(Stole this pic from another post,but my 2 look the same). And YES I'm positive the bowls I have are both JG bowls.

the one on the right, lets see the rear of the bowl also.

the one on the right, lets see the rear of the bowl also.

Hi jim,

Both bowls are long gone now, I can't take any more pictures of those two exact bowls.  I might have some others that I can get pictures of.  What features exactly do you feel are noteworthy on the exit side?

The way I remember, both looked the same on the exit but I haven't measured the short flange bowl at all to compare.  At least, nothing jumped out at me as being drastically different.

Cheers,

Joe

Something I want to throw out there just because.

Many of the tricks, techniques and modifications are rpm and hp specific.

What I mean by that, there is no silver bullet that works in everything.

River boats do things different than circle boats that do things different than drag boats.

If you have a snappy little bitch of a big block that can go from calm to a pissed off 7,500 rpm in less than an 1/8 of a second,  you will have a different set up than if you have a marathon motor making a meager 800hp for hours at a time. Same holds true if you are trying to get the pump to generate the most possible top speed but need it to be able to turn and vary nozzle velocity.

Drag racing is not for me,  but I thought it was important for the readers to note that there is a multitude of ways to skin this particular cat.

GT

Both are definatly G bowls.outlet sides are identical. Plan is to push about 800-850 hp through it in my lake barge.

While its off...ad a stuffer an detail the vanes.

Ohh...I am..and Much more!

If u can't load the pump bowl  don't do jack


Sent from my iPhone using SoCal Jet Boats

Joe,

Forgive my ignorance here.

I have been playing with these things for a very long time and feel I have a pretty strong grasp of how they work.

That being said I have nowhere near the tools and technology that you have at your disposal.

Here is where I'm struggling.

When the hull is sitting in the water, the entire pump is full of water.  Especially if the engine is idling. The bowl is a hydraulic receiver. How would one bowl "fill quicker" if said bowl is already full of water?  The pressure on each bowl will pressurize at exactly the same time given the same rpm and hp increase.  Providing the outlet sizes are the same.

I feel that the differences would be completely immeasurable.

That being said, the way I understood it was the tighter volumetric area between the outer rim of the impeller and the bowl made less volume to move on the initial hit and the velocity of the water (not volume) would be accelerated more readily,  having nothing to do with "filling the bowl more quickly".

I'm sure it's just verbal translation, but just wanted to point out that the pump is already full of water when the throttle is mashed, there would just be less water to have to "rotate" meaning less initial mass to have to get moving.

I always enjoy reading your posts, I love that these old pump designs are still seeing the attention they are. This one just hit me funny.

GT

Thank you brotherman, I always enjoy reading your's too.

I think that I am having trouble with the right words.  Basically I am saying, don't spend any money replacing a good short flange Berkeley bowl with a long flange Berkeley.  You will never tell the difference!  If you have a choice, opt for the long flange.  B1racing maintains that money spent on a Dominator is a better choice (but you are opening a can of worms with OD issues with a TA).

Let me approach it from a design standpoint (Brace yourself for the ramblings of a madman).

A purely centrifugal pump creates pressure by converting velocity.  An axial flow pump creates pressure by moving volume through the restriction of the nozzle.  A mixed flow pump combines elements of both, volume and velocity.

Ignoring the stator vanes in the bowl, the cross-sectional shape of the pump should form a venturi.  The inlet restriction of the venturi is formed by the inlet eye of the impeller.  There should be a smooth transition from the exducer of the impeller into the bowl with no change in cross-sectional area for some distance.  This relatively small cross-sectional area maintains the velocity of the water coming off the impeller.  The venturi gradually expands and allows the velocity of the water to slow.  As the water slows, the velocity is converted into pressure to be used as thrust.  This is where I believe the Dominator bowl has a distinct advantage over the Berkeley.  Until I can get my hands on an Aggressor to measure it, I can't say for sure, but I think it's similar in shape.

