Freestyle 148 MAG setback- set ups- recommendations-experiences

[orangefinger]

I am trying to get my arms around the setback 148 MAG and to understand what changes might be helpful to advance the performance of this pump.

Freestyle -Engine 876cc, MAG 148 Setback , Standard length Cone , 84mm 65V nozzle, worx 201 , 9/15 Hooker .

The pump comes on very late and only at high RPM , and standard 360 spins ( on water not aerial ) are almost impossible thus it appears the engine is bogging down at low RPM. The pumps performance feels delayed and I am not sure if it takes too long to push water out or cant push it out fast enough ??

Please let me know what nozzle size, cone, impeller pitch you are running and what your experiences or advise would be.

If you are at higher elevation ( we are between 4500/5500 ) all info would also be appreciated, but as long as I have sea level info that would help and give me a starting point, hence we have set up many 144's already with no problems.

Thank you

 

[WB800BLASTER]

pretty sure you need a higher prop pitch on both the low and high end.

 

[orangefinger]

anyone else chime in....??

Why would you think the pitch is too low .??

 

[raytherace]

First of all, hooker prop is for 144mm pump not 148mm. We had built an hurricane with a 910cc ADA billet cylinder, TL, PFP, Novi and all the good goodies with a 148mm set back pump and 11/17 was a bit high. So I guess 10/16 would be perfect for that setup. For your setup a 148mm prop 9/15 is suppose to be close to the perfect pitch IMO, no need to go higher, maybe lower. We had built also an BOB 1100cc with 148mag and 12/18 prop and it was a bit high also for a freestyle application. We had also tested some big engine with 155 pump and had test some weird pitch like 8/12 with an 1000cc and it rip a lot. We realized that with the standard pitch, we had a lot of top end that we had no need soo as for now we order prop with custum pitch who the number are closer to each other like 8/12, 9/13, 10/14.

just my .02 cens

 

[Tyrant1919]

What prop did you have in the 144?

If you're having trouble accelerating, you definitely have to pitch down or increase your nozzle bore. One of the two.

If you started with a 144, 9/15, and an 84 nozle, then went to a 148, 9/15, and 84 nozzle, you're now pushing a bit more water. You may have to pitch down to a 8/14, 7/13. I'm not an expert on pump/prop selection, but it's fairly similar to selecting a prop for an R/C airplane.

EDIT: Damn, you've built some skis ray.

 

[jMike]

I have a gen3 with a 148mm SB, 10mil DASA with TL etc... We ride at 2200'

I'm running 12/17 with an 85mm nozzle and it seems about right.

 

[Matt_E]

The impeller pitch numbers given here may not mean much because they are all for Skat's standard 148mm impeller, which the OP does not have. He is using a custom Hooker - those pitch numbers may not translate to the standard impeller the same way.

 

[orangefinger]

THe 9/15 we have was made by Skat for the 148 Pump

Yesterday I ran the 144 MAG with 8/13, 85mm Nozzle, Worx 201 and SHORT CONE, which really opened the pump up and let me do 360 spins ( not areal )
with ease and for the first time with both feet in rear of tray,as well as consecutive 180 Hopps , with this set up I have the feeling the power band at low-mid-bottom high is on the spot, but top High appears to be spinning a little with no thrust,( could be hull intake , my weight etc ) so today I will try to nozzle DOWN a little to see what happens 84mm or even a little less.

As for the Setback 148 MAG, best advise here from ray I think is 8/12, 9/13, 10/14, which I will try with starting 85mm Nozzle and standard Cone ??

Which cones did you run on these and is there like a " golden rule " smaller pitch should have smaller cone or so ..??

 

[orangefinger]

On another note....should I be looking for a smaller spread ??

8/13 Spread =5
8/12 Spread =4 same as 9/13 and 10/14
11/17 Spread = 6
9/15 Spread = 6

Would possibly a lower spread be a general rule of thumb ..??

The first number is the leading edge pitch. This indicates the amount of water being scooped into the
pump. A lower number means a bigger scoop, which means more water goes into the pump. The second
number is the trailing edge. This is the edge that accelerates the water, a higher number means more
top end. (if your motor can pull it)
The "spread" is the difference between the 2 numbers. The bigger the difference between the numbers,
the greater the amount of water that gets processed thru the pump. The bigger the spread (or window)
however, the more torque you need to be making to pull the prop through this greater volume of water.

 

[masterblaster]

you say in your first post its a 9/15 hooker then later down its a custom made skat prop? in a 148 your cutback and your spread make a even more dramatic diff than the 144 does.It pretty much has to be right on.

 

[kevbo]

On another note....should I be looking for a smaller spread ??

8/13 Spread =5
8/12 Spread =4 same as 9/13 and 10/14
11/17 Spread = 6
9/15 Spread = 6

Would possibly a lower spread be a general rule of thumb ..??

The leading edge, especially at the tip must be very flat in order to establish a boundary layer. This makes the impeller more efficient at low speeds. If the leading edge is too steep there will be flow separation and vibration out of the hole. All of the load is at the last two inches of the blade. Raising or lowering the trailing edge makes a big difference.

 

[norcal ex]

I have a 8/13 for sale. My pump is non set back. I do not know if you can get this one to work.
Bought 3 weeks ago and used it one time. My motor is a 950. It was good in my ski but I went just a tad larger. No burning out at all.

 

[XJCrawler]

Did you ask art for impeller recommendations? He said if I ever wanted to go 148mm with my 888 he had the perfect impeller for me

 

[orangefinger]

XJCrawler ,

I did talk to Art and the 144mm Impeller he recommended SKAT A ( secret Pitch ) for this engine was close but not perfect, with us being at 5500 Feet the pitches change, the starting point was good but other impeller performed better, furthermore the 148 that we have is setback which will make a further difference.

I am just trying to get my arms around a set up with 144 and a setup with 148 that will work and transfer the power adequately.

 

[orangefinger]

norcal ex ,
pm me your price, also what nozzle, cone, and intake are you using ??

 

[Scraggly]

XJCrawler ,

I did talk to Art and the 144mm Impeller he recommended SKAT A ( secret Pitch ) for this engine was close but not perfect, with us being at 5500 Feet the pitches change, the starting point was good but other impeller performed better, furthermore the 148 that we have is setback which will make a further difference.

I am just trying to get my arms around a set up with 144 and a setup with 148 that will work and transfer the power adequately.

how is that??

 

[XJCrawler]

XJCrawler ,

I did talk to Art and the 144mm Impeller he recommended SKAT A ( secret Pitch ) for this engine was close but not perfect, with us being at 5500 Feet the pitches change, the starting point was good but other impeller performed better, furthermore the 148 that we have is setback which will make a further difference.

I am just trying to get my arms around a set up with 144 and a setup with 148 that will work and transfer the power adequately.

He should have a starting point with a 148 for you though

 

[orangefinger]

higher elevation requires change in pitch.. ??

Or the fact that we have a lake 5500 Feet ? Reno is 4500...??

 

[Matt_E]

how is that??

Higher elevation means less motor power, so you cannot take the same pitch impeller for a standard sea level engine and expect it to work the same at 5500 ft.