Injecting water into a rich a/f mixture is not a good idea

[Richard L]

Not so long ago, a user of our WI system has lost some 40+ WRHP during a dyno tuning session, not surprise to know that he was quite disappointed. Only after a few months later and have discovered that his engine is tuned to run an a/f ratio of around 10.5:1.

I would really like to hear from anyone if they have suffered the same experience? :(

[Forum Admin]

That may not have only been too rich for normal conditions it is way too rich when running water injection I would think. The tuner was bogging the engine down.

[JScoob]

I wonder if this was vishnu? I remember reading a thread about a guy who lost that much whp while attempting to get tuned at vishnu. IMHO I think tuners who don't know (or believe) in WI tend to not tune WI cars correctly, which perpetuates their belief that WI doesn't work.

I think the tuner didn't realize that not only could, but should lean out fuel with WI engaged. I'm almost afraid to get my car pro tuned at this point in fear it would actually get detuned.

What I want to do is get it tuned without WI and then proceed to tune it further with WI myself. The only problem is that this strategy only works with user tunable solutions (ie wrx UTEC). I eventually would like to get ecutek, but that means it can only be with WI - and again, the 1 ecutek WI tuned I've read about resulted in no gains (which I believe was not tuned right).

Any more details on the ecutek/aquamist integrated solution?

[Forum Admin]

I would rather not point fingers at tuners and don't know if this first thread post was in reference to the tune you are refering to on one of the WRX boards. Assuming that WRHP is indicating rear wheel - this may be a different occurence. Vishnu has stated their position on water injection and likely their tuning method is affected by that position, but I would rather let them speak to their results and keep third person types of stories more generic rather than specific. Even if I disagree with those talented tuners out there that don't use or like water injection, I prefer to engage them directly in those conversations.

Any tuner that understands tuning with knock suppression technologies (such as race gas) has the experience needed to utilitize the benefits of water injection. They may or may not choose to do so or appreciate the similarities, even though they are not the same.

There are professional tuners who have tuned or are willing to tune for water injection, though they may take longer to find. Also as you said self-tuning is an option if you have the engine management to do it.

Also if you have a tuner you are familar with and like to use - don't hesitate to send them here to read the papers posted on it or to have them join in to ask about tuning. If your tuner is open to new (to them) things, you will likely be happy with the results having worked with a tuner you know and trust - especially if they are willing to take a bit of extra time to do it right without charging you for the extra time.

While you can't pull fuel with an Ecutek on your own - if you have an aggressive say 95 octane map programmed and then use DD to advance timing a bit you will get some of the benefits though as always not a full dyno tune benefit. Just make sure you use a boost cut in case you ever have a system problem since while Ecutek will pull timing it won't increase fuel for knock events which is why for the time being I am not encouraging a higher octane map - though it is possible if someone wanted to do it.

[JScoob]

Well, depending on what the aquamist/ecutek integrated solution is, I'm actually leaning towards the cobb accessport/accesstuner combo. You get the benefits of reflash with unlimited map switching. I dunno how they pulled that off, but they claim they did it. The only suck is that the Tuner is not due out till Feb 04.

The other option for me is to get ecutek tuned with non WI and keep my UTEC to self tune for WI. That way if I have WI problems, I can just switch to the base tuned map. I wonder if anyone has done that? Most don't do both ecutek and UTEC.

[Shaker666]

An A/F ratio value below 11.5:1 is, IMHO, a sad attempt to cool the chamber down under very high boost conditions.

[Richard L]

An A/F ratio value below 11.5:1 is, IMHO, a sad attempt to cool the chamber down under very high boost conditions.

Any excess fuel yields a guaranteed percentage of carbon monoxide that exits the tailpipe accompanied by a molecule of oxygen. Since CO only produces 30% of power compared to 100% power of CO2. Apart from wasting fuel, you are also throwing power out of your exhaust pipe. :sad:

[GT-2]

I'm more than happy to tune a car (Impreza) for a water injection setup PROVIDED I am sure and confident the owner understands the risks involved, I use a System 2C myself run directly off my M800 ecu, recently it stopped working due to the 10 amp fuse going (recommend use 15A btw), luckily I was using full wideband control up to 2.2 bar boost so all that happened was that my Knocklink got very active, fueling corrected itself BUT I was running at 0.82 lambda which is scary lean for an Impreza engine. I had used the WI setup primarly for charge temp control then got bitten and added 50% methanol, suddenly I could run race fuel ign as std !!. It uses Optimax plus NF booster as its std fuel strategy.

