Bowl pressure reading

[76miller]

I have a hole tapped into the bowl, and I was going to run a mechanical sending unit from there up to the front of the boat for some #'s. I have been changing loaders and just want to see how much bowl pressure I'm getting. Was wondering what gauge to use?? I can't find a water pressure gauge. Only the normal water temp, oil pressure, etc. Would a fuel pressure gauge work good enough ? I think they are all calibrated according to weight, and water is heavier than fuel. What do you guys use????

[Sleeper CP]

Liquid filled boost gauge. The liquid really knocks out a lot of the vibration, makes it much easier to read at speed. Try AutoMeter
Sleeper CP
Big Inch Ford Lover

[Cs19]

If your trying to check bowl press. you need a guage that goes up to 250-300 psi. If you want to check inlet psi. that only requires a 0-100 psi. guage.
Alot of people confuse the 2, bowl press is after the impeller, inlet is before the impeller.

[Sleeper CP]

I assumed he ment intake pressure as most people do when they say "bowl pressure". We'll see.
Sleeper CP

[76miller]

I guess I meant inlet pressure. What the loader is delivering, or before the impeller.

[H20MOFO]

What would be considered a "good" inlet pres. I realize too much pressure will hurt rpm's, and not enougph will cause cavitation.

[76miller]

30-35 lbs. is a good reading from what I have been told.

[CPBRIAN10THMTN]

Ideal is 30 and 35 is even a little high, placement is critical too, on a berk, you want to drill and tap the 2nd "e" in the berkeley logo on the intake housing. I have water pressure gauges in stock too if you need em, i think they even come with line kits and everything.:D

[Sleeper CP]

It really depends on the boat and intake.
Currently our CP is seeing 32-35 at 98mph, I'm shooting for 40.
Was told for our boat by the best in the industry that " 40 is good, 50 is better and if you can see 60 on the bottle at 110mph that would be great":)
So it does depend on the hull, but typically 35psi would seem like a good number to shoot for and if you can get it without hanging hardware 1/4" below the keel that's great.
Sleeper CP
Big Inch Ford Lover

[CPBRIAN10THMTN]

The 30 i mentioned was based on joe schmoe's stock or mildly modified pump and motor, for you sleeper, more the merrier:D

[sanger rat]

Why would you want any more pressure than necessary to keep the impeller loaded? I have pressure taps at 12:00 and 7:00 one inch from the face of the impeller. My readings are 40# on the top and 30# on the bottom. I plan on trimming the loader to balance the two.

[BUSBY]

something to think about is that air compresses, if you are running a mechanical gauge in the dash, you have to realize that the water will compress all of the air in the line, therefore not giving an absolute accurate number, the shorter the line to the gauge the better the reading ...
or, you could prime the line with a one way check valve ...
just some food for thought ...
BB

[Xerophobic]

Not uncommon for whitewater boats to see 40's with a full rock grate so I would think its not that hard to overstuff with a loader
Cheers

[Michael2000]

something to think about is that air compresses, if you are running a mechanical gauge in the dash, you have to realize that the water will compress all of the air in the line, therefore not giving an absolute accurate number, the shorter the line to the gauge the better the reading ...
or, you could prime the line with a one way check valve ...
just some food for thought ...
BB
The air might compress, but it will be at the same pressure as the liquid, so it's not a problem. Line length doesn't matter either. Again, the pressure has to be the same at both ends.
Michael

[hotbo]

i have to agree with the high pressure readings,why run more pressure than you actualy need.:confused: i done alot of testing with pressures on my boat this summer and found that i could lose or gain 1-4 miles per hour by different pressure on my inlet side,i ended up with 27psi doing the best.i went from hardley nothing and cavitating 10 psi all the way up to 40psi and my boat seemed to like 25-30 the best .they are all different so youll have to test alot.:D

[jrork]

Anybody got any pics on fitting placement? I saw the post about the second "e" but since I dont have a Berk I would like something visual to compare what others are doing.
thanks a bunch......john

[Cas]

here's a real good thread from 2006 about locations and readings.
http://www.***boat.com/forums/showthread.php?t=107709&highlight=timinator

[jrork]

Thanks Steve. I'd forgotten about that thread. Loved it and even me and Micheal tried bumping it up early in the year and it just died off. Love to see it back up at the top

[billet racing 1]

