Water Methanol Injection System


Patrick Norausky



The quest to improve the performance of an Audi is normal for an Audi enthusiast. Sometimes a reasonable cost per horsepower ratio is sought. With regard to a water methanol injection system , $25 per horsepower seems realistic. This is based on achieving a 20 horsepower increase for a $500 total investment.

Water methanol injection systems are not new but may be new to some potential users because of advances in technology and better understanding of an engine's thermodynamics. During the Second World War, water methanol injection systems were installed on aircraft engines. In some cases, just water injection was used. The history of water methanol injection is easily found by doing an Internet search e.g. Google. It is a proven fact that water methanol injection systems are efficient and effective to improve the operation of both gasoline and diesel engines. Further, enthusiast seeking a cold air intake system should realize that water methanol injection is the premier approach.

Before beginning the installation, it is wise to check the operation of the Mass Air Flow (MAF) sensor, oxygen sensors, water and air temperature sensors to establish that these sensors are in good working condition.

Acquire the wiring diagram for the MAF from the Bentley manual, www.alldatadiy.com or a friend. It is essential that you learn about the connections to the MAF and properly select the signal wire. In the case of my 2000 Audi A8, a solid green wire is connected to position number 5 clearly marked on the connector. Always verify the signal wire via an electrical diagram if your Audi is different than mine.

Obtain a water methanol injection system from a recognized performance company and gather the material, tools, equipment and manuals needed to complete the installation project.

As appropriate, when the system is activated, look into your review view mirror and watch the vehicle behind fade into the distance.


Auidpages.com and/or the author assume no responsibility nor liability regarding the adoption of the water methanol injection system covered in this article. Further, neither Audipages.com nor the author endorse any product or service shown or mentioned in this article. Proceed to use at your own risk.


A new Snow Performance Water Methanol Injection System Kit was purchased from a source on eBay. The system kit consisted of the following:

Ultra High Out Pump
3 quart Reservoir
10 feet High Pressure Tubing
3 feet Black Wire Loom
1 General Instruction Manual

Mechanical Packet
1 Nozzle Holder
1 Reservoir Fitting-3/8" NPT to ¼" tube
1 E-6000 (GOOP)
Mounting screws and washers (not used for installation)

Electrical Packet
1 Green LED
2 Blue Butt Connectors (not used for installation)
2 Small Eyehooks (not used for installation)
1 Wire Splice (not used for installation)
1 Male Connector (not used for installation)
1 Female Connector (not used for installation)
VC-25/MAF Controller
10 Tie Wraps
Level Switch Upgrade (not used for installation)
2 Butt Connectors Number 8 wire
10 Butt Connectors 16 gauge wire
6 Female Spade Connectors
6 Male Spade Connectors

60 milliliter/minute
100 milliliter/minute
175 milliliter/minute
375 milliliter/minute
625 milliliter/minute

Manuals and References

Bentley Audi 2000 A8 Repair Manual (Compact Disc)
Audi 2000 A8 Subscription (alldatadiy.com)

Water Methanol Mixture

1 Gallon of a 50/50 mixture of water methanol referred to as "Boost Juice".

Mounting Material

2 Pieces of 4 feet of .063 Aluminum Angle
4 Self Tapping Screws M5.5 x 50.8 (Pump Mounting)
6 Self Tapping Screws M4.8 x 25.4 (Amplifier, Aluminum Channel)
8 Hex Cap Screws M6- 1.00 x 30 (Air Box Mounting and As Needed)
8 Hex Cap Screws M7 -1.00 x 30 (Reservoir Mounting and As Needed)
8 Nuts M7 - 100 (Reservoir Mounting and As Needed)
8 Washers M7 (Reservoir Mounting and As Needed)

Electrical Material

25 feet Number 8 Copper Wire, Green
25 feet Number 8 Copper Wire, Black
25 feet 16 Gauge Copper Wire, Red
25 feet 16 Gauge Copper Wire, Black
20 feet Shielded Cable
2 Toggle Switches with Cover and Red LED
1 Fuse 15 Ampere
1 Fuse Tap
10 feet Shrink Tubing ½'
15 Butt Crimp Connectors for 16 to 18 gauge Wire
2 Eyelet Connectors
4 Butt Crimp Connectors for Number 8 Wire
20 feet Plastic Insulation Tape
20 feet Rubber Insulation Tape
Solder as Required
Aluminum Insulation Tape as Required
1 Foot of ½ inch Inside Diameter Rubber Hose (Grommets)

