Thread: jet works valve,
12-19-2009, 09:43 AM #1
jet works valve,
I posted this a while back. I found it on the net. is this stuff true? where exactly(in pics!) do you install this? Any pics of installed jetworks vales on various polaris skis? do you all use them? does it work?
As for exhaust: The hotseat waterbox yielded a wopping 20 rpms on my 150psi 1200 Polaris with bigger carbs (44mm) and lots of sound. Opening up the exhaust on a single piper will yield very little (and as mark said may actually cost speed). The jetworks valve does wonders for holeshot and there are 2 different routes to go on the stinger that dumps into the exhaust. Reducing the size (on a stock motor) increases holeshot and minimally robs power on top...On a motor pushing more air and fuel (higher compression, reeds, carbs, etc...) using the jetworks valve to keep the water out down low and opening the size of that stinger actually yields some impressive top end results (50-100 rpms depending) and does not affect holeshot...Most people will tell you that's crazy on the various boards but that's a Sharp's trick on their single pipe monsters...
Is installing this as a mod A good thing on a stock 1200.? Anyone have 1 installed?pics?
12-19-2009, 11:53 AM #2
- Join Date
- Jul 2007
- near Toronto, Canada
How a Jetworks valve works
The Jetworks valve installs in-line with the small hose water feed to the exhaust water injection orifice.
Normally, the water pressure from the jet pump, in addition to flowing water through the engine and exhaust pipe water jacket, also injects a small stream of water directly into the exhaust pipe interior. This injected water spray cools the exhaust gases, so the downstream rubber couplings and water box do not overheat and melt, or burn the hull material.
As RPM rises, so does the water pressure from the jet pump, and the water spray into the exhaust flow also increases.
At idle and low RPM, there is enough water spray to keep the exhaust gases cool, but exhaust flow and gas volume is low, since the engine isn't working hard. That means the injected water accumulates inside the waterbox, until the water level gets high enough that any further water accumulation gets forced out, even at low RPM.
After idling for a while, the waterbox has a medium-high level of water inside. When you then pin the throttle, the engine exhaust flow immediately increases. But the water inside the waterbox acts like a partial plug.
The exhaust pressure builds up, and then most of the water in the waterbox gets blown out. As soon as the excess water is pushed out, the exhaust back pressure drops, and the engine can produce more power and thrust.
This feels like a momentary limit on engine power, while that water is getting pushed out.
The Jetworks valve is pressure sensitive. At high water pressures (mid-high engine RPM), it allows water flow into the exhaust injection, and maintains the necessary cooling.
At low RPM, the water pressure from the jet pump is lower, and the Jetworks valve limits water flow into the exhaust. This means that less water accumulates inside the waterbox, so when you grab the throttle, the engine can immediately produce full power without first having to build up back pressure to clear the waterbox.
This is the performance gain from installing a Jetworks valve.
One downside is that at low RPM, there is less water injection into the exhaust. This means less water cooling of the exhaust gases. The exhaust system can handle some excess heat without damage.
If the jetworks valve becomes clogged or stuck, the heat can become too much, and the exhaust system will start melting and burning.
Last edited by K447; 12-19-2009 at 05:35 PM. Reason: Corrected low speed Jetworks valve operation
12-19-2009, 12:41 PM #3
well. i'll do a fair amount of idling around so maybe not then on this ski.(slx).
12-19-2009, 03:49 PM #4
I have never heard of a melt down from idling a long time...there isn't enough heat generated at idle to cause the heat needed to melt down...the water that remains in the box is enough to keep things running fine. I ran one on my old 2000 slx and I have to go through some very long no wake zones where I ride a lot...20-30min long and I have never had any issue with over heating. Personally I would get one...makes a big difference in taking off.
12-19-2009, 03:58 PM #5
12-19-2009, 05:22 PM #6
From what I have read about the Jet Works valve, it still allows a little water through when closed, to avoid such issues. I may be wrong, but I will try to find where I read that. You then set the pressure at which it opens to allow full flow, either with shims on the regular valve, or by turning the housing on the pro valve. I am sure I read that they do have some (limited) flow at idle pressures though...
Edit: This is right from the Jetworks site:
The JETWORKS FLOW CONTROL VALVE allows unrestricted water flow to the stinger for better top speed. Yet it controls the amount of water at low speeds for better response. It also allows for an easier tuning of the carburetors. It does not interfere with normal engine or exhaust pipe cooling and is compatible with all electronic water injection systems.
12-19-2009, 05:37 PM #7
- Join Date
- Jul 2007
- near Toronto, Canada
12-19-2009, 08:05 PM #8
12-19-2009, 11:31 PM #9
12-20-2009, 08:10 AM #10
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By Hydrotherapy in forum Yamaha PWC Performance (2-stroke)Replies: 10Last Post: 01-17-2007, 01:04 PM
By oklagp1200r in forum 4-Tec PerformanceReplies: 23Last Post: 11-18-2006, 01:51 PM
By 01xdime in forum 4-Tec PerformanceReplies: 8Last Post: 08-14-2006, 11:02 AM
By christian gpr in forum Yamaha PWC Performance (2-stroke)Replies: 10Last Post: 04-23-2006, 02:35 PM
By jetsurf in forum Yamaha PWC Performance (2-stroke)Replies: 2Last Post: 03-27-2006, 07:43 AM