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View Full Version : AA vs. A Impeller test results



BowTie Rick
05-06-2002, 12:53 PM
First, thanks to all of you that helped me figure out what the heck I was doing. I finally got the AA on and ran it this weekend at the polio pond. Beyond choppy, but still got good numbers. My RPMs will not go past 4500-4700 WOT and speed actually increased 3 MPH. It used to hit my rev limiter at 5400 and not go as fast. Needless to say, I was pleased with the results. I still think there is another 5 MPH to be had though. My thoughts are now on getting more of the boat out of the water. I want to off the jet-o-vator and get a place diverter and ride plate. Does this sound like the next logical step in my quest? Remember, this is an Ultra 21 LX, the one with the cockpit forward for more seating in the back. I think my fat ass and friends are not getting high enough up out of the water. Ideas and suggestions are welcome. Used diverters even more http://free.***boat.net/ubb/tongue.gif

Bense468
05-06-2002, 01:31 PM
I knew that double A would be good for you. I don't know about getting rid of the jet o vator. They are pretty much the same thing. Place is just a newer. If you want a ride plate you need a split bowl not sure what you have or you can have yours tapped like HBjet did to accept the turn buckles. Good luck

flat broke
05-06-2002, 09:24 PM
Originally posted by Bense468:
I knew that double A would be good for you. I don't know about getting rid of the jet o vator. They are pretty much the same thing. Place is just a newer. If you want a ride plate you need a split bowl not sure what you have or you can have yours tapped like HBjet did to accept the turn buckles. Good luck
Bense,
I would venture to say that there are more ride plate installs using tapped holes than afixing the turnbuckles to the steering adapter flange on a G bowl. What I'm getting at is that you do not need a split bowl to run a ride plate. In fact, the ride plate on my boat anchors the cradle under the bowl with two bolts that drive into tapped holes in the bowl, and I have a G. I'm not giving you crap just putting the straight info on the table. http://free.***boat.net/ubb/smile.gif
As for BowTieRick's orriginal question, the bigger hastle will be pulling the intake to machine it for a shoe and rideplate. I feel that you would be heading in the right direction by going with the shoe/rideplate combo in conjunction with a diverter. This will give you the most control over the setup of wetted parts and ultimately your ride attitude. It sounds like its time to pull the mill, install the blower and send it off to the dyno so you have a little time to pull the intake and get the shoe and rideplate done up. http://free.***boat.net/ubb/wink.gif
Good luck,
Chris www.liquidaddiction.net (http://www.liquidaddiction.net)

wsm9808
05-07-2002, 10:42 AM
bowtierick, What speed are you running at 4700 rpm now? I have an A in mine and it runs 70mph at 5200 rpm. I bought a blower last week and expect it to push the rpm well over 6000, which is faster than I want to spin it, so I will probably end up changing to an AA also. Does it seem to accelerate harder(faster) with the AA?
Thanks
Chris, did you email that guy about the blowers? I bought one of the polished 250s he had and it is in excellent shape. Cant wait to get it on the boat, but we have weekends planned around the boat for the next three weekends, so I wont tear it down till after memorial day.
Scott

AGGRESSOR JETS
05-07-2002, 10:54 AM
Originally posted by BowTie Rick:
I want to off the jet-o-vator and get a place diverter and ride plate. Does this sound like the next logical step in my quest? Remember, this is an Ultra 21 LX, the one with the cockpit forward for more seating in the back. I think my fat ass and friends are not getting high enough up out of the water. Ideas and suggestions are welcome. Used diverters even more http://free.***boat.net/ubb/tongue.gif
your ok with the Jet"o"vater- Look at Place on his Droop-Ride Plate system. This will cover 2 functions for you. 1" drop on thrust line lifting your tail & 2 ride plate. Also have you looked at your bottom.
I don't know if you are heavy- if so, you are getting lift from the larger Impeller. If not and are average wght. look for other-you should be able to get more MPH on say a "A". Not talking about your ass just hull weight and distribution.

