posted on January 11, 2011 17:00
AEM Water/Methanol Failsafe Device Evaluation
By Mike Kojima
We are very familiar with water and water/methanol injection; many years ago, we were one of the first to tune with modern water injection systems and took advantage of water's ability to inhibit detonation and provide charge cooling in forced induction engines. With water you can run more timing, more boost, leaner air fuel mixtures, a combination of all three or just use water to gain a measure of safety and to control engine temperatures for track use.
|Our test car already had an AEM Water Methanol injection system installed. This is the version with the latest fast responding recirculating pump. The monitor can be adapted to work with most water injection systems. You just have to plumb in the flow meter, however it integratess fully with the warnings already built into the AEM system. Brian Kono of Afterhours Automotive fabricated this cool aluminum alloy bracket to mount the water tank, pump and filter so it would not intrude into our trunk space too much.
There were some drawbacks to water systems. We have personally seen three cases where an engine was destroyed or severely damaged due to a malfunctioning water injection system. In one case a Hobbs pressure switch failed in the open circuit position allowing the injection pump to pump water at full capacity into the engine which hydrauliced a rod. In two other cases, clogged nozzles and high boost destroyed engines with detonation. In both cases plastic shavings from pushing water fittings together during assembly worked loose and blocked the small orifice water atomizer nozzles completely.
|The AEM nozzle is cleanable and has a built in filter screen to resist clogging. The nozzle on our car is not the latest and greatest from AEM, the current AEM nozzle is improved with an integrated check valve and is smaller. This nozzle has the check valve in line a few inches back.
|The AEM nozzle comes with 3 different metering orifices for different flow rates, we used the largest one for our car.
In one of our personal cars, calcification slowly blocked the nozzle over time rendering the system less effective. Fortunately we heard the detonation and investigated the root cause before the engine could be damaged. On our system, we had hooked a mechanical water pressure gauge to try to monitor the system but it was not sensitive enough to detect a partially blocked nozzle.
|The is the standard AEM warning LED that flashes when the water injection is low on fluid or there is an error code stored in the control unit. We hooked the warning line out on the water injector controller to the auxiliary line in on the monitor so it will go into alarm mode for low fluid or for error codes as well.
Tuesday, January 11, 2011 5:39 PM
Sounds like a system that can actually inspire confidence. I've never really felt that comfortable with water/methanol injection for the same reasons listed in the article; it's difficult to use an expensive engine management system on an expensive engine and then rely on a crude water injection system to keep everything safe under high boost.
Being an ECU nerd, it would be really nice if there was a CAN network link to report parameters to the engine ECU, etc. That's obviously only possible if you can integrate that into the existing ECU's engine management strategy (which is already possible with the higher-end stuff) but it's probably only a matter of time before the AEM ECU and AEM water injection systems can communicate with more than just a warning output signal.
Wednesday, January 12, 2011 2:30 AM
Good on AEM for taking this on, but it needs to be pointed out that Aquamist systems have had all of this functionality for no less than 3 years now.
It's time for AEM to take it further than 2007's offerings. Please, advance the tech!
Any water/meth injection system that ever locked up an engine due to lack of failsafes and such did not belong installed in a car in the first place, IMO.
Wednesday, January 12, 2011 4:42 AM
What new failsafe does Aquamist have? The last I checked, they added a high speed control valve and a low water pressure warning function but nothing based on actual flow. One of my cars has an Aquamist system and I would like to update it.
Wednesday, January 12, 2011 4:58 AM
Any DDS3-based system from Aquamist can trigger any failsafe based on water flow being out of (configurable) range.
Maybe I misunderstand AEM's offering. It does something more than that with regard to flow-based failsafe triggering?
Wednesday, January 12, 2011 5:28 AM
I haven't been to the Aquamist website in a long time but it looks like the new HSF3 has a flow meter and gage. I don't think it has alarm range setting and data logging like the AEM system though.
I really like the compact Aquamist pump, it is a pity that they seem to have discontinued it.
Wednesday, January 12, 2011 6:44 AM
Yeah, there's been a flow meter and gauge for a long time man :) The trigger happens when you drop below or rise above the thresholds you set on the flow at setup time (via the selectors on the front of the DDS3).
WL = "Water Flow Low Threshold"
WH = "Water Flow High Threshold"
Any chance you could crop the AEM app image so we can get a closer look at the words in the image? It looks like a nice app, but I'm not sure it offers anything functionally new.
Wednesday, January 12, 2011 7:45 AM
I am going to work on a better map and image, I had a suction side air leak in my install that I am gonna fix today which probably caused some of the scatter.
To my knowledge, the AEM system has the best capability as its more than just a simple high and low range, you can actually trace the flow pattern on your vehicle.
Wednesday, January 12, 2011 7:47 AM
Here is the difference:
It would seem the AEM is really for variable pump speed systems and not fixed speed systems like the aquamist.
Wednesday, January 12, 2011 8:28 AM
I have read in the past that one of the benefits of water injection, as it relates to more complete combustion, has to do with the way the surface tension of the atomised water particles creates more surface area with the fuel as it comes in contact with the water, much as a drop of fuel landing in a puddle of water nearly instantly spreads and thins out exposing more fuel molecules to the air. Could you expand on this and indicate how big a benefit it is?