Tools and Equipment

Yellow Paint Marker
1 Right Angle Drill ½ " Chuck
1 Drill ½ " Chuck or Drill Press ½ " Chuck (Optional)
1 Drill Bit 5/16 "
1 Drill Bit 11/32"
1 Circular Metal Cutter 3/4"
1 Tap 1/8" -27 NPT
1 Utility Knife and New Extra Blade
1 Hand Saw for Metal Cutting
1 Metal Hand held Shear
1 Clamp
1 Table Vise
1 Work Light
1 Circuit Tester
1 Socket 10mm
1 Socket Wrench
1 Open end 10mm Wrench
1 Upholstery Tool
1 Soldering Iron (50 watts)


The description of the water methanol injection system kit will be covered in two segments:

1. Preparation, and 2. Installation


Refer to the Bentley Manual and/or other reference sources in order to accomplish the following:
    1. Put the driver and passenger seat in the far back position. Remove the driver side and passenger side carpets.
    2. Remove the side panels around each side of the transmission tunnel.
    3. Remove fuse location cover in the passenger foot well.
    4. Remove all trunk liners
    5. Remove two bolts that secure the rear seat.
    6. Unclip and remove the threshold covers along the front and rear doors for driver and passenger sides. As need, use an upholstery tool to ease the effort to remove and adjust the carpet along the thresholds.
    7. Keep all screws in plastic bags with identification of location.


Choosing the location for the reservoir depends on the preference of the owner. Some owners choose to use the existing windshield washer reservoir. In this approach the owner may forgo the reservoir for the indented use to clean the windshield. Then again using a washer solution that is methanol based but a weak solution would allow cleaning the windshield and with a change over device be used for water methanol injection. However, the the intended achievement of 20 horsepower would not be realized because of the dilute mixture.

This article addresses a dedicated reservoir for water methanol injection and 50/50 water methanol solution. So let's get started with the installation.

The left side of the trunk was selected as the location for the reservoir because of the existing opening and cavity in the floor.

Location is ideal because the access cover can conceal the reservoir and pump assembly.

The radio amplifier shown here in the cavity needs to be removed.

A 10mm socket was used to remove two screws holding the mounting plate and amplifier in a cavity. The amplifier was secured to a mounting plate 4D0868867C by four screws. These four screws were removed with the 10 mm socket. The electrical connector on the side of the amplifier was removed to allow repositioning of the wiring harness and to learn the extent the wiring would permit placement of the amplifier on the underside of the upper shelf in the trunk.

Relocated radio amplifier

With the amplifier held by hand against the underside shelf in the trunk, a mounting hole position was marked with a yellow paint marker. This potential position was evaluated for any possible contact with hidden wiring, The other three mounting positions were examined based on the same concern about hidden wiring. Mounting holes were drilled using a 5/16 inch bit. Four self tapping M4.8 x 25.4 secured the amplifier.

A piece of aluminum angle was cut to an overall length of 15 inches. The center lines between the two securing holes was 13 and 13/16 inches. The vertical piece of the angle was cut back on each end by one and one half inches. This allowed the angle to fit in the cavity while being able to have a flat surface to secure each end with a screw used for the amplifier mounting plate. A second piece of angle was fitted into the primary angle and secured with two self tapping screws M4.8 x 25.4. This arrangement created a channel with improved torisonal strength. Two pieces of aluminum angle were cut to 13 and 1/2 inches for use as the vertical uprights to mount the reservoir.

Cuts to the aluminum angle are shown for horizontal and vertical sections. Two screws M7-1.00x 30 and two M7-1.00 nuts are used to secure the horizontal piece the two vertical rails. Mounting holes were marked for the reservoir on the vertical uprights to allow the reservoir to fit in the trunk opening at the highest point while being able to remove the reservoir cap for filling. Mounting holes were drilled with a 3/8 inch bit. The reservoir was secured with four screws M7- 1.00 x 30 and nuts M7 -1.00. Also, a 1 and 1/2 inch angle was placed at the intersection of the vertical and horizontal surfaces to strengthen each vertical upright. These angles were secured with four self tapping screws M4.8 x 25.4.

