The Ecoboost motors are direct injection engines, you can't make any kind of comparison of detonation tolerance for compression/boost /w X octane vs a normal motor since the method of fuel injection is the main reason they are able to run such high compression with boost using standing premium unleaded gas vs a normal motor.

    It's a neat technology, I know I was impressed as hell with my Ex-girlfriends 335i (the low end grunt of a TT car with the high winding power up top of a high compression N/A mill).
     
  19. SSeatr

    SSeatr Active Member Established Member

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    I ordered them from MMR they are .020 stoker pistons notched valve reliefs. mark said they were doing the math and i would have been over 10:1 but when my builder put it all together he gave me the sheet saying 9.98:1

    i thought it was going to be 10.25-10.5:1 and was a little nervous about the CR with the turbos i was planning on running, until i read more into E85 and now im happy with the higher CR
     
  20. truebluedevil02

    truebluedevil02 Captain Jackstands Established Member

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    my 408 is around 12:1 comp and im considering strapping on a large single turbo/non-intercooled setup on E85. Right now I run a 50/50 mix of 91/100 octane although it will run on pump 91 I just want to be safe.
     

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