setback vs height

[ultrafast]

Is there any kind of formula for setback to height. I run 16 in of setback on my reaction i run out of water press at 2 in below pad. Will be putting a sportmaster on my etec soon and hope to run it upb a bit more then. Just got driveshaft built and gearcase will gontogether soon.I know some of the sob guys are running this kind of offset how high are you running. I am running a Bravo1 propeller seems to give me the best all around lift.

[Sonik]

The "general" rule of thumb as I've understood it is that for every 1" back, you can go up 1/4". Obviously thats rough math but it seems to hold true at least on my application but I understand that there are alot of variables involved with that equation.....bottom type, gearcase type, water pickup location. Seems wierd to me that you're that far back and still have water pickup problems @ 2" below.Pad bottom or traditional V ???

[whipper]

As Sonik said regardless of setback as long as your even with the pad or below you should have water pressure. I would find some level ground and make sure your prop shaft hight is were you think it is first. Do it right no corners missed when leveling the trailer,hull ect.. Make sure with a level your cav plate,prop shaft and flywheel are all at neutral trim before ya measure. If theres nothing wrong with your pickups then you must be way above the pad or trimming to much.
If you have water pressure at idle and midrange and only at wot you don't this is most likely the case. I was over an inch bellow for two years thinking i was at 1/4 below to even until measured properly. It can happen. Even most garages arnt level they slope out almost an inch over 20-30ft. Make sure you take the time to do this properly with different length levels. Knowing exactly were your at will make you faster. To high and your slow to low and your slow.:cheers: {this is for LWP gearcases}

Regarding a non lwp gearcase ,lots of guys say speeds above 85 are around were they cant get water anymore. Sorry i missed that one in your post about not having Low water Pickups. Measuring is still good to do to make sure. if your running with to much positive trim thats also going to take away from the water flow to the side pickups. You might try less setback unless your putting the lwp ups soon anyway.

[ultrafast]

sportmaster going on in november i have 12 psi but does not keep it cool need 16 psi to keep it cool you may be right on trim perhaps running to much positive trim . i am going to hang motor up 2 in when i switch gearccases of course ibwill be starting over on setup anyway as i am going from 1.87 to1.75:gears.