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

Hi everybody. I have been reading diff threads/posts on this forum for awhile but have never posted. I have been enjoying but not participating, this has changed since I think I have the components I need to start my project. I just need some educated advice and helpful comments that may be particular to my car, hence the post here.

I have a 04 Dodge SRT-4, the major things done to the car that are for engine performance are: Stage II with toys, a piggy back controller (SMT-6 based), upgraded exhaust and a Zeitronix wideband for double checking A/F ratios and EGT temp (EGT probe not hooked up yet).

With regards to the factory stage II upgrade with the toys option:
The toys option has a HOM switch (HOM =High Octane Mode) for running race gas. My best understanding of what this switch does, is allow increased timing when using race gas (higher knock threshold). However if the PCM sees knock that it thinks should not be there when HOM has been switched on, it overrides the switch and reverts back to non HOM mode (thinks that you do not have race gas in the tank and switches to back to base map), this is for the safety of the engine.

From what I?ve reading (correctly or incorrectly), WI if installed, setup correctly, and properly tuned may allow the use of the HOM switch without using race gas. Besides some of the other benefits of WI this is my main goal of using WI on this car.....if it can be done.

I have had the piggy back controller for awhile now and have always intended to use the piggy back and WI together. Right now the Piggy back is setup/tuned to make more power, keeping the A/F around 11.0 - 11.5 (no higher till EGT probe hooked up). Without the piggy back the factory tune was dumping fuel (around 9.00 -10.5 under full boost). Also, at this time the piggyback I?m using can not be used to advance timing only retard (see web link).

I recently purchased an Aquamist 2C system as the basis of my WI system. I was intending to install the Aquamist jet and HSV post intercooler but before throttle body in order to reach or meet my goal of using the HOM switch without buying race gas. However, If the car has a piggyback controller that can control a HSV (see web link), should I be looking more closely at injecting into the intake manifold (port injection)? What setup or placement of injector(s) do you think will help most in simulating race gas? If it applies, what WI mixture do you think will be needed for this? With regards to fluids, keep in mind the idea is a low cost replacement to race gas, I would like to keep things simple once setup, and not have to spend time on a weekly or monthly basis sourcing anything exotic or expensive (distilled water=less than $.99 per gallon).

Here?s a link to the piggyback I?m using from PSI-FI motor sports
http://www.psifimotorsports.com/ECU.htm

Here?s a link to a description of the stage II with toys from Mopar
http://www.mopar.com/srt_stage_2.htm

Here?s a link to the Zeitronix wideband
http://www.zeitronix.com/Products/zt2/zt2.htm

Hers a link to my Exhaust upgrade from MaxFab and Mopar
http://www.maxxfab.com/welcome1.html1.html


If anybody has some comments or needs additional info or just wants to talk about what I?m proposing to do with WI on this car, please feel free to post.

Thanks
Jack

Jack,

Thanks for submitting your SRT for the discussion - hope it will bear fruit as more people may chime in and offer solution to get over some of ways to over come the rich a/f ratio being programmed at HOM. Does the HOM also runs rich?

The piggyback is one solution - not sure how it works to trim fuel etc. The most common method is to trim the MAF, TPS or MAP sensors. They will all have other side effects at WOT, since the ECU is not going to see full WOT voltage etc. Please outline your thoughts and how WI can replace the 10:1 afr.

I have read the Psi controller and assume the following:

1) You are trimming the fuel by modifing the load sensor
2) You will be creating a map for the WI to drive the 2C.
3) HOM will altomatically advance the ignition and boost on the stageII.
4) You are already running bigger injectors on stage II upgrade? (part of the kit)

I think your set up will work well with the 2c. I do have a question. Is the "map switch" on the Psi switchable on the fly if water injection is interrupted?

"Does the HOM also runs rich?"

Yes but it?s been awhile since I?ve used it (weather and road conditions not conducive to racing or high boost runs) and I do not remember the values displayed on the wideband controller when I was using it, sorry.

?The piggyback is one solution - not sure how it works to trim fuel etc. The most common method is to trim the MAF, TPS or MAP sensors. They will all have other side effects at WOT, since the ECU is not going to see full WOT voltage etc.?

