Jet Tech Help Needed

[No Butt No Putt]

My 18ft Crusader 468 with a stock Berk with a race loader ran
71mph at 5300rpms.

Im not sure what impellor im running yet, but the front edges are all good. Im going to pull the bowl next week.

The questions are.
What impellor whould I be running?
And at what rpm?
Should I wait to make impellor changes untill after i add a diverter and droop?

Heres a pic of the boat running. I also start to porpus(sp) at top speed with 1 or 2 people in the boat if im light on fuel.

 

[atomickitn]

it sound like you are pulling an A/B impeller, if you are happy with the performance of that ( being an all around good choice ) stay with that.
the droop snoot will / should take away all the porpoising....but you did not mention if you had a shoe / ride plate....this is essential to how the boat runs on top speed...
as far as getting a lil more out of your pump if you don't have a diverter, then get one with the adjustable inserts, to fine tune the nozzle ...jets use to be my thing....hope all is good

 

[No Butt No Putt]

it sound like you are pulling an A/B impeller, if you are happy with the performance of that ( being an all around good choice ) stay with that.
the droop snoot will / should take away all the porpoising....but you did not mention if you had a shoe / ride plate....this is essential to how the boat runs on top speed...
as far as getting a lil more out of your pump if you don't have a diverter, then get one with the adjustable inserts, to fine tune the nozzle ...jets use to be my thing....hope all is good

Thanks for the info Bobby. I have a droop and Diverter lined up, I just dont have them yet. Also I have NO shoe or ride plate. If I go to a bronze B will I see and more MPH or RPM's?

 

[No Butt No Putt]

Oh and its good to hear your lady made it home safe. :beer

 

[atomickitn]

Thanks for the info Bobby. I have a droop and Diverter lined up, I just dont have them yet. Also I have NO shoe or ride plate. If I go to a bronze B will I see and more MPH or RPM's?

no stay away from the bronze ....you dont make enough HP to even be considering the $ factor.....I would not even go to the stainless as well. you might want to look into adding a ride plate, instead of the bronze impeller better money spent....
thanks for the thoughts about windy..

 

[atomickitn]

oops you asked about mph rpm......the smaller your impeller the more rpm, but the less surface it has to move water.....most standard impellers that come in jets of your size are an A....check the tag on the bearing housing where the shaft gos through.....it should tell you what you have ....if you have a standard A, that can be machined to an A/B and you will see more rpm. but will lose the hole shot.....the moer power you put to it the faster you can spin the shaft.....thus creating more MPH.. I hope this helps

 

[No Butt No Putt]

oops you asked about mph rpm......the smaller your impeller the more rpm, but the less surface it has to move water.....most standard impellers that come in jets of your size are an A....check the tag on the bearing housing where the shaft gos through.....it should tell you what you have ....if you have a standard A, that can be machined to an A/B and you will see more rpm. but will lose the hole shot.....the moer power you put to it the faster you can spin the shaft.....thus creating more MPH.. I hope this helps

I can get a bronze B from widowmaker for next to nothing. He has my droop also. We are guessing the 468 is making in the area of 500hp. Still dont think the bronze b is good?

 

[atomickitn]

I can get a bronze B from widowmaker for next to nothing. He has my droop also. We are guessing the 468 is making in the area of 500hp. Still dont think the bronze b is good?

not really if you were making hp in the area of 750+....then yes it would be a great choice......but if it is next to nothing....then you could install it just to have a piece of mind....even then I would send it to greg shoemaker at GS marine and have him check it for size and size it for your application...A/B

 

[atomickitn]

in my last 21 ft jet with a delta pad, I ran an insert pump with all the stuff mentioned, and an aluminium empeller...my motor was making around 550hp, and 620tq....it ran in the upper 70's with a full load 6 people and all ther crap, and coolers....and i did not have to wait for it to plane...

 

[IMPATIENT 1]

get a ride plate on that thing!!! that'd been the 1st thing i tried before buyin a droop. i built a 84mph taylor sj and it never porpused at all, only thing i ran was a shoe and ride plate kit, stuffer, divertor, and c-bowl don't lose mph trying to carry the hull anymore than it already does, from your pics it looks like the hull does that job well enough on its own.try the ride plate 1st before dropping $$$ on a droop, all it did on my heavy vhull was cost me mph. the boat aired out better, that's it, lost 3mph.

 

[No Butt No Putt]

not really if you were making hp in the area of 750+....then yes it would be a great choice......but if it is next to nothing....then you could install it just to have a piece of mind....even then I would send it to greg shoemaker at GS marine and have him check it for size and size it for your application...A/B

Well i think I will pull the bowl, and check the inpellor. maybe clean the bowl up some with a dremel. and try the droop and diverter before i do any impellor changes.

 

[No Butt No Putt]

get a ride plate on that thing!!! that'd been the 1st thing i tried before buyin a droop. i built a 84mph taylor sj and it never porpused at all, only thing i ran was a shoe and ride plate kit, stuffer, divertor, and c-bowl don't lose mph trying to carry the hull anymore than it already does, from your pics it looks like the hull does that job well enough on its own.try the ride plate 1st before dropping $$$ on a droop, all it did on my heavy vhull was cost me mph. the boat aired out better, that's it, lost 3mph.

