best prop in 148mm mag pump

[steve-uk]

hey guys, just fitted a 148mm, 6 vane mag pump to my REV Hull, wondering what the best pitch for bottom end will be.

motor is a 701, stock carbs, b-pipe, after market flywheel, delta v-force 2 reeds, msd enhancer, ATP snake head

interested in comments

:fing02:

 

[Matt_E]

That seems like a mighty big pump for such a small motor.
I suspect you'll end up with an extremely low pitch.

Out of curiosity, why are you going with a 148 instead of, say a 140 Mag?

 

[SuperJETT]

From all the reading on here, I'd say that's way too big also. EME1000's use a 145 Mag and they are one of the strongest engines available.

 

[steve-uk]

i checked on the skat trac web site and the 6 vane is designed as a replacement for the oem pump on lower horsepower motors

http://www.skat-trak.com/magnum.html

the 12 vane is for the higher hp motors

 

[Matt_E]

OEM replacement for a similar sized pump, perhaps.
You might want to talk to a good builder about this.

 

[steve-uk]

as stock is 144mm, i struggle with why 148mm would be too big? 2mm per side extra?

the volume is not that much more, and surly more flow is better, hence people having reducion nozzles bored?

or am i missing something?

 

[Matt_E]

I am no expert, so I can't really give advice worth giving.
I've just never seen or heard of such a small motor (relative) turning such a large pump.

Give Jetworks or Team Scream a call and talk to someone who knows what they're talking about. (Instead of me)

 

[steve-uk]

lol.. ok .. sounds like a plan

 

[QJS]

Steve, if you take it to the extreem and imagine an impeller 6 feet in diameter, its easy to see why it would take a huge amount of power to turn it, particularly when under load. Conversely if you imagine an impeller 2 inches wide it would take very little power to turn it. If you take a look at oem ski's you will fing they don't use 148mm pumps on anything with an engine as small as yours, I would say a 140mm magnum would be your best choice.
Chris.

 

[steve-uk]

thanks Chris

maybe that means its time to get the bigger motor....

i have it fitted right now and to be honest it rips pretty hard, i got three props with the pump 8-15.5, 9-16, and a 14-19

im running the 14-19 but wondered if there was a better choice with what i have

 

[norcal ex]

i would use the lowest pitch prop

 

[junkyardj]

hmmmm why dont you call impros and see if they can repitch you to something more suitable? or did i already say that? JK xox

 

[AdamOntario]

I've got 140 mag with 14/19 prop running 4mm 803cc jetworks with TL, bpipe, dual 46 blackjacks. and I'm thinking of going lower pitch like 13/18

 

[Matt_E]

hmmmm why dont you call impros and see if they can repitch you to something more suitable? or did i already say that? JK xox

You can't just infinitely repitch impellers.
The mag impellers come off different casting for different pitches.
An impeller that started life as a 16/23 can't be repitched to a 9/12.

 

[junkyardj]

You can't just infinitely repitch impellers.
The mag impellers come off different casting for different pitches.
An impeller that started life as a 16/23 can't be repitched to a 9/12.

his prop he has now seems to be pretty good couldent they repitch it for a bit more bottom?

 

[SurferSmurf]

wouldn't the 8-15.5 be a steeper pitch???????????? if so use it and stop wasting time posting and asking questions. you canadians really are DUMB. Ha ha. :spankme: :hitwithrock:

:AR15firing::AR15firing::AR15firing::AR15firing::AR15firing::AR15firing::AR15firing::AR15firing:

 

[Cross]

thanks Chris

maybe that means its time to get the bigger motor....

i have it fitted right now and to be honest it rips pretty hard, i got three props with the pump 8-15.5, 9-16, and a 14-19

im running the 14-19 but wondered if there was a better choice with what i have

As someone who has ran a 148 mag pump in a SJ, I would say run the 8-15.5. The prop you are running now is WAAAYYY to tall on the bottom end. It should really wake up the bottom end with the 8-15.5.
I dont know where you got the pump set up, but it sounds exactly like what I sold a few years back when I parted out my boat. I really liked it, kind of wished I didnt sell it now.