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Discussion Starter · #1 ·
Definitely not a pro by any description but this is a question for the Pro's, I am asking a question about some work done by a PRO..
On my personal boat, when I had the Intake machined for a shoe by a v-drive builder here in Tucson, every thing came out really nice. The biting edge of the shoe, the angle of the shoe, and the suction housing all blended perfect. According to said V-drive builder, all that hardware had to blend perfectly.
My buddy just paid a PRO for the same work, and the final product was slop. Most importantly in my non Pro head is the Shoe that sits 1/2" in front of the machined edge on the suction housing, with parallel angles. The Pro said that is perfectly acceptable, and my common sense says that is unacceptable. So does a step in the biting edge of the shoe where it meets the suction housing acceptable?
Thx for the replies...
 

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Step

Yes the step is acceptable. If yours has no step how will you add shims, to lower the shoe?? If yours has no step and you add shims you will end up with a vertical step across the face of your shims.

Most of the shoes have about a half inch flat step so if you need to add shims you can blend the shims to match the angle of the shoe or the ramp of the intake.
 

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Definitely not a pro by any description but this is a question for the Pro's, I am asking a question about some work done by a PRO..
On my personal boat, when I had the Intake machined for a shoe by a v-drive builder here in Tucson, every thing came out really nice. The biting edge of the shoe, the angle of the shoe, and the suction housing all blended perfect. According to said V-drive builder, all that hardware had to blend perfectly.
My buddy just paid a PRO for the same work, and the final product was slop. Most importantly in my non Pro head is the Shoe that sits 1/2" in front of the machined edge on the suction housing, with parallel angles. The Pro said that is perfectly acceptable, and my common sense says that is unacceptable. So does a step in the biting edge of the shoe where it meets the suction housing acceptable?
Thx for the replies...
that extra room can be used for shiming down the biting edge of the shoe. I know my low pro has about an 1/8 th of step.
 

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Discussion Starter · #4 · (Edited)
Shoe

I definitely understand the ability to shim down as needed. We set my intake/shoe level with the keel. Must have got lucky first time around. Never once cavitated, never was disappointed. Not sure why dude set the shoe level with keel and only able to shim down on a tunnel boat that isn't really proven...
but if the difference in shoe to suction housing angle isn't super important I guess I admit my common sense is wrong...
 

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The way it was explained to me was, the area in the step will basically just hold a pocket of water and it wont hurt flow. The reason for the step is not for shimming the shoe, its created by moving the biting edge of the shoe forward (closing off the intake). And once your set up is finalized, you can go back and blend it with epoxy if the step bugs you. But it wont make much difference.
 

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I definitely understand the ability to shim down as needed. We set my intake/shoe level with the keel. Must have got lucky first time around. Never once cavitated, never was disappointed. Not sure why dude set the shoe level with keel and only able to shim down on a tunnel boat that isn't really proven...
but if the difference in shoe to suction housing angle isn't super important I guess I admit my common sense is wrong...
I much prefer a thinner shoe with a step of 3/8 to 1/2". with no shims, I want the biting edge at least 1/8" or more above keel centerline. then adjust with shims based on what pressures are telling me. I NEVER run with the biting edge "even" with keel centerline - it is always above. maybe 0.020 to 0.060, but it's always above keel centerline. without that step, trying to fine tune for suction pressure is a total pain in the ass.
many many years ago a friend of mine had a brand new tunnel. took it to ming and it ran fine for a few laps. then he took it to firebird, the boat was overcharging and caused it to hippity hop all the way down the track. the shoe was thick, blended, with biting edge even with keel centerline. he parked it because he didn't have any way of shallowing the biting edge. had to get another shoe.

there has to be some adjustability. and those steps have absolutely no impact on performance.
 

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More explanation please...

I'm not quite following. I've had my boat for 15 years and know most of the jet parts, but I've never tuned the jet. Propless is talking about moving the shoe forward and BP is talking about shimming it down. I took some pics of my set-up, and hopefully if they're of the right portion of the shoe some of you guys can explain the step and shimming in a little more detail.
Thanks
 

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00 cp, what they are talking about it's the area on top of the shoe where the shoe is flat before transitioning into the suction housing.

Zach, it is fine and won't affect performance.

Sent from my VS980 4G using Tapatalk
 

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Steps are fine and are there for a reason, .500" is quite a step though.
not that big a deal. say, if you're going from 13 1/4 to 12 1/2, .5 isn't all that much. would rather have a little more than not enough.
 

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I'm not quite following. I've had my boat for 15 years and know most of the jet parts, but I've never tuned the jet. Propless is talking about moving the shoe forward and BP is talking about shimming it down. I took some pics of my set-up, and hopefully if they're of the right portion of the shoe some of you guys can explain the step and shimming in a little more detail.
Thanks
moving the shoe forward is not possible. that requires a different shoe machined so the biting edge is further forward, closing the opening a little. for a myriad of reasons, one boat might run with the opening at 14", while another boat might run an opening of 12 1/2". the decision to change opening size is based on a lot of different data points.

a "step" would be like a shelf between the top of the shoe and bottom of the intake that it bolts to. if there is no shelf, shims have to be exactly the same shape as the intake/shoe, and a wall is built. anything that "hangs over" the shoe, below the intake, creates a disruption. the edge of the shim has to be behind the top of the shoe cove, and in front of the intake opening. shims are usually fabbed so they can be stacked, like several "mini-steps". as long as none of the edges hangs over, there is no negative effect on performance. in faster boats, it's important to have adjustability in this area.

in your picture, there is no shelf or step between the shoe and intake. I'm not seeing a seam between the shoe and intake, just the seam between the intake and suction piece. looks like someone spent a lot of time with some type of filler.
 

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Thanks

Thanks BP, that helps a lot, although I would like to actually see the step and shims if anybody has pics or a link since they don't appear to be on my jet.
The boat with the pump was purchased directly from Bill Scotten. The impeller has been changed, along with loader, inducer and stuffer, but as far as I know nothing with the shoe.
 

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Discussion Starter · #13 ·
So for the most part, the answer is the same...It all depends on the the pressure readings...
And once you start getting into triple digits, the pressures need to be right on the money - top and bottom....
 

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So for the most part, the answer is the same...It all depends on the the pressure readings...
And once you start getting into triple digits, the pressures need to be right on the money - top and bottom....
So for the most part, the answer is the same...It all depends on the the pressure readings...
And once you start getting into triple digits, the pressures need to be right on the money - top and bottom....
well, not really sure what you mean by "it". just for discussion, if by "it" you're referring to shoe type, biting edge depth, length of opening, then it doesn't "all" depend on pressure readings. pressure readings are certainly important data points, but there are other things to consider as well as pressure. there's no one solution fits all, as in "pressure = x, so adjust xy". doesn't work that way. any adjustment to address one thing can have an unintended consequence that negatively affects something else.

just an example - if a boat has 45psi suction pressure at 65mph, it is no guarantee that it will have 45psi suction pressure at 110. at 110, that 45 could be significantly higher. or fall into the dirt. plus, ride and handling characteristics change as speed increases. the objective is to get a boat to be as safe as possible at it's maximum capability. a boat that seems just fine at 70 could be completely out of control or on edge at 110. conversely, a boat that seems just fine at 110 could be a complete tank at 70. while the shoe isn't the answer to everything, type/depth/opening are important elements that have to allow some adjustability.
 
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