Bottom line, if mapped for the WI then fuel has to be reduced due to the water occupying the space normaly occupied by air, that means if the water is NOT working the lean running results. Given the above then ign can be advanced to take advantage of the cooler charge.

The alternative is to have the car mapped without the WI working and then enable it when aggressive use is wanted i.e. Nurbergring, Phil Gardner (Sti 5) had me map his car like this and it behaved faultlessly thro' several years of Ring abuse. yes you lose some power as the afr becomes richer but ... charge is cooler and so the engine is safer.

bob

[Donkeypunch]

I had my car tuned on a snow performance kit using a UTEC and VF22 at XXtuning. The tuner needs to understand what he can do with the engine management, and what water injection will do to the base tune (prior to tuning with water injection. There the tuner gets a baseline AFR, and then goes from there. Granted UTEC is easy to scale fuel out of, but I know quite a few people running ECUTEK with WI, no problems. You have to scale the fuel out with water alky injection no matter what type of fuel you run, 91, 93 or 95 or better. You have to eventually make the AFR good for the engine. 12:1 being about ideal for a subaru 2.0 ltr. Of course more fuel is going to hurt the engine. You a prone to more misfire, and lose power due to lack of oxygen to combust the fuel right. THe fuel we use isn't oxygenated like nitromethane. That is why tuning for WI/WAI is essential to a safe/powerful tune.

DP

[Richard L]

There is no reason not to tune the car to work with water injection provided you have a failsafe mechanism incorporated.

I think in general, boost drop in absence of water is good enough to save an engine from damaging.

I know an ECU reflashed car presents a problem as it cannot switch to a non-WI map but we are trying to work with Cobb AP - they told me that there is something exciting coming through very soon when we last spoke.

Richard

[Sampi]

Hi, I just installed Aquamist S1 system to my Audi A8 1.8T quattro 1999. It has a swedish BSR chip in it and it dynoed nicely 144 kW and 340 Nm last time.
Now I went to dyno again to check the effect of recently installed Supersprint catback exhaust etc. and installed S1 after that. 98 fuel is recommended with the chip, alltough I?ve been using 95 in daily driving. Well, I fueled the car with 98 octane pump gas for the dyno run and got LOWER figures from the dyno. Engine was running heavily rich (AFR 11-11,5:1,), S1-installer said that benefits of S1-system are seen only after AFR of 12,5:1. S1 brought only minor benefits when engine and room were hot. What could cause that overfuelling? Ofcourse S1 shoud be adjused with progammable chip to make it more usefull, but could that gasoline hassle be the cause of ECU?s eratict behaviour?

[Richard L]

Hi, I just installed Aquamist S1 system to my Audi A8 1.8T quattro 1999. It has a swedish BSR chip in it and it dynoed nicely 144 kW and 340 Nm last time.
Now I went to dyno again to check the effect of recently installed Supersprint catback exhaust etc. and installed S1 after that. 98 fuel is recommended with the chip, alltough I?ve been using 95 in daily driving. Well, I fueled the car with 98 octane pump gas for the dyno run and got LOWER figures from the dyno. Engine was running heavily rich (AFR 11-11,5:1,), S1-installer said that benefits of S1-system are seen only after AFR of 12,5:1. S1 brought only minor benefits when engine and room were hot. What could cause that overfuelling? Ofcourse S1 shoud be adjused with progammable chip to make it more usefull, but could that gasoline hassle be the cause of ECU?s eratict behaviour?

I have just posted a similar answer on the following thread:
http://www.aquamist.co.uk/phpBB2/viewtopic.php?p=7057#7057

Please read it first and I will try to see if I can help you to tackle your current situation.

First of all. Untill you did a back to back dybo plot on the same day, it wouldn't be a good comparison. Anyway - putting WI on an already rich afr is not going to help power at all. Your combustion temperature may already being overcooler.

It the summer, you may have a positive gain on WI but in winter, we get a few post on this topic.

Richard

[JohnA]

True, the majority of people stick W.I. on top of an engine running extremely rich and then they complain that W.I. is useless (or even loses them power)

I did dyno runs on mine and only started seeing pure gains as the AFR dipped to 12:0 and beyond (13:0, didn't have the nerve to run leaner under full boost:oops: )

Adding water as the AFR was 10.5:1 did nothing for extra power - didn't lose power either, as I was way beyond the manufacturer's limits. At 12.5:1 I was looking at 8% more power with around 10% water/fuel ratio.

[Revhead]

Not so long ago, a user of our WI system has lost some 40+ WRHP during a dyno tuning session, not surprise to know that he was quite disappointed. Only after a few months later and have discovered that his engine is tuned to run an a/f ratio of around 10.5:1.