Secondly, GDI (Gasoline Direct Injection) technology is becoming more common in production engines as a way to help control predetonation, among other things, and something I would like to see used as a basis for a future build. I think Ford's Eco Boost engine may be the current state of the art in a production car. In GDI, fuel is being injected at the last possible moment before ignition, leaving precious little time for fuel molecules to spread themselves around water particles. Is there enough time to reap that combustion benefit? One of the direct benefits of GDI is combustion chamber cooling. If water injection is also used do we need to worry about getting the combustion chamber too cold? No matter what, I feel the cleaning benefits of water injection justify its use for that alone, but I wonder if it may need to be tuned a little differently in a GDI engine?
Lastly, a significant percentage of water injection users are also adding methanol to the water in amounts up to 50% by volume. Could you comment on the benefits of adding (or not) methanol to the water and at what percentage those benefits reach their peak (I've heard 50%)? Any additional effect in a GDI engine?
Wednesday, January 12, 2011 8:56 AM
some details on the aquamist
Wednesday, January 12, 2011 7:30 PM
@Markingtime, water injection is primarily used to reduce combustion temperatures. So it's often a NOx control strategy. I have never heard of the interaction of water and fuel that you mention.
With regards to GDI, I'd say Audi/VW is at the forefront. They developed the technology in a boosted application on their R8 LeMans car. Porsche, I guess being related to Audi/VW, has also extensively developed DI technology in NA applications with their knowledge gained from the American Lemans cars. All that tech has transfered into their new 911s. Ford just happens to be marketing it the most. Mazda has had their DI 2.3L turbo engine for a while. Mitsubishi has had DI engines in Japan since either the late 90s or early 2000s. The engines required low sulfur fuel and the US didn't have it.
Anyways, how will water injection affect DI? Assuming the water is well atomized, I don't think it'll affect the fuel atomization too much though it might reduce the amount of fuel atomized. Especially since the water injection will happen at full load, I think the fuel spray pattern and distribution is less critical. I could be wrong on that though!
As for methanol, it itself is a high octane fuel. It has a lower heat of vaporization as compared to water (roughly half I think), but it also has a lower boiling point. So it should vaporize more easily and absorb more heat than just water alone. I seem to recall someone mentioning that going 100% meth has no benefit over 50/50 mix. From a tuning standpoint, I think with pure water, you only have to modify the timing and not the fuel. With 50/50, maybe you can still only modify the timing? With 100% meth, probably have to modify the fuel tables. I have no personal experience tuning with water/meth injection, so just guessing.
Wednesday, January 12, 2011 9:08 PM
Methanol has about half the specific energy of gasoline (generic) so fuel tables would only need to be adjusted if a significant amount of methanol is used. You'd have fairly significant problems with displacement of oxygen from too much vaporized methanol. So I guess the problem wouldn't be adding too much fuel, but rather removing too much oxygen. Same thing ultimately, and obviously still dependent on the amount of methanol.
Like you said, water injection should only interfere with direct injection if the water is not sufficiently atomized or the temperature during the direct injection event(s) is too low to prevent proper fuel atomization. That should take a pretty decent amount of water. I would assume that before that point, power would fall off dramatically because of the displacement of air by the large amount of water vapor, so fuel atomization may not be the primary problem.
Thursday, January 13, 2011 6:14 AM
I have installed a few HFS-6 Systems over the last 2 years and they worked pretty good. I talked with AEM in 2009 at SEMA and they told me that they were still a little lacking compaired to Aquamist, but that was their main focus. To have superior technology and a better product in time!
I have to admit the PC Programmable aspect is way better then the Aquamist setup of dip switches and dials. Although the Aquamist gauge is also nice to include warnings, and flow rating as well. I also like how the HFS6 can disable most boost controllers, and/or trigger your engine management to limp or switch maps automatically if any error is detected. We use these systems in Rally cars without issues of breakdown from vibration as well.
I have had AEM, Aquamist, and I think it was a Devils own pump side by side at one time and they are all using the same injection pump. The quality seems to be in the high speed valves, and flow monitoring devices, and fail-safes that they use.
Water-Meth is becoming more popular these days just from ease of use. We can now buy "Boost-Juice" which is 49% Meth 51% water inexpensively and the customers dont need to worry about mixing or using the "Right" windshield washer fluid.
Saturday, January 15, 2011 3:33 AM
[ Caught up on reading ] : Pretty cool little piece. AEM I.M. definitely appears to be the better flow-based failsafe trigger.
Saturday, January 15, 2011 3:36 AM
Ryan@VEXPerformance said: "I have had AEM, Aquamist, and I think it was a Devils own pump side by side at one time and they are all using the same injection pump."
Ryan, I think you'll find that this is not true. Just because they all have the same packaging externally does not mean they are the same specs. I am pretty positive the Aquamist units are made by ShurFlo to an exact design criteria specified by Aquamist. Maybe AEM has their own set of specs for ShurFlo as well, I don't know, but don't assume they're the really the same.
Monday, January 17, 2011 6:15 AM
Quartermiles posts have been deleted by his request. Relatated posts have also been removed.
Saturday, March 17, 2012 2:58 PM
#1 Octane rating's don't necessarily apply to alcohol fuels..
#2 Latent heat of vaporization = Water > Meth
(unfortunately water doesn't add any energy to combustion as a fuel)
#3 100%meth injection mos def DOES have advantages over 50/50 mixtures.. with any %water you are actually making the vapor mixture weaker just so silly things like increasing mechanical boost pressure & screwing with ignition timing can be done to make "power"
most bandaid users should really ask themselves..
who is more "Foolish" ??
the Silly sensor being Tricked into giving a more favorable reading one hopes to see?
or the fools using this falsePositive reading to base ignition timing strategy?
inconsistent fuel vapor mixtures only add unneeded complexity!!
and Danger as well when the knock is from Mr.Murphy