I use a liquid filled oil pressure gauge. Really messes with people when the gauge shows 0 lbs. I tell them, wait till we really get going, it will read about 40 lbs then.
Jerry

[Boostedballs]

The air might compress, but it will be at the same pressure as the liquid, so it's not a problem. Line length doesn't matter either. Again, the pressure has to be the same at both ends.
Michael
I agree, your reading should be the same whether the sensor port is in water or air. The difference is- if the the water (or air) is forcing against the sensor port, this make the reading higher. The reading might be lower if the port is facing away from flow, like a syphon.
As far as line length- I think a long line going from the pump all the way up to a mechanical oil pressure gauge is a good idea for 2 reasons. One, water won't get inside your gauge; and 2, is that the air in the line compresses and dampens the 'pulse' so your needle will be easier to read the average pressure. Yes, a liquid-filled mechanical gauge will do the same thing but I wouldn't want to use an electric sensor right on the pump, I doubt they are stainless inside.
Side note- The same setup on your oiling system on the engine block should not be setup with a long line full of air because you want to know EXACTLY what the pressure is doing at an instant and not dampen the line pressure and mask an oil pressure problem. I'm sure most of us use the electric sensors for our oil pressure in our boats anyway but some guys might like the mechanical gauge. In that case, you can get a more accurate reading from the mechanical gauge if you loosen the fitting on the gauge while the engine is running just enough to get the oil to flow up to the gauge then retighten. Since liquids don't compress, this will greatly reduce the dampening effect of the line. The oil should stay in the line after the engine is off if the line is thin enough and the fitings are sealed.
I think I'll set mine up with a 1/8" line going up to the dash and put a cap on it so it is hidden away. I can hook up an air gauge to it for testing and disconnect it when I'm done. This way I don't have to cut more holes in the dash and I won't have to try to match the gauge to ones I already have.

[ol guy]

Air will comprees fluid will not. Ask around about loading the pump before putting the hammer down. In the staging before the lights alot of guys will see a blinking yellow because they are trying to "load the pump". All the air you collect bouncing around will really mess with the reading you are trying to get. If the pump is loaded you will know with how the boat leaves. Stuffer plates and ramp plates can only do so much. Inlet pressure depends on the air in the bowl at WOF and how you loaded the pump prior to the launch. And that will tell the story. MY 2 CENTS. MARK

[76miller]

Well, 30-32psi (inlet pressure, before impeller)was the outcome. Forgot to mention I'm running a prime-a-jet on the bowl so it bleed out all the air in the bowl, and the test line. I'm pretty happy with the hardware setup now. Gained 200 rpm and 4mph with a loader change and nozzle angle. I've got a custom built loader from MPD for sale ! Its a nice piece, just didn't work for my application. If anybody is interested let me know and I can post the measurements.

[sanger rat]

What was the difference between the loaders?

[76miller]

The ramp length was different, and there was also some degree of blocker in the new one. I think that really helped with the lift and the correct pressure.

[TIMINATOR]

Thanks CAS for mentioning the pump deal. I have found that if the load is quality water, (little air or turbulence) you can reduce the load pressure quite a bit (I ran14-16 lbs at 100+), IF the top and bottom pressures are nearly equal. The less load pressure to keep the impeller loaded results in less drag. This is why you run taps at the top and bottom. Otherwise with only a middle tap, you can have 80 on the bottom and 10 on the top, be very inefficient, and show what is considered to be a reasonable pressure(at the center tap). At this point you are leaving speed on the dock! The impeller doesn't pull water from the "O" in Dominator, or the "E" in Berkley, you want to know what the impeller sees at the wear ring,top and bottom, and it wants balanced pressures across its face. Yes, I run SIDE pressure taps just in front of the wear ring on the HP stuff. IMO having just one tap 2" in front of the wear ring is a waste of time, and gives a false sense of well being. I have tapped pumps at the top and bottom just in front of the wear ring on pumps that had a tap in the "O" in Dominator, its amazing how much you can change the top and bottom pressures without affecting the "O" tap pressure by very much. Some of the older pump guys still like to use the "old way" because all of their old info was taken that way and they believe they have a good data base in which to work from. Some people even like points ignitions, and don't have flow benches either.
Listen to Sanger.
TIMINATOR

[Placecraft Dragstar]

You should not of told him that Timinator, Now sanger rat will think he know's what he is doing LOL