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Raw Water Pressure

Posted: January 15th, 2018, 9:59 am
by dcrahn
Typically, what pressure range do crank driven raw water pumps operate in, idle up to wide open throttle? I've been a little under the weather lately and have not worked on my project. So, it gives time to think about some improvements and search the web. I want to add a pressure gauge to my dash so I can keep tabs on what the pump is doing.

Re: Raw Water Pressure

Posted: January 15th, 2018, 12:29 pm
by waybomb
I have no idea what design pressure would be, but I would also guess that it varies by rigging and exhaust design.

fwiw - I have 35psi relief valves on PV's engines.

Re: Raw Water Pressure

Posted: January 15th, 2018, 8:59 pm
by Viper
dcrahn wrote:Source of the post.....I want to add a pressure gauge to my dash so I can keep tabs on what the pump is doing.

It's a good feature to have but I would prefer monitoring the temperature at the exhaust instead. No matter what fails in the cooling system, an exhaust temp monitor/alarm will tell you right away that something has failed even if you have full water pressure after the pump. While monitoring pressure may not catch a problem in some areas, exhaust temps which are at the end of the cooling circuit will react immediately no matter where the failure is. They're on my bucket list for the engines and generator.

Re: Raw Water Pressure

Posted: January 16th, 2018, 9:36 am
by dcrahn
Viper wrote:Source of the post
dcrahn wrote:Source of the post.....I want to add a pressure gauge to my dash so I can keep tabs on what the pump is doing.

It's a good feature to have but I would prefer monitoring the temperature at the exhaust instead. No matter what fails in the cooling system, an exhaust temp monitor/alarm will tell you right away that something has failed even if you have full water pressure after the pump. While monitoring pressure may not catch a problem in some areas, exhaust temps which are at the end of the cooling circuit will react immediately no matter where the failure is. They're on my bucket list for the engines and generator.

Agreed! I have 8 EGT sensors in my race cars headers that are recorded with my Racepak Datalogger. I check that very closely after every pass. But, I would still like to know what the raw water pump is doing.

Re: Raw Water Pressure

Posted: January 16th, 2018, 10:00 am
by g36
fwiw an easy exhaust temp monitor i have nmea network on my boat and took 2 temp sensors put them on the exhaust outlets renamed them such and monitor the temps easily and can set alarm points to be notified of issues earlier than the temp guages show

Re: Raw Water Pressure

Posted: January 16th, 2018, 10:08 am
by bud37
dcrahn wrote:Source of the post Typically, what pressure range do crank driven raw water pumps operate in, idle up to wide open throttle? I've been a little under the weather lately and have not worked on my project. So, it gives time to think about some improvements and search the web. I want to add a pressure gauge to my dash so I can keep tabs on what the pump is doing.


Where are you thinking to tap the gage into ? The system is open ended so readings will be greatest at the pump outlet and probably close to very little at the exhaust manifold mixing point IMO. Small scale would again IMO give you the best shot at seeing variables.....hope you are feeling better........ :beergood:

Re: Raw Water Pressure

Posted: January 16th, 2018, 10:14 am
by dcrahn
bud37 wrote:Source of the post
dcrahn wrote:Source of the post Typically, what pressure range do crank driven raw water pumps operate in, idle up to wide open throttle? I've been a little under the weather lately and have not worked on my project. So, it gives time to think about some improvements and search the web. I want to add a pressure gauge to my dash so I can keep tabs on what the pump is doing.


Where are you thinking to tap the gage into ? The system is open ended so readings will be greatest at the pump outlet and probably close to very little at the exhaust manifold mixing point IMO. Small scale would again IMO give you the best shot at seeing variables.....hope you are feeling better........ :beergood:


I am converting to a 1/2 freshwater cooling system and was thinking about somewhere between the raw water pump and the heat exchanger.

Re: Raw Water Pressure

Posted: January 16th, 2018, 10:27 am
by bud37
I have an idea....might be a bit anal but.......I might wait until the system is up and running with all new stuff ( impellers etc ) and get a temporary gage and tap some different spots to get readings, then choose a gage to fit, lets say 0-15 or ??....that way you can monitor degradation fairly accurately .....just spitballin....

Re: Raw Water Pressure

Posted: January 16th, 2018, 10:31 am
by bud37
bud37 wrote:Source of the post I have an idea....might be a bit anal but.......I might wait until the system is up and running with all new stuff ( impellers etc ) and get a temporary gage and tap some different spots to get readings, then choose a gage to fit, lets say 0-15 or ??....that way you can monitor degradation fairly accurately .....just spitballin....

Kinda like pressure in the slicks 0-30 is useless if you are running 6.5......then 0-15.........woops hit wrong doodad. you get the idea.

Re: Raw Water Pressure

Posted: January 16th, 2018, 10:35 am
by dcrahn
bud37 wrote:Source of the post I have an idea....might be a bit anal but.......I might wait until the system is up and running with all new stuff ( impellers etc ) and get a temporary gage and tap some different spots to get readings, then choose a gage to fit, lets say 0-15 or ??....that way you can monitor degradation fairly accurately .....just spitballin....


My thoughts exactly! Even though the impeller in the pump looked okay, I replaced it away and I hope to in the very near future fire the engine up in my shop and check everything before it's installed in the boat.