The Piggy back that I?m using is just that, a piggy back it does not replace the PCM it alters some of the sensor signals being sent or read by the PCM. The web site I linked to doesn?t go into details on what it does exactly to ?trim fuel?. If I?m not mistaken it alters the MAP signal. But it does this ?map clamping? in 3D (RPM, LOAD, TPS) versus a specific voltage clamp at high boost levels.


"Please outline your thoughts and how WI can replace the 10:1 afr."

The factory is dumping excess fuel to keep combustion temps low, which helps with engine life or limits them (DCX) to being vulnerable to warranty claims due to engine damage. By taking away some of the excess fuel using the Power Paq my power goes up but so does the risk of doing damage (if I go too far). If I can replace some of the excess fuel with WI, and introduce it in the right amounts, at the right time, I think I can keep the power I have tuned into the system already and keep the intended safety net that the factory had tuned for but did by dumping fuel. IMO I should be able to tune more aggressively, by reducing fuel dumping even more (but using my head and not getting too greedy) by further tuning the map in the PowerPaq with a wideband and EGT readings.

With race gas and the HOM switch enabled the car does make more power (proven to me by seat of the pants feel, others have been to the dyno and have seen the effects in black and white). I hope to be able to use the effects of WI to reduce the knock threshold, again by introducing it in way to reduce knock. The factory PCM is looking to see higher expected knock values when HOM activated. If it does, it allows more timing (significant to making more power). If not it overrides the switch and reverts to the non HOM settings. If I can get the system setup and tuned properly I think I can get the car to run with a higher knock value as if race gas is being used. This will allow me to run the car with the HOM switch activated at will and without using expensive race gas.

Right now this may sound like I want to do two separate things with the WI, but I think it?s doable if I do it right and knowledgeable people help/guide me. At worst I think I can keep the current Power Paq map, and just attack the HOM problem without fear of doing damage since my Power Paq tune, IMO is conservative.

?1) You are trimming the fuel by modifying the load sensor?

See above, if still not clear I can send user manual

?2) You will be creating a map for the WI to drive the 2C.?

Yes, I will be using the Power Paq to drive the 2C HSV. I will have a map specifically for my default tune but with WI. This way if have WI problem I can revert back for safety.

?3) HOM will automatically advance the ignition and boost on the stage II.?

See above, I think it?s better said that, it will allow more timing if it sees expected increased knock threshold values. I don?t think the HOM switch activation effects boost control. However the PCM in stage II has been calibrated for increased boost when WOT.

?4) You are already running bigger injectors on stage II upgrade? (part of the kit)?

Yes the injectors are larger and I think the factory sizing was in anticipation of the next stage as well (stage III), since I have stage II w/the toys option, the stage III upgrade for me from Mopar would not include larger injectors.

?I think your set up will work well with the 2c. I do have a question. Is the "map switch" on the Psi switchable on the fly if water injection is interrupted??

Example to switch from map A to map B: you have to shut off, then have key on and then toggle the map switch from map A to map B. So no, you can not switch between maps on the fly or have the maps controlled/loaded by something like a low fluid signal or clogged injector warning.

F.Y.I. I'm going to let some other SRT-4 users (also WI enthusiast?s) know about this thread so as to check my statements for accuracy. And maybe join in with comments.

I took sometime to digest the information.

I can see that you have a few options to incorporate WI with certain degree of safety.

Option1:
System2c with a DDS2/3 flow sensor - as soon as water flow is detect, you should be able to use the output to switch a relay to enable the HOM switch (y ou may need to find out which wire from the HOM unit tell the ECU to switch MAP)

Option2:
System2c with a DDS3 flow sensor - as soon as water flow is detect, you should be able to use the output to switch a relay to connect the factory boost solenoid to work. If water is not redected within a set time by the DDS3 undwer boost conditions, the wastegate will remind at default boost.

Option3:
Upgrade the 2c to 2d and use the "fault output" to de/select the above options when "water fault" is detected.

If you pick a preferred option, I will make a wiring diagram for you.

I like option 1, looks and sounds simple but effective. HOM has two wires one is ground the other to the PCM (ECU). Also like the DDS3 but it's not ready yet, is it?

Also what do you think about injector placement? From what I understand, I want to mount it after the IC but before the thottlebody. What?s your opinion with this considering the WI to make the HOM option work without race gas? Should I look into placing 4 injectors into the intake manifold? Should I inject closer to the throttlebody, or closer to the exit side of the IC? Should I run a mix of methanol and water or just water?

