impeller/rpm/hp chart ?

[wsm9808]

Anyone have an impeller chart handy? I just rebuilt my pump and motor. I got to run it for the first time today, but I'm at the inlaws lake house 250 miles from home for the rest of the weekend and dont have my books with me.
I,ve got an A american turbine impeller in a dominator pump with pretty tight clearances. Motor was turning 5200rpm on the autometer tack and 5400rpm on the medalion indash tach.
Question is how much HP is the A impeller absorbing at 5200rpm and estimated top speed. My speedo cable kept popping off at 65mph and my dumb butt ran off and left the GPS at home. Boat was accelerating way harder than it did this summer, and before the rebuild the rpm was only 4600 at 62mph.
Thanks

[Heatseeker]

One of the guys came up with a nifty Jet Pump Calculator. I ran your numbers, using 4600rpm at 62mph as the baseline. Using the Dominator pump results were:
523hp@5200rpm at 75 mph.
Using the American Turbine pump:
446hp@5200rpm at 75mph.
I imagine your actual perfomance is right in there somewhere.
Hope this helps.
John

[LVjetboy]

I'd agree with Heatseeker. Assuming your hull doesn't have a nasty hook to buck the trend and that your 4600 before, and 5200 after data points are readings from the same tach, I'd estimate 75 mph (on the same speedo of course). Very nice!
If you'd like to run other points, here's the link to the JPC:
JPC (http://www.angelfire.com/extreme2/dragnjet/Perfomance.html)
Which now includes half sizes and Legend pumps.
Speaking of pumps vs impellers, if you have a Frankenstein http://free.***boat.net/ubb/smile.gif, that is a Dominator pump housing with an American Turbine impeller, my guess is your best estimate of hp is to run JPC numbers with the impeller manufacturer instead of the housing manufacturer. For example, 5200 rpm = 446 hp. Tighter than normal clearances will throw your numbers off from the manufacturer's curves...something I can't account for just yet. Let us know what happens on the GPS run!
Cheers,
jer

[wsm9808]

Thanks for the help. I'm still kicking myself for leaving the GPS at home. It is impossible to measure changes with out good data, but the boat was a blast to drive. With the new pump and motor it startled me and my girlfriend the firstime I nailed the throttle(not to mention what it did to her mom who had never been in a jet before). I wish I had a little more time on the water, but after about 30 minutes the wind got up to 30mh and the 2ft waves were about to swallow my little 19ft pickle.
That reminds of another Question I had. Is it just me or does it seem like the tunnel hull boats run faster when headed INTO the wind? Mine always reads about 2mph faster when headed into the wind as compaired to running with the wind to my back.

[pgf127rt]

Scott, sounds good for the new motor and pump, and to answer your question, yes the tunnel should run faster into the wind, as with a hydro the more air you pack the less drag there is, just as in a vee boat it will run faster on light chop, than on slick water, less adhesion. On my flats I always ran a rough running surface as compared to a slick one, why, bubbles are faster than slick.

[PC Rat]

Speaking of rough surfaces, I was thinking of sanding my bottom- um, I mean the boats bottom this winter. I have heard to use 320 grit sandpaper to rough it up. My boat is a PlaceCraft tunnel, so should I use the 320 from the tunnels out, and then make it very smooth maybe like 600 or finer right in front of the jet intake. How far in front of the jet should it be sanded smooth? Which way do you sand with the rough paper across or along the bottom? I was also thinking of roughing up my ride plate and tunnel plates.

[pgf127rt]

pcrat, on my flats I hadd the painter open his gun to create an over spray texture, just rough enough to create turbulence in the water passing under the boat, thereby creating a loose effect, since I have retired I have heard of several of the racers using the rough surface, as far as sanding to get the effect I am not familiar with that, I would rather use the speed coat product on the running surface than to try and create the effect with sanding.
a sure way to check my theory is to take 2 pieces of glass and put a drop of h20 on one and put them together, then try to separate them, suction huh, now overspray one with paint and repeat the process.

[wsm9808]

My boat has some sort of speed coating on the bottom, grafite I guess. It is dark grey color and is slick to the touch, and it will turn your fingers grey when you touch it. It is real smooth though. I've read these smooth "slick" coatings dont really help free up the bottom any, but the "textured" rough bottom like you mentioned will help.
PGF, how did the boat look after you got it sanded and polished?

[pgf127rt]

Scott, it doesn't look like the same boat, it is beautiful, looks like it will be ready to go about the time the weather takes a dump, but this is Texas, just wait a day or so and it will be summer again, I hope.

[wsm9808]

Can't wait to see it PGF, I will for sure give you a call next time we come through your area. I'm glad it buffed out nice, it is a great looking hull.

[wsm9808]

http://wsphotofews.excite.com/023/sW/ma/Zk/jY91997.jpg
Just wanted to post a pic of my boat I took the day after Thanksgiving. Hope no one minds
http://wsphotofews.excite.com/009/zP/CZ/NW/jR83207.jpg
[This message has been edited by wsm9808 (edited November 25, 2001).]
[This message has been edited by wsm9808 (edited November 25, 2001).]

