09-21-2009, 02:47 AM #1
Is it better to relief cooling water pressure?
I see many people doing some water routing mods, specially a bypass from one of the head's water outlets.
On my carbed GP1200R the stock cooling worked fine, but know I'm going 1300 with stock milled head, single pipe, jetworks mod (fercho style, secondary water line), with Dynafly and 05 pump. Keeping in mind reliability, is it better (or even mandatory) to relief some of the added water pressure or leave it stock???
Does water intrusion becomes a new concern for me? How about cooling effectiveness? with or without bypass.
09-21-2009, 04:39 AM #2
09-21-2009, 05:52 AM #3
- Join Date
- Oct 2006
09-21-2009, 06:24 AM #4
novis dont make heat, they feed
high comp head? what 145 ? 165? superjets run this standard
VF-3"s...they are a reed valve, they only make the engine more efficient.
porting? or cleaning?
c'mon, were still talking recreational PWC's here, keep it simple, keep it fun.
09-21-2009, 06:59 AM #5
The question is wether added pressure and cooling will add risk of water intrusion and affect performance to a degree that justify adding a bypass.
09-21-2009, 07:02 AM #6
- Join Date
- Oct 2006
09-21-2009, 10:40 AM #7
Bypassing one of the head outlets is done mainly to help heat the pipe up. Figure once you lose the cat the pipe will run cooler. Warmer pipes scavange better. However, I never noticed any difference in either my stock 1200 ski or the 1390 ski.
The other reason was to bring the pressure down. I can only see this being a concern with a big big prop which will flow more water through the cooling system. I also heard it helps with pressure on the big rubber coupler at the U to Stinger connection but I personally never had any issues there.
09-21-2009, 06:33 PM #8
Why not do it? It's really easy to do and It keeps #3 cooler
09-22-2009, 03:43 AM #9
- Join Date
- Dec 2005
- Lake Havasu City, AZ
My suggestion is put a pressure gauge in the line, between the pump, and the inlet into the exhust manifold. Any time you run over 30 psi you should reduce the pressure to 25 - 30 psi max. Most skis that run low 70's or above need to check pressure. Why risk more chance of water intrusion when 25 psi will flow all that is required for cooling. JMO
What has happened to other riders is the hose will only leak at WOT by the house clamp and can spray water to the carb area and be ingested. I had one 80+ mph ski burst brand new water hoses. This is also a problem on some Sea Doo skis, and we addressed it with a pressure relief in the line from the pump.
From the back fitting, on the stock head, use a T, and an inline valve, to control flow overboard. With individual heads - dump #3 overboard.
Better safe than sorry.
09-22-2009, 10:02 PM #10
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