Thanks for the info. The good thing with these parts (droop & diverter & impellor) is I can go out and try them all before I buy. I have kind friends.
i want to do the shoe and ride plate just dont want to spend $1500 to do it.

 

[IMPATIENT 1]

Thanks for the info. The good thing with these parts (droop & diverter & impellor) is I can go out and try them all before I buy. I have kind friends.
i want to do the shoe and ride plate just dont want to spend $1500 to do it.

bolt on shoe and ride plate kits aren't more than 300 the 84mph taylor i mentioned above had a 12je pump(that i bolted a shoe /ride plate kit on) i'll dig up a vid of it runnin , i've got 1 where i'm racing a bbc powered sj with split bowl, droop, and you can see most of my power was pushing the boat, not carrying it.my sj was a 11 to 1 460 i built to handle a 300hp shot, think i was runnin a 200 in the video.

 

[IMPATIENT 1]

bbf powered sj with c-bowl, stuffer, a cut berk impellor, place divertor, shoe and ride plate kit(bolt on) , proloader

vs.

bbc power sj with split bowl, droop, proloader, ab cut berk, place divertor, no shoe, just a stock ride plate.


same boats, @the same weight, but my bbf had a tad more power but look how they ride different from each other. the white 1 tried to carry the hull more than needed, mine didn't, it let the hull/ride plate do the carrying and the difference was pretty clear. that guy changed his set-up to match mine soon after that race

http://s55.photobucket.com/albums/g157/jbt21479/?action=view&current=tomandtravisracempg.flv

 

[No Butt No Putt]

bbf powered sj with c-bowl, stuffer, a cut berk impellor, place divertor, shoe and ride plate kit(bolt on) , proloader

vs.

bbc power sj with split bowl, droop, proloader, ab cut berk, place divertor, no shoe, just a stock ride plate.


same boats, @the same weight, but my bbf had a tad more power but look how they ride different from each other. the white 1 tried to carry the hull more than needed, mine didn't, it let the hull/ride plate do the carrying and the difference was pretty clear. that guy changed his set-up to match mine soon after that race

http://s55.photobucket.com/albums/g157/jbt21479/?action=view&current=tomandtravisracempg.flv

Do you have any pics of this setup on your boat? I heard that the shoe and rideplate bolt on kit wasnt any good due to the fact that it hangs to low.

 

[IMPATIENT 1]

Do you have any pics of this setup on your boat? I heard that the shoe and rideplate bolt on kit wasnt any good due to the fact that it hangs to low.

sure, i can see how some would think that, but the kit is just a rough part, you gotta "sculpt it" i had to have my shoe milled down almost in half but once i found that sweet spot, it was wellllll worth the 30 bucks of millin fee. don't have any pics of the set-up here at work, i do on the home pc, i'll post up some for ya this weekend.

by far the best way is to have the intake machined for shoe and ride plate, but the bolt on kit is the next best thing imo.

 

[bp298]

sean, the attached link goes to a pic of tom bandy's 19' hallett.
http://dragboats.com/gallery/picture_detail.php?PictureID=23687&RecID=14

the engine is a 49something bbc, single carbed, making just at 700hp. this thing routinely runs 92-95 in the quarter, but he uses the heck out of it on the river. the setback, pump blueprinting and all hardware were performed by mpd. the bowl is an mpd c to split conversion.

the thing is, you can accomplish anything with your boat that is within your $$ limits. low to mid 70s is just fine, considering what your power guestimate is. also considering the rpm you're turning at that speed, i wouldn't necessarily suggest impeller changes, as there are other things that could provide more benefit for the dough.

i wouldn't even remotely consider grinding on a bowl, as we're more likely to screw it up rather than make it better. bowl and impeller blueprinting is best left to pros with a proven track record in performance. the best thing you can do is get a diverter on it, and perhaps a droop and see what that does.

got my boat off the trailer and on the cart... i'm jazzed.

 

[cave]

Best thing I ever did was get a Place Diverter. I like the Hydro but most favor the manual shift. Less things to break down. With a Diverter, you can plain faster with less rpm's. Once on top you can find the sweet spot. It will take some time to find it but once you do you will feel the difference. GPS without then with the diverter. I not to sure about the inserts on a lake boat. But they look cool.

I added an American Turbine Droop and I am out of the water but lost a bit on the top end. Give & take. The water is so rough were I boat with all the wake boats. Cant really get over 65 without a kidney belt. Late in the day its Off road furry on water. The diverter helps out big time.

If I could get a bronze Imp for a good price I would. A SS even better. Always plan for more HP. If the $$$ is available.:beer

 

[bp298]

I not to sure about the inserts on a lake boat. But they look cool.

inserts can make a difference, how much of a difference depends on what you're starting with. my p/d nozzle wasn't round, it was "sorta" round, to the point that it wasn't possible to tell what the I.D. was. it's easy to bore the nozzle, or have someone bore it to fit ftn inserts.

 

[IMPATIENT 1]

Do you have any pics of this setup on your boat? I heard that the shoe and rideplate bolt on kit wasnt any good due to the fact that it hangs to low.

this is the only intake pic i have of the sj's bottom. shortly after that pic, i flipped the boat back over and speedcoated the bottom, cut the shoe down.