I would really like to hear from anyone if they have suffered the same experience? :(

I wonder if the tuner's intention was to get extra power by fitting the water injection alone without optimising the other engine's supporting hardware(ie increasing boost). IMO, the tuner may have thought the water injection as a pure power adder(ie nitrous).

I may be wrong here but the reason one(for me) would run a water injection is to maximize the whole setup(run as much boost, compression ratio, ideal ignition advance..etc) with commercially available fuel.

Bottom line, if mapped for the WI then fuel has to be reduced due to the water occupying the space normaly occupied by air, that means if the water is NOT working the lean running results. Given the above then ign can be advanced to take advantage of the cooler charge.

I agree...or increase boost. :D

[keithmac]

On my Megasquirt you can use the output from the pump as a trigger to go onto the second fuel tabel and spark table, so if the pump doesn`t trigger the maps don`t switch, seems the safest way to do it? if the pump/wiring fails the engine just runs in non-water mode.

[1 Quick Bunny]

Keith, would you mind sharing specifics on this? Especially your wiring specifics. I still don't have mine fully integrated.

[Wolf_Tm250]

Adding water as the AFR was 10.5:1 did nothing for extra power - didn't lose power either, as I was way beyond the manufacturer's limits. At 12.5:1 I was looking at 8% more power with around 10% water/fuel ratio.


I have an HFS-5 progressive system Motec-PWM driven:

could anyone tell me HOW to know I'm getting a 10% w/f ratio entering my engine ?

TIA !

[JohnA]

...could anyone tell me HOW to know I'm getting a 10% w/f ratio entering my engine ?

TIA !
Example: If you have six 500cc/min injectors then they provide 3000cc/min when maxed out, right?
If they are operating at 80% duty rate when you WI is operational, that means they are providing 2400cc/min.

If your WI with the pressures/nozzles you've got provide 240cc/min, then you have (at that point) a 10% w/f ratio :smile:

[Wolf_Tm250]

...could anyone tell me HOW to know I'm getting a 10% w/f ratio entering my engine ?

TIA !
Example: If you have six 500cc/min injectors then they provide 3000cc/min when maxed out, right?
If they are operating at 80% duty rate when you WI is operational, that means they are providing 2400cc/min.

If your WI with the pressures/nozzles you've got provide 240cc/min, then you have (at that point) a 10% w/f ratio :smile:


Sorry JohnA....

I didn't explain correctly what I meant to know....

I perfectly understand what you wrote me... fortunately :lol: :lol: :lol: :lol: ....

but what I'd like to know is WHAT is the relation between the PWM values in my PWM-Motec map, AND the water quantity coming out from my nozzles....

Moreover, given that I have a progressive pump, the water injected varies even with the water pressure supplied by the water pump...

Could I use the cc/min value in the DDS3 flow sensor as a good, real value to make my calculations ?

Thank you very much.

[slowMX5]

On my Megasquirt you can use the output from the pump as a trigger to go onto the second fuel tabel and spark table, so if the pump doesn`t trigger the maps don`t switch, seems the safest way to do it? if the pump/wiring fails the engine just runs in non-water mode.

One thing that I am keen to get working is to use the flow meters Vout as a fuel/ignition trim. This could either apply a trim to reduce timing and add fuel to ones WI map if the signal disappears or one could use it in reverse to add timing and pull fuel from the table in proportion to water flow. That way one runs a safe default map with timing and fuel adjusted as WI flow increases.

When I was looking at this a couple of years ago (been too busy to look into it over the last 2 years) the DDS2s output signal was too noisy - not sure if it has been smoothed yet or is the DDS3 has a smooth signal that can be used?

[RICE RACING]

Not so long ago, a user of our WI system has lost some 40+ WRHP during a dyno tuning session, not surprise to know that he was quite disappointed. Only after a few months later and have discovered that his engine is tuned to run an a/f ratio of around 10.5:1.

I would really like to hear from anyone if they have suffered the same experience? :(

Great thread Richard !

I have seen this in my own current car, but I put it down to non audible misfires. When I have had a super strong ignition system on various other cars I have done I have not seen losses in that magnitude but they def do exist.

[Richard L]

Spark power has a great deal to do with how much fuel and water cam jam into the comnustion chamber. Too much fuel produce partial oxidation of carbon. Carbon monoxide only produces a 1/3 power of Carbon dioxide.

[stevebez]

I have a slight problem with my pending install - and after reading this it seems I may struggle to get success without a retune ....

