Freestyle Set-back vs non set-back

[j0hnny]

ridden stock 144 mag 144 setback mag and stock 155. all with prop setup for the engine being run. the 155 thrust is so much cleaner and favors my style of riding. i will take volume over pressure any day. i am not trying to win a race. Tell me again how a 144 anything can outflow a 155 at any given rpm. you will be wrong.

 

[MarkyMarc]

@TheBuzzard. Well stated...

 

[sneds]

This is way l understand it (and I could be way off but it makes sense to me). Your pump acts like a compressor and by moving the impeller back it reduces the volume behind the impeller. This will allow the compressor to build pressure faster and therefore respond quicker.

 

[TheBuzzard]

i'm sure there is a case for reduced turbulence behind the prop. the less distance the water has to travel from the trailing edge to the exit nozzle. the less turbulence, friction and other water migration factors limiting flow are involved. maybe sj/js can school us on that last part......

 

[kevbo]

12 vane stators use shorter blades than stock 6 vane stators. Since they are made to mount in existing hulls, we end up with extra space inside the pump that holds more air. It is this trapped air that expands and blows water out of both ends whenever the inlet flow is interrupted which hurts hookup. Set-back pumps are just a proper design for 12 vane stators.

 

[OCD Solutions]

IMO, the most gain is to be noticed by switching from the OEM pump to basically any Mag pump regardless of setback. If you can afford setback then go for it but if you are building on a budget then I believe the money is much better spent elsewhere, (like a Solas Mag at a third the cost).

FYI, I have $550 into the Solas Mag in my wife's ski and $1800 into the setback Mag in my ski. The housing split on my Skat when it was a little over a year old and it cost me $385 to have it pressed into another housing. If it splits again, setback be damned, it's up for sale and it will be replaced with a Solas Mag. The setback Mag has been nice but I'm over it.

 

[masterblaster]

ocd, when you put the skat setback together, use high quality urathane sealant heavily on all 3 connecting locations and remove exess from inside.

that said ive run 144 skat setback in the same day same ski same prop,then a solas 144 and felt no diff in white water surf riding or flat water spins jumping out of the water. Tried the same thing with a older skat standard 148 then a newer punched out 148 setback with same prop,same result. no noticeable diff. Id still buy the setback for one reason,hype is very effective here,and in freeride,flatwater skis in general...at least when you go to sell it if you want to move up to a larger pump youll be able to sell it quick and recoup most your money,the extra cost of the driveshaft though jetmanic is not really a big deal,But no one would be able to tell the diff in a double blind back to back test. its too late though the hype has become reality,the same way it use to be that a 155 pump was way too much for a standup ski just a few yrs back,search it and read what many said about that back then.

 

[j0hnny]

reading even 2013 threads that a 155 pump is only for the insane guys with 1200cc engines is funny.

 

[masterblaster]

yep,go back a little further in time and you will see much worse...

 

[j0hnny]

Well my new dual stage 170 is going to set the world on fire!!!!!!! (can you tell im really bored today?)

 

[OCD Solutions]

I tried to look back and dig up the comments from 2009 when I asked about putting a 144 Mag in my 07 SJ with a ported 760. I couldn't find the thread but the summary is that it was a unanimous "no" with the reasoning being that it was just too much load for my engine. These days your a fool for not having one. Oh how things change.

 

[masterblaster]

or too much hookup and not enough slide capability in surf....lol I find it really funny how one person says something with the tiniest of merit a few people repeat it,next thing you know hype machine gets heated up,month later its unarguably factual..lol

these days I throw everything at a ski setup i possibly can just to set my own opinion,some of it pretty crazy really,but some awesome stuff has been learned in the process as well..