Both the long and short flange bowls have shortcomings.  The short flange allows expansion immediately as the water leaves the bowl.  As the water enters the stator vanes, it is restricted again until there is an abrupt increase in cross-section as the water transitions from the bowl into the droop.  Every time the water expands, velocity is lost and energy is lost again when the water is restricted again.

In contrast, picture 1, looking through the impeller vanes into the bowl, illustrates the interference of the long flange with the exducer side of the shroud of the impeller.  Basically this is a wall that the water crashes into just as it exits the impeller.  With a shouldered wear ring, the impeller would be back about .100", reducing that wall by the same amount.  MY theory is that the suction surface of the bowl should be cut down.  My measuring indicates that .100 can be removed from this surface before you start to run into issues with the impeller nut threads on the shaft interfering with the shaft seal.  I believe the benefits of this are threefold; 1. Volume is reduced, 2. The stator vanes are moved closer to the impeller, and 3. The wall is further reduced.

A note of caution here:  The surface that mates with the suction housing, along with the corresponding diameter, register the bowl to the suction and this drives shaft bearing alignment.  If this surface is not machined exactly parallel to the original surface, the pump will kill shafts and bowl bushings.  Misalignment of the bowl also causes interference between the impeller and wear ring.

I have debated this wall theory with Chris and he feels that it really makes no difference and in a dedicated race boat, money spent on a Dominator will yield the greatest return.  However, all of this applies to a Dominator bowl as well.

Jack at MPD has developed a setup for cutting the inside of the flange to remove the wall.  I think that this improves the transition from impeller to bowl but increases internal volume.  Does it make a difference?  I can't say, but 017 will run 8.000 on all engine with a Berkeley G bowl. 

Dwayne at HTP was parting off the flange and welding it back on (picture 2).  I don't know the details of this, but I speculate that it moves the bowl vanes closer to the impeller by nature of the cut, but is done to provide access for grinding the bowl vanes with reduction of volume secondary or even simply a byproduct of the process.

At one time, there was a lot of talk about bowl shims.  The theory was that a bowl shims spaced the bowl vanes .100" farther away from the impeller, therefore "loosening" the pump like an automotive high-stall torque converter.  Some swear that it gives a little more RPM, where others say it makes absolutely no difference at all except to reduce the bowl register.

I have some other theories regarding just how close should the impeller vanes be to the bowl vanes.  The guy at American Turbine says that the largest impeller they make is 6A and anything larger hits the bowl vanes.  I think that there is an ideal distance, but unless you have the horsepower to push a 6A impeller there is no point in discussing that because the vanes of the typical impeller cut can never get close enough to test that theory with readily available bowls.

The theory behind Dwayne's Hi-Tech Stuffer Plate http://www.hi-techperformance.com/HPParts.HTM is that it displaces as much unusable volume as possible, therefore helping the pump to react faster.  I discussed this with Jack at MPD and he didn't feel that it was worth the effort to replace the plate style stuffer (picture 3).  Jack said this concept stems from the large Hamilton jets where there is so much surface area and a large volume of water churning about creates excess drag on the impeller.  John Mills went so far as to install a Teflon o-ring in an HTP stuffer plate to seal the back side of the impeller.

Since I am getting tired typing on a cell phone, and my head is starting to hurt...

Cheers,

Joe

Indeed!

Here is a picture of an inducer prototype that I designed back in 2011.

For now, all i am going to say is that it is sometimes necessary to take a giant step backwards before you can take a quantum leap forward.

Just remember that you saw it here first!

Looks like a Sport Jet impy.

Shhhhhhh.

GT

Ebay.

Mercury sport jet impeller.

Here you go Joe, the one on the right is a prototype. The left is a stocker.

I saw those but dismissed them as incompatible because of their hub design.

The bell shape of the hub design tricks an axial flow pump into thinking it is more like a mixed flow pump.  As the water transitions up the bell shape as well as the pitch of the blades varying to produce a venturi shape, greater pressure is produced and it develops faster compared to a straight hub design.

However, if this design was adapted to a mixed flow, the bell shape of the hub would shroud flow to the inlet eye of the impeller causing pseudocavitation.

With replys I keep getting feel like I'll be an expert in no time!