A little off topic:
I mounted an RCI 1 Gal jr dragster fuel cell to a strut bar in my trunk for water supply. Should I mount the pump here (can easily mount it to the fuel cell bracket I made). Or should I mount the pump and other Aquamist components under the hood someplace, not much room under the hood with the factory air box? Also do I need or should I get an accumulator for my setup?

You would do a wiring diagram for me?I would like that?it would be of great help I?m sure, and I appreciate it?thanks very much for your help and feedback.

I am aware of your post but I am a bit tied up an dwill post the drawing a text very soon.

Here is the first attempt to link all the parts together. Ideally, the presence of water will trigger the HOM switch to tell the ECU to start the high octane map.

http://www.aquamist.co.uk/forum/2C-DDS3-PSI.gif

That is def a great diagram for us Richard, thanks for taking your time to write that. You even included the Turbo Toys!!! Nice! (You probably have alot of inside knowledge about it from working with MOPAR ;) )

Thanks much for the work Richard.

I'm in NJ, any suppliers in the states have the DDS3 yet, big Mopar meet 14th of May, would like to have this and get it installed - tuned before then? Also would like to get the new injectors and adapters, more hose/line, fittings etc...

Again thanks for this, I'm dying to try it.

We have only a few allocated for our dealers since they are the first to try it out. Please email me on richard@aquamist.co.uk and I will try to get you one ASAP if you don't mind paying the transatlantic shipping cost. I think it is about 65 dollars by FedEx.

ok.. so I too am trying this HOM mode without high octane fuel...
My mods are about the same as Turbojack's with the exception that I have a voltage based MAP clamp.. (tricks the ECU into thinking less boost)

When reading the paper posted on this website, this line caught my attention:

When adding 5%-7% water to fuel without leaning rich fueling levels - a degree or two of advance will produce almost the same power result as without water injection (leaning slightly will increase the power output). This is good for people who have engines tuned for high octane or race fuel but on a daily basis want to use lower octane grades. This is purely an economic use of water injection - power use requires fuel and timing tuning.

So would it be correct to say that running 5-7% would actually be better for our purposes... instead of running 10-15%?
Assuming we got ourselves to a 11-12 AFR... then turned on W/I at 5-7% and not retuning at all?

Thanks for your input.

I would like to point out that the 5-7% w/f ratio will only replace the cooling effect of dumping fuel between 12.5 to 10.5. It is not meant to replace the effect of race fuel overall.

If you see any post that put the give people the impression that 5-7% w/f of water will replace the vast octane gap between 89 to 116 numbers, please correct it for us - it is not true.

Water can be added to the bridge the gap between pump fuel and race fuel but the exact amount is not fixed, given that you can injection between 5% to 25% of water to fuel, you need to take one step at a time. Each and every engine set up is different but you can be sure that water will be able to yield positive results if you have the patience to follow it through.

Using race race is not the "end all" solution for power. Race fuel has higher resistance to knock but other aspect is not often discussed.

Having achieved MBT timing and High boost - essential for power, but in-cylinder temperature is often ignored. Higher power means more heat is available to heat up the pistons. Unless you run a wide piston/bore gap (reserved for race engine), when piston/bore clearance is reduced, friction will increase drastically lead to high temperature region around the edge of the piston where it suffers the most high temperature and pressure stress - end flame region. Even if you run race fuel, water is still an asset.

So when you dial in the HOM, baby step down your water flow until you have achieved the perfect match with the HOM map fixed by the Dodge engineers. It would help if we know what that strategy is - I doubt if they will publish it.

I was trying to find out how to calculate GPH to cc/min and found this site...
http://www.azmoon-m.com/other/conv_table.asp

based off my calculation to get 10% water to fuel... with stage 2...
Stage 2 has 682cc/min injectors.. so thats 2728cc/min of fuel at WOT..
so 10% means I need 272.8 cc/min of water ...
272.8/62.89=4.3 GPH
so the injector I would need for my system is 4.3 GPH...


I'm going to start with a 3.0 GPH, and step up the PSI a little bit..

am I correct in saying that a smaller injector, say rated 3.0 GPH @ 60PSI, will atomize the water better when its running 3.9 GPH @ 100psi?

Also could you double check my math?