gstark
05-07-2002, 11:41 AM
I have a AA cut in my Legend pushing a Caliber 1 230. Pump is setback with a rideplate and hydraulic diverter, spun by a 502/415 HP. Beam is 102", LOA is 21' wet, and 3500lb, so I am pushing a real load.
Also have a set of Dana tabs - love these.
With 10 people on board I can run 53-54 mph (GPS) at 4900 RPM (based on two tach readings) and have hit 58 max with a lite load. Even with a light load the hull runs pretty wet based on video I've shot.
I have the cab-fwd seating as well, so it sounds like we are in the same ballpark. I know the hull has more speed, it just needs to get more hull on top of the water (and a blower in the future).
I've ridden in the same boat at 75mph with a 540Merlin. Top end is nice, but I'll take my holeshot any day, it is rather strong.
I doubt you'd notice the difference between a PD and a jet-o-vator.
One last thing, check your bottom straightness.

BowTie Rick
05-07-2002, 12:18 PM
My numbers are similar to gstark's. I can go 53 at 4500 with passengers. When it had the A it only went 49 at 5000. I had the pump looked at by Rick at CP Perf. and Tom and Bob at Rex. No one can see a problem. I am thinking blower time but know HP is not always the cure. I have no idea what the weight is as I built it from a bare hull.

flat broke
05-08-2002, 06:33 AM
Originally posted by AGGRESSOR JETS:
Originally posted by BowTie Rick:
I want to off the jet-o-vator and get a place diverter and ride plate. Does this sound like the next logical step in my quest? Remember, this is an Ultra 21 LX, the one with the cockpit forward for more seating in the back. I think my fat ass and friends are not getting high enough up out of the water. Ideas and suggestions are welcome. Used diverters even more http://free.***boat.net/ubb/tongue.gif
your ok with the Jet"o"vater- Look at Place on his Droop-Ride Plate system. This will cover 2 functions for you. 1" drop on thrust line lifting your tail & 2 ride plate. Also have you looked at your bottom.
Dave,
I think it is top notch of you to recommend another manufacturers product, but honestly, the PDC ride plate does not work as it should. The plate needs to be an extension of the intake for the boat to get up and ride on, not a glorified non adustable trim tab that just happens to mount to the bottom of the droop. I'm not trying to slam PDC's ride plate, but it would suck for Rick to go out and spend the cash on it when those funds could have been diverted towards a "real" ride plate. Plus with the traditional ride plate setup, he'll also get a shoe machined in and once he starts going faster can have greater control over his setup and intake pressures.
Chris, www.liquidaddiction.net (http://www.liquidaddiction.net)

AGGRESSOR JETS
05-08-2002, 09:07 AM
Originally posted by flat broke:
Dave,
I'm not trying to slam PDC's ride plate, but it would suck for Rick to go out and spend the cash on it when those funds could have been diverted towards a "real" ride plate. Plus with the traditional ride plate setup, he'll also get a shoe machined in and once he starts going faster can have greater control over his setup and intake pressures.
Chris, www.liquidaddiction.net (http://www.liquidaddiction.net)
I agree with the long term if his program is to keep stepping on it. The Machined shoe and ride plate/Cradle is the way to go. Ive only seen Places Ride Plate/Droop in pictures and it seems like a good affordable fix.
If he is into a budget controlled step up program, he has arrived at that point, not only re-machine the intake-also to look at the entry and re work it, before reseting the intake.
V bottom I still think a Std Droop may be well worth while. plus he comes out 7 1/2 degrees up for the BIG ROOST -Dave

froggystyle
05-08-2002, 09:21 AM
Not to start flames here or anything, but I have seen the PDC ride plate work great getting a boat out of the water. It IS adjustable, and with a little creativity you could absolutely use the mount for the ride plate to mount a more standard version. I would recommend this setup for anyone short of a racing set-back design that needs the shoe for other reasons. Cheap, and works great.
I gained a ton of speed adding the PDC droop, and the roost is phenomenal.
Good call Dave... you beat me to it!

froggystyle
05-08-2002, 09:22 AM
BTW, 77 mph, 5600 rpm with "A" in a 21' Ultra.

