Impeller

[1Bahnerjet]

Can impellers make this big of a difference, I replaced my old Berkeley JC with A impeller And put in a berkeley with aggressor bowl, with B impeller, Place diverter, ride plate. The old Pump ( with Mild 454 ) had more pop off the bottom And more RPMs on top. What could be wrong?

[btbuilder2]

i would have to say,first did you check clearences between the impeller and wear ring, should be 6 to 8 tho over all,,next i would have to say that you dont have enough horsepower to turn the B impeller, it sounds to me like you need to go to a,,,A/B cut impeller,, you also may want to install a nossle reducer you you can,, oh and one more thing,, how is your ride plate set up, you may have it set wrong,
p.s i have a A/B CUT impeller that has one run on it for sale if you need!! also have some wedges 4&6 degree

[1Bahnerjet]

btbuilder2:
i would have to say,first did you check clearences between the impeller and wear ring, should be 6 to 8 tho over all,,next i would have to say that you dont have enough horsepower to turn the B impeller, it sounds to me like you need to go to a,,,A/B cut impeller,, you also may want to install a nossle reducer you you can,, oh and one more thing,, how is your ride plate set up, you may have it set wrong,
p.s i have a A/B CUT impeller that has one run on it for sale if you need!! also have some wedges 4&6 degree The impeller(legend) Was Installed by Pleasure boat specialties (san jose) clearences were checked. the place diverter has the red insert in nozzle but i don't remember what degree he set the ride plate at But it is bent up not down.

[1Bahnerjet]

1Bahnerjet:
btbuilder2:
i would have to say,first did you check clearences between the impeller and wear ring, should be 6 to 8 tho over all,,next i would have to say that you dont have enough horsepower to turn the B impeller, it sounds to me like you need to go to a,,,A/B cut impeller,, you also may want to install a nossle reducer you you can,, oh and one more thing,, how is your ride plate set up, you may have it set wrong,
==================================================
p.s i have a A/B CUT impeller that has one run on it for sale if you need!! also have some wedges 4&6 degree The impeller(legend) Was Installed by Pleasure boat specialties (san jose) clearences were checked. the place diverter has the red insert in nozzle but i don't remember what degree he set the ride plate at But it is bent up not down. ================================================= Oh, It was set 8 Degrees up

[LVjetboy]

Was your old A impeller Berkeley? Legend impellers absorb more hp than Berkeley for the same cut* so going from a Berkeley A to a Legend B is only about 100 rpm gain at your power level all other things equal. Impeller designs differ.
For example, going from a Berkeley A to Berkeley B...gains 250 rpm...over twice the rpm.
But in your situation, all other things may not have been equal considering your old Berkeley J/C with A impeller may've been worn with minor leading edge blade damage and excessive wear ring clearance, those factors could've causes your old pump to run a couple hundred rpm above normal...giving you a net loss of 100 rpm with the switch. Not something you'd expect, but certainly possible.
jer
*mfg curves
[ January 05, 2003, 12:45 PM: Message edited by: LVjetboy ]

[1Bahnerjet]

LVjetboy:
Was your old A impeller Berkeley? Legend impellers absorb more hp than Berkeley for the same cut* so going from a Berkeley A to a Legend B is only about 100 rpm gain at your power level all other things equal. Impeller designs differ.
For example, going from a Berkeley A to Berkeley B...gains 250 rpm...over twice the rpm.
But in your situation, all other things may not have been equal considering your old Berkeley J/C with A impeller may've been worn with minor leading edge blade damage and excessive wear ring clearance, those factors could've causes your old pump to run a couple hundred rpm above normal...giving you a net loss of 100 rpm with the switch. Not something you'd expect, but certainly possible.
jer
*mfg curves ================================================== I don't know what brand impeller was in the JC pump but it was rebuilt by G.T. Performance just before i bought boat 2 years ago. there is one thing i didn't say. i replaced loader scoop, both scoops are hardin marine "SE" sport edition, but the one i took out (that i used with the JC pump)had half the ramp cut off for a more open design, maybe i should put the old grate in just to see?

[LVjetboy]

Uhm...well, loaders certainly affect hole shot...and a more open design lets more flow at launch. So that may explain your loss of pop.
As for top end rpm...I'm still leaning to my original post. I'd think Pleasure Boats could tell you the impeller they swaped? But for most non-race pumps, I'm guessing the brand of the impeller in many cases follows the brand of the pump.
There's the old saying true...change one thing at a time to know what is due. Or did I just make that up? Not that most follow this course, including myself of course. But it sure makes troubleshooting a lot easier.
jer
[ January 06, 2003, 01:36 AM: Message edited by: LVjetboy ]

[1Bahnerjet]

LVjetboy:
Uhm...well, loaders certainly affect hole shot...and a more open design lets more flow at launch. So that may explain your loss of pop.
As for top end rpm...I'm still leaning to my original post. I'd think Pleasure Boats could tell you the impeller they swaped? But for most non-race pumps, I'm guessing the brand of the impeller in many cases follows the brand of the pump.
There's the old saying true...change one thing at a time to know what is due. Or did I just make that up? Not that most follow this course, including myself of course. But it sure makes troubleshooting a lot easier.
jer ================================================== ================================================== Yeah its a B cut Legend, This pump came out of the Blk./red Bahner that was in the reader rides section of Hot Boat Mag. Nov/Dec.2002 (pg.78) that boat had over 500 H.P. My Bahner with its 454 has 350-375 H.P. so it could be :( the pump just wants more POWER?

[LVjetboy]

I'd say the pump wants more than your impeller and engine can give. BTW, I ran those numbers for 350 hp. Lucky guess. The deal is, impeller matching to hp all good for squeezing that last mph, but payoff tempered by how far off the peak and the slope of the curve. More mild = less peak and slope.
Squeezing gains from impeller matching a tweak, but for real gains consider more hp, as in more $$$. Very sad but true.
jer