WI info needed for supercharged 2.2

[Rampage2.2]

I?m considering adding a water injection system to my supercharged 2.2 4 cyl.

I?m wondering what all I would need to get started or even if my engine will benefit from WI for that matter. I don?t know anything about WI other than I?ve read it will help stop detonation and that?s why I?m interested.

Here?s what I?m working on - a 1984 Dodge 2.2 4 cyl. I?m going to be adding a roots type B&M mini supercharger to (66 cu.). I have a 6 PSI pulley but I may get an 8 PSI if all goes well with the install.

I believe I have about 9:1 comp, maybe slightly higher. I?m running a Weber 38 DGES carb that has a #145 main jet currently installed. I plan on retarding my timing a few degrees, going to colder spark plugs and thermostat.

In order to reduce my compression ratio and avoid detonation I?ve considered going to lower compression pistons, but that?s a lot of effort. My supercharger?s manual says to install 2 headgaskets (double them) to drop my compression, but this seems like it may cause reliability problems. So I?d like to look into a WI setup so that I can leave my compression where it is and still avoid detonation.

Having said all that, what WI system if any will work best in my application? Where would the nozzle mount in my case? ? The top on the air cleaner?

This will be on a street driven car - how long will a tank last? Is it best to run just water or is there a mix? What nozzle size would be best to start with?

Any other suggestions?

Thanks.

[sebastian]

Like you, I've found sometimes it's hard to get a response on this forum. Being fairly new to WI myself, I'm not the guy to take any real advice from. Anyway...

- Most of your questions will be answered by conducting extensive searches within this forum.

- When properly installed, WI will resolve your detonation problem.

- Don't f@%& with your compression ratio unless a certified tech has a plan and states it?s doable.

- Jet location(s). If possible, inject immediately post supercharger.

Hopefully, more knowledgeable folks on this forum will assist you further.

[hotrod]

If you are using a positive displacement blower, I would suggest you inject infront of the blower.

The blower being a positive displacement device, places a hard limit on the amount of air that can flow. Your boost and air flow is locked in by the overdrive ratio of the blower. If you cool the air charge post blower you will actually lower the boost pressure, but still have the same air flow due to charge air cooling.

If you inject after the blower the only gain you will get is a reduction in detonation limit by the cooling effect of the water on the manifold temps and the in cylinder effects.

If you inject ahead of the blower you will get higher air flow at the same overdrive ratio. By cooling the air ahead of the blower it will move more air with each revolution. The water mist will also tend to improve the internal sealing and thermal effeciency of a roots type blower, giving you less compressional heating for a given overdrive ratio.

It may be most useful to inject on both sides if you still get detonation with the pre-supercharger injection.

Larry