WI quantity calculations

[hotrod]

The engine bogging down shows up mostly as a subjective evaluation by the driver. In its usual usage the engine might stumble or hesitate a moment or just have a brief period where power seems to be down a bit. In severe cases bogging is very obvious, its like the cars ignition was turned off for a fraction of a second, or the car acts like it suddenly got much heavier and the engine had to work much harder than normal for a second or so.

An ideal engine, properly tuned, has good throttle response and seems eager to pull. When you blip the throttle for a down shift for example, the engine has a very sharp crisp response. It revs immedialtly and willingly. Under hard acceleration you get the feeling the engine "wants to rev -- it wants to pull".

On an engine that has a bad tune ( could be too much water injection or other things like improper timing etc.) the engine is not as crisp, there is a small but detectable lag between when you change the throttle setting and when the engine responds. It simply feels a bit flat. On an engine that you can hear the intake sounds it sometimes sounds like its strangling or choking on the excess water. A lot of tuners will say the engine sounds "soggy" it feels and sounds water logged.

In severe cases there may be an obvious loss in power when the WI first engages as the excess water actually reduces power output, then as the engine revs it gets the power back plus a small improvement at the top end. This might indicate a turn on poiint that is too early or the jet is too big until the engine gets higher up the power curve.

All very subjective, but one of those things you'll usually recognize when you see it.

Its like the driver who comes in for service and tells the service manager the car runs fine but just doesn't feel right, its a bit sluggish etc.
On examination the shop might find something like bad plugs. The symptoms were noticable to someone familiar with the car but a total stranger might think the car was running normally.

Larry

[TAZ]

Larry,

Managed to get the service bulletin from shurflo for adjusting my pump for up to 100PSI (from the 60).
It describes the procedure to do it....
(if you want it i can sent it via an email....).

Now i'm fixing a distribution manifold to connect the pump, accumulator, solenoid (drives the nozzle system) a preassure gauge, a preassure switch for the manifold and some spare ports for future use.
The order for the ingector nozzle has been set (spraying systems nozzle system) and the steel pipe replacement of the feed to intake manifold is planned to support the nozzle and future additions ... :twisted:

Just an info....
Any schematic for converting my setup with preasure regulator will be much appreciated???

[Slump]

Originally Posted by hotrod

The engine bogging down shows up mostly as a subjective evaluation by the driver. In its usual usage the engine might stumble or hesitate a moment or just have a brief period where power seems to be down a bit. In severe cases bogging is very obvious, its like the cars ignition was turned off for a fraction of a second, or the car acts like it suddenly got much heavier and the engine had to work much harder than normal for a second or so.

Larry

Here's a dyno chart showing "too much water".

The blue curves had far, far too much water.

The difference between the blue and red curves where simply turning down the amount of water.

[hotrod]

Hey very good dyno plots, those very clearly show the "fluttering" effect some folks report when you get too much water.


It also points out how easy it is for a vendor who doesn't like WI to make it look bad, all he has to do is over inject the water and you get an instant 20 hp drop in power output.

Larry

[b_boy]

Bogging most often occurs in most peoples cars when they leave the car in a high gear, and when trying to accelrate the car "bogs". It kind of chugs. I think it's a series of misfires.

Pressure will tend to slightly raise saturation point, increased temperature tends to greatly raise it. Hence rain when air cools, and lower pressure signals rain. Also, you can see that warm air can hold a great deal more water. At 50 F, air will hold about 4 g per cubic foot, and at 90 F, about 14 g per cubic foot.

At 30 psi, 50 F holds the same 4 g per cu ft. At 90F, 30 psi, sat. air holds 15 g per cu ft.

Good calculator:

http://www.engineeringtoolbox.com/8_240qframed.html

dry=wet bulb temp equals 100% saturation of air.

[SaabTuner]

Many WWII aircraft injected as much as 50% water to fuel even at A/F ratios richer than 11:1, often leaner than 20:1 as well.

I think that's more a problem with the ignition system. The Aquamist WI setup shouldn't even be capable of drowning the engine.

The water in the air might be making it too easy for the spark to jump the stock gap. I wonder if a larger gap would be appropriate when running high water/air ratios.

Also remember that, by the time your cyllinder fires, the temperature of the air in the cyllinder is well over 350F.

Adrian~