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1998 Toyota 4Runner - Meth Addict

1998 Toyota 4runner
Harry Wagner | Writer
Posted January 8, 2014

Adding Water/Methanol Injection To Your Engine

When you think of water getting into your engine the first thing that comes to mind is probably that you hydrolocked it by crossing water that was too deep. But did you know that small amounts of water can actually be good for your engine?

Water injection cools the intake charge and steam-cleans your cylinders. Methanol is a fuel that can be injected at the same time to keep your engine from running too lean. This idea isn’t new. It was used on B-17 bombers back in World War II. Now instead of fighting the Axis powers we are applying the same technology to a Japanese engine, namely the 5VZ-FE V-6 in our ’98 4Runner.

Bolting a TRD supercharger onto the top of the 3.4L engine was relatively easy, but getting it to run right with the added boost proved tricky. Our biggest problem was detonation when we punched the throttle hard from low rpm. If we coaxed the engine up to higher revs gently, it was fine, but that is not always an option in the mud or sand. The problem is fairly well known: Fuel must be added to compensate for the added air coming into the engine.

We made a call to DevilsOwn Methanol Injection to get a universal Stage 1 kit. The kit, which was inexpensive and very complete, uses a simple on-off pressure switch to activate the pump. The Stage 2 system adds a progressive controller but it is more expensive and more complicated than the Stage 1 system we installed. If you are really pinching pennies you could piece together your own system, but by the time you get quality parts and burn gas making trips to the part store you wouldn’t be too far ahead of the DevilsOwn system.

Installation was done by Alex Baker at Samco Fabrication in an afternoon, but the system includes thorough instructions and could easily be installed at home over a weekend. We used the windshield washer reservoir due to space; DevilsOwn includes a self-sealing fitting for this. The reservoir holds about a gallon, and we have been consuming about half a gallon of 50/50 distilled water and methanol for every tank of fuel (about 250 miles). It is possible to wire in a light or gauge to indicate when the reservoir is low, but we just top it off every time we fill the tank. The system was inexpensive, installed quickly, and has cured all of our part throttle issues. Sometimes putting water in your engine is a good thing!

Step By Step

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  • The TRD supercharger is an Eaton design with three lobes that produces around 6 psi of boost with the stock pulley. The URD SuperGrip pulley we are using increases boost to 8 psi.

  • Nozzles are rated in gallons per hour (gph); we used a 3-gph nozzle on our engine. DevilsOwn has a useful nozzle size calculator on its website that uses your engine displacement, boost pressure, and maximum rpm to calculate the approximate nozzle size for your application.

  • The heart of the system is the 250-psi pump that Samco Fabrication mounted inside our front bumper. The pump is plumbed to the factory windshield wiper tank with the included self-sealing, filtered tank tap. And yes, we still retained the windshield washer functionality. What do you think is used in those wiper fluid formulas that won’t freeze? You guessed it: methanol.

  • The DevilsOwn Stage 1 system uses a simple pressure switch to determine when to inject the water/methanol. Stage 2 systems use a progressive controller that ramps up the volume, instead of merely being on or off. The tradeoff is the added expense of the Stage 2 system.

  • Samco Fabrication drilled our K&N FIPK intake and added a brass fitting. Then the nozzle was threaded in with plenty of pipe dope to prevent leaks. This injects the water and methanol right before the throttle body and into the supercharger.

  • NGK brand BCPR7ET spark plugs are two steps colder than the factory specifies. The major structural difference affecting the heat rating is the length of the insulator nose. A colder spark plug has a shorter insulator nose, which helps prevent detonation.

  • HEET is intended as gas line antifreeze and water remover from your fuel, but it is almost pure methanol. It is also easy to find at just about any parts store in the country.

  • We even picked up 2 mpg at the pump with the addition of the water/methanol injection. This took our mileage from a deplorable 15 mpg to a merely bad 17 in mixed driving conditions.

  • The result is a clean installation that solved our issues with part throttle detonation and improved our mileage to boot, all at a reasonable price. If you have the space, it is hard to beat buying a 55-gallon drum of methanol. If your buddies are running methanol injection too, you might all chip in money and then they can just stop by to score some meth from you.

Other Options
Underdog Racing Development has made a business out of addressing the shortcomings of TRD superchargers, with several options to solve the lean condition that can result in hashed bearings or melted pistons. Underdog’s original solution used replacement fuel injectors with higher flow rates, a high-volume fuel pump, and a performance calibration unit to eliminate part throttle pinging and high-rpm lean conditions. Underdog also has a kit that adds an injector to the EGR port of the supercharger to richen the fuel mixture and cool the incoming air, and a performance calibration unit that requires minimal tuning by the end user. These methods are more expensive that the water/meth injection we added, but you never have to worry about filling up your water tank or searching for methanol in the middle of nowhere.


Devil's Own
Samco Fabrication
NGK Spark Plugs
Wixom, MI
Underdog Racing Development
Gold Eagle (HEET)