Restricting for cold weather

[beachedflunkey]

Last Fall/Winter I ran single cooling, a .25" restrictor after the head, then teed to a .25" line going up my handlepole into my wetsuit and a .375 to my headpipe. This ran great and kept me warm all Winter (approx 85+F off the head in 38F water).

So, now that I have dual cooling (still on a 701 but w/porting and ADA head), would it be too much pressure to leave both .375 incoming water lines unrestricted and still restrict down below .375 total coming off the head? Or should I pinch off one of the incoming water lines?

 

[SuperJETT]

Pressure is a good thing and really doesn't matter unless you have too little and have localized boiling, it's the flow you're worried about.

Just use restrictors to get your outlet temp from the head where you want it. My old engine builder liked ~120F which is pretty hot.

Last season I believe I had dual outlets (I have parallel cooling, one line feeds the pipe only, one feeds the engine only) off the head and I think I had 3/16" or smaller restrictors in both.

 

[beachedflunkey]

I missed this post yesterday. Thanks for the reply jett. Both my lines come into my exhaust manifold so I was worried about 3/4 coming in and only 1/4 coming out.

It does seem like life would be simpler the way you are running cooling. Quick question (I'm sure it's in the tech faq amongst 80 pages of cooling tips) - would I need to retune my headpipe a bit to compensate for the colder temperature if I switch to a dedicated 3/8" cooling line for my pipe?

 

[SuperJETT]

Yes, you probably would need to retune a little, though not much I bet.

 

[sjetrider]

Darin, where do you T off to stinger (waterbox)? From the head or the head pipe? Also are you just running 2 pissers out of boat then? An where do you have your headpipe screws set with this set up?

 

[SuperJETT]

exhaust circuit:

• pump to bottom of headpipe
• top of headpipe to restrictor (helps maintain high pressure in the headpipe so the water injection responds quickly - less volume to pressurize so when revving, it hits high pressure quickly)
• restrictor to tee
• straight leg of tee to Jetworks flow valve
• tee'd leg of tee to bypass fitting
• Jetworks flow valve to stinger

engine circuit:

• pump to tee'd leg of tee
• 2 sides of tee go to exhaust manifold inlets
• 2 outlets on head to go sides of tee (with restrictors as needed to maintain proper temperature)
• tee'd leg of tee goes to bypass fitting

This gives me even cooling of both cylinders, and allows me to change the flow of either circuit without affecting the other.

As for the headpipe settings, I think I'm top = shut, middle = 1 turn or so, bottom = barely cracked.