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Thread: Centrifugal Supercharger Discharge Swirl

  1. #1
    Junior SCH Member eeyore's Avatar
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    Centrifugal Supercharger Discharge Swirl

    Hi, Some years back I did a litle work with a very high boost turbo applacaition that was not filling a plenuim properly, the bassis of the problem was the swirl created in the discharge air and how that swirl effected the flow into the plenium. The fix turned out to be a simple "Cross Hair" divider in the tube just off of the compresser housing,
    I am thinking about adding such a device to my S-trim Vortech to see if it may also help, not that I am having the problems the turbo applacation was having, lot less boost and the turbo applacation was a complely diffrent intake design, but thinking canceling out the swirl shouldn't hurt!

    Any body tried this? Any thoughts?

    Thanks! Bill

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    SCH Owner Michael's Avatar
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    How did you know the high-boost turbo system wasn't filling the plenum correctly? I would have thought that a high-boost system (I'm assuming plenty of flow) wouldn't have an issue filling a plenum. Am I wrong?

    But you've asked a good question. I think you're right - canceling out the discharge swirl shouldn't hurt.

  3. #3
    Junior SCH Member eeyore's Avatar
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    Quote Originally Posted by Michael View Post
    How did you know the high-boost turbo system wasn't filling the plenum correctly? I would have thought that a high-boost system (I'm assuming plenty of flow) wouldn't have an issue filling a plenum. Am I wrong?

    But you've asked a good question. I think you're right - canceling out the discharge swirl shouldn't hurt.
    Hi! The Application was a in line 4 with direct port injection, individual throttles on each port attached to a common plenum, running 45lbs of boost. After two broken crankshafts with the same cylinders connecting rod exiting through the bottom of the motor. They invested in some EGT's for their Data acquisition unit only to see a sharp slope across the cylinders. The fuel system flowed consistently across all the cylinders, There was no way to change ignition timing on each cylinder if it was timing it would have showed up across the board. Had to be air distribution! The Inlet on the plenum was in the center, so one would think the center two cylinders would have seen the greatest amount of air, but not the case, as the air swirled into the plenum, it pressurized one side greater then the other.

    I was thinking about doing the cross this week, but I also am do for a valve adjustment, so I may wait to build the divider so I do not have skewed results!
    Thanks!
    Bill

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    SCH Owner Michael's Avatar
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    An inline-4 running 45psi boost?!? What application was this for?!?

    Do you have any photos of this 'cross hair' device you developed?

  5. #5
    Junior SCH Member eeyore's Avatar
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    Hi Michael! The application was a Suzuki powered Funny Bike, I can't take credit for the Cross Hair. My solution was much more complected, a laminar flow device, I really was trying to talk them into a inter-cooler, but they were dead set against it. When another racer suggested the cross hair baffle...we all kinda giggled at the simplicity of it. A very strong example of over thinking the problem.
    I do not have a picture of it, but just picture two flat pieces of aluminum, a couple of inches wide, placed in a x (or plus sign) pattern then welded into the discharge tube creating four 90 degree pie shapes. If and when I try it, I will take pictures and post my results.
    Bill

    PS Saw your modeling work on that impeller....must say...wow!

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    SCH Owner Michael's Avatar
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    This device you're talking about sounds similar to that Tornado Air product. I think we've all seen the infomercial; it's alters the incoming airflow making it more turbulent. If I recall correctly, the reasoning behind it was that the more turbulent the air, the more violent the combustion process. The more violent, the more efficient. At least, that's the theory.

    In this case, it sounds like you were after a smoother airflow allowing more complete filling of the plenum. Makes me wonder if the plenum's shape, the intake piping angle, etc... along with the high flow/high boost created a unique situation that resulted in a particular airflow path that didn't allow the plenum to fill? Regardless, it would be interesting to see if such a device would help supercharged cars to gain some performance, even if it's a marginal increase.

    And thanks for your compliments on the CAD models. I've actually posted a few more photos on the SuperchargerHelp.com facebook page. Here's the link: http://www.facebook.com/pages/Superc...69880969703423

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    Junior SCH Member eeyore's Avatar
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    Michael, From a Air Flow stand point, it is completely opposite of of that Tornado Air, so lets call it a Anti Tornado Air!
    I went ahead and did the mod to the discharge tube, so we will see!

    Bill

    http://i1101.photobucket.com/albums/...SCN0206_01.jpg

    http://i1101.photobucket.com/albums/...SCN0207_01.jpg

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    SCH Owner Michael's Avatar
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    Looks good. Nice clean work.

    Curious if the placement of a device like that would be important. In other words, would a device like that be more effective if it were placed directly into the discharge outlet of the blower or would it be better placed further downstream? I guess it would depend on where the air turbulence would be at it's highest.

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    Junior SCH Member eeyore's Avatar
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    Inconclusive, First pass the truck was lazy, nosed over before the shift points, something it does every now and then on the first pass..kinda strange because I do a full driving warm up.
    Second pass it ran with in .02 of last weeks dial, but on returning to my pit spot, I discovered a impressive stream of coolant spraying out of the head gasket,
    nothing learned
    Bill

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    Junior SCH Member 64wagon's Avatar
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    Centrifugal Supercharger Discharge Swirl

    Is this a blow through carb application? I had a lot of burnt motors tring to figure this out. put a 4" spacer between top hat and carb then cut 1/2" off spacer till it loses power then add then add a 1/2" back. I did this test on the dyno but was told that it will work by the seat of your pants.
    Andy

  11. #11
    Junior SCH Member eeyore's Avatar
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    Quote Originally Posted by 64wagon View Post
    Is this a blow through carb application? I had a lot of burnt motors tring to figure this out. put a 4" spacer between top hat and carb then cut 1/2" off spacer till it loses power then add then add a 1/2" back. I did this test on the dyno but was told that it will work by the seat of your pants.
    Andy
    Hi Andy! It is carbureted but I am using a enclosure, I talked with a gentleman a couple of weeks back that had a hat application that was putting most of the air flow through one venturi on his carb! I would guess that the additional height you describe allows the air make the turn in the hat and straighten out before entering the carb...Makes sense!!
    The gasket failed at a water passage, not seeing any signs of combustion failure, What looked good was all my exhaust ports and combustion chambers had very even coloring, slightly lean, but distribution seemed good, no signs of detonation.

    Thanks! Bill
    Last edited by eeyore; 06-05-2011 at 11:50 PM.

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