Impeller ?

[Taylorman]

Tried a new impeller today with negative results. I was running an Alum Berkeley A Impeller at 4750 rpms at 63 mph. Today I put in a Bronze Aggressor impeller that i bought off ebay which is suppose to be an Aggressor C cut. I measured it at 6 5/8 which by my calculations is an Aggressor A/B or a Berkeley B/C. With this smaller impeller, im turning 5000 rpms, an increase of 250, but am now at about 61 mph. Can someone give me an explanation of why I did not see a speed increase. I knew that its not guaranteed to increase speed just because of an increase in rpm's.
[ March 09, 2003, 07:37 PM: Message edited by: Taylorman ]

[HBjet]

What condition was the Aggressor impeller in compared to your Berk that you took out? Also, something that may work for one setup, might not alwats work for another.
HBjet

[Johnwithjm]

I went the other way from an Aggressor mag bronze to a berk stainless and it was night and day.

[Taylorman]

The Aggressor I bought from Revndave. He posts here. He said it was race detailed by Tom Papp.
Its was in better shape than my alum berkeley impeller. I realize that more rpms is not always faster but can you explain why.

[Jetty 468]

Is there any hook in the hull ?

[MikeF]

1976 Taylor SJ, Olds 455, Berkeley 12JE with Alum. Berkeley AB Impeller (Soon to be Bronze Aggressor C Impeller......soon to puttin that Berk back in wink )

[77charger]

maybe chet can explain tis one! argue
At what rpm does your motor make its peak hp.the new aggrsor impeller might be letting your motor go past your peak.or might need to rev higher to get the speed increase.

[Jet Junk]

My understanding is that a smaller impeller is less effecient. I.e. an A impeller at 5000 rpm moves more water than a B at 5250 rpm.

[Jet Hydro]

Taylorman It sounds as if you don't have it set up as tight as your old impeller. Did you check your old impeller clearances before you removed it to see where it was set at?
Did you install a new ware ring and if you did are you sure it fits right?
Did you change your nozzle size to make up the difference?
There are a hole slue of things that can change when you play with an impeller. You might take it to a shop that sets up impellers and give them a try or
call (SPAM --> ) Duane at Hi-Techperformance, I`m sure he can give you a few pointers. Duane tested mine last year with a Aggressor C that would hall the mail at 5800 rpm 82mph. I run an Aggressor A now but My C gave me just about as good of hole shot as my A does. Duane know`s how to set up those impellers wink
[ March 09, 2003, 08:53 PM: Message edited by: Jet Hydro ]

[HBjet]

Jet Hydro:
Duane tested mine last year with a Aggressor C that would hall the mail at 5800 rpm 82mph.Isn't an Aggressor C the same size as a Berk B?
Jet Hydro:
I run an Aggressor A now but My C gave me just about as good of hole shot as my A does. Duane know`s how to set up those impellers wink If the A and C holeshots are the same, why don't you run the C for a higher top end? It's my understanding the smaller impeller would give you a higher top end, and the larger impeller would give you a better holeshot.
HBjet