posted on February 07, 2011 22:00
AEM Water Injection Failsafe Device: Part 2 - Catching Our Mistakes and Upgrading Our Water Injection System
By Mike Kojima
Over the past few months in-between other projects we have been tinkering around with AEM’s water methanol injection kit on our in-house Evo IX project car. You can read about the kit here. A few weeks ago we installed AEM’s new injection monitoring system which you can read about here.
In looking at our data, something didn’t look right; there was too much scatter at higher flow rates for the volume of our pump. The flow would fall off drastically, especially at high rpm and there was a lot of variation in the flow. Even considering throttle modulation and the fast responding Evo IX turbo, the data didn’t look quite right. The system was functioning correctly but we felt that the flow should be greater under high loads.
|The kind of logs we were getting from the system didn't look right to us. Full throttle runs should leave consistent flow traces and ours were scattered like this. The flow would rapidly drop as well and the lines would converge at a low flow point. This was weird. We decided to look into why this was happening.
This led us to look for problems. We started by looking for leaks or restrictions in flow before the flow sensor. We found no obvious obstructions like kinked lines in the system at all. When we tested the pump's flow by pressing the test button under no load the flow was fine. We next decided to check the water filter. When we were about to open the filter case, we found that while we wiggled our suction side lines, they would leak a few drops. We had found found our elusive problem, when installing the system we tried to make the water lines short and sanitary. Unfortunately we made them a little too short and some of the suction lines were not fully seated in the push fittings.
|The scattered data forced us to run the control limits very far apart to prevent annoying alarms. The wide limits hampered the effectiveness of the monitoring system as well.
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Tuesday, February 08, 2011 3:14 AM
Can't wait for the tuning part... Water alone is a very atractive proposition... :)
Good article guys!
Tuesday, February 08, 2011 9:30 AM
I also look forward to see what can be done with just water. On a side note, is straight water injection CARB legal? I wasn't able to find any state released info saying it was.
Tuesday, February 08, 2011 9:37 AM
I thought the advantage of using a water/meth mix was that the methanol provided an octane boost. Wouldn't straight water only serve to lower the intake charge temperature?
Tuesday, February 08, 2011 11:18 AM
The water itself will decrease detonation, which is the same as adding higher octane fuel. Yes the water lowers the intake charge by the heat vaporizing the water and making the charge less likely to detonate.
Im sure there are benefits to adding methanol, but you can do it with water only. So why worry about finding the right crap to put in there when water works! good stuff guys!!!
Tuesday, February 08, 2011 11:32 AM
With winter temps being so cold where I live, I'd run methanol just to keep the water from freezing.
Tuesday, February 08, 2011 1:19 PM
From my personal experience nothing makes more power than straight methanol despite all the theories that are around about the best mixtures.
It should be noted that there are no water injection kits that are truly safe for running a flamamble liquid though. This is probably the major reason all kits do not recommend more than a 50/50 mixutre.
Tuesday, February 08, 2011 1:23 PM
Should be flammable above.
Tuesday, February 08, 2011 3:38 PM
I assume straight water injection would allow a margin of saftey on engines running near their stock limit due to cooler intake charge. I am interested if it would be of benifit on a stock EJ257 running near the "limit" of stock reliablity (argued to be around 400whp on a proper tune).
I assume that a 50/50 mix would give more power, but I am not interested in the power at the moment. It would be nice to see if straight water injection can give a knock resistance benifit like E85 can, which would also make more power as a result. One does it directly with a higher octane rating, and the other does it directly by lowering temps (right?).
Tuesday, February 08, 2011 4:14 PM
When the engine isn't running so well, remember to pour a couple bottles of NOS into the water tank. Like that guy did with his motorcycle.
Tuesday, February 08, 2011 5:12 PM
Methanol vaporizes quicker than water, so a water/meth mix would actually lower the intake charge more than straight water.