From Stage 2 Website by Mopar:

Fill the tank with 100 (R+M)/2 octane unleaded fuel, press the red switch located on the Turbo Toys bezel, and discover instant torque and power gains. The PCM will increase spark advance and adjust fueling to take full advantage of the 100 octane unleaded fuel. The red indicator lamp will illuminate when High Octane Mode is active.

During High Octane Mode operation, the PCM prevents damaging detonation via the OEM knock detection system. High Octane Mode will be bypassed if damaging knock is detected. The red indicator lamp will blink when High Octane Mode is bypassed. Spark advance and fueling are returned to standard levels in bypass mode. The blinking indicator light can be turned off by pressing the red High Octane Mode switch. Entering bypass mode is an indication that higher octane fuel is required.

NOTE: It is recommended that the level of premium fuel be as low as possible when adding high octane fuel. The tank level should be reduced until the low fuel indicator is blinking and filled completely with 100 (R+M)/2 octane unleaded fuel before the High Octane Mode is engaged. The use of leaded fuels will cause damage to the vehicle?s catalytic converter and oxygen sensors.

Your calculation is accurate according to the table. But please do test the flow by injecting water into a measuring glass.

I am trying to think of a way to tap into the "panel" so that we know the HOM is activated. May be the red led is a good indication to give a "do ahead" signal for the water injection to activate to replace race-fuel.

Ideally if water fault is detected, we have a means of cancelling the HOM mode. Alternatively let the panel to do it automatically when knock is detected..

Priming pump and pulse extender
 

Richard I have some questions about placement and hookup of a pulse extender that was made for me

The water supply is coming from a fuel cell that is mounted in the trunk (priming pump is mounted to the fuel cell mounting bracket). The pulse extender that was made for me is is in a hobby box along with the needed 12V 10-20A relay.

After looking at the diagram posted in the "Double The Flow Rate of your Aquamist Pump" thread and looking at pages 6 & 7 "DDS3 - Generic Connection Diagram" of the DDS3 manual.

from DDS3 manual page 6:
on the junction box pin 21 is priming pump power
on the junction box pin 22 is priming pump ground

Can I mount the pulse extender w/relay in the the trunk next to the priming pump and do I, using the red wire from pin #21 solder into red wire relay power for the pulse extender? Do I, solder the black wire from pin #22 to the black wire on the priming pump (ground)? This sounds correct to me just need for you to confirm.

Do I run grey and black wires from the pulse extender (H1 & H2) in the trunk to the 806-201 water pressure switch which is under the hood near the Aquamist pump?

So as to avoid any confusion I have supplied additional info with what I have:

The priming pump that I have is an Anco generic washer pump (kit number 65-01, P/N on pump 99600), this has two wires:
1) red = power
2) black = ground

The pulse extender and the relay are together in a hobby box (your schematic was used when making it). The wires exiting from the box are:

1) Black - labled H2 (water pressure switch?)

2) Grey - labled H1 (water pressure switch?)

3) Red - labled power (to pin #21 on DDS3 junction box?)

4) Yellow - pump (to red wire at washer pump?)

From what I can tell after writing this I think I'm correct with above. If I'm not correct or if you see an error (maybe typo) please correct me.

Thanks
Jack

turbojack wrote:

The pulse extender and the relay are together in a hobby box (your schematic was used when making it). The wires exiting from the box are:

1) Black - labled H2 (water pressure switch?)
2) Grey - labled H1 (water pressure switch?)
3) Red - labled power (to pin #21 on DDS3 junction box?)
4) Yellow - pump (to red wire at washer pump?)

Since the pulse extender is made for you by someone, could you ask the person to post the circuit with "wire out" colour so that I can check. I know some colours are pretty obvious, but I would like to be 100% sure before saying "YES"

I have forwarded the request for him to come here and post. He and I are suposed to talk tomorrow, maybe he has time before then to answer your question.

Thanks,
Jack

I think I can quite confident that you can wire the set up as you mentioned - except for the red and black wire for the following reason.

The #21 and #22 from the DDS3 juction box is only limited to 1A of current. In case your priming pump is drawing more than 1A, it will affect the DDS3's power supplying stability to the rest of the components and devices.

Please wire the Red to a healthy switched +12V with a wire gauge about 12-14awg (also place a 5A inline fuse for safety) capable of carrying 8-10amps. The black wire to any chassis ground.

The rest will be connected as follows:

- Yellow to Priming pump red.
- Grey to pressure switch (806-162) grey side.