The pump is a pusher type output that requires a gravity feed input. On the top of the pump a yellow mark was placed to identify the input. With the reservoir secured, the pump placement could now be defined. A cardboard template was made of the pump's four mounting holes. The top horizontal edge of the template was made to align in reference to a horizontal line through the mounting holes. A yellow line was drawn on the side of the pump as a reference for the template to allow the pump to be placed one inch above the bottom floor of the cavity. The template was placed on the inside wall of the cavity. The top edge of the template was checked with a small level to establish a level condition. The template was secured with masking tape and mounting holes defined with a yellow paint marker. The template was removed. A 5/16 inch drill bit was cut to an overall length of 2 inches. A right angle drill was used to make the four mounting holes because of the narrow width of the cavity. The pump was fastened to the inside wall of the cavity with four M5.5 x 50.8 self tapping screws using a 10 mm socket.

A piece of the the 1/4 inch tubing was cut to length to fit from the reservoir to the pump. It should be noted that cutting the tubing is accomplish with a new razor blade. The tubing is held firmly on top of a wood surface. The blade is placed perpendicular to the tubing and a cut is made. This process is essential to best achieve a proper seal in all fittings associated with the injection system.

The two retaining screws for the back seat were removed. The seat was separated from the back of body's trunk frame by approximately eight inches. Be careful not to disconnect wiring associated with the back seat. A gap at the corner of the trunk and seat body on the driver's side was ideal to route the tubing. About six feet of the twenty foot section of tubing was passed through the gap from inside the car to inside the trunk. A piece of 1/2 inch clear tubing six inches long was used as a grommet to protect the tubing. Some tubing slack was created for the tubing within the trunk space The length of the tubing was cut and connected to the output side of the pump.

Carpet was lifted up along the entire length of the threshold on the driver's side. As needed an upholstery tool was used. The tubing was placed under the carpet in a manner to best protect the tubing from damage.

A 3/4 inch hole was drilled in the bottom section of the driver's side firewall near the electrical ground location.

A piece of 1/2 inch ID rubber hose 2 inches long was used as a grommet to route the tubing through the hole. Tubing was secured inside the front driver's wheel well with a plastic tie. A 3/4 inch hole was drilled in the bottom of the engine compartment. The tubing was routed through a 1/2 inch ID rubber hose 2 inches long into the engine compartment. All grommet and metal interfaces were sealed with E-6000 (GOOP).

The location of the water methanol injection nozzle was marked with a yellow paint dot on the air tube near the bend in the tube that is attached to the throttle body. A second yellow paint mark on the edge of the air tube is an alignment mark with the mating connection at the throttle plate.

The air tube was removed from the engine and placed with a clamp on a drill press. A 11/32 inch drill bit was used to make a hole in the tube Threads were made in the hole with a 1/8-27 NPT tap. The threads of a 375 milliliter nozzle were carefully coated with sealant and screwed into the nozzle holding connector. The threads of the nozzle assembly were then carefully coated with sealant. Then the nozzle assembly was screwed into the threaded hole in the air tube. The end of the tubing was cut with a razor blade making the cut perpendicular to the tubing and creating a clean cut. The tubing was then pressed into the special fitting in the nozzle assembly. Fifty milliliters of water was poured into the reservoir. The air tube was held outside the engine compartment. The pump in the trunk was activated and the water was pumped without encountering any leaks. The air tube was set aside in the engine compartment as the next step involved removal of the air box.

The four screws that secure the top of the air box that contains the Mass Air Flow (MAF) sensor were removed with a Phillips head screw driver. From the Bentley wiring diagram, number 5 connector is the signal wire where 0 to 5 volts is sent to the Engine Control Unit (ECU) depending on the air flow conditions. Further, this wire is shielded to protect its signal integrity from the many frequencies generated within and around the engine compartment.

