Rpm drop??? Going frm aluminum to bronze????

[396_WAYS_TO_SPIT]

Just curious to see if anyone has experimented with different grades of impellers on the same hull,pump,motor. Lets say that you ran a berkley aluminum B at "X" rpms. Then you switched to a bronze b and it spun less rpm's. Do you think that the weight of the impeller would cause this? I am thinking of the idea trying to swing a bag of rocks that weighed 10lbs. Then you added more rocks that brought the weight up to 30lbs.

[78CoLe]

sounds like a question for duane My .02 is i was told that the weight doesnt effect it as much as the flex but sh#t who knows

[396_WAYS_TO_SPIT]

Thats what I have heard but it doesnt make sense. THe rotating mass changes dramatically.......

[Jet Hydro]

The rotating mass will cause some but not as much as you think. The Mag impeller might be getting a better bite.
You said a berkley aluminum, who's mag impeller are you installing?

[396_WAYS_TO_SPIT]

old style dominator mag bronze......
What about an inducer??? Can they pull down r's???

[Ken F]

>old style dominator mag bronze<
there is your difference.
Inducer is a small impeller installed in front of your regular impeller which helps load the center of your larger one on take off. They won't make any difference on the top.
KEn F

[Squirtcha?]

Ran it on the JPC and here's what it came up with. Apparently there is a pretty big difference between the dominator and berkeley impellers.
The numbers (horsepower and rpm) are arbitrary and I just plugged em in as an example.
http://www.jetheaven.us/photopost/data/500/19396_s_impeller-med.jpg

[centerhill condor]

changed to bronze from aluminum and the boat runs the same. The bronze weighs more than the aluminum and that affects how the drive "spools up" or accelerates but I haven't noticed a difference.. the boat performs the same.

[Ken F]

396-post up your speed and ET differences as well as RPM if possible.
It sounds like your impeller is "hooking-up" a lot better than the aluminum berkley was. I'd almost bet you are turning less rpm, and going faster in both ET & speed.
Ken F