Cooling and restrictors.

[Foximus]

So my question is not so much the routing of cooling as much as it is with how I should deal with my flow control valve. Ive basically created a jetworks valve that pops off between 2-4 psi approx. As you can see in my diagram I have 2 bypasses. And mostly my question is should I run the second bypass that is infront of my control valve (leading to the stinger) I'm not sure that with the bypass there, that enough pressure will be created to dump pop the valve.


Should I just add another restrictor into the second bypass or not run it at all?

 

[Foximus]

Also on reviewing my own diagram... I think I may go to a dual circuit, dual cooling setup as superjett has talked about. This may make it easier to adjust.

 

[Mike W]

Also on reviewing my own diagram... I think I may go to a dual circuit, dual cooling setup as superjett has talked about. This may make it easier to adjust.

I've tried many different setups and this one works the best (for me anyway). The only difference is I have the two outlets on the head T'd together running to one pisser with a 6mm restrictor. Also the line running to my FCV is running out of the t'd part or the T fitting with a 4mm restrictor in the straight section after the T. Make sense?

 

[Ericfox]

you try that powerbomb out yet mike? I am sticking with the 38s... but was curious to see how you like it...

I have mine setup the same way mike described it.... actually exactly like it.... I have the jetworks quick release restrictors with the 6mm after the head and the 4mm in the line before the pisser that comes after the T that the jetworks FCV is on...

 

[SuperJETT]

With the restrictors, it's going to depend on what **your** pressure is, not what anyone else recommends. Prop pitch, nozzle size, i.d. of fittings, etc etc will determine the pressure the valve sees at what rpm. Test test test.

 

[Ericfox]

just pop your FCV off with your ski in the water... hook up a pulse tachometer and set the FCV to open at about 3500 rpm... at least I think that's about right...

 

[Matt_E]

Is there a good reason to run 2 outlets on the head when you're only supplying on one line?

 

[Mike W]

Is there a good reason to run 2 outlets on the head when you're only supplying on one line?

Whatever the reason it will cause uneven cooling of the cylinders. I ran two outlets before I was advised to run the two top outlets together.

 

[Mike W]

you try that powerbomb out yet mike? I am sticking with the 38s... but was curious to see how you like it...
I have mine setup the same way mike described it.... actually exactly like it.... I have the jetworks quick release restrictors with the 6mm after the head and the 4mm in the line before the pisser that comes after the T that the jetworks FCV is on...

I sent you a PM

 

[Foximus]

With the restrictors, it's going to depend on what **your** pressure is, not what anyone else recommends. Prop pitch, nozzle size, i.d. of fittings, etc etc will determine the pressure the valve sees at what rpm. Test test test.

Cool. That summarized it the best for me.


Anyway. I got my lines running perfectly. I used a 1/4" double barb fitting shoved into the line as a restrictor and it puts the perfect amount of pressure to my valve. Only thing is now that the water coming out of the motor pisser seems to be too cool. I would say it is not 120*.... The water coming out the pipe is hot though, but again I'm pretty restricted on the pipe.


Also, whats a good starting point to run on the top screw? 3/4 turn out?

 

[Mike W]

Cool. That summarized it the best for me.


Anyway. I got my lines running perfectly. I used a 1/4" double barb fitting shoved into the line as a restrictor and it puts the perfect amount of pressure to my valve. Only thing is now that the water coming out of the motor pisser seems to be too cool. I would say it is not 120*.... The water coming out the pipe is hot though, but again I'm pretty restricted on the pipe.


Also, whats a good starting point to run on the top screw? 3/4 turn out?

I have mine set at:
-Top and bottom closed
-Middle open 3/4 out
This is for a freestyle setup.

 

[McDog]

Supertune and Jr. both told me not to use any restrictors if the water temp is above 60 degrees. I'll probably not be able to resist checking it with a thermometer though, just because I'm rectal like that.

 

[Mike W]

Supertune and Jr. both told me not to use any restrictors if the water temp is above 60 degrees. I'll probably not be able to resist checking it with a thermometer though, just because I'm rectal like that.

I should of stated that as well. I will be taking the restrictor from the head real soon. I'm sure our water temp is above 60* now. The other restrictor is in so the FCV will work correctly.

 

[Pablo]

Doing some thread searching and was looking for answers. I forgot to order a new FCV for my current build/ski and am about to finish today. If I'm not running a FCV for this weekend, would you guys recommend using a restrictor for the stinger/water box line. Mcdog and I were talking and thought that the water box may be on the wet or cool side of where I want it. To restrict or not to restrict, and what diameter? Water temps are mid 80's plus. I'm running a single cooling setup. Whadyathink?

 

[Kny21]

3-4 mm will do on just the stinger... could run nothing but you'd have a soft bottom end with all that water sitting in the water box coming off throttle.

 

[Matt_E]

Humm, older thread.

I do run both outlets on the head now despite having only one inlet.
This was recommended by the builder of the engine package to get even cooling flow.
I run restrictors in both outlets.
2mm for <35 Degree water
3mm for <45 Degree water
4mm for >55 degree water