The connector to the MAF sensor was disconnected. The number 5 connector wire was isolated and aluminum tape placed 1 and 1/2 inches apart on the wire.

A soldering iron tip was used to heat the insulation between the pieces of tape. Once heated the insulation was carefully scraped from the wire using a utility knife blade. The bare wire was cleaned. The tip of the soldering iron (150 watts) was placed under under the bare copper wire and the wire was heated. Solder was melted on the top of the wire and allow to flow over the the length of the bare wire until it became tinned. A foot long piece of 18 gauge blue wire was stripped one inch at on end. The bare end was cleaned and wrapped around the tinned signal wire. The soldering iron tip was placed under the bare wrapped wire. Solder was then melted over the top of the wrapped wires. A good connection was made.

It should be noted that creating a splice with the special connectors provided with the water methanol injection kit were not used because concern existed that splicing with the connectors could fail over time since the primary signal wire was 24 gauge. Such failure concern has been cited in papers associated with using these connectors. Proceeding on, the other end of the spliced wire was pushed through an existing grommet in the side of the air box. This wire was connected to the primary wire of a shielded cable via a set of spade connectors. These connectors provided the provision for future disconnection.


The copper shielding on the cable was separated and twisted. A butt connector was used to connect to a 16 gauge wire that was fastened to a ground location. The air box was reattached to its bottom section. The four Phillip head screws were replaced with four 10 mm hex head screws M6-1.00 x 35.

The shielded wire was grounded inside the vehicle when a connection was made for the primary wire being routed through a switch and then to the water methanol injection Controller. The Controller was located under the dash near the hood release. As a note, the shielding must be grounded at both ends of the cable for the shield to be effective. This grounding condition creates a Faraday Cage" and shields the signal from unwanted electromagnetic radiation. As mentioned above, my installation of the water methanol injection system included an on and off switch for the MAF signal to the Controller and, also an on and off switch for electrical power to the Controller at the operator's option. The electrical wiring diagram from Snow Performance for the water methanol injection system does not include these two switches. It is not my intention that the water methanol system be ready for activation as based on settings in the Controller. In this regard, I made provisions in a separate instrument panel for the MAF signal switch and the power switch to the Controller. A green LED lights when the pump is operating and this LED light is a standard component of the Snow Performance wiring circuit.

A 3/4 inch hole was drilled in the passenger side foot well on the right of the relay panel. The shielded cable was routed though a 1/2 ID rubber hose acting as a grommet. The hose and metal interface was sealed with E-6000 (GOOP).

The shielded cable was connected to the switch as discussed previously. A 15 ampere fuse tap was made in the red section of the fuse panel at location number 5, Front Fog Lights. A twenty foot piece of number 8 copper wire (green) was connected to this tap and routed to the trunk for power to the pump. Also, power was routed via a switch for power to the Controller. So on the special instrument panel, the left switch controls electrical power to the Controller and the right switch controls the MAF signal to the Controller.

A copper wire number 8 (black) provide a direct ground from the battery to connect to the pump and the Controller. Both power (green) and ground (black) wires were placed under the carpet on the threshold and under the seat and through the right gap leading into the trunk. A 1/2 inch ID 2 inch hose provided a grommet for the power and ground wires. In the installation, the power (green) wire is placed along the back side of the trunk and then along the left side of the trunk connection to the pump using spade connectors.

A primary reason for failure of electrical/electronic equipment can be directly traced to a poor ground. This is the reason for a dedicated ground (black) wire from the battery.

A section eleven inches wide and fourteen inches high was cut from the trunk liner for the driver's side. Cutting was done with metal hand shear. This opening in the liner enabled the liner to easily be installed around the back of the reservoir tank. Also, this allowed the liner to be fastened by the original two screws at the base of either side of the reservoir frame.

With the liner in place, the removable cover could be installed returning the trunk to its original inside configuration and concealing the reservoir and pump assembly.

All mechanical and electrical components were tested as sub-units and found to function as required. The reservoir was filled with two quarts of a 50/50 mixture of water methanol referred to as "Boost Juice". A trial run of the system was made. The extra boost was noticeable. The vehicle in the rear view mirror continued to fall further behind!!!