Custom/Hybrid stock sj pump inlet widening

[harrypotter]

has anyone ever tried this ? read the thread on the guy who did a d.i.y set back, if i find a cheap mid shaft i would like to try it . just wondered if anyone has messed with the tunnel and/or inlet

 

[Sanoman]

Been wondering about this myself.l started a thread looking for trashed rn hulls.Maybe we can get some ski builders imput on your question.

 

[Waternut]

The BOB hulls made theirs longer and they say it makes a difference but I didn't really notice any difference. Maybe it's supposed to increase the pressure ahead of the pump but when the hull comes out of the water, the only reserve is behind the pump shoe and everything else would just fall out. A wider inlet track should increase the pressure in front of the pump as well but it may also distort the flow going into the pump as well which would make it worse.

 

[CARBONX2]

Wider inlet helps acceleration and hurts topspeed. Do a search on older forums for Raider hull topics

 

[davidy]

you need an engine that can move that much water. i dont know that making it bigger with just a 701 would help too much

 

[kevbo]

The SJ inlet is relatively large and shaped for low speeds, very good for smaller engines. It should be widened anytime a larger diameter pump is used. The performance increase is only at very low speeds where inlet pressure is at its lowest. A great pump design trainer is in making an FX1 work, that POS will end up teaching you everything you need to know about pumps.

 

[Flash-FX]

has anyone ever tried this ? read the thread on the guy who did a d.i.y set back, if i find a cheap mid shaft i would like to try it . just wondered if anyone has messed with the tunnel and/or inlet

Additional pump loading would probably kill performance on a stock powered boat. At what speed does the boat need better hook up?

you need an engine that can move that much water. i dont know that making it bigger with just a 701 would help too much

X2

The SJ inlet is relatively large and shaped for low speeds, very good for smaller engines. It should be widened anytime a larger diameter pump is used. The performance increase is only at very low speeds where inlet pressure is at its lowest. A great pump design trainer is in making an FX1 work, that POS will end up teaching you everything you need to know about pumps.

Sounds like we know almost everything about pumps....lol.

 

[Idok]

and we thank you for paving the way!

 

[Freakrider]

The SJ inlet is relatively large and shaped for low speeds, very good for smaller engines. It should be widened anytime a larger diameter pump is used. The performance increase is only at very low speeds where inlet pressure is at its lowest. A great pump design trainer is in making an FX1 work, that POS will end up teaching you everything you need to know about pumps.

Kevin,

Well said...

A friend tried putting a 155 pump in a blaster 1 with a 760 motor the pump did not work well at all , it was starving for water...He put the 144 back in and the ski ripped scary fast !

 

[harrypotter]

I have a stock sj cut up, putting rocker in the back and cutting the front . While it's being torn apart I was wondering weather to mess with the pump cavity a little . Engine will be an xscream 865 with a recommend set up from them .

 

[kevbo]

Additional pump loading would probably kill performance on a stock powered boat. At what speed does the boat need better hook up?


X2


Sounds like we know almost everything about pumps....lol.

Not hardly, but I have found answers to performance problems in an area that nobody ever talks about.