Impeller question?

[ULTRA28]

Merry Christmas to you too.
I don't want anybody to think I'm knocking Aggressor with that post, because I am willing to do actuall apples to apples testing if Dave from Aggresssor wants to give me a call, I'm always willing to try to improve on what we've got going on. I'm just saying that a 20 mph gain just by changing the drive can only be done if you get rid of the pump and put on a prop and you know I'm NOT saying I like props better than jets. Just that props with equal horespower CAN run 20 mph faster in some cases, but there is no way that an equally set up pump, motor, boat package can gain that much speed by just changing the pump. Even Dave from Aggressor would have to agree with me on that.

[froggystyle]

What is interesting is that Agressor has self-admitted that they are comparing apples to oranges. When claiming that their "A" impeller has the same design characteristics as a Berkeley "AA" impeller, they admit that they are dissimilar impellers. "As you can see, it has an open face..." or something to that effect. "Water travels longer..."
With similar performance characteristics of a Berkeley AA, it sounds like they need to put the Aggressor into a different box, labeled "AA". You will see big mph gains going to a Berk "AA" from an "A" if you have the motor for it.
If you are comparing two similar impellers, and one has a performance increase because of weight, cup shape or something like that, then yes... You are comparing like products. This is like Merlin calling a 509 a small block, because it is less cubic inches than the 540. That doesn't mean they can compare it to a 350 Chev!
Aggressor, re-name your "A" a "AA", and then compare it to a set-up Berk. Apples for apples guys...

[LVjetboy]

I'd like to thank both Dave and John for sharing information with us. Participation from manufacturers and builders is great to see!
Speaking of apples and oranges, looks like Bronze and MagBronze aren't even in the same league strength-wise. So when speaking of "Bronze" we need to be more specific if the alloy is actually MagBronze.
Another interesting point is the higher stress levels in the Aggressor impeller (assuming the same input hp?) related to blade design. It would be safe to assume that other manufacturers also experience different stress levels based on impeller design if it varies from Berkeley. I know Dominator cuts typically run as if they are one size larger too. Although I don't know if this correlates to higher stress loads as in the Aggressor design. So an alloy near design limit in one may be over in another.
I'd still like to see some actual test data for Aggressor impellers (hp vs rpm) But for now, the JPC gets an Aggressor chart based on Daves comments above.
jer

[Cas]

After reading all that was said in this thread I've come to the conclusion that Panther Jets just have to be the best. The reason for this is they come stock with SS impellers and they are never mentioned in these debates. I'm guessing they are so far above the rest that you all leave them out and that makes me proud to own one.
http://free.***boat.net/ubb/biggrin.gif MUHAHAHAHAHAHA http://free.***boat.net/ubb/tongue.gif

[Jetmugg]

I'm not picking any one manufacturer over another - just shedding some light. It's not always enough to quote tensile and yield strengths of materials. You also should look at the %Elongation before failure. That is one area where most austenitic stainless steels (300 series) hold an advantage over Manganese Bronzes. (properly called Mn Bronze). It's not uncommon for 316 or 304 ss material to achieve over 50% elongation before failure. Mn bronzes usually get about 1/2 as much (roughly 20-25% elongation).
SteveM. - Still suggests cupro-nickel (70/30) as a good alternative to bridge the gap between Aluminum and Stainless Steel. Approximate Tensile strength - 80 Ksi
Approximate Yield Strength - 40 Ksi
Approximate % Elongation - 30%

[MikeC]

Cool SteveM, I was hopeing you caught that one. Thanks for your professional input!
As far as the "A" being better than the "B" or the other "A" or the "L" or the "D", (geez, I'm starting to sound like that cheerleader Jackass)..... I'd like to input my small experience with "A" and the "B" impellers.
I've tried an Aggressor C, (wich is supposed to be like a Berk B right. I did not go anyfaster then the Berk A!!!!!! I actually went the same speed in my 21 foot Kona. I found my holeshot was not as good with the Aggressor, but it did start pumping water at a higher rpm and the midrange kicked in hard..... Funny, my top rpm stayed the same 4500. I don't have a problem with Aggressor, but I get tired of the BS. "Bolt it on and go Faster/Quicker". I think they would do a lot better if they just sold there stuff as new and improved lada lada lada.....
I raced several other Jets with Aggressor Imp's in my PlaceCraft/MPD-Berk B (stock Berkeley) and I smoked'em from the get go, even with a V-Blocker in......
Squirtcha, did you go any faster with your Aggressor Imp??
Anyway, I'd like to try one of Daves parts again one day, geez, who knows, maybe he'll get luck one day and ??????? waaaahoooooo! Keep trying Mr. Jones.
See ya's at the track,
MikeC

[LVjetboy]

Hi Mike! Haven't seen you post in awhile...any winter PC plans I should know about? http://free.***boat.net/ubb/smile.gif
Good point about ductility Steve. I wonder what's the trade-off between %elongation and strength properties for a typical impeller design? For example, if you have a material with 1/2 the ductility, how much higher in yield and tensile for the same failure rate with these materials? That and I'm also wondering, where's the d*** lid to my blender?
jer
[This message has been edited by LVjetboy (edited December 09, 2001).]

[kanedog]

Will you guys be broadcasting the fist fight between Chet and hbjet on the net?
Some people take their metal knowledge very seriously.

[AGGRESSOR JETS]

Merry Christmas to all of YOU!!
John:I don't know the conditions. I do know our Impeller is good for 3-5 MPH on stock application Jet Boats. Our Bowl is 2-4 MPH when set up RIGHT.
In Higher Horsepower Our Impeller is 10MPH & our Bowl is worth 6-8MPH at the Blown Gas HP .This has been Tried & Tested-Don Harris-Blade Runner, Harold Bruce-R& D special,Dan Nelson-Jett Performance(Dan was threatened by IHBA -To Slow down or Park It),Tom Papp has a whole stable of them across the nation now. Ray Waller-Fuelish Reaction(the guy back east, IHBA Told him to slow down or park it) and so many more not listed.
"it can be done"! JUST wait untill our Duals
Hit! as most of the Jet Racers tell me thy can eat 1/2 there lunch by the time the props finish the 1/4 Mile! and with our 2 New Dual Drives undergoing testing 1 will produce 9,000 Gals.per Min (ENOUGH TO SUCK THOSE PROP BOATS INTO THE HOLE IT WILL CREATE) and a Thrust output @ between 2,400& 2,600 pounds (Static Pull).
A Second Dual Drive is designed for a small block and will produce 1,800 pounds of thrust. All Drives will transfer through a gear box to single input motor on a single intake mount.
John -KEEP UP YOUR GOOD WORK and Have FUN
Dave Aggressor.
Originally posted by ULTRA28:
Merry Christmas to you- Even Dave from Aggressor would have to agree with me on that.

[Slick]

Dave, welcome to the board. It's great having input from the manufacturing facet of things. Unfortunately you've been premised by a few blow-hards.
Here is the reason for my post. Dan Nelson is going to be rebuilding my pump this year. Does that mean he's going to replace my SS berk with an Aggressor bronze "B"? I'd really like another 20mph!!!!! Yeeeeeehhhhhaaaaaa.
I know those weren't your words, but I had to ask, just to be a $hit.
Later
Slick