flat broke
05-09-2002, 07:39 AM
Froggy,
No worries on the ride plate recommendation. I never said don't put a droop on the boat, in fact I offered one up to Rick to test with, I just feel that if you're going to spend the money on a ride plate, spend it on a ride plate that is a true extension of the intake surface, not the Place style. He may get enough lift out of the droop that he doesn't see fit to pursue the rideplate. http://free.***boat.net/ubb/smile.gif
Chris www.liquidaddiction.net (http://www.liquidaddiction.net)

BowTie Rick
05-09-2002, 11:15 AM
Talked to Greg Shoemaker yesterday and he said "first and foremost" get the botttom looked at. That sounds like a project for winter not the start of summer. Vortech wants to drop a blower on it and test but I am shy of the idea as it may only make matters worse. I will have to get a new carb and manifold for the blower and that will tap me for funds on helping the pump. K&N does not pay all that great http://free.***boat.net/ubb/tongue.gif

ChetCapoli
05-09-2002, 06:58 PM
what do we have here... flatbroke and froggy?? You guys feelin ok or what? http://free.***boat.net/ubb/biggrin.gif
Chet

flat broke
05-10-2002, 07:12 AM
Originally posted by ChetCapoli:
what do we have here... flatbroke and froggy?? You guys feelin ok or what? http://free.***boat.net/ubb/biggrin.gif
Chet
Did I miss something? Froggy and I were merely exchanging ideas trying to help someone out. A minor difference in opinion, but you will notice, it was handled as it should be http://free.***boat.net/ubb/tongue.gif As for if I'm feeling okay? Yep, and thanks for askin Chet http://free.***boat.net/ubb/smile.gif
Hey Rick, If Vortech is pushing hard to do that blower install, I have a pretty healthy 468 in a 20' spectra that could use some waking up http://free.***boat.net/ubb/smile.gif I'll even spam the hell out of them on my site and around here if the blower does well and we're talking "free blower" http://free.***boat.net/ubb/smile.gif
Seriously though, on the bottom, you can straightedge your boat with it on the trailer. If everything looks good, you wont have to worry about stipping her and flipping her over (sorry bout the Freudian Slip) http://free.***boat.net/ubb/smile.gif
good luck,
Chris
[This message has been edited by flat broke (edited May 10, 2002).]

froggystyle
05-10-2002, 09:27 AM
BTW, I would love to commend you for going the non-obvious direction with impeller selection. So many people equate RPM with performance that they hesitate to go the other direction. Plus, I think that since it is so much cheaper just to cut down an impeller, people naturally gravitate towards that route.
I am installing a stainless A2 in my boat here next week, and I will post the results afterwards. Good to hear you are having success.

BowTie Rick
05-10-2002, 09:59 AM
Flat broke, no way man, I got dibs on it. Actually things are moving forward with it again. I am working my K&N connections and have a lead with Demon for a carb. That was going to be the biggest expense. The price for them blew me away. Even with a killer discount I was looking at $500+ I still need frickin swim steps and there is no way I was going to have this killer boat I had to pee out the side of!! I think working the bottom and a few more ponies will do the trick. Froggy, thanks for the compliment. It means a lot from a guy who got the triplets in his ride http://free.***boat.net/ubb/biggrin.gif

froggystyle
05-10-2002, 10:07 AM
Originally posted by BowTie Rick:
Froggy, thanks for the compliment. It means a lot from a guy who got the triplets in his ride http://free.***boat.net/ubb/biggrin.gif
Those are just women bro... I would love to see triple digits on my boat more!

Squirtin Thunder
01-17-2006, 10:47 PM
:cool: First, thanks to all of you that helped me figure out what the heck I was doing. I finally got the AA on and ran it this weekend at the polio pond. Beyond choppy, but still got good numbers. My RPMs will not go past 4500-4700 WOT and speed actually increased 3 MPH. It used to hit my rev limiter at 5400 and not go as fast. Needless to say, I was pleased with the results. I still think there is another 5 MPH to be had though. My thoughts are now on getting more of the boat out of the water. I want to off the jet-o-vator and get a place diverter and ride plate. Does this sound like the next logical step in my quest? Remember, this is an Ultra 21 LX, the one with the cockpit forward for more seating in the back. I think my fat ass and friends are not getting high enough up out of the water. Ideas and suggestions are welcome. Used diverters even more http://free.***boat.net/ubb/tongue.gif

Taylorman
01-18-2006, 12:18 PM
Very interesting since im about to put a AA in my boat. Did you notice a big difference in the hole shot?