I will redraw the wiring diagram in the morning to include the custom made pulse extender box.

I'm glad your around to answer questions like this Richard, It puts my mind at ease.

Thanks
Jack

I have revised the drawing to conform to your latest addition (priming pump).

We still need to clearify how the "water fault" signal is interfaced with your current set up.

I gather from various posts from other SRT owners that the HOM line is not accessable. So uit leads me to consider other action such as lowering the boost. It can be done with the DDS3's pin #11 and #12 to cut the wire that goes to SRT's bleed valve. I need your help on that. Perhap some one can post me a picture and let me know the wiring colour that energise the valve from the ECU.

Alternatively, we can leave that part alone and let the knock sensor to switch off the HOM mode upon presence of knock. What you you think? I will update the drawing further.


http://www.aquamist.co.uk/forum/gall...DS3-PSI-v2.gif

The info I have is from documents in PDF format. Here's the links to the documents

http://www.dodge-srt4.com/howto.shtml
(Mopar Stage 2 Turbo Toys Instructions)
(page 4 has wiring diagram for the toys)

The info I have are from documents in PDF format. Here's the links to the documents:

http://www.dodge-srt4.com/howto.shtml
(Mopar Stage 2 Turbo Toys Instructions)
(page 4 has wiring diagram for the toys)

http://www.dodge-srt4.com/tech.shtml
(PL Body Service Manual)
(pg 8W 30-26 has wastegate wiring info)

I've been hearing from other SRT-4 owners that also looked at what I'm trying to do. A couple are trying to do the same thing (HOM activation) with diff parts and components and ideas. For example, heres a copy of a comment from another SRT-4 owner after he had read about my Aquamist WI & HOM activation plans that I posted on the SRT-4 forums:

"Very nice. I take it that the yellow line is a momentary ground. Hard to tell. This was the problem I ran into. The ECU does not like constant ground. Very interesting."

I then replied with:

"I think I understand what you mean. The ECU needs to be able to override this. The DDS3 after making checks will activate the switch with a pulse. Even if the DDS3 say's things are good, the ECU can still say no."

To which he replied:

"What I had problems with was that pin C14 (white wire on HO Switch) need a 1 second pulse to ground to activate HOM one to deactivate... re-set so fourth. So with the varables in mind how do I educate my controler as to what state HOM is in. Ground side of the blinky red diode is good before the resistor. But no... There was a reson the red LED was a bad idea on either side. I can't remember what I found but I think it was voltage leaking from the ECU... Anyway
I started playing with the photocell side of a 12V Bolinger fiber optic tranciever. It knew when the light was out. It knew when it was on, and even better it knew when it was blinking... Then I lost intrest.
Please post what you come up with. I havn't abandoned my little bag of radioshake parts yet.
What is real nice is the use of a flowmeter rather that a pressure switch to see if fluid is moving."

So from reading peoples comments I'm a little lost.... taking everything perceived away and starting at square one.

From what I understand how HOM should work (NO WI, or DDS3):
You add race gas and then you hit the HOM switch and then run the car. The PCM/ECU sees the HOM has been activated and switches to an enhanced timing MAP or it just plain allows more timing based on HOM switch activation (more power). While in HOM mode the PCM lights up a Red LED to inform the driver of HOM activation. IF the driver activates HOM without race gas the red LED still lights up but... if after getting into the gas pedal the PCM receives a signal from the knock sensor that is not within the defined threshold of the HOM map it reverts to the base map (or reduced timing) and flashes the red LED informing the driver, hey you hit the HOM switch but you don?t have race gas in the tank, not going to allow this, possible engine damage.

The ideal scenario with WI:
The DDS3 makes the WI checks and activates HOM via sending a signal to the PCM just as if the switch was hit. The PCM activates the HOM map and lights up the red led. The DDS3 see that WI is still working fine. The driver gets into the gas pedal and because the WI has been setup and tuned correctly the red LED stay lit and the car has more power.

The problem scenario with WI #1):
The DDS3 makes the WI checks and activates HOM via sending a signal to the PCM just as if the switch was hit. The PCM activates the HOM map and lights up the red LED. The driver gets into the gas pedal and because the WI has NOT been tuned correctly the PCM reverts back to the non HOM map and blinks the red LED. The DDS3 does not care about the blinking red LED and continues to work even if HOM light blinks. The driver sees the HOM LED blinking and notices that the DDS3 is fine and realizes the tune is off. This IS NOT A WI failure problem it?s a tuning problem. To me this is how it should be.

