Dodge SRT-4, HOM toys option, and WI injector placement

[turbojack]

Originally Posted by Roverdose

i see, so you can press the hom switch and get a few revs going before it turns itself off?

Drew

As it works without water injection

Add race gas to nearly empty tank (fuel warning bell or approx 1/8 tank). Run the car a couple of miles to use up lower octane still in the lines and to make sure any still left in tank mixes well with the newly added race gas. Hit the HOM switch and run the car. A red LED will stay lit after hitting the HOM switch (informing the driver that HOM is on and working).

As long as the PCM does not see a signal from knock sensor that would imply that there isnt race gas in the tank, you can run on HOM for as long as you have race gas.

IF for any reason the PCM gets a signal from the knock sensor that would give the PCM reason to suspect that you DO NOT have race gas after hitting the HOM switch, the PCM will override the switch and default back to stock mode and the red LED would blink (informing the driver that HOM has been shut down by the PCM).

Using the HOM allows for more timing = more power = car faster.

[turbojack]

We need to decide at some point how water injection will play its part.
I suggest the follwoing list of priority (order of importance):

1) Replacing high octane fuel at "HOM" mode
2) What action to take under water fault conditions
3) Actively disable the HOM mode or allow the ECU to switch off the HOM
4) Lower the boost pressure to wastegate setting by the DDS3

Question:
The rate of injection is determined by the PSI-FI and how can we tell the PSI-FI that we are in HOM mode?

At present the DDS3 will not know when the water should be injected so it cannot flag a logical fault under these conditions - it will only report that water is flowing or not. We can put an interface circuit to tell the DDS3 and PSI-FI at the exactly the same time that HOM mode is activated.

Is there a spare input on the PSI-FI to that effect? Once we have extablished this, we can sail forward.

Richard I'm working on a full reply to your questions.

So far I can answer:

OK, I agree #1, is to get the WI up and going and see if can get HOM to function using just WI. #2, let the DDS3 shut down WI components on failure of WI components/lack of flow. #3, let the PCM switch off HOM. #4, have the DDS3 control the 806-234 to limit/control boost.

The PP (Power Paq) can turn on the water injection but I dont know for shure if it can accept an input....stay tuned

[Roverdose]

i get what your saying.

what i wanted to say is if you press the hom button, can you drive anywhere before it turns itself off?

because this will determine whether or not you could use water to replace the higher octane fuel and/or where to start injecting.

say you press the hom button on tickover (without race gas) and it turns itself off! that would tell me you need to inject water from tickover.

Drew

[turbojack]

Originally Posted by Roverdose

i get what your saying.

what i wanted to say is if you press the hom button, can you drive anywhere before it turns itself off?

because this will determine whether or not you could use water to replace the higher octane fuel and/or where to start injecting.

say you press the hom button on tickover (without race gas) and it turns itself off! that would tell me you need to inject water from tickover.

Drew

I can drive the car with the HOM switch activated, anywhere and as long as the car has gas, even with the red LED blinking (PCM override). I think the water injection will need to be tuned so that it reduces knock in about the same way race gas does (or as close to that as possible I can get). I'm sure some experimenting will take place to achive this.

Tickover? I'm sorry, does this mean on startup? If yes, the HOM activation will not be disabled by the PCM unless it sees a value from the knock sensor that is not within the PCM accepted parameters. So, on start up the engine is basically at idle, knock should not occur here, and the red LED will be solid. Once the engine RPM is increased and or is under a load, knock may happen and if the PCM say's no go, it shuts down HOM (but not the car, and it does not put it in limp mode) and the red LED blinks.

[Roverdose]

Once the engine RPM is increased and or is under a load, knock may happen and if the PCM say's no go, it shuts down HOM

when is that then? at a certain revs / throttle position / boost?

Drew

[turbojack]

Originally Posted by Roverdose

when is that then? at a certain revs / throttle position / boost?

Drew

Knock can occur due to bad gas, high temps, load etc.. so to say it occurs under at a precise repeatable parameter for all situations would be wrong. If it did the PCM could be programmed to look at just this parameter and make an adjustment, because I do not run the car under the same conditions consistently the PCM needs to get real time input so as to be flexible enough to counter knock under varying conditions. If I were to do extensive data logging and I were to only run at the track I might be able to eliminate or limit the amount of variables so as to make the tuning easier but since the car is daily driven all year long, I can't, so I'll live with some of the inconsistency and try to compensate like the PCM does within the available means I have.

[turbojack]

This past Saturday I installed a second jet in the cold side pipe. This jet is past the charge air temp sensor. So now the injectors are placed as follows .9 jet in the end of the IC and a .7 jet in the cold side pipe. The car pulls noticeably harder with the second jet installed and the HOM light stays solid red no matter how hard the car is driven or the outside temps (temp today was 95 degrees). In the up pipe I sill have another injector fitting that?s capped off right now that I can add third injector to if I later decide to revise the system for what ever reason.

It seems to me that the current setup is doing two things with the two jets. The first jet located in the IC end tank is cooling down the charge temp considerably since before and after readings when that jet was first installed showed a drop of about 40 degrees. The second jet that is located after the charge air temp sensor is injecting water that is not getting atomized as well as the first and it is these water molecules (on top of the cooled down charge temp from the first jet) that is completing the effort to reduce or limit the knock.

I was thinking that I could have the water injection system activate HOM but after driving with this setup for awhile now I like it as it is and have no regrets. The only thing I need to do is hit the HOM switch after starting the car. If I could change anything at this point is to have the HOM activated when the car is running so wouldn?t need to remember to turn it on?..me = lazy

Only a couple of Aquamist components left to install, the piggy back tune rechecked out to confirm settings, and the HOM/WI system will be complete. Next step I think will be pre-turbo injection.

[Richard L]

Every picture paints a thousand words, Sorry for the delay turbojack - I have only just sized them up and thank for the pictures.

[turbojack]

I have more pictures to take of the hard pipe I replaced the stock one with. This new hard pipe has the jet adapters and the second jet I just installed. I still haven?t got the car detailed so I don?t have pictures of the outside for you just yet....hope to do this Saturday, but I?m relying on my buddy since he?s the expert with the buffer.

When you have time (I feel bad asking...but I need a little assistance so I do the install correctly), can you revise the schematic to reflect the additional components I received. More specifically the FIA2 806-441, the adjustable pressure switch 806-157, and the 2-way inline valve 806-234.

Also, I'm not an WI expert but I really feel that the second injector up by the throttle body has iced the cake with regards to the HOM LED staying solid red....it's really a blast to know that no matter what, it works. I'm so happy with WI, the Aquamist components, and your assistance and advice.

Oh and another thing, it?s been pretty hot here the past two days and tomorrow will be possibly hotter according to the forecasts. I have no doubt about the HOM light staying solid even with the outside temps above 95 degrees.

[Richard L]

I think I have put most bits in - please let me know if you like anything else included.