Pump is 140 while impeller housing and exit nozzle is 144

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Hi Guys,

Thinking of installing a 12v magnum pump(which a pal gave to me some time back) to my superjet.

However, theres a situation… Pump is 140 while impeller housing and exit nozzle is 144…. ..

Any idea anything bad could happen if I am to proceed with the installation? Or should I get the pump edges machined to match the edges of the 144 housing/nozzle?

Cheers,
Kelvin

You definitely want to have the impeller housing sleeved down to 140mm; which will require a 140mm impeller. Going from big to small to big will hurt performance. Especially the big (impeller housing) to small (pump stator). The sudden step will increase cavitation and reduce the pumps efficiency tremendously.

The reduction nozzle being 144mm isn't that much of a problem unless you're going for every tenth of a mph and every % of hook up and acceleration. Then I would suggest you get a Skat nozzle kit.

Something else to note if you already haven't.... Typically with mag pumps you need a strong limited set up at the least. Mag pumps provide improved acceleration and hook up. This is due to the larger hub and improved stator vein configuration. On the flip side it requires more horsepower to process water through a mag pump due to its design. You can expect a slight loss in top speed compared to a stock pump. However, the gain in acceleration and hook up significantly outweighs that loss though.