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  1. #1
    GZA's Avatar
    Join Date
    Sep 2010
    New Zealand

    Pump tunnel sizing

    Can someone school me on pump tunnel sizing? After a general thought process around it, but also some specifics relating to the 15f ie if a big pump goes in, does the tunnel size need to be increased? When is too big etc?
    I've tried searching but havn't found to much.
    Cheers, Rob

  2. #2
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
    Join Date
    May 2008
    I had a shit machine shop prep my pump shoe for my 155mm ultra 250 pump and it really hurt my speed, they didn't bore the inside out but instead tapered it back to fit. I cut it out by hand with a large diameter flap wheel and a couple of sanding disks for my angle grinder and I picked up 3 mph with the same setup everywhere else. I just cut the shoe out in the center and cut back the "hump" in the middle of the shoe (if you pull it you will see what I am talking about). The tunnel will support the speed no problem, it may cavitate a bit off a dead stop but its fine otherwise. You would want a fairly aggressive grate though.

    I may have some pictures of it when I was working but I will have to look, Ask user Dawson how his was setup.

    good luck,


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