The problem scenario with WI #2):
The DDS3 makes the WI checks and activates HOM via sending a signal to the PCM just as if the switch was hit. The PCM activates the HOM map and lights up the red LED. The driver gets into the gas pedal?shortly after the DDS3 sees WI failure?dumps boost and stops WI. Because WI fails PCM sees knock sensor reading above threshold ?.reverts MAP?red LED blinks. Driver either first sees DDS3 warnings or red LED either way doesn?t really matter since both systems have fail safes not dependant on driver action. Because the driver sees the DDS3 has found a failure in the WI he knows to look into the WI system. Again, to me this is how it should be.

The problem scenario, with WI #3):
The DDS3 makes the WI checks and something fails. Because of WI failure DDS3 never activates HOM, and PCM never lights up the red LED because the DDS3 never activated HOM. Again, to me this is how it should be.


OK, now why does the DDS3 need to know if PCM makes the red LED blink? If the DDS3 does not see a problem with WI, WI functions as designed. Just because the PCM say?s?hey you got no race gas in the tank, why does the DDS3 need to know, why should it care? The DDS3 does have control over a boost solenoid and will allow raised boost, this raised boost level will not be so much so, that without HOM working it will be dangerous. I always intended to tune the car first without any dependencies of WI for safety. The PCM will revert map regardless of whether WI works or not, IF it sees a knock threshold above HOM values.

I?m thinking that if the DDS3 can activate the HOM switch (turn on) then the DDS3?s HOM turn off capabilities is not necessary because the PCM takes care of that based on knock threshold values in the PCM. To me this is a fail safe that does not need to be messed with or enhanced in any manner.

IMO the answer is having the DDS3 just send a momentary pulse to the PCM. This pulse would be a mimic of the pulse of the switch when activated by hand. I must first say, that maybe I just don?t understand some basic electronics and this is not possible without also tying into the red LED so as to complete some type of circuit. I see the HOM activation by the DDS3 as a turn it on and forget it type of thing. Let the PCM via the Knock sensor say keep HOM on or turn it off because some parameter has not been successfully met. If I can, I would like for the DDS3 to turn HOM on and not care if red LED blinks. The proper function and control of the red LED by the PCM can be one of my tuning tools for WI.

Thanks
Jack

This link is pefect, I can now complete the entire wiiring diagram. Excellent link. Thank you.

I have a question, When you are dialing in higher boost, does it matter if the "HOM mode" is on or off?


http://www.aquamist.co.uk/forum/gall...k/turbotoy.jpg

I think HOM functioning and boost control are seperate things. MY answer is NO to your question, dialing in higher boost does not matter if HOM on or OFF

There is another part of the turbo toys package. DAB is Dial A Boost, this is used as a traction control device while at the track. I use setting 2 almost all the time street/track unless roads or slick from weather.

http://www.aquamist.co.uk/forum/gall.../turbotoy2.jpg

From the picture, numbered 1 to 5, please let me know what number 1 is for can I assume the following?

2 - Push to spray intercooler
3 - Indication of DAB level?
4 - DAB?
5 - HOM mode - press for a few seconds to activate.

A few more questions please:

1) Where are the blue and red led situated?
2) Does it have to be wired, drill and install by the user.
3) Was turbo toy's location occupied by a blanking panel on the standard car?

1) is rear window defrost

2) push to activate auto IC spray hold down to manually spray

3) got me on that one had to go look at the car. Never really noticed. It does nothing, and I dont know what it is. I'll need to figure that out since it now bugs me that I dont really know.

4) DAB settings. In the picture it's on 3 (0, 1, 2, 3) it's a thumb wheel type of switch

5) HOM switch activation. Push once to activate (turns on red LED)

additonal questions:

1) the location of the red (HOM) and blue (IC sprayer) are up to the owner/installer of the toys option I put mine just under the boost gauge pod (which now is occupied by the DDS3).

2 &3) the toys switches are supplied in a panel (as in the picture) that directly replaces a cubby hole panel for cigs or glases etc... no drilling for the toys panel, but to install the LED lights you need to drill holes, again location of lights is up to installer/owner.

