Freestyle japanese pump pics please help find link

[ridetrp]

i tried to search i forget where it was posted, can somebody post the link where there was pictures of the bun hull from the bottom,showed the pump area. thanks

 

[ph1lthy11y]

i would also like to see this

 

[CARBONX2]

These ones?

 

[CARBONX2]

another

 

[Christian_83]

Thats intake duct is insane!

 

[CARBONX2]

Think of it as a bellmouth like on a carb to help flow/volume

 

[kevbo]

I cannot see the inlet radius but it appears to have a 60 degree inlet ramp. Stock Superjets are 45 and couches close to 30.

 

[Waternut]

I cannot see the inlet radius but it appears to have a 60 degree inlet ramp. Stock Superjets are 45 and couches close to 30.

What are that advantages and disadvantages to this?

 

[yamanube]

What are that advantages and disadvantages to this?

More volume I would say, a steeper inlet could probably lead to cavitation at high speeds (maybe? my theory why a couch would have less angle) but at low speeds it would be way more volume.

 

[kevbo]

More low speed volume equals higher inlet pressure, less cavitation, and more thrust. Half of the reason for larger pumps is greater volume and the other is for improved low speed efficiency. This is why I advocate larger pumps once more than 17 degrees of pitch is required to load the engine. This mainly matters from 0-15MPH, with more speed dynamic inlet pressure enable smaller pumps with steeper props to work efficiently. Work with an FX1 from stock to 140 and then 144mm pumps. The biggest difference is at low speeds and rough/foamy water.

 

[D-Roc]

Great info kevbo. Your part of the reason my ski looks like this.