Originally Posted by PatrickB
Yup I got it last go around but that clears even more up. I don't want to run %100 meth on my street car 50/50 is a pretty good compromise nor do I want 2 systems! Hehe. Thanks for the information man I appreciate it. Any particular books you have been reading or forums? I would love to be more versed. I am actually very intersted in removing my ic. I am less conservative I think then you I run 15psi on my stock 1.6 and I am going to give 20psi a shot.
Also can you speak on the merit of phase change pre tb. Seems like most ecu's run a 3d map based on air temp sensor at the tb. Thoughts?
Well, I have a good handle on the science because I have a BSAE, an MSAE and am a registered PE in Mechanical Engineering (thermo is considered part of mechanical engineering). Plus, my BSAE is from Annapolis. I'm sure you can imagine that thermodynamic cycles involving water were somewhat emphasized there.
However, the science is just a starting point. Actual observations on the car count for a whole lot, it's just that sometimes you need the science background for proper interpretation. I will tell you that I was very surprised by the results of my WI installation. I fully expected to have much more phase change in the intake tract than I do. Your temperature results confirm mine . . . for the most part water doesn't change phase until the combustion stroke starts.
There are some good NACA reports on water injection on the internet. Also, search for Harry Ricardo. He is considered the father of water injection. RB Racing also has good info on their website. See http://www.rbracing-rsr.com/waterinjection.html
BTW, if I were going for 20psi (or, in Fae's case, "ALL OF IT"), I would consider an intercooler mandatory. The higher your boost, the better the intercooler works because your charge temperature is higher (greater "delta T"). That's one disadvantage of pre-turbo injection, you reduce the effectiveness of the intercooler.
Thermodynamically, if you get cooling through liquid phase change prior to the throttle body, it is equivalent to the effect of an intercooler. It lowers temps. That's actually not 100% true because the phase change also creates more gas, which helps keep pressure up. So, it's a bit better than the intercooler from that standpoint.
One thing to keep in mind about intake temperature sensors is that they do not have immediate response. In addition, you have to be careful with their mounting so they are seeing the intake temperature rather than engine bay temperature. There are plenty of horror stories out there about heat-soaked intake temperature sensors.