Basically the car runs very rich (sub 11:1) - typically because its oversafe position and also for IAT cooling... motor has a hoplessly small I/C which cannot cope and ECU pulls timing once IAT's reach 60C, and starts to pile in fuel from there on up ... at 90C the blower shuts down...

I am curious how the ECU map is configured for lower IAT's in terms of AFR's/fuel flow ... so guess I will only know this once the system is up and running...

[Howerton Engineering]

There are few variables in the equation. Where is the IAT sensor in the inlet track. Will you be injecting before it so it is wetted? If so, you will just need to lean the fuel maps for whatever mixture you are sparying to bring the AFR's back to a reasonable level. If you have a rough idea of the heat compensation curve for your car(how much timing it pulls at what temp thresholds) you will get an idea of what can be gained even without changing the timing maps.

If practice, the right amount of methanol sprayed in the inlet track will provide substantial cooling. This is the type of application where I really like using methanol, as it will flash off and cool better. Straight water will not cool (according to the sensor ) as well as methanol. Each application is always a bit different so it will take a testing to find what works for you.

[stevebez]

Where is the IAT sensor in the inlet track. Will you be injecting before it so it is wetted? If so, you will just need to lean the fuel maps for whatever mixture you are sparying to bring the AFR's back to a reasonable level.

Can you elborate on this a bit ... why would a wet bulb read lead to more rich conditions? all else equal. The IAT and MAP are a few inches from the I/C exit. The intercooler is a long narrow water/air type.

Either jet location option will result in a wet bulb read.

[Howerton Engineering]

Some people spray after the sensor to avoid "tricking" the ECU. I see it as a tool, that when used right works well without tuning of the ECU. Some cars like the STI, run on a MAF with built in IAT before the turbo so in that case, no cooling effect is transmitted to the ECU.

May comment was to say that is you use methanol to cool the IAT sensor, more so than water will, that methanol is fuel and if the car is already at an optimum AFR the methanol will move the motor to a richer mixture.

[dsmtuned]

Not so long ago, a user of our WI system has lost some 40+ WRHP during a dyno tuning session, not surprise to know that he was quite disappointed. Only after a few months later and have discovered that his engine is tuned to run an a/f ratio of around 10.5:1.

I would really like to hear from anyone if they have suffered the same experience? :(

I thought I would dig this thread up from the grave after experiencing this phenomenon on the dyno last week.

My turbo DSM made about 15AWHP more without WI on the dyno. This was on 91 octane pump gas. I am new to the tuning software ECMLink and had a base tune with 11.1:1 AFR as the target in the WOT load maps for safety while I was getting used to the software. The timing was very aggressive at 21* near the top of the RPM range. The boost was set to 22psi with about 35lbs/min. The WI mixture consisted of 50% methanol and 50% distilled water. Since I have the time now, I went to the dyno to get a baseline so I have something to compare with when I get the car really well tuned.

I attached a dyno plot of all 4 runs for reference, although it is a little hard to decipher the individual runs. I really wanted some WI data, so the 1st run (002) was without WI. It was also a calibration run, so the data is not totally pertinent. There was obvious knock with the ECU taking 3.2* of timing away due to knock.

The 2nd run (003) was with my second nozzle only (larger nozzle). This run made about 288WHP. There was no knock, but the AFR went down to 10.8:1 on my log and even lower than the dyno wideband O2 sensor would read. This run maintained the power further into the RPM range because of knock control.

The 3rd run (004) was with both nozzles (WI at ~15% of total fuel injected). This run had the lowest HP (~282WHP) and lowest TQ. It, of course, also had the richest AFR at about 10.5:1 on my wideband. There was no knock, but power was not maintained into redline, I think, because the mixture was just too rich.

The 4th run (005) was again with no WI and made the most power at 295.8WHP. This one knocked like crazy (ECU took 6* of timing away), causing the power to peak and then drop off quickly.

I know this engine can handle a lean AFR with the WI. My previous tuning method was an air-flow converter, which modified the airflow signal from the MAS throughout the RPM range. I had a custom burned chip, which defined the timing and fuel tables in the ECU, but I fine tuned the AFR and timing with the air-flow converter. It was a constant trade-off, timing vs AFR. I found a sweet spot and ran a 12.8@109 in the quarter mile at about 12.9:1 AFR and 20* of timing on 91 octane gas and the 2 nozzle WI set-up with water/methanol 50/50. So I know with the proper tuning (leaning of the AFR), I can get an even better quarter mile time, and dyno.

So what I learned from this is that there IS such thing as too rich a mixture for WI.

-Craig