Wich impellar

[BOOGEYMAN]

How do you guys know what impellar to run in your boats? Is there a chart/graph that matches up rpm with HP or something? I just bought a jet and was courious on how to know if you have the right impellar for your application.
Thanks, Travis.

[SmokinLowriderSS]

Here's the selection guide from Berkeley:
http://www.berkeleyjet.com/products/impeller-info.htm
Most lake boats tend to run an A cut I believe, really big muscle lake boats may well run AA or AAA impellers. Some do run smaller ones tho (B's & C's), is whatever their setup combination of engine/hull/acceleration/speed makes them happiest. Some folks looking for better fuel consumption will go to a AA from an A as it cuts their RPM back about 300 per cut. That can be more tho if they get too far behind the power production of the engine tho.
A larger impeller can be "cut" to a smaller "size". The rear face of the impeller (the "outlet" side) is machined away. An AAA can be carved all the way to a "D" if you so desired on a lathe.
Typically (but not every boat is identical) the larger impellers which push more water at lower RPM accelerate harder & pull harder from a stop. The smaller cuts generally wind the engine higher and will run a few mph faster but trade off the acceleration a bit. now, exact water flow "per size" varries by manufacturer as well. I am happy with a Berk "A" in my boat. An upgrade I am doing has me going to a Manganese/Bronze from Aluminum. My boat works most of it's time pulling skiiers/tubes and I was advised to go with a particular brand that seems to pul hardest out of the hole. I will be running an Agressor "B" because it flows the same water per RPM as my old Berk "A" because the design is slightly diferent.
That's pretty much the nutshell version I believe. Some others here may flesh it out some more. My boat has been dad's for 25 years and tho I have a ton of time driving it, I have only a couple years of experience in modding it and have learned a lot here on the boards as well as other places. :boxed: