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Discussion Starter · #1 ·
I purchesed an impeller under the impression it was an A cut and when i recieved it today A2 is stamped on the impeller... Im running a built olds 455 and worried about rpms... What kind of difference is there between the A and A2 cut??? example holeshots and top speeds and rpm.....?
 

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The difference could be a couple hundred RPM's and mph.
I run a full Aggressor A which is equal to a 2A Berk etc.
My hole shot and midrange pull is strong but, I would be going a tad faster at the top via more engine rpm's if the impeller was a (A).
However, I like to cruise at 28-3000 rpm and with a smaller cut imp I'd be giving up a bit on that side.
 

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Discussion Starter · #3 ·
is your boat pretty responsive in the mid rpm range??? i wanted the most top speed possible out my boat and i was 65 with my A while cavitating badly... My holeshot should be better with the A2 then huh at the cost of a few mph
 

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Resident Ford Nut
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is your boat pretty responsive in the mid rpm range??? i wanted the most top speed possible out my boat and i was 65 with my A while cavitating badly... My holeshot should be better with the A2 then huh at the cost of a few mph
"midrange" by boat hits hard and I'm sure the Aggressor has something to do with it....but keep in mind the loader, shoe etc and general set up is helping everything.
Cavitating "badly" badly sounds like you're starving the pump for water.

*One other thing you must be cautious of is, the 455 is known for holding oil up in the heads and running the lower end/pump dry. There are some other things about a "stock" 455 you may want to read up on before you go spinning the snot out of it.
My brother had one...he put external oil drains in the back of the heads and beat the life out of his...he couldn't kill it. 455 is a torque strong engine, it just may need some simple modifications before you'll want to run it hard and long at upper rpm's.
 

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Discussion Starter · #6 ·
"midrange" by boat hits hard and I'm sure the Aggressor has something to do with it....but keep in mind the loader, shoe etc and general set up is helping everything.
Cavitating "badly" badly sounds like you're starving the pump for water.

*One other thing you must be cautious of is, the 455 is known for holding oil up in the heads and running the lower end/pump dry. There are some other things about a "stock" 455 you may want to read up on before you go spinning the snot out of it.
My brother had one...he put external oil drains in the back of the heads and beat the life out of his...he couldn't kill it. 455 is a torque strong engine, it just may need some simple modifications before you'll want to run it hard and long at upper rpm's.
My 455 is higly modified and ive done everything possible to the motor including the head drainbacks to help the oiling problems.. Its a nasty build and should be up near the high 400's hp range.. Ill tryin this impeller out and see how i like it. The A impeller had me in the 5200 range at top speed with a SHIT holeshot. The impeller looked like it had cobble stones ran through it. Fully rebuilt pump and motor id like to see 70 considering i had 65 before. But if this impeller is gonna keep me in the 46-4800 range ill glady miss a few mph for reliablilty.
 

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My 455 is higly modified and ive done everything possible to the motor including the head drainbacks to help the oiling problems.. Its a nasty build and should be up near the high 400's hp range.. Ill tryin this impeller out and see how i like it. The A impeller had me in the 5200 range at top speed with a SHIT holeshot. The impeller looked like it had cobble stones ran through it. Fully rebuilt pump and motor id like to see 70 considering i had 65 before. But if this impeller is gonna keep me in the 46-4800 range ill glady miss a few mph for reliablilty.
A chewed up Impeller will kill it's bite and efficiency for sure.
I would try the 2A and the good thing is (if) you're not digging it you can always cut it down.
Record RPM/MPH readings at different areas.
Keep us posted of the results.
 

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A chewed up Impeller will kill it's bite and efficiency for sure.
I would try the 2A and the good thing is (if) you're not digging it you can always cut it down.
Record RPM/MPH readings at different areas.
Keep us posted of the results.
im guessing it can be turned down to an A??
 

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Discussion Starter · #10 ·
It can be cut down to a "D" if you wanted...but you DON'T want that!
They cut material off the back of the blades thus making them shorter.

Now if they are cut down are they restamped???
 

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smoknoldy
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oldsmobile's and Impellars

A Built Olds should run great on a "A" cut Impeller. A built Oldsmobile should run 5200-5400 rpm on an "A" cut Berkley or similar like American Turbine. When you Bought the Impeller did you measure it to see if it was a "A2" or an "A". It might have been cut down! There's other issues here does the bowl have a stuffer, is grate a speed grate that loads the Impeller, etc?

Engine wise Mellings High flow oil pump with the Mondello relief spring kit, and oil galley restrictor kit. The Cam shaft oil galley plug that oils you timing chain needs to be soldered up. With roller rockers I would not be afraid of 5400 rpm just watch you oil pressure, oil pressure tells you everything. Joe Mondello also has a chromemoly strap kit for your Main Bearing Caps also! Joe Mondello is in Paso Robles, Ca.

Smoknoldy - 468 inch Oldsmopile turns 6100 rpm with a "B" cut American turbine Hi Helix in a Berkley Pump. The Boat Placecraft Tunnel!
 

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RAT PATROL
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cut impeller

Now if they are cut down are they restamped???
not always. measure it and it will tell you exacly what you have.
quote from (seloc publications marine jet drive) book
berkely impeller specification
berk (a2) large dia. 9" small dia. 7 7/16" machined angle 57.5
berk (a) large dia. 9" small dia 7 1/4 " machined angle 60
hope this helps
 

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Discussion Starter · #13 · (Edited)
not always. measure it and it will tell you exacly what you have.
quote from (seloc publications marine jet drive) book
berkely impeller specification
berk (a2) large dia. 9" small dia. 7 7/16" machined angle 57.5
berk (a) large dia. 9" small dia 7 1/4 " machined angle 60
hope this helps
How do i go about measuring??? im guessing a dial caliper??? and as for the angle im guessing its the angle from the flat surface of the small diameter to the large diameter across the fins??? Shit id reall like to know what i have haha either way i am sending it to HTP to have a ultimate wear ring made to fit and a rebuild kit maybe they can double check the cut for me.. I had a rebuild kit from Cp but htp is much cheaper ;)



 

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E-7 Sheepdog (ret)
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Duane should have no trouble telling you what cut it is and marking it as such if it isn't already.

If the impeller is all rough/beat-up looking/feeling, it needs some smoothing. All that "damage" will just tend to increase cavitation problems, which it sounds like you have plenty of as is.

I run an Aggressor B cut, in a heavy old Taylor SS, her holeshot is very strong, and no cavitation problems UNLESS I flat-foot it from idle, which causes me to blow the pump dry.
5400 RPM off the nitrous.
I love the UWR setup. Running my seccond. First ran tight for 16 years, till I changed impellers, changed UWR's with the rebuild.
 

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mo balls than $cents$
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Duane should have no trouble telling you what cut it is and marking it as such if it isn't already.

If the impeller is all rough/beat-up looking/feeling, it needs some smoothing. All that "damage" will just tend to increase cavitation problems, which it sounds like you have plenty of as is.

I run an Aggressor B cut, in a heavy old Taylor SS, her holeshot is very strong, and no cavitation problems UNLESS I flat-foot it from idle, which causes me to blow the pump dry.
5400 RPM off the nitrous.
I love the UWR setup. Running my seccond. First ran tight for 16 years, till I changed impellers, changed UWR's with the rebuild.
is your b aggressor the large diameter? i just made the switch from a a.t. b-cut i was turning 6750-6800 on motor, 7800 on 1 stage of nitrous :mad: broke a couple rocker studs last weekend doin it, so now that i've got this aggressor in their, yall got me worried i went to big. does aggressor impellors bite that much harder than a a.t.? they're both the large diameter impellors for dom. bowls, lil over a 1/8th inch wider o.d. than a berk.

btw arron, all b.s. aside your boat was hauling asssss in that video ryan got :)devil well done! 1st ss i've seen run like that other than the twin engine dealio ss of andy's.
 

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How do i go about measuring??? im guessing a dial caliper??? and as for the angle im guessing its the angle from the flat surface of the small diameter to the large diameter across the fins??? Shit id reall like to know what i have haha either way i am sending it to HTP to have a ultimate wear ring made to fit and a rebuild kit maybe they can double check the cut for me.. I had a rebuild kit from Cp but htp is much cheaper ;)



Is that a JE pump? I went from a uncut A to a B do'nt no what the outcome will be with 454. Keep us posted of your outcome:)hand
 

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Prune-Picker
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How do i go about measuring??? im guessing a dial caliper??? and as for the angle im guessing its the angle from the flat surface of the small diameter to the large diameter across the fins??? Shit id reall like to know what i have ;)



You live in the Sac area and can't find a place that knows jets? Amazing!
You aren't going to get many usefull measurements with that little caliper.
Is the green impeller on the left the one you've been running? That is an older Berkeley that was originally an "A". Someone has cut it with a steep angle, leaving the 9" large diameter untouched. It's effectively about a "B". The wear area has grooves, which are usually death to aluminum impellers in sandy conditions. The leading edges are wasted, which causes severe cavitation.
The impeller on the right is a late model Berk (or clone) that has the appearance of an A2 on the trailing edge. You need a deep jaw caliper to measure the large diameter. If that is still 9", the impeller is an A2. If it measures significantly less than 9", you need to show it to a knowledgeable jet guy to find out what cut it really is. The bigger question is, why is the newer impeller marked 7.180 & -.045? Those numbers indicate the impeller wear area is cut way undersize and will need the smallest production wear ring available. Once the impeller wears a bit it's finished.
Matt, you've indicated that you invested a lot in your engine, adding all the good stuff. Put some quality in the jet!

Cs
 

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jetboataholic
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Now if they are cut down are they restamped???
Mine was restamped.



Sorry, don't know who did the work or what kind of impeller it is (it came with the boat and the owner couldn't remember), and I don't know the exact measurements (forgot to measure it with my big mics, before putting the pump back together:)sphss). But based on the stampings, it was an A2 and now it is an AB, but the small measurement that I was able to get with my small calipers that I had with me, was really strange 7.130" (7 1/8"), but I measured the large dia. with a tape measure (hillbilly style)lol, and it was like 8 1/2", but again not an exact measurement by any means.

If they sent you the wrong one, couldn't you send it back and have the right one sent?:)eh:)

Good luck!:)hand
 

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B.A.M aka "Black Azz Mike
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That impeller on the right is an A cut. The one on the left is a B cut. I run a B in my pump and it looking just like that green one. Unless its an agressor, then it would be an A cut. Agressors are a cut above everyone else.
 

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E-7 Sheepdog (ret)
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is your b aggressor the large diameter? i just made the switch from a a.t. b-cut i was turning 6750-6800 on motor, 7800 on 1 stage of nitrous :mad: broke a couple rocker studs last weekend doin it, so now that i've got this aggressor in their, yall got me worried i went to big. does aggressor impellors bite that much harder than a a.t.? they're both the large diameter impellors for dom. bowls, lil over a 1/8th inch wider o.d. than a berk.
Don't know what you mean by "Large Diameter". It's for a standard Berk pump (Running an "F"), cut from an AA (as cast) to a "B", because a Berk A cut suits her needs 95% of the time. The Agg. B fits just the same.

I have absolutely no way to compare an Aggressor bite to an ATJ, ask Pops or Duane, they deal with them far more. Berk it is one impeller cut, because the Berk blades stop about 1/8" short of the front of the casting, while Aggressors run to the face, the dif. being about the same as one size cut on the back.

btw arron, all b.s. aside your boat was hauling asssss in that video ryan got :)devil well done! 1st ss i've seen run like that other than the twin engine dealio ss of andy's.
Thx, she was running her best. I think she impressed both Ryan and I that weekend. LOL
I'm quite sure he fully expected to just walk the trash-talker with the windshield. I kind of expected it too.
When I matched his speed, and he only hole-shot me about 1 boat length, I was stoked.
Too bad we seem to be hitting a "wall" at 68.8 from drag somewhere. Going to locate that and address it this winter most likely. Just going to enjoy driving her this year.

The motor is done. 650HP available.
Time to address the pump.:D
 
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