Blower Injector Spacer/Shoes

Discussion in 'PSI Superchargers Tech Questions' started by Eric Vollmer, Sep 8, 2009.

  1. Eric Vollmer

    Eric Vollmer Member

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    I was just wondering what kind of performance gains there are in a blower injection spacer and shoe combination for a 14-71 PSI roots blower on a 526 cu in. big chief motor at 50% overdrive? I understand it makes the air more efficient but what am I looking at gaining and by how much? I'm talking mostly et and mph gains but will I see a reduced intake temperature, more boost earlier in the run or overall? Any thoughts would be greatly appreciated
    Thanks
    Eric
     
    #1
    Eric Vollmer, Sep 8, 2009
  2. secondwindracing

    secondwindracing top alcohol

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    I played with them and really didn't see any thing..Dave
     
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    secondwindracing, Sep 8, 2009
  3. Eric Vollmer

    Eric Vollmer Member

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    Dave, appreciate your input. If you don't mind me asking, what all did you try and did you get the shoes from somebody like DMPE or Chuck Ford? I was looking at the Chuck Ford parts to modify my PSI and was wondering if it was worth all the money?
     
    #3
    Eric Vollmer, Sep 8, 2009
  4. secondwindracing

    secondwindracing top alcohol

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    DMPE I also tried all the mods on the blower also tried the buzzard vs big and ugly and couldn't see anything another word bang for the buck...a very soft bang:)..Dave
    I might add if this was done to a fuel car I think it might help??
     
    #4
    secondwindracing, Sep 8, 2009
  5. hemi altered 378

    hemi altered 378 Blown Altered

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    Eric.....
    honestly i wouldn't even try to modify your blower, theres no sense in that. just trade me even for my fully modified 1996 SSI :D
    give me a call when you get a chance
    Darren
     
    #5
    hemi altered 378, Sep 8, 2009
  6. Mike Canter

    Mike Canter Top Dragster
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    I think how much a spacer helps is dependent on how the hat matches the opening in the top of the blower, the design of the hat, and is dependent on if you shift at 8000 rpm or shift at 10000+ rpm. If that hat has a 10.5" opening on the bottom and the hole in the top of the blower is 9.5" then that step is at the worst possible position for the incoming airflow at the back of the hat. In this case using a custom made DMPE CNC spacer that matches the two openings and smoothes out that airflow will show you lots of power increase maybe even up to 150 HP (seen on DMPE dyno tests). If the hat already matches the blower so there is no internal step to break up the incoming airflow then the big advantage in the spacer is only by moving the hat forward and up to make the angle of the incoming air better and in this case not as much gain seen. Also both the above gets more critical with higher RPM and more air flow.

    If you take a flashlight and hold the blades wide open and look inside you should be able to see the back end of the rotors with no mismatch step and the straighest angle you can get. Any turning of that airflow will reduce the airflow any mismatch will reduce airflow.

    Becareful of "off the shelf " spacers that do not match the hat and blower opening configurations. They can be a total waste of money and can make the problem worse.
     
    #6
    Mike Canter, Sep 9, 2009
  7. Eric Vollmer

    Eric Vollmer Member

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    Darren,
    I'll give you a call one night later this week. I think as good a deal that sounds, I'll have to pass on swaping blowers, haha.

    Mike,
    Thanks for the insight. After reading your post I don't think there would be much gain for me to spend the money on a spacer and shoe insert. I have quad star hat that matches the top of the blower and I'm not turning any crazy high rpm's. Thanks for the help.

    Eric
     
    #7
    Eric Vollmer, Sep 9, 2009
  8. crdafoe

    crdafoe Member

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    Mike: What about where the scenario you described is reversed, ie the hat opening is smaller than the blower top opening? The hat is a 10.5" (PSI low profile square door with the BNR adapter) and the blower is 15" (older Littlefield 14-71 HH). Would it be advantageous for the bottom side of the spacer to maintain the 10.5" opening, and make it so the rearward most 4.5" of the blower top doesn't have any air going into it, or the reverse, so the front 4.5" doesn't have any air going into it? Or would it be better for the spacer to be 10.5" on the top and the full 15" on the bottom?

    I'm sure the best solution would be to get a better, newer blower, but until that time comes, this is what i've got to work with.

    Thanks
    Chris
     
    #8
    crdafoe, Sep 9, 2009
  9. Mike Canter

    Mike Canter Top Dragster
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    Good question and I don't know the answer on if a 15 opening is better. I know that the standard now appears to be 10.5 or smaller.
     
    #9
    Mike Canter, Sep 9, 2009

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