abones

water pressue at idle 1000 rpm 3Lbs
at 3200 10 lbs, and 5800 15 lbs!!! engine temp constant at 150 throughout rpm range cruise or hard on the throttles. running bone stock 540 bulldog cooling system, on a 502 with tube headers and 1 inch dumps on each header bank (4 dumps) 13---15 lbs should be fine in my humble opinion

zt260

10Psi can cause hot spots in the heads. Eventually it can really hurt you. But most importantly you are seeing the Psi increase with rpm. According to him, he is not. That's a problem.

ratman

should i open that hloe up? if so to what size? thx, ratman

zt260

If you open that hole up you will lower your water pressure. You need more water coming in to start with. Then and only then you can open the muffler hole up to lower your pressure to 15psi at cruise.

RLW

I see you have Mercury Water Pressure dumps. What was the pressure prior to their installation?
Where are you plumbed for the water pressure gauge? Mine is off drain hole in block.
In retrospect, I am seeing the exact same pressures ZT260 is running. I run a crossover with an orificed bybass (3/8") to T-Stat housing with T-Stat.

ratman

the merc valves were installed with the new motors. bought the boat with out power. i have pressure senders in the drain holes of the block as well. no t stat.

ratman

im running big brand new kpm strainers from fred at trick

gg10

min 10psi wot, max 20 psi, pressure is only half the story, volume is what you want, I run a two stage pump, each has its own pickup, sea strainer with a check valve, no thermo and lots of dumps of motor, 4 corners, 500 hrs aluminum heads lots of power, learned the hard way, smoked a lot of seats.

Fine509

We have 2-4 psi. @ idle
15 @ wot.
Carbed 540's, We have the shower caps running with extra water from the blocks. We tried many things to reduce it and the only thing we found is that we put on Mazier electric water pumps and they regulate the amount of pressure in the blocks.

Raceangel77

You are an intelligent man , and a complete scholar dear chap! You are absolutly correct. In our kpm pump we have designed in bypass technology in our our pump so that the water reverses around the pump and uses the pressure from the pickup , whilst also regulating the amount pf pressure going to the block.

The KPM pump also has what is called " soft start " which introduces water slowly to eliminate air pockets.

The pump flow is not linear it delivers max flow at 2500-3500 revs when going onto plane. This is were you need the torque and maximum cooling.

When on plane at WOT we use the natural water pressure to do the work and in effect the pump impellers fold down , at which point they are not wearing down the impeller or the chamber.Thats how the kpm pump lasts so long. As I said to one engine builder its like leaving the starter motor on all the time. The KPM pump will regulate the flow to ensure that the pressure is not to excessive. Also thats why we also reccomend a Pressure relief valve.

This is why static flow testing will not work with our pump. You have to test it in a dynamic situation and duplicate the input pressure from the pick up water. Thats why our competitors think that the flow of our pump at max revs is lower than theirs. ITs not they are just testing it wrong.

We surveyed engine pressures with lots of engine builders and the average we got was
At idle 3-7 psi
criuse 10-12psi
wot 15-19 psi

Of course this is all dependant upon restrictions..

If you go on to www.teamkpmracing.com all the data sheets for pickups and system design are there for you.
If you email us we can do the whole calculation for you if you like. Or we can email you our design handbook.

Jules

Your post has made my day