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Thread: how much compression is needed to run alky

  1. #1
    Member MASTER JOURNEYMAN
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    how much compression is needed to run alky

    i have a buddy who has a 377 sbc in a dragster it has 10-1 pistons he changed over to enderlie stack and alky having problems and someone told him he didnt have enough compression to run i told him i would ask around thanks

  2. #2
    Senior Member MASTER BUILDER
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    You will likely get a variety of responses ranging from 10:1 is fine to throw as much compression at it as you can. I know because I asked a similar question last year.

    As a result (and further research) I am taking my 358 SBF from 11.2:1 to 13:1 as part of my changeover from Enderle (hat) injected gas to alky.

    But this could be only a part of the solution. What types of problems is your buddy having?

    Murff

  3. #3
    Administrator RACING JUNKIE bjuice's Avatar
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    i think ron owens said at one time he had great luck at 10:1 compression.
    i have ran it at 14:1 compression and found increased Tq..

    Murff is right it likes a little more compression..sort of more is better theory but you will see benefits at the lower CR also

    you will also get a wide variety of the maintenance of alcohol vs gas..

    what are you looking to gain (expect)..i guess the Order has to suit the bill.

    also just to put this on the table..the most economical /less hassle way of increasing your CR is to have the heads angled milled..if you motor is a candidate...

    Several builders on here that can help you with advise to doing the work for you.

    Brian
    Bjuice..

    "I'M YOUR HUCKLEBERRY ! "

  4. #4
    Member MASTER JOURNEYMAN
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    thanks for the replys i will let him know he should be ok the hole reason for the switch to stacks are he has a front engine slingshot and he likes the nostalgia of the enderlie

  5. #5
    Senior Member RACING JUNKIE
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    I guess a better question would be...

    What was he running before?

    What pump is he running now?

    What size nozzles are in it?

    What size main jet is he running?

    Has the system been flowed?

    What's the barrel valve leak down at?

    It's rather hard to trouble shoot via the net without more information.

  6. #6
    Senior Member RACING JUNKIE
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    One of the best running motors I had was a 10:1 with alky carb.
    Is it the best maybe not but will work fine.
    David Lanning
    IHRA NHRA 387B

    Fleenor Racing Transmission
    419-280-1406
    Lanning Electric
    Complete Drag Car Wiring
    APD Race Engines
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  7. #7
    Senior Member MASTER BUILDER
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    Compression

    The more you run the better. For every point of added compression you will gain 4-6% in over all horsepower.
    Competition Engines & Hardcore Engine Parts
    www.cnc-motorsports.com
    info@cnc-motorsports.com

  8. #8
    Senior Member MASTER BUILDER
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    Is he running a mag? Ignition related problems are very common with alky engines. Mags usualy clear them right up. I don;t care how big of an ignition box you got. Consider, with a MSD type ignition, with a 6al or similiar, as RPM increases, spark energy goes down. As you fill the cylinder with more and more alky, it pust out the fire, and they will miss fire. A mag, as RPM goes up, spark energy goes up.

    My advice would be get a mag, if you don;t have one. 10:1 on alky engines, actualy will pick big power. Typicaly in the range of 50+hp, compared to gas. When your at say 14:1, the engines don;t pick up that much power, more like 20, and they typicaly pick up tq.

    Alky in equal parts, has less BTU energy that gas. But, where the gains come from, is because you run so much more volume of fuel, basicaly double the amount. So, I am not sure off the top of my head what the actual BTU energy amount for each type of fuel is, but, for the example, we will say gas has 12,000btu, and alky is 8,000 for the same amount of fuel. Where the gain comes from, is that you run twice as much fuel, so, that amount of alky, has 16,000btu, so, a net gain of 4000btu. If you can light it effectively, and not waste it, it will make more power. The mag will light it. I have seen gains of 100+hp from switching from conventional style ignitions, to mags. the more potential the engine has, the more potential the potential gain is. On one 565 big chief deal, the engine was making 1050 with a minor miss up top. The miss, was basicaly, the ignition giving up. It wouldn;t process the fuel. The engine was no way making max potential, as, the same combo on gas, was over 1100 before. We talked the guy into getting a mag, and, the engine came to life, making 1190hp. We made about 30 of that power, from adding even more fuel. Alky arries its own oxygen too, and, as long as you can burn it, and process the fuel, it can make more power. But, the mag change, with the same fuel tune up, it picked up 110hp.


    Frank
    Advanced Performance
    www.get-ap.com

  9. #9

    just my thoughts

    I disagree totally with frank at advanced engines and the reason i do is that i have built blown big blocks and small block with alot of boost and alot of alchol and some with alittle nitro added and i have used mags and i also tryed MSD 10 plus and the 10 plus has worked great and some of the guys that are running a mag have now gone to the msd set-up and they both are very happy, i like the msd as it gives you alot more options then the mag,,, just my personal opion, we all have them.

  10. #10
    Senior Member MASTER BUILDER
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    I have personaly have seen it go the other way with the MSD 10. Guys fight it, then, mag it, and presto, more power, and all the mysterious issues go away. But, like you said, more than 1 way to skin a cat.

    Frank


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