Loosing water from lines, port injection?.

[keithmac]

Hello all, I`ve just fitted a 6 jet kit to my Mitsubishi GTO TT, at the moment it`s in it`s early stages.
The pump is followed by a 1 bar checkvalve 1/2 meter of 6mm line and the line is then split into 6 lines
for the individual injectors.

The problem I`ve got is when I`ve been driving around and accelerate hard I`m not getting water
injected into the manifold, I can prime the system for 5 to 10 seconds and this pushes all the air
out, or I can do one full throttle pull (with knock), if I get on it again straight after the water injection
works and all is well.

WI is activated at 10psi, I can`t figure out wether the water is been sucked out of the lines due to
manifold vaccuum (is 1 checkvalve enough?), or if boost under 10 psi is forcing the water backwards
though the pump?.

I had a 1mm single jet setup on first injecting before the throttlebody and didn`t have this problem.

I`m fitting a primer pump this week, but I don`t think this will have any effect on the water evacuation
from the lines (clear lines to the jets are empty after normal driving).

Anyone any ideas?, how do I check the checkvalve is working properly?.

Cheers, Keith.

[NAnderson]

It seems that there is quite a bit if tubing between the check-valve and each individual nozzle/intake runner. That leaves a good bit of water to be ingested, even though you've got a check-valve in there. I'd recommend placing the check-valve as close to the nozzles as possible, with the ideal situation being a check-valve for each nozzle placed just before it. I'd guess that a good bit of the water that's present in the lines just after the check-valve is getting sucked in to the engine, and then when the W/I system does kick on it's got to purge all that air out before water is finally injected.

The vacuum present in the intake manifold is MUCH higher that that which is in the intercooler piping before the throttle body. It's no wonder you didn't have problems like this with the old setup.

BTW, is that a 6G72 in your GTO? The engine bays of our USDM 3000GTs/Stealths are mighty cramped with that engine in there. I can't imagine how it must be with that GTO!

[keithmac]

Yeh it`s a 6G72 Twin Turbo, engine bay is cramped as you say, took long enough to find a place for the Aquamist pump!. Working on the engine is a real ballache most of the time!.

I may have a rethink on the line routing, try and get the lines as short as possible after the checkvalve, may even move the Aquamist pump closer as well when I have it in bits to fit the priming pump.

Was also thinking of sealing the water resovior and runing that at manifold pressure so there`s no pressure differential at the nozzles, probblem is I`m using the washer bottle for space reasons and it would take a lot of work to seal it..

Thanks for the pointers!.

[BlackWolf]

You can use a solenoid just before the lines split in two as seen on the photo above and you can wire it up so it goes open with 10psi like your WI does. I think that might help stop water being sucked into the engine with vacuum.

[keithmac]

Yeh a solenoid was my final option, maybe try 2 checkvalves first though after the y before it splits into the 3 lines. Going to shorten the lines first and work from there.