[LVjetboy]

My experience compliments pgf's reply.
Running into the wind is faster...experienced first hand on the day before the "Festival of Lights" at Havasu last year. This is because air friction is much less that water friction, and the wind helps lift the hull...reducing water friction by hull lifting at a greater rate than air friction is increased from the headwind. May also apply to a shallow-v but not sure.
jer

[pgf127rt]

Scott, the boat sure looks great, we gotta be careful except for the weedeater on mine, the boats look alike.

[wsm9808]

Dang, a couple of days ago I was riding around in my boat, and tonight there is 2 inches of snow on the ground and still coming down. forcast for the weekend is 70 degrees. you gotta love texas wheather.

[HBjet]

Here is a chart I finally dug up.
http://home.socal.rr.com/boatbutts/chart.bmp
I also had this one
http://home.socal.rr.com/boatbutts/imp.bmp
I hope this helps...
HBjet

[DEL51]

Wsm,That is such a beautiful boat!! I want one,when i can afford it.How much would a hull and trailer cost?Is that an Elimiator or liberator?We need more posts like that.DEL51

[wsm9808]

Thanks for the compliment Del. It is a Stallion, I believe it is a splash of the Nordic hull. As for the cost of a new boat, Liberator sells their 19ft pickle for 29,000 with a 454, and around 34,000 with the 502/502. I want a 21ft Liberator with a cover engine like the one Blown509liberator has, and plan to try to sell my boat around the middle of the summer next season. I hope to get around 12,000 for mine when I sell it.
Thanks for the chart HB
[This message has been edited by wsm9808 (edited November 28, 2001).]

[DEL51]

Wsm,PlEASE KEEP ME IN MIND WHEN YOU GO TO SELL THIS BOAT!You should be able to reach me on the forum or access my e-mail address frm this post.I also considered the 21 for more passenger room,but i really like your ride.DEL51

[wsm9808]

OK,I need some suggestions to help dial in my set up on my boat. I GPSed the boat today, no wind, dead calm water(smoothest water I have ever seen) no wakes or rollers. Tack read a dead solid 5200rpm on one and 5400 on the other. Speedo was 75mph and GPS showed top speed at 69.3 . I feel at that rpm with an "A" and fresh pump, I should have more mph. I have a loader with to 2 angle ramps welded to the sides, would a pro type loader help.
The jet calculator says I should get around 75mph, and one guy on another thread says he is getting 84mph at 5200rpm with an "A". I could sure use some input on what has worked for some other people on their boats. There are some pics of my pump a few frames up on this thread.
What speeds are some of you running and at what rpm and Impeller?
Oh yea, the bottom is straight with no hook or rocker and the leading edge of the shoe is 1/2 inch deeper than the bottom of the boat and tapers down to .400 where it butts up to the ride plate.
Also, the fastest runs seemed to be with the nozzel all the way up, but it was only 1/2mph faster than when set in the middle. And even with the nozzel all the way up like in the picture above the rostertails are not as high as on a lot of boats I've seen. I guess I need a pic at speed to see what kind of set it has.
Thanks
[This message has been edited by wsm9808 (edited December 06, 2001).]
[This message has been edited by wsm9808 (edited December 06, 2001).]

[LVjetboy]

What can I say? GPS is an evil invention http://free.***boat.net/ubb/smile.gif. The 75 predicted by JPC was based on your before data of 62@4600. If the 62 mph data point was the same speedo that is now telling you 75, then JPC was right on. If the 62 was GPS, then I think there’s more speed hiding in your setup. My guess is a 600 rpm boost will give you at least 10 mph on a tight pump and good setup. But there are others here more qualified than I to suggest setup issues. All I’ve done so far is play with my loader and ride plate http://free.***boat.net/ubb/smile.gif.

[wsm9808]

LVjet, I saw you boat over on the liquidaddiction site. Looks real nice, and good photo quality too. The original 62mph@ at 4600rpm was with the speedo, I didnt have the GPS before, and the old impeller was a 9 1/4 inch with .080 wear ring clearance. The acceleration now with the "A" set at .026 is unbelivable compaired to before, so that is good, but I was hoping for around 75mph, but I dont know if I can find 6 more mph buy tweeking the set up.

[LVjetboy]

Thanks for the comments. Chris did an excellent job on the web site and writing narrative to go with those pictures.
Since the 62 was on the same speedo, you got a 10-13 mph increase with pump and engine rebuild...not bad! Just that your speedo at 62 was probably reading high back then too.
I think you're right that 6 mph is tough to get from tweeks, but you still may have free speed hidding. I think you have the right approach...have a friend take a shot at speed and record wetted surface before making changes. Could be more lift will net you 2 or 3 of the 6. A custom loader can help with lift too. I've seen a post where a custom loader netted a gain of 2 mph in top end. Then there's always the bottle http://free.***boat.net/ubb/smile.gif
jer