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View Full Version : Looking for more speed. New to the jet boat thing.



Scott Upchurch
06-20-2015, 11:02 AM
16757This is what I'm workin with, running about
4500 to 48 rpm 63 65 mph, around 500 horse, looking for more speed
whats the next step? Place diverter? Do they even make a kit for this old
setup?

"THE ADVOCATE"
06-20-2015, 12:06 PM
A diverter might help get another couple mph. Then you can start swapping out intakes, carbs cams and ignition for some small gains. I have heard it takes about 100hp gains for big results on jets. Good luck and have fun, very clean float you have there!

T8er S.
06-20-2015, 12:29 PM
http://www.cpperformance.com/p-920-manual-place-diverter-kit-for-berkeley-12jc-jg-jb.aspx
Get the diverter (you won't be sorry). You got a 12jc pump so yeah you can get a kit. What size carb you running? Welcome aboard.
:rooster:

Scott Upchurch
06-21-2015, 02:12 PM
Thanks a lot guys! Running an 800 cfm Holley mech double pumper. I appreciate the help!

T8er S.
06-21-2015, 03:29 PM
You're good on carb.
:chopper:

jetboatperformance
06-24-2015, 08:40 AM
Jet Trim (Place Diverter) is the hands down winner for "bang for buck" improvement on your Jet , it takes a significant HP increase to garner the equivelent increase in speed and overall performance Call if we can help, best prices , unmatched customer service ... Tom

http://www.jetboatperformance.biz/pages/place_diverter.html

wolfie
06-24-2015, 09:32 AM
x2 on using Tom@JBP!!!

polishedball
06-24-2015, 01:48 PM
This is what I'm workin with, running about
4500 to 48 rpm 63 65 mph, around 500 horse, looking for more speed
whats the next step? Place diverter? Do they even make a kit for this old
setup?
Diverter's are great. I am curious about your speed and horsepower though.
If you have 500 HP on tap and are getting 4800 RPM, it would indicate you have a 9.25 impellar. By your speed / RPM I would guess you have an "A" impellar in that jet, the 4800 RPM would indicate more of a 350HP number.

White Lightning
06-25-2015, 09:04 AM
If you want more umph, you'll need more breathing on that set up. OTT headers will make a significant improvement after the diverter. Like Jason said, distributor, then cam, then bigger heads, then another cam, then a tunnel ram with more carb, then another cam.........then a blower......then another cam...lol.

Welcome to the addiction! :happy2:
Rob

Scott Upchurch
06-28-2015, 06:13 PM
Think the pump may be worn, haven't had it apart yet
500 isn't an absolute number either, built mine from a
mondello web page build sheet to the t, but it probably
could use a dyno pull or two to get it putting up
the hp it's supposed to have.

wolfie
07-01-2015, 09:51 AM
You'll notice more RPM and less overall speed once the pump starts wearing. Get yourself a diverter, get that hull dry when you're running and you'll see more RPM and speed.