Water Injection

[TurboFan]

I've heard very limited things about this. It appears it helps with the acceleration but doesn't aid in top speed.

Where does it spray the water?
Any idea on flow rate?
Does it use a secondary pump?
How does it help exactly?

Thanks guys. I'm sure there are more out there who want to know. [img]smile.gif[/img]

Wes

[Bill O'Neal]

Water injection controls the tempature of the exhaust gasses and the speed that they travel in the exhaust tuned pipe. By using it, you can have the best of both worlds, a high performance exhaust system capable of very high rpm and still have a real good holeshot. Without it, you are limited to what you can do with the exhaust system to promote performance. You can also run much higher exhaust port timing in the clyinders.
The key to Sea Doo's domination in 1995-1996 XP models was the water injection, the tuned pipe and the higher than anyone elses' exhaust port timing. In conjunction with rave valves, Sea Doo had a 110 hp motor in a 90 HP world.....

The pump hanging out the back of every watercraft is more than enough to feed a little water injector, even while producing enough water flow to put out a house fire. No, you do not need an extra water pump.

[Technical Support]

What is the coupling between the injection and higher exhaust ports?

[Bill O'Neal]

Coupling?

Do you mean why can you have higher exhaust ports with water injection?

[Technical Support]

Yes.

[Bill O'Neal]

If you were to take a normal clyinder and raise the exhaust ports to 200 degrees, it would kill your bottom end power if you didn't run an extremely low picthed impellor, or add water injection and use a higher pitched impellor that allows for better speeds.
So with the help of the water injection, you can use higher exhaust port timing with a taller impellor.

[Rick g]

I have MSD water injection on a Rossier pipe, I can't feel any difference wheather it's on or off, feels the same either way, wierd.

Rick

[ July 16, 2003, 10:41 PM: Message edited by: Rick g ]

[TurboFan]

Thanks guys. Is it a volume or a pressure that's entered into the exhuast? And where is it typically tapped into? Do you need to be worried about getting water into the engine?

I know that sounded silly, me asking about the second pump but I asked because I know there is only the one line from the pump comming into the hull and I didn't know if that was sufficient for whatever you're trying to do.

[Bill O'Neal]

Rick you are not feeling it because your exhaust system is not as highly tuned as say, a Factory Pipe system.

Turbo,
Volume or pressure? It takes both to move a stream of water.

If you mount an injector at the very top of the exhaust pipe, like on a 787 system, you had better point the spraybar downstream if you do not want to get water into the engine.

[TurboFan]

I"ll rephrase my question, is it a spray of water that comes out at high pressure or is it more like a fountain? The difference between a garden hose with no end or one with a sprayer that shoots the water 20ft.

Since I think I could rig one up myself as long as I know what it's all about do you feel there would be any benefit on my 91 XP?

[Bill O'Neal]

Turbo,
It would be more noticable if you had an exhaust system built especially with water injection in mind when they designed it.

Like the guy with the Rossier system, you might see a slight gain in accelleration at best.

[TurboFan]

I've been thinking about my university days and I've come to the conclusion that the exhaust works as the exhaust valve in a 2 stroke motor, and the water is there to change the volume at different engine speeds.... Am I close? And will it affect me? I have my doubts as it's shaped differently than a tuned pipe like what's on my CR125. I want to see what you guys say though.