Dasa 850 impeller pitch (144mm 12 vane pump)

I'm chasing some advice on my impeller pitch.
Current setup:
Krash 2017 Predator
DASA 850
144mm 12 vane solas pump
MSD enhancer
JSA Flywheel being installed in a couple weeks
Dual 46mm Mikunis
B Pipe (limited chamber)
12/18 Solas large hub
72kg rider

I guess I'm just looking for some experience on impeller pitch for my setup. Do I have the right pitch? Should I go up or down to get the most out of what I have?
I have no plans on going up in pump size. I can justify the new impeller if I need it though :cool:


  • 20200930_152232.jpg
    176.4 KB · Views: 11
  • 20201127_111536.jpg
    169.7 KB · Views: 11


Port for the Sport
St Cloud Florida
How does it feel right now? If its a heavy hull which i think krash are the 11/17 will be snappier. The Dasa 850 engines arent known for bottom end power so it would help bottom end. Whats the nozzle diameter and pump cone size?

Sent from my SM-G781U using Tapatalk

Big Kahuna

Tuscaloosa, AL
@Big Kahuna you reckon I should drop my pitch? Excuse my naivety on this topic, can you explain why I should go shorter?
I missed the part about prop you had. I had originally typed 11/17 or 12/18. But You cannot compare a Solas 12/18 to a Hooker 11/17 and think they are just 1 degree different. The designs are different and while the numbers may be the near the same they can be worlds apart on what they will each do!. That said, how does your Solas feel, Do you feel like your punching a hole in the water (Too small of a pitch) or does it feel like it wont get going? (To tall of a pitch). Here is an example of the Hooker props. 9/15 for stock to mild,
10/16 for Mild (Pipe and Head) to Porting up to Big Bore 84/85mm with Porting,
11/17 Mod (Porting, Porting for Racing, High Compression Head, Larger Carbs ex 46-48mm 800cc motor, etc etc.............
12/18 would work for previous possibly,

When you look at prop pitches per mfg. Look at the range of each design.
Skat will have say a 7/12, 8/13, 9/14,10/15 or 11/17, 12/18, 13/19, 14/20
Solas 12/15, 13/16, 14/17, 15/18 or 14/18, 14.5/18.7, 15/19, 16/20

So, you can see there is a progession, the lower number in simple terms is for a stock motor, highest for a more build motor. You can take 2 props and they will both will work, one will typically have less bottom and more top, or vs versa on the other prop. Figuring out the right prop is just part of tuning and can be difficult. Brian at Torrent Pumps is really good at helping to pick prop pitches. Dave at IMPROS was good as well (He sold it to Glen Perry I believe), I do not know the new owner.
Hope this helps and did not confuse you.
I have some experience with the large hub Solas 12/18. It was the only size available and I had to make it work on a 701, which it did after a LOT of bending.. Ill say, out of the box, this 12/18 too much load for any stock cylinder engine regardless of displacement. A power valve 850 with a good ignition may be able to pull it. I would make sure your nozzle is at least 85mm and pitch it down a little if needed. I will work great without too much work.
Top Bottom