JTD water injection

[stefz]

I am installing my water injection system today, and have decided to start off with a simple pump on/pump off switched by throttle position.

I am using a 140cc min (100psi) mist nozzle, and planning to switch on when over 75% throttle..

I've read in various places, upto 10hp can be pocketed by addition of WI, with benefits to mpg also, aswell as the obvious reductions in EGT..


Any users of WI on a 16v JTD ? what rates are you using. (I have a few nozzles to try)


I would like to hear from experience?

[TribesMan]

In turbo cars I guess the boost pressure is a better option for switching the water injection.

If you switch by throttle position, you might have problems, when you try to floor the car at very low revs.

About the power gains. If you car is on standard map, and you will only use the water injection (no methanol) there will be no power gains whatsoever. Because only colder intake air wont help you gain any power, (standard ECU is not limited by air, but by fuel injection and you cant fix that unless you make a remap).
You need more fuel to make more power.
Fuel is supplied either by methanol in the W/M injection (but that will only show if you use 50% mix and flood the engine with that mix with 250+cc/min nozzles, because the methanol has very low energy density compared to diesel), or if you car is remapped properly for W/M to allow higher quantities of fuel (standard remap wont do the trick, you will need to adjust it if your car is already mapped).
There might be a marginal drop in mpg, but the EGTs will go down dramatically.

140cc/min nozzle is a perfect choice for your size of engine.

[stefz]

what kind of system are you using TribesMan, what rates

[TribesMan]

Well... my system is still under my desk

I was experimenting with gasoline fuel injectors, but that didn't work, and the project is on hold since then.

A friend of mine uses a progressive kit and 2gph nozzle on a GT (he also tried 3gph but that didn't give any noticeable advantage in cooling, EGTs went a bit down, but IATs were practically the same). His system is switched by boost pressure. We were able to squeeze out additional 15HP from his engine, after W/M and a new remap. Without a remap and with W/M 30% mix the difference was under 5HP. But AFAIK he only uses water now, no methanol.

I will do the same on my car (mostly because of good effect on intake cleaning...) only I will inject proportional to air intake, not boost.

[turbonutters]

Originally Posted by TribesMan

I will do the same on my car (mostly because of good effect on intake cleaning...) only I will inject proportional to air intake, not boost.

How will you be measuring the air intake?

[TribesMan]

With MAF obviously...

[turbonutters]

The cars own?

[TribesMan]

Of course...

[turbonutters]

Great.
Won’t the management complain when you tap other systems into its reference wires?

Sorry I am asking a lot of silly questions.

[sussexa]

i hope not ive been tapped into signal from map sensor for quite a while checked with fes readings seem plausable with it switched on or off no difference.i would imagine the maf is similar 1-5v.

[turbonutters]

Yes it is similar working from 1 to 5v.
So hopefully it will be fine.

[TribesMan]

Well I always use voltage followers to "tap into" the ECU management sensors. They produce almost no load on the sensor output and they are very unlikely to produce any side effects.

MAF output is from 0-5V, but 0-1V is used for negative air flow, and 1-5V is used for positive air flow. And there is one more thing do consider. Voltage output is not linear but logarithmic. So the output is very sensitive at low airflow but at higher airflow there is very little difference in voltage output.
At 4V output there is ~350kg/h of airflow, at 4.5V the airflow is ~550kg/h. So you need a sensitive controller.

[turbonutters]

Thanks great information