Water injection systems. What are they?

[The_Handier_Man1]

From: Colin  (Original Message)
Sent: 3/10/2003 6:41 PM

I just got my copy of RX for RV Performance and Mileage by Geraghty and Estes that I ordered from half.com. I thank the person that suggested it, I'm sorry I don't remember who it was (couldn't find the post.) Geraghty mentions water injection systems many times in the book, as if they were a necessity for RV engines. I never heard of them before, although the concept seems obvious. Do they make a big difference? Where can I buy one? How much do they cost? Are they easy to install? Do you have to completely re-tune the engine after you put one in? 



Sent: 3/10/2003 11:18 PM

Water inj. was used to keep eng. timing hi,with a hi comp eng. Helping with the poor fuel we have today,and 20 years ago.



From: dave76Chieftain
Sent: 3/11/2003 9:52 PM

One place is http://www.racetep.com/wik.html
another that may work is http://www.racetep.com/wik.html



From: Colin
Sent: 3/11/2003 10:17 PM

Dave, thanks for the info. I looked over the site. Did you buy one? How has it worked?



From: dave76Chieftain
Sent: 3/12/2003 6:34 AM

I have never bought an injector but do understand what it does.  It would not go over well for most people because you have to fill the water tank when you fill up for gas.  People tend to get lazy LOL.  With an RV though, you have this big tank of water so you could refill the injector tank from there.  Little 1/4 piping and it would be almost automatic (maybe a ice cube like refill set up like in a refrigerator?).  The water allows you to advance the timing higher with out the engine pinging.  Key though is to have a unit that responds to engine load (vacum and rpm). not just RPM



From: Derrek
Sent: 3/12/2003 8:38 AM

Does anyone here currently have one of these systems installed on their unit? Or have you seen them used before? They claim the possiblity of a 25% increase in fuel mileage. Is this really possible? Sounds like a good system if it works. Cheap compared to other upgrades and supposed to be easy to install. 



From: neil
Sent: 3/12/2003 9:21 AM

These systems were around in the 50's and if memory serves, I don't think they performed as advertised. Aside from that I would be concerned about adding water because of the hardness. I think the calcium would remain in the engine plating out on cylinder heads, valve seats, and rings. I think a short term gain may cause long term headaches.   



From: neil
Sent: 3/12/2003 10:17 AM

I would have an additional concern about the high moisture level in the cylinders on shut down. Because of the heat the moisture exists as steam in the cylinders this  separates the water from the solids. When that steam condenses in the cylinder on cooling, the condensate contains co2 which forms carbonic acid which is very corrosive. Maybe someone out there who is more knowledgable can address these concerns. But the bottom line is that I'm a graduate mechanical engineer with 40 years experience under my belt and I would not put on my engine even if it doubled my miles. Having said that I get 10mpg on my engine, if I were getting 5mpg who knows.



From: neil
Sent: 3/12/2003 10:22 AM

I also think it would shorten the life of your exhaust system significantly.



From: Derrek
Sent: 3/13/2003 12:17 PM

Thanks for the reply Neil. You brought out some very good points. I don't think that the calcium would do the valve seats or the inside of the combustion camber any favors. I could even see the possibilty of the exhaust becoming restricted or plugged by hardness deposits.   



From: Postoak
Sent: 3/13/2003 7:54 PM

Hey fellows, Skypilot (now Postoak) here.  I remember back in the middle  or late fifties there was a water injector came on the market.  A lot of guys I knew bought one and several of them started burning valves so they started putting Marvel Mystery oil in them and  done more for the engine than water ever could.  Not long after that, Marvel Mystery Oil co. came out with their own Oiler.  I don't know if the ones now are the same but I assume their supposed to do the same thing.