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Created October 5, 2021 10:19
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Water / Methanol Injection for the Audi S4 B9

Injection is done via two nozzles placed (roughly) perpendicular to either intake manifold.

Parts

Main components

Changeable components

Fittings

Setup

Tank Placement

The tank comfortably sits in the spare wheel well once the spare wheel and jack / any accessories have been removed from that compartment. It allows the false floor to continue to sit flush, and also provides room for the low level sensor to fit in the side of the tank.

The compartment floor is made of two "layers". One of these layers must be cut out for the tank to mount flush. You can keep the outermost layer if you don't care about your false floor not staying flush.

The low level sensor must be drilled into the side of the tank (preferably on the left). You can then use the 1/4" Tube to 3/8" NPT 90deg Compression Fitting as the tank outlet. It's important not to use push to connect fittings as they're prone to leaking. Ask me how I know.

The pump is capable of priming itself even when sat above the tank outlet. For this reason it fits perfectly on the "shelf" behind the battery, still fitting under the false floor. You want to use your 2x 1/4" Tube to 3/8" NPT Compression Fittings in the inlet and outlet of the pump, and run your 1/4" nylon line between the pump and the tank. You can then route your 1/4" nylon line from the pump to the front of the engine bay, above the intercooler.

Solenoid Placement

I have the solenoid sitting under the bonnet/hood latch. Use your 1/4" Tube to 1/8" NPT Compression Fitting on the inlet side of the solenoid, and attach the 1/4" Tube to 1/8" NPT T Fitting to the outlet. You then want to run your 1/4" nylon line from either side of the T fitting to the inlet manifolds in your vehicle.

Nozzle Placement

You want your nozzles to be sitting as close to the inlet manifolds as possible for the best droplet distribution. These are serviceable parts though and there's a good chance you might end up changing them down the road, so make sure you put them in an accessible location. Tap the two holes opposite either inlet manifold and then screw both your 2x NPT Nozzle Holder with 1/4" Compression Fittings into either hole. You can then glue the nozzle holds in place, cut the 1/4" nylon line to the correct length and insert it into the compression fittings on the nozzle holders.

MAP Sensor Placement

I run the CarbnLabs FMIC which comes with charge pipes. These charge pipes include bungs for WMI nozzle placement, but they're also set at the perfect location for the MAP Sensor.

You want to place your 100PSI Honeywell MAP Sensor Kit as close to the throttle body as possible for an accurate reason. The bung on my charge pipe is next to the OEM TMAP Sensor, so mine was placed there.

TorqByte CM5-LTS Controller Placement

You can place this pretty much wherever you want in the vehicle, it just means the routing for your wiring will be slightly different. As my car is RHD the most logical place was under the front passenger seat.

There is a hole in the floor for the front passenger seat where cabling for the seat is ran down. It's also large enough to occupy the controller. This also provides ease of access to the controller for datalogging.

The controller comes with a USB cable for configuring the firmware and also datalogging. I purchased an extension cable so that I could access it easily from my driver's seat.

Another option is probably behind the glovebox if you find adequate room. Judging from me taking my car apart before you could likely fit it under the steering wheel behind all the trim. Just be careful with the wiring as you want to introduce as least noise as possible.

Wiring

I must admit that I didn't wire in the kit myself, but rather left it to a professional. They ran the cabling for the battery connection to my controller, along with the cabling for the low level sensor and the pump.

The RPM signal was taken by connecting to one of the wires for an ignition coil on my car. The CM5-LTS then lets you scale this signal, and also cleans as much noise as possible from it. It results in a clean, steady RPM signal that matches the car.

I've also implemented a failsafe trigger in my setup. If the current draw for the pump exceeds or drops out of the "safe zone" that I've defined in my CM5-LTS configuration, the throttle body to my car will be cut. It will cause a drivetrain malfunction that is cleared once the car has been restarted. This allows me to cycle the WMI kit off.

I've also added a switch for my WMI kit so that I can turn the controller off if needs be. I've placed the switch in the glovebox. It cuts the ignition signal to the CM5-LTS controller, so although it will remain powered it will not power itself on.

My low level sensor is not wired to the controller but to an LED that is placed in my dashboard. Once the LED triggers I know I have roughly 30% of the tank remaining.

CM5-LTS Configuration

Using TorqTune

I will provide instruction on how to setup and configure TorqTune if needed. I run the latest BETA firmware (TorqTune v2), so it differs from the OTS software available for the controller. You can contact TorqTune and they will instruct you how to obtain TorqTune v2. It involves downloading a piece of software from them to identify your controller's serial key. They'll then send you the appropriate BETA firmware for the CM5-LTS that you flash through TorqTune v2 to actually use the new configuration utility.

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