I know this is done with nitrous, and I'm just starting to research water/meth now.

Are there any advantages/disadvantages to direct port injection...right on the intake runners already past the throttle body?

Perrin did this on their H6 STi. I want to go to this eventually, probably when I go to a FMIC. The gains would be had if you can trim each cylinder. Hydra gives the ability to do fuel trims on each cyl IIRC. Now to trim each cylinder for meth I suppose you could let hydra do it. Or have a solenoid on each line to each cyl. Now you wouldn't want big jets. Maybe 150 or 175 ml/min per cylinder, depending on application. Bigger turbo, bigger nozzle. To optimize this, I would say go to aftermarket fuel rails, so that the fuel system is nice and robust. You can see the nozzles on each intake runner in this thread. Nice setup. Plus their running an aquamist system. This is probably the way I would go also.

http://forums.nasioc.com/forums/showthread.php?t=959768

DP

...... One of the disadvantages of direct port is that the flow of alc/water doesn't follow the flow of air. Ie-Certain cylinders might bet more air because of the design of the intake manifold(or whatever) and having the injection before the intake manifold might compensate for certain cylinders running lean. You'd also lose out on some of the intercoolling effect of the water/alc on the air. The only real advantage is that it might make the injection go to each cylinder more evenly, and as stated b4, that might be a disadvantage. At least that's the way I see it.

peace

...more of an expensive PITA than anything else, for a street car.

a FULL race car.....then i'd start thinking about something like that.....but for street.....nah

I'm considering this for my IS300.
Def not a daily driver.
The intake runners are straight, not curved and equal length.
So yeah, I may do this. Thanks for the pics and advice.

I run DPI on my car at the top of each intake runner and the reason i did it was for evenly distributed water flow to each cylinder to cool the intake valves and provide more in-cylinder cooling, i'm not interested in using it for cooling the charge air as i have good enough IC for that. If you do run DPI always check your jets frequently for flow and spray pattern caused from full or part blockages..

Here are a few more negs. Having 6 of certain parts instead of 1 means more can go wrong. It's easier to monitor if 1 nozzle clogs.....

peace

I run DPI on my car at the top of each intake runner and the reason i did it was for evenly distributed water flow to each cylinder to cool the intake valves and provide more in-cylinder cooling, i'm not interested in using it for cooling the charge air as i have good enough IC for that. If you do run DPI always check your jets frequently for flow and spray pattern caused from full or part blockages..


Interesting.

So your air intake temp sensor is before the nozzles.

That's one of the issues I was worrying about. Not utilizing the cooling effect of Meth.

Correct my intake air temp is measured pre-turbo(standard location).. but as i said before i'm not interested in cooling the intake charge outside the cylinder and i don't use meth so it doesnt really worry me.

http://www.enginerunup.com/images/uploads/DirectPortCloseup.JPG