water injection

[moshem74]

hi

http://website.lineone.net/~da.cushman/misc/mannject.html

 

is it good on any car or just on turbo cars?

thank you.

moshe.

[NorthWet]

... is it good on any car or just on turbo cars? ...

The functionality and value of water injection has been debated for a long time. There was a recent USMB thread about alcohol injection that also discussed water injection.

 

My thought is that if you are curious, try it and let us know how it worked. I would be critical of anyone who claimed amazing advantages and then offered to sell you a water injection system, since they have a vested interest in your buying his product. But his website seems to be showing how to do it yourself.

 

My only word of caution is that you make sure that your connection to the intake system does not get exposed to full intake manifold vacuum, as this could be very detrimental to your engine.

[All_talk]

Water injection does work as a detonation/pre-ignition limiter, its based on the idea that water takes a lot of heat energy to evaporate (true phase change, not vaporize), normally this heat extraction occurs in the cylinder under compression, as most turbo systems don’t generate the proper temp/pressure requirements to evaporate the water in the intake tract. But as long as its done before ignition the effect works. The down side is that it takes up space in the cylinder, reducing volumetric efficiency.

 

Its been around a very long time and I know it was used in planes during WWII for high boost “emergence power”. But in the modern automobile its bit of a band-aid, popular in the ’60-’70 when adding a turbo to high compression N/A engine. With a proper engine management/FI system it really shouldn’t be necessary. ’80s vintage turbo systems like our Subies use supplemental fuel for much the same effect, that’s why they run very rich under boost, this and some timing retard form the knock sensor control detonation/pre-ignition. Newer systems normally use a combination of intercooling, timing and some extra fuel to do the same thing.

 

Gary

 

P.S. Water injection might be of some use on a N/A engine…. Say I wanted to run my ’65 Pontiac with 10.5:1 compression on 87 octane gas with stock timing. But some later model, lower compression heads (with hardened valve seats) might be a better choice.

[oddcomp]

http://www.turbododge.com/forums/forumdisplay.php?f=59

 

just some talks about various injections and such