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  1. #1
    Hayabusa Master

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    Default What does dual stage mean?

    I was reading about the RR Merlin engine developed in WWII. It had a two speed dual stage supercharger with inter-cooler.

    I get the two speed. But what is dual stage? Also, P51's were authorized to go to 16+ pounds of boost for no more than 5 minutes in combat. How high a boost do you turbo guys run?
    The mystical trend of our time, which shows itself particularly in the rampant growth of the so-called Theosophy and Spiritualism, is for me no more than a symptom of weakness and confusion. Since our inner experiences consist of reproductions and combinations of sensory impressions, the concept of a soul without a body seems to me to be empty and devoid of meaning. - Albert Einstein, 5 February 1921

  2. #2
    Seasoned Pilot scrappy's Avatar
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    Default Re: What does dual stage mean?

    i wonder if it had to do with manifold pressure.

  3. #3
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    Default Re: What does dual stage mean?

    I'm betting dual stage is the same as the air compressor terms. The intake charge is compressed twice. It would be like mounting two turbos in series. Output of turbo #1 goes into the input of turbo # 2. I've seen some HD trucks with both turbo and roots style supercharger in this method.
    Last edited by Professor; 12-30-2010 at 02:41 PM.
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  4. #4
    Rookie Brokenchickenleg's Avatar
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    Default Re: What does dual stage mean?

    The US Army's M109 Howitzer is powered by a Detroit Desiel V-8 that has a huge turbo flowing into a big supercharger. It made a a really cool whine when on the throttle but it didn't go over 25 mph. (kinda like a lot of Ford products....)

  5. #5
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    Default Re: What does dual stage mean?

    Quote Originally Posted by Professor View Post
    I'm betting dual stage is the same as the air compressor terms. The intake charge is compressed twice. It would be like mounting two turbos in series. Output of turbo #1 goes into the input of turbo # 2. I've seen some HD trucks with both turbo and roots style supercharger in this method.
    Sounds logical to me.
    The mystical trend of our time, which shows itself particularly in the rampant growth of the so-called Theosophy and Spiritualism, is for me no more than a symptom of weakness and confusion. Since our inner experiences consist of reproductions and combinations of sensory impressions, the concept of a soul without a body seems to me to be empty and devoid of meaning. - Albert Einstein, 5 February 1921

  6. #6
    Top Gun megawatt's Avatar
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    Default Re: What does dual stage mean?

    Not sure about what it means with the Merlin engine but here is what I think it is on my turbo. I run around on about 8lbs of boost with a spring, I have a XS boost controller that when I squeeze the flash to pass switch the wastegate stays closed until it hits 12 lbs of boost. AKA my 2 stage or dual stage or second stage of boost.

    However my bike is still a stage 1 turbo bike run on FMU. Does this make sence?


    Hell yea its fast you dumb @$$, its a turbo Busa.

  7. #7
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    Default Re: What does dual stage mean?

    Bingo! The compressed charge is feed from the first "stage" compressor into the second "stage" which multiples the compression of the intake charge. Often there are two very different sized compressors used to help reduce lag.

    The term compressor could mean supercharger and/or turbo. Anything the can compress the ambient pressure.
    Quote Originally Posted by Professor View Post
    I'm betting dual stage is the same as the air compressor terms. The intake charge is compressed twice. It would be like mounting two turbos in series. Output of turbo #1 goes into the input of turbo # 2. I've seen some HD trucks with both turbo and roots style supercharger in this method.
    Turbo busa can run 40+psi but not with pump gas.
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  8. #8
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    Default Re: What does dual stage mean?

    Quote Originally Posted by Commuta_Busa View Post
    Bingo! The compressed charge is feed from the first "stage" compressor into the second "stage" which multiples the compression of the intake charge. Often there are two very different sized compressors used to help reduce lag.

    The term compressor could mean supercharger and/or turbo. Anything the can compress the ambient pressure.


    Turbo busa can run 40+psi but not with pump gas.
    This makes a lot sense. Thanks.
    The mystical trend of our time, which shows itself particularly in the rampant growth of the so-called Theosophy and Spiritualism, is for me no more than a symptom of weakness and confusion. Since our inner experiences consist of reproductions and combinations of sensory impressions, the concept of a soul without a body seems to me to be empty and devoid of meaning. - Albert Einstein, 5 February 1921

  9. #9
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    Default Re: What does dual stage mean?

    Quote Originally Posted by Brokenchickenleg View Post
    It made a a really cool whine when on the throttle but it didn't go over 25 mph. (kinda like a lot of Ford products....)


    Yeah, but the whining you hear in Ford is coming from the driver, after he loses to a Hyundai...
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  10. #10

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    Default Re: What does dual stage mean?

    Apparently its 2 impellers in the same turbo housing which serially compress the charge. There is a nice explination and a drawing on the thread below at WW2Aircraft.net;

    Two stage Superchargers - Aircraft of World War II - Warbird Forums

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