Reply With Quote5600 RPM berk "A" approx 500HP. Boat is 19' spectra in my avatar ,gps'd at 72 MPH
How many r's can a stock berk "A" impeller take? How high have you all spun one & how much power (est) were you making? I was just wondering.
Clay
[ October 01, 2003, 10:21 PM: Message edited by: skeepwerkzaz ]
5600 RPM berk "A" approx 500HP. Boat is 19' spectra in my avatar ,gps'd at 72 MPH
I was wondering that also. As I look at all the charts on the web and the Soloc Jet book, they all same something diffrent.
Many of us have spun Berkeley impellers way above 5500 rpm at times. But it's not safe. How long will they last that way???????? 2 days, two years, who knows. Best to go bronze after 500 HP and be safe.
One thing I noticed. The aluminum impeller is very light weight and the stainless isn't much heavier, but the bronze weighs a stinkin ton. I think the price differential between bronze and stainless is like $300? I can't help but wonder what, if any, difference there is in performance and pump parts longevity with all the additional weight of bronze imps.
If I were to ever spend the money on a better impeller (and running 600 hp with N20 @ 5600 rpm I guess I should), I'd go right to the stainless rather than that heavy ass'd bronze.
[ October 01, 2003, 08:06 AM: Message edited by: Squirtcha? ]
Squirtcha?:
One thing I noticed. The aluminum impeller is very light weight and the stainless isn't much heavier, but the bronze weighs a stinkin ton. I think the price differential between bronze and stainless is like $300? I can't help but wonder what, if any, difference there is in performance and pump parts longevity with all the additional weight of bronze imps.
If I were to ever spend the money on a better impeller (and running 600 hp with N20 @ 5600 rpm I guess I should), I'd go right to the stainless rather than that heavy ass'd bronze. Several points here-Bronze Impeller &
Mag.Bronze are night & day in strength.
Please understand if you are talking Bronze
you are talking a impeller I would not
run over 650 HP- Bronze Alloy is a
simple pour alloy.
Most Metal Tec's on here will tell
you Mag Bronze is a very hard alloy
to pour & get a sound Impeller.
We have beat this Bronze alloy to
death trying to get the right alloy
to withstand the pressure loads we
require.
Our Mag Bronze Impeller weight is
2 pounds lighter then our 17-4 stainless.
In all cases on our impellers you can
trim the shroud down and remove several
pounds off.
We did this for a short time and then
stopped.
Next Year we will resume additional
trimming as a option, yet on big motors
I do not recommend it, inside pressures
get big time.
Now I say all this as maney run 500 HP
on Alum. impellers and when I talk to them
I hear "I KNOW"
The Highest "A" on our Impeller was around
8300 RPMS- 17-4 Stainless
The Highest on our 9 1/8" "B" cut was 8600
David Kirkland- Smoking & Stroking.4-5 years
ago. 17-4 stainless. Knowing Dave's motors
I would guess 3500+ HP not sure.
Suggested List:
Price - Our Mag Bronze @ $695.00
Our 17-4 Stainless @ $1,289.00
99% Mag.Bronze Covers/Big Fuel Motors 17-4
See ya @ IHBA World Finals- Dave Aggressor
Squirtcha?
You are running 600 HP @ 5600 and Spectra's only turns 5600 and claims 500 HP. Does the different hull design and pump builders make that much of a difference? Thanks again for the info guys, I really appreciate it.
Clay
Skeep, this particular boat [1978] is completely original ,has the original impeller with the s/s wear ring which isn't as tight as a shouldered bronze wear ring wink . I had the pump inspected and has 25 thou total clearence so I've left it alone to maintain the boat as original as it can be .There's no cavitation at all on the holeshot and the speed I've got out of it speaks for itself. So there was no point replacing the wear ring.With the supertrapps on ,it turns around 5300 ,so don't really worry about running alu impeller.I had alu impeller in my 20 jet boat for 26 years [ was also turning around 5300] .All the busted impellers I saw was caused mainly by thrust bearing failures or someone "blueprinted it" with very tight clearences
I've put about 600hp to an alum A imp for about 8 years. Its a 400 hp sbf with a 250 hp plate N2O kit (don't think I'm really getting 250 hp from the plate kit cause the motor isn't built for the N2O.) I've run about 400lbs of N2O through it.
I finally got bit when trying out droops/wedges at the drag races. It cavitated (I think due to an air bubble) when I launched it and the impeller grenaded. It was a billet aluminum impeller I'd been running for about a year, I'd used a cast al A before that.
This is a legend jet pump and I turn 5k rpm with 400hp motor and 5600 with N2O. When running w/out N2O, I jump wakes/rapids and no problems, but I'm just pushing it too much with the N2O I guess.
I'm in the process of building a new motor and I'll prob end up going to stainless as I'm gonna add about 200+ hp to what I've got now.
just my exp,
jd
skeepwerkzaz:
Squirtcha?
You are running 600 HP @ 5600 and Spectra's only turns 5600 and claims 500 HP. Does the different hull design and pump builders make that much of a difference? Thanks again for the info guys, I really appreciate it.
Clay Clay,
I think we're talking apples and oranges to a degree. I'm running an Aggressor A impeller that has been cut down to an AB. I've always heard (and maybe Pops 1 can add something here) that there is a half size difference between Berkeley and Aggressor. In other words an Aggessor AB would rev about the same as a Berkeley A? Not sure if that's right or not though, or if it is...........why it is.
Also not clear on Spectra's rpm. The first one says 5600 rpm and the second one says 5300 rpm.
I just couldn't resist jumping on the coattails of your post as it was always something I was curious about.
Ye-ouch
Just noticed the price of a stainless impeller. Holy crap dat's a lota scratch.
[ October 01, 2003, 12:35 PM: Message edited by: Squirtcha? ]
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