Ps. I was planning on posting pictures of all the components (incl DDS3 in the former boost gauge pod), how do I do this?

are you going to run into det (knocking) when turning the boost up on the std ecu mapping?

what boost are you running now? what will you be turning it up to? and when are you planning to inject the water?

if the ecu is expecting race gas, it will be from tickover to top revs. if you inject water too late the hom may have been turned off already.

Drew

These are excellent information and ideas that will help me in my wring scheme. I am taking every point on board and have suggested the following strategy as a starter.

If the aim of WI is to replace race fuel, then the whole project should be simple. Based on that assumption, I suugest:

1) Detect teh HOM mode by monitoring the red led - when the WI sees the "low" signal from wire terminal #C14, it can switch on the water injection - may be some interfacing circuitry, but put that aside for the time being.

2) If knock presists after depression of gas paddle after WI is mapped, the HOM mode will drop out and so does the WI - until bigger jet is used or a new map is created.

3) If WI fails, the above will also automatically cancel the HOM by the ECU.

What do you think?

You need to store your pictures on a public accessable site first then you
post the url of that site between [img]url[/img] quotes.

You can email me the pictures: richard@aquamist.co.uk, I should be able to do the rest.

I have one more question, looking at the wiring diagram, can the wire such as the c14 accessable from the back of the panel?

Quote:
"1) Detect teh HOM mode by monitoring the red led - when the WI sees the "low" signal from wire terminal #C14, it can switch on the water injection - may be some interfacing circuitry, but put that aside for the time being. "

Answer:
If I understand this correctly and the low signal is what makes the red LED blink the WI would be injected when the red light blinks. When the red light blinks, the the PCM has diababled HOM, too late for WI at this point. I think that when the DDS3 first sees a signal going from the HOM switch to the PCM it's time to turn on the WI is better.

Quote:
2) If knock presists after depression of gas paddle after WI is mapped, the HOM mode will drop out and so does the WI - until bigger jet is used or a new map is created.

Answer:
I see no reason to stop water injection if if PCM sees knock. The PCM will bypass HOM if it sees knock, but WI can still run. IMO the DDS3 uses info to control WI components. The PCM uses info to control fuel, AND disable HOM if knock threshold is exceded (I have just way over simplified what the PCM actually does but please except this for the sake of reading this). I was just thinking about using the DDS3 to activate the HOM switch, it will have no control over it other then turning it on, after this DDS3 is done with HOM. The PCM still controls whether it will stay activated based on knock values.

Above should also answer #3 in same post

Quote:
I have one more question, looking at the wiring diagram, can the wire such as the c14 accessable from the back of the panel?

Answer:
yes

Several SRT-4 are already upping the boost without water and without the HOM. Without stage II or with stage II the boost can be raised (factory stock settings bypased by the owner), however the PCM will still retard timing when knock present.

I'm using the factory supplied adjustment instructions for Stage II on the factory supplied stage II wastegate actuator. This yields for me about 16.5 -19.0 (conditions apply). Right now I dont plan on upping the boost since at this point I'm trying to concentrate on HOM without race gas. As far as when I plan on injecting water, the actual WI tune will be handled by same people who market the piggyback I'm using. They have a fair amount of experiance of using the piggy back to control the HSV plus they have a very good working knowledge of the SRT-4. So I dont know at this point yet.

Because whether the HOM working or not is dependent on what the knock sensor sees and then feeds to the PCM, I think the key will be to find out when the car is near MBT since if I've read correctly this is where knock will be most prevalent. While road tuning and watching info via a ODBDII scanner I might be able to start a basic tune fairly close and then tune thu expermenting and datalogging till I can get the HOM light to stay lit. if it blinks I know the tune is off.
[/quote]

Looking at the wiring MOPAR wiring diagram, the +ve end of the red led is wired directly to a steady +12V via a resistor.

In order for the led to light up (HOM is ON), the c14 junction has to go "low". When the led blinks, the c14 junction will go "high, "low", "high", "low" etc.

My logic tell me that when c14 goes low, it is at the "HOM" mode.

The function of the HOM switch is not important as it is momentary so I cannot determine what state it is in after it was pressed until the red confirms it. It can also cancel the HOM mode after a momentary "press".

Am I on the right track?

I think your right on the money. However understand YOU are better then I in reading and interpreting a wiring diagram, and understanding what the symbols actually mean (I have to look them up in a internet glossary).

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

Drew

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.