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Greatly enjoyed the webinar on water/meth injection with the Motec M1. As you point out, the current GPR package lacks a driver switch for fuel volume trim. It has a driver switch option for fuel mixture aim (target AFR) main and trim, but nothing for fuel volume trim. Those with a development package can cure this pretty easily by some simple changes in M1 Build. Make a new switch ("Fuel Volume Trim Switch") with A/B functionality, then add that switch as a third axis to each individual Fuel Cylinder Trim table. Then link a driver switch to a digital input and connect that input to an output from the water meth setup so that when meth injection is on, the desired level of fuel volume trim is immediately applied rather than having to await closed loop control to get it there. In my case, I am using the failsafe output from an Aquarist HFS-6 to a digital input, then linking that digital input to BOTH my Ignition Timing Main Switch and the new Fuel Volume Trim Switch. Thus, when the Aquamist unit is on and working correctly, the more aggressive ignition map ("B") will be active, the Fuel Volume Trim Switch will be on, and a roughly -10% fuel volume trim will be applied. Conversely, when the Aquamist unit is off or fails for whatever reason, tripping the failsafe, the safer ignition map ("A") will be active, the Fuel Volume Trim Switch will be off, and no automatic across-the-board fuel trim will be applied (all other fuel trims will continue to be active).
Another tip when integrating a water/meth setup like the Aquarist that runs off injector duty cycle with the M1. Use one of the extra injector slots as for the IDC control of the unit (Injector 9 in a V8 setup like mine), then use the individual fuel cylinder trim for that cylinder to scale the injection with whatever variables you want. The standard GPR package provides axes for RPM and MAP, so one start with base of IDC injection, then increase or decrease that injection in a multiplicity of load cells across the RPM range.
Yes the lack of a fuel volume trim makes proper integration with the M1 a little difficult. I've actually built a fairly complete water injection control module in Build that incorporates a 3D PWM pump control table based off MAP and RPM, trims for fuel volume, ignition timing and boost aim, and a failsafe system based off flow and water level. There wasn't much point demonstrating this though when it's not accessible to anyone else. I believe the mentioned 'nitrous control' strategy will be a workable solution for the fuel volume trim dilemma.
Great tip on the injector output for the Aquamist integration. It sounds like you've got quite a well sorted system operating there. Good work!
Thanks, Andre. I probably would do a separate module as well but for the fact that I already have the HFS-6 installed on my car, and I like those screwdriver adjustable trimmers on the HFS-6 controller box. You should market and sell your module!
I just tinker away in the background Peter. None of my code is really commercially viable and I wouldn't have the time and resources to support it either sadly.
Every now and then I'll come up with something cool/unique/interesting or just plain hair-brained that I'd like to try and spend the next couple of months tinkering and testing as time allows. My flex fuel system is something I'm reasonably proud of, as is my rolling launch control system that's controlled via the cruise control stalk - Relatively useless in a car that has under 200 kW atw but I wondered if I could write the code to do it and it turns out I could :) Most of all I guess I'm living proof that you don't need to be a coder to learn how to use Build.
Bump to an old(ish) thread.
I'm putting together a WMI setup for my motor, planning to use the Aquamist pump and fast acting valve controlled by a PWM module from a 3D map of MAP vs RPM. Just wondered what your thoughts are on individual port injection vs a single larger jet, post intercooler? Is it worth the extra hassle & expense in your experience? I've read conflicting information of the effectiveness of port injection, due to the relatively long vaporisation time of the mixture. I'll probably be running a 50/50 mix with a fuel trim to suit, if that has an impact.
I haven't had any personal experience with direct port WMI. Obviously an obvious advantage is the ability to ensure equal distribution, but there's less time available for the water/methanol to remove heat from the air before it enters the combustion chamber. That's not to say it's useless once it enters the combustion chamber though as compression causes a large rise in heat and the WMI will help reduce heat in the combustion chamber as it goes through a phase change. Since I don't have any first hand experience it's a little hard to advise. The only way to confirm which is superior is to test both (which is expensive). I tend to like the single point nozzle pre throttle as it is very simple and there's less to fail.
I've used direct port meth previously. My experience showed that the time to vaporise the meth is not an issue. On the dyno we actually had water condensing on the inlet manifold runners, signifying the phase change was occurring. Was quite amazing to see.
Thanks guys. I think I will try both options and try and get some numbers.
If you do a back to back test I'd be interested in hearing your results.
Hi everyone! I thought to ask here instead opening another thread.
I have few qestions about WMI. I've recently bought an AEM kit, and I want to have clarified some points before tuning. I've read around the web, that to proper adjust the fuel map while tuning, the tuner should not lean the mixture by the fuel map, but decreasing the WMI flow.
Is this true? Or is just a way to determine the proper size of the nozzle before actually tuning the fuel map? Maybe I'm missing something here.
Another question is how to proper mix 50/50 water meth. Is it true that they shoud be mixed by wheight and not volume?
Big thanks guys!
First things first you need to tune the fuel table normally without the WMI operational. If you're using a 50:50 water/metahnol mix then you will need to adjust your fuel delivery to account for this, otherwise the engine will run excessively rich. This really needs to be done with either a trim table in your ECU or potentially dual fuel maps that are switched when the WMI is active.
You can mix the water/methanol by volume or weight. In my opinion it's not really that critical as long as you maintain the same technique each time you mix. The specific gravity of methanol is lower than that of water so you'll end up with a difference in your volume mixture if you use weight and vice versa. Obviously mixing by volume is the easiest solution for most and that's what I've done for my own testing.
Where do you put the nozzles? I have my IAT sitting in the middle between the inter cooler outlet and the throttle body.
so before or after the IAT sensor?
If before, Will the spray ruin the sensor? I guess you want to measure the inlet temp with the water/meth spray.
The spray won't ruin the sensor but it will certainly give you a misleading IAT reading (for the same reason that if you put your hand out the window of a car while it's raining, your hand feels cooler than the ambient air temp. I prefer to mount the injection nozzle after the IAT sensor but sometimes this simply isn't possible. If you're going to mount the system with the nozzle spraying onto the IAT sensor then you'll need to consider this and monitor the affect on the measured IAT during the tuning process.
Thanks for clearing that up Andre, I’m actually installing an AEM kit now as well and had the same questions as @motoren.