Looking for some information on this subject. Seems that water injection is pretty popular with the forced induction crowd, but could it be used surpress detonation in a high compression normally asperated using pump gas. Seems like a good alternative to running race gas all the time on the street. Any thoughts?

 

There is no reason it wouldn't work under the right conditions. Keep in mind that water injection will actually cost hp unless your setup is already experiencing detonation or you have had to retard timing past the optimal point to avoid detonation. Detonation is by defnition inefficient combustion and, of course, it can break parts.

I don't have any idea of how much you would gain though. If you want to try it, my friend Bob Kennedy puts togther a moderately priced kit with high quality components. He uses an rpm based controller which would be perfect for an NA setup. It's on his web site at www.kennedysdynotune.com. My system is from Carroll Supercharging and has a boost based controller. Don't bother with any system that doesn't use a high pressure pump: you need the water to be injected as a mist with very small droplet size if it's gonna work properly.

Rich Krause

 

I have often thought about this myself......actually Rich, I was going to talk to you about this for my setup.....definatly since I was thinking about raising my compression even more with the additional headwork I plan on doing this winter.

What do you think Rich? In an application that is theoretically say 13:1 compression (or at the point any NA LT1 motor would start detonating on 93-94 octane) to run on pump gas, full timing (or more timing)? I have looked into some calculations, but with these dynamics it is tough to predict anything accurate.

Also Rich, what about on an NA motor while spraying? I am going with a 200 shot next year, which would require me to pull at least 6 degrees of timing (not a big deal)....

Thanks
Jason

 

I tried it on my 12.77 to 1 motor and didn't have good results.

I'm thinking of trying propane on my current setup.

 

Jason: it would be an interesting experiement. My gut feeling is that the benefit would be small and need a lot of fiddling to realize. You can definitely have too much water, which really kills power. In any case, race gas will be needed with nitrous and a CR in the range you are talking.

Timing requirements decrease with nitrous, as the burn rate of the intake charge is higher when nitrous is injected. Water, in turn slows the burn rate and would allow/require some of the timing to be added back when spraying. The optimum timing would also need to be worked out on the dyno, which is time consuming and expensive. It would be too dangerous (to your motor) to do at the track, IMHO.

In the end, I doubt it would be worth it. In a blown application the real advantage to water is the cooling effect on the intake charge. The slower combustion (octane raising) effects are also useful, but I think much less important.

Rich Krause