IGetWet

I’m replumbing my setup a bit and would like to try and get a little info/experience for reference before I buy all the required parts and pieces. I’m mainly doing this to removed my intercooler from being constantly fed from the two stage pump. Right now lower feeds Hardin big strainer, to two stage pump, then one stage to motor cooling and one stage to intercooler.

How im thinking of replumbing:
lower to strainer,
strainer to single stage pump to feed motor.
1” npt 10psi pressure relief valve off of other strainer port, then to intercooler. So in theory once pressure in strainer exceeds 10psi then the intercooler gets water.

So my question is will enough pressure build up in the strainer to open the PRV with the normal pump still pulling water out of it? At what point would it get to that ppessure? Ideally it’d be when planing, 10-15mph.

I was was thinking of buying the pressure relief valve and attaching to the strainer and running a hose from it out of the engine comp to where I could see if/when water begins to flow out. For these testing purposes would it cause damage not to have water running through the intercooler? I could try and get out early her in WI when the water and air is still cold.

Thanks guys

dunnitagain

That will be hit and miss, I would just force feed it through the hull . Then the cooler is only getting water flow at speed.
I assume your doing this because of Idle Quality with cold water in the intercooler?
If your feeding a dual pump through a Bravo , your severly limiting flow through the Engine and Intercooler anyhow.

IGetWet

That was my original idea, feed it through a thru hull. But if I can get away without putting holes in the transom, I think I have to try. Then I’d have to use my strainer for the intercooler and no strainer for the motor, or try to fit another strainer somewhere. Then there’s finding the perfect spot for the pickup and type of pickup. And I’d have to monitor the pressure and still probably need a prv so I’m not forcing too much to the intercooler.

Idle quality wasn’t an issue, but during planing you could hear the motor blowing out the unvaporized fuel. Almost like a misfire.

Th dual has been fed through a SCX lower, sportmaster lower, and now SCX-4 lower. All resulted about the same pressure in the motor. 2-3psi at idle, 15-18 at WOT (I think). So yes I think the motor could use more psi and flow. That’s another reason for the change.

Brembofreak

15-18 Psi ist not much at WOT. That was wondering me! I see over 30 with an dualpickup Bravo.
But i have the standart Merc reducers in the exhaust water outlet!
Did you have them in or take them out?
I want drill them up if this year waterpressure from an Sportmaster go higher!And at last,i will take them out when pressure did not go lower by drilling!

Did other guys have the restrictors in the tailpipes from cmi or most take them out??
Michael

F-2 Speedy

12 to 15 running down the lake is ideal.......30 is way to much, take out the reducers. jmo

IGetWet

Pressure and flow are two different things. 30 is high for a raw water cooled motor but sounds normal for the newer closed loop engines. My smartcraft never complained about water pressure. I do not have the restrictors in the exhaust.

Brembofreak

hmmm,i have an 600sci and merc want to see 30 or a bit more at WOT say their instruction.The engine is closed cooling so pressure only in coolers and heatexchanger!
What happend when pressure only at 20psi? go in guardian?
I will try to play a bit with the restictors this year when the shorty is mount.It can not be bad to have a bit more waterflow through the exchanger and headers!
Michael

fossil fuel

I don't normally see strainers on the pressure side of the pump. On most boats the strainer is the first thing on the suction line past the seacock valve. That's supposed to keep most of the junk in the strainer and not in your pump. My diesel volvos are weird I thought because the factory mounts the strainer on the pressure side. I guess the thought there is possibly a shredded impeller shows up quickly. But did the junk that went through the pump help shred the impeller??/.....

Griff

I would feed the engine off a thru hull pick up and through the sea strainer and then feed the chiller off the drive. Maybe add a small strainer for the chiller.

dunnitagain

Are you carbed or Injected? Anything that introduces fuel above the intecooler will have that loaded up effect from off Idle . Especially after extended Idle.
I have a throttle body injected whipple engine in here now , what a sloppy pig that is off idle! Blows black smoke when you crack the throttle. Hind site
I would have replaced the intake with a port injected style to clean up the fueling.
I think you will have fuel condensing in the intercooler fins regardless.
Hell , just test it , bypass the intercooler water, do your normal planning procedure , and see if it helps having a dry warm intercooler core.
I dont think you will gain anything , but Ive been wrong before.