I understand not wanting to have to worry about finding the right stuff to put into your car, though. But in most parts of the country, running straight water isn't an option, because of below-freezing temperatures. Heck, even the Mojave Dessert gets below freezing at night time during the winter.
Tuesday, February 08, 2011 7:30 PM
It never gets that cold where I live plus I am old and I don't care about making every last horsepower. Just wait till you guys see the power I got with just water, something thats nearly free.
Wednesday, February 09, 2011 2:01 AM
Water has a higher latent heat of vaporization than methanol so it could lower the temp more than methanol if the charge air temp was high enough to vaporize a lot of the water.
Wednesday, February 09, 2011 9:27 AM
Im with Mike on this one, laughing at the frozen parts of the country from my SoCal machine shop in my tacky aloha shirt and it's not even friday....
Anyway, I would assume that to benefit all components involved we would want to be using only distilled water, OR RO purified water, is Deionized water overkill? what's the minimum here to avoid mineral build up on the nozzle and in the (water injection) valves???
Wednesday, February 09, 2011 9:47 PM
I personally prefer the 50/50 mix. It is just right. Great power and great efficiency. With water alone you get a higher detonation free threshold to tune with, but nothing beats the 50/50 mix. I have tuned cars on 50/50 that have gained 45-50 hp over 91 alone. You will gain less with water, but it is still substantial.
I love water/meth. It is so damn efficient. Much more efficient than E85. E85 gives you the power (I call it crack for turbo cars), but you lose 30% of your mpg. Water/meth is there when you need it and gives you the same mpg as 91 octane when you do not need it.
The scary part with water/meth is with clogged injectors and failed pumps. You need a damned good failsafe to protect your engine.
Along with all the failsafe that Kojima has added to his Evo 9, I have programmed the ECU to drop the boost whenever knock reaches a certain level. Yeah, we can do wonders with the stock ECU!!! We can store two maps and switch between them, we have huge maps with amazing resolution, we have knock cell flash, we have launch control maps. IMO, there is absolutely no reason to go with standalone on the Evo 8/9. The stock ECU is amazing.
Thursday, February 10, 2011 11:50 PM
I use RO water because I have a unit on my sink. Presumably the monitor will catch a clogged nozzle. In my previous experience, mineralization was not as much of an issue as minute plastic debris. Minerals would form on the surface of the nozzle but not the orifice.
Distilled and DI water is pretty corrosive.
Friday, February 11, 2011 5:23 AM
What you posted is misleading. It implies to me that you are taking credit for Tephra's work. I'm not saying that was your intention but if I didn't know better that is what I would take from it.
Friday, February 11, 2011 8:10 AM
He is NOT taking credit for Tephra's work. It is pretty obvious. He is saying that the latest stuff being done with the stock ECU is pretty cool.
Friday, February 11, 2011 12:31 PM
Wrecked, I did not mean to imply that at all. Anyone who has tuned Evos knows fully well that all credit goes to Tephra. I am just stating the obvious. By "we" I am including the Evo opensource community. I bought my Evo and started tuning just when the community was taking off back in 2005. A lot of established tuners today (Bryan, English Racing, etc...) got started at the same time when I did. It was a great time to be an evo owner. We shared everything that we did. I did a huge write-up on how to tune an Evo back in 2007 that is still being used to this day. I included everything I knew except ECUboost (I kept that to myself). That is why I used "we." We spent hours on the ECUflash forum on evom. It was somehting to behold. People sharing their findings and no one holding back.
Friday, February 11, 2011 4:41 PM
Yes I know who you are and that's why I didn't claim that you were actually trying to take credit for Tephra's work. I just thought it might come across that way to someone who isnt a part of the Evo community or hasn't been for long (probably most people on Motoiq?). I hope you didn't take offense to what I said because none was meant.
I have carefully watched the development of the Evo opensource community and think the development that has gone on is truly awesome. I have to agree with you that the stock ECU is all 99% of owners will need. It's actually a superior platform to the popular standalones in my opinion.
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