Squirtin Thunder
01-18-2006, 12:32 PM
In mine I went from 5100@73mph with a bad dist.~4600@69mph 4lost mph but then replaced dist. and pick rpm back up to 5300~5400@78.3 loaded heavy. The best part was slow speed manuverability, off plane.

P-Money
01-18-2006, 03:09 PM
Double AA spinning 6000rpm in a Cole 20.5 bowrider with a Berkeley JG pump (loader, but no ride plate or shoe, yet), any ideas on the speed?

Squirtin Thunder
01-18-2006, 03:16 PM
Double AA spinning 6000rpm in a Cole 20.5 bowrider with a Berkeley JG pump (loader, but no ride plate or shoe, yet), any ideas on the speed?
85mph ~ 90mph

sleekcrafter
01-18-2006, 03:57 PM
Tell me how this can be a compairison between AA and an A impeller? First off the A impeller was original and well used, and the AA was a new unit. The second thing is, the tests were not done on the same day and same conditions. 4500-4700 rpm is a big variance in a jet boat, hitting 5400 when trying to take off is some pretty good cavitation. Thirdly Jim you brought this back from the dead, and claimed you lost 500 rpms with the AA and a bad distributor form 5100 to 4600. Then when fixed you claimed 5300-5400rpms and a bid speed increase, I don't doubt you gained, but think about it, what would you have run in the first place, if you were running right inthe first place. I can see no true comparison here, to relight this tread. If this were all true, running AA impellers makes you faster, everone would have them. Not all boats are the same, all boats are not used in the same matter, some pleasure boat, some river race, and some race. A hundred RPM in a jet boat is a lot of power, especially when you approach 5000 rpms will the AA impellers. Each impeller has it's own place, the AA impeller is not suited for many boats, and in many cases will cause loss of HP and top speed. These are the hard facts about jetboating, we must live with. Perhaps just a new impeller is all that is needed to restore the performance, back into these 30-40 year old boats we run. Think about the targeted performance range before casting off hard earned moneys for the bigger impellers, as you might not like the desired results. After all a tight A/B pump will toast a worn AA pump, and we know what the result would be on top end too. just my 2 cents
Sleek

Squirtin Thunder
01-18-2006, 04:28 PM
The best part was slow speed manuverability, off plane.
I also have to add my fuel milage was 4.7 ~ 5.3mpg. I know my MPD"B" was most likely faster being I could have turned 6300rpms. I will be running a A3 next season mostly.

sleekcrafter
01-18-2006, 04:36 PM
Double AA spinning 6000rpm in a Cole 20.5 bowrider with a Berkeley JG pump (loader, but no ride plate or shoe, yet), any ideas on the speed?
75-80mph sould be attainable
Sleek

sanger rat
01-18-2006, 05:38 PM
I'm moving up too. Aggressor B to Aggressor A. We'll see what it does in the spring. Chuck did you guys get hit with the freezing rain too? Stressful two days for me.

sleekcrafter
01-18-2006, 06:26 PM
I'm moving up too. Aggressor B to Aggressor A. We'll see what it does in the spring. Chuck did you guys get hit with the freezing rain too? Stressful two days for me.
We have been kind of dry lately, no snow really since Xmass. I saw GrandRapids have rain every day for 29 consecutive days! WOW what a mess thats got to be. Hang in there only another three months of this weather.
Are you going with the new Aggressor by majorbronze? I was going to go Stainless, but Thinking about staying bronze now.
Sleek

sanger rat
01-18-2006, 07:22 PM
It's not the new style bronze. But it's sitting waiting for me to put it in. At least i don't have to shovel all this rain. :cool: