Even though I have an Air/Water Intercooler I have started testing my "Tom Graham" DIY water injection system to get
further cooling. Many thanks to Tom for the inspiration on this!
Ok, just did my first test run with the new water injection. I had one problem with the system and that was water
leakage. When I built it I did not use the correct "goop" and that cause quite a bit of water leakage (spraying on
the underside of the hood instead of into the intake). I'm in the process of re-gooping and re-testing. Even though
I lost a lot of water I did get some data but I am not sure what it means. Note that the WI was activated manually
(no pressure switches) and used for the entire time I was under boost.
Without water injection:
Boost peak @ 4100 rpm = 8.6 PSI
Boost peak @ 7700 rpm = 9.6 PSI
Air temp increase during boost = 18*C
Peak HP and Torque = 173 and 150
Peak knock count = 17
With water injection:
Boost peak @ 4100 rpm = 9.4 PSI
Boost peak @ 7700 rpm = 9.9 PSI
Air temp increase during boost = 14*C
Peak HP and Torque = 163 and 147
Peak knock count = 13
So what does this mean? I'm not sure. I can definitely see that I am getting more boost, a cooler peak intake temp,
and a little less knock with the water injection. BUT, it does look like the water injection is costing me 10 HP. I
am not sure why. A few people have told me that I should not be using the WI until boost pressure is 2-3PSI below peak.
For my next test, I'll wait until around 5600 RPM and then start the injection. I don't know what that will do but
that is why this is called TESTING.
This shows results that are typical of what I saw. The first power run was done without WI and the second one was done
with WI. Note that the boost pressure (orange line) was higher in the second run but the increase in air temperature
(blue line) was less (from start to finish). You can also see some of the knock (red line) is gone.
The graph below shows the difference in horsepower and torque when using and not using water injection. Even though
the boost pressure is higher with the water injection you can clearly see that the horsepower and torque are lower
for the entire power curve:
This is the original setup of the JRSC elbow with the 3/4" idle air hose connected:
Making the nozzle:
The long hose with the check valve was what I removed. The short hose with the check valve and air filter was put
in it's place. This is only possible if you have removed your AFM.
Luckily I had several JRSC elbows to choose from. One had a larger opening (not sure why, must have been an older
model - I can see where it would be weaker and maybe prone to cracking) that my nozzle would almost fit it. It made
this job much easier.
Ty-wraps did not work. Too leaky.
An exploded view and the goop I used to seal everything with:
The finished product. Only one problem - it still leaks. I'll have to pull it off the car, disassemble, and re-goop.