Re: dual water pickups xr bravo
 

509,
yes that is the theroy that Hydromotive goes by. Any holes on the front of the bullet cause problems. Wheather or not it will increase speed is up to the boat setup, but that is what they go by. I like their nosecones for the two Checkmates I have owned. That is the only experience I have. But that is what they like.. Will it increase speed and lower drag?? I think so, but have never done any back to back tests. I do know on my old Checkmate with short bullet, I was hitting a wall at 78mph. The hydromotive cone, broke me thru that wall..
Give them a call and see what they have to say..

Hope this helps explain it a bit better.
Dick

Re: dual water pickups xr bravo
 

OK, so it sounds like I'm better off with duals (deep-v Cafe Racer). Now the question is can I drill out the side pickups myself? Seems like the casings for lwp and dwp would be the same, the only difference being getting the holes drills out.

Re: dual water pickups xr bravo
 

Mercruiser bulletin 2001-01 covers this issue in detail.
It states clearly that the dual water inlet gear case may not supply enough water pressure and flow to the engine in high X dimension installations.
I have experienced this first hand on a blower setup where I couldn't get enough water pressure to the motor. Once the upper holes were plugged I had more than enough. The pressure was blowing right out the top holes prior to plugging.

Stainless 1/16 NPT plugs (Merc p/n 22-16581) are used for this issue on high X dimension boats.
I can fax the bulletin if you PM me.
Hope this helps,
Dave

Re: dual water pickups xr bravo
 

Dave,
Good info to know I would like to have that info.. I will pm you.. thanks!

Steve,
I see no reason you cant drill the holes to make it a DWP. But just drilling wont completely do it. If you notice how the holes are shaped on the side pickup, they have little troughs leading up to them. I did some work on my OB lower once. I was told to tilt the troughs downward to better accept the water flowing on the side of the case. So after you drill them, I would grind a small relieve to make a trough to channel the water. And I would imagine you could fine tune it by drilling only a couple of holes and then adding them to suite your needs..

Hope this helps
Dick

Re: dual water pickups xr bravo
 

Dick, Thanks for the reply! I'll have to do a test in spring and see if there is any speed differences between the two styles. When I bought my XZ with DWP, the top half of the side inlet was tapped and plugged already. It was run on a Eliminator with a high X and was sucking air previous to the plugs be installed! Steve

Re: dual water pickups xr bravo
 

I have a DWP XR on my 25 Outlaw with Imco ext box running a high x dimension. I was told to go for the dual pickup despite the high x because it is faster due to reduced resistence. My boat runs over 80mph. The side pickups release excess pressure from the low pickup. It works really good.
I have 4 1/2 inches from pad to propshaft and it would seem that (on a V bottom) the drive has to be even higher before a LWP is neccessary.