SJ Setback Pump Idea

[FLY6584]

Well Legdragger's X-2 setback pump thread inspired me to think about applying the same concept to a superjet. Who know's maybe it's been done already.

Anyways I've heard of blaster guys using a 2nd wear ring to set the pump back for racing so I figured why can't you do this in a superjet.

It seems like you would just need an extra wear ring and be able to join the two wear rings together and drill 2 new holes in the hull for the rear wear ring. Then if you could come up with the right length drive shaft you'd be good to go.:dunno:

It's seems like a cheap way of turning a stock pump into a setback pump. I'm guessing it would set you back about 3.5in compared to only a 1.5in setback you get with a setback mag pump.

Just thought I would throw this out there and let the experts pick it apart and determine whether this would be worth it.:biggthumpup:

 

[RiverRat]

Also factor in that a mag pump weighs almost 2x what a OEM pump weighs so the benifits might not be as significant, if you are doing it to shift some weight

 

[FLY6584]

Also factor in that a mag pump weighs almost 2x what a OEM pump weighs so the benifits might not be as significant, if you are doing it to shift some weight

I was thinking along the lines of setting it back for more leverage when trying flatwater backflips. Not so much a weight thing.

 

[MADMAT]

I'm guessing it would set you back about 3.5in compared to only a 1.5in setback you get with a setback mag pump.

This sounds interesting. I have a spare wear ring but I'm waiting for someone else to try it first.

 

[Goose]

its in the works ill be testing it in a few weeks

 

[Goose]

also the mag setback pump the pump its self does not move back the impeller is just closer to the vaines.from what i understand. i talked to alot of people and about this and no one is really shure what its gonna do

 

[FLY6584]

its in the works ill be testing it in a few weeks

Right on:woot: :arms: Can't wait to hear how it turns out. Keep us updated.:biggthumpup:

 

[showmepro1200]

And post pics too. Unless this is a topsecret idea you don't want to get out of the 'lab' :smile:

 

[nikad58]

My old super stock (Sean Workmans old boat) had a 8 vane skat pump that was done that way (extra wear ring).. they also stretched the intake & grate to match the set back (a longer intake) it hooked up great ! As a matter a fact i rode it last weekend and now i can truly say.. that boat i miss the most !

 

[SUPERJET-113]

My old super stock (Sean Workmans old boat) had a 8 vane skat pump that was done that way (extra wear ring).. they also stretched the intake & grate to match the set back (a longer intake) it hooked up great ! As a matter a fact i rode it last weekend and now i can truly say.. that boat i miss the most !

I've help my friend that owns that ski now pull the pump before and yes its a second wear ring welded to the wear wing and then the big long alum pump shoe welded to that and all custom fiberglass work done to accomodate it.

Ya, that thing is a Crazy Train top end monster.. I can vouche for that, Ive rode it many times!
Rius barely pulls on top end by around 1 mph says Ernie(current owner of that AP Designs ski) and if you have ever seen Rius in action lately, you see he doesnt F around!
I remember when I found that ski for Ernie and he bought it from Butch and I had my daughter standing on it in my avatar for awhile and 11 PM'ed me over at PWCT and said "You focker did you buy that? That was always my dream ski"..

LAMEY touched everything on that ski and it shows!!

We always wonder if that pump type setup would be good or bad for added help in being a total backflippin mofo machine...??!?!?!? hmm?

 

[Legdragger]

Only one way to find out how it will work........right Goose:biggthumpup:

Could you post to refresh my memory of how the yamaha pump goes togehter. I would love to see what two wear rings look like stacked on a SJ pump.

 

[meatball]

yamaha goes together like kinda like legos. If you wanted you could put 50 wear rings on if you had big enough bolts.

 

[WaveDemon]

what drive shaft are you going to use. I don't think any stockers will fit.

 

[SUPERJET-113]

Yup, all custom titanium driveshaft in that ski.. thanks to Lamey..

 

[Goose]

im using a stock drivehaft cut in half and had both ends surface grinded to a 6 point to match my coupler sleeve with a very tight tolerance to keep it from moving and used 2 c clips to keep it in place.you have to drill the threads out of the one wear ring and make longer studs to bolt the pump togather.i also had to make brackets that are notched out and allow you to bolt it in stock location in the back they bolt to the ears of the nozzle and then up into the ski in the stock holes.right now im gettin heim ends to extend the steering cable since its too short.other than that with the hull shortned 3in and the pump set back 3in it looks like it could be a knee banger

 

[geraban19]

hummm...

Sounds good.

 

[CarterB]

post pics!

 

[dbrutherford]

also the mag setback pump the pump its self does not move back the impeller is just closer to the vaines.from what i understand. i talked to alot of people and about this and no one is really shure what its gonna do

A set back mag pump just has the stator veins shortened. It doesn't mean the prop sets closer to the stator veins like a "cut back" prop.

Say they stock stator section is 3". Then a set back mag pump has stator veins that are 2". Hence the pump would be a set back 1" pump. The 1" distance is made up with a 1" longer driveshaft or a 1" longer long nose prop.

Set back mag pumps are supposed ot help with top end or for racing.

the reason for moving the whole pump back is to create a bigger volume of water infront of the prop. Also to have the nozzle sticking out the back of the ski farther. Other than that, I am clueless.

Pete I will be sending you a PM in a few days. I have some questions to ask you.

 

[Goose]

I only wanted to move the whole pump back to gain leverage i didnt move the prop closer to the stator thats what skat does.I wanted leverage and gain volume in front of the prop to keep it hooked up.on a shortned hull the pump was too far back and made the intake pop out of the water and not hook up was the end result.