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UNDER CONSTRUCTION

Methanol and Water Injection

Why do you use methanol and what is necessary to set up methanol injection?
Tim's Methanol Enrichment Tech: This is the advanced class. First the problem with a VW is that it is air cooled. The longer and more boost you make, the hotter it gets. Also, the temperature of the air going into the engine is hot. You can run better and more expensive fuels, pull the timing back, and you will still get to a point where it still detonates, no matter how much fuel you put in. The problem is the heat.

Some have used water injection and it will effectively raise the octane and lower the combustion temps. Problem is controlling the water injection. Most methods just turn it on or off. Also pumps, and solenoids are very expensive.

We found that the Bosch fuel pumps, fuel pressure regulators, and injectors will tolerate methanol. I would not recommend leaving methanol in the system for more than a few days because methanol is corrosive and will chew on everything that is not stainless steel or compatible with it. If you rinse, or "Pickle" the methanol system when it is not in use or storage, you will not have any problems. (When methanol sits in a tank, it will absorb moisture out of the air, and will turn into a green jelly and other nasty things you don't want to mess with). The methanol does 3 things for us. First, it has BTU's. There is energy in it as compared to water. Water converts to steam and absorbs heat, which works great, but you do get a bigger yield out of a fuel that burns cooler. (We also get a compromise here because we are still putting in the Av-Gas as the primary fuel. The heat from the Av-Gas helps light off the methanol better, and the methanol cools the combustion temps, but not as cold as 100% methanol would. Also note that we are not mixing two different liquids with two different specific gravity's. They are being mixed as an atomized spray in the intake airflow, and then homogenizing together in the combustion chamber).

Second, it burns slower in the combustion chamber and has a cooler flame front. This stabilizes the combustion and because of the slower burning, you don't have to pull your timing back. Third, by adding a injector up stream of the air flow, it will "Flash" or evaporate quickly and act just like a big expensive intercooler. By using this, you don't spend the big bucks on an intercooler, don't have the weight and all the plumbing, and you gain throttle response by not having long pathways to the engine or the volume tank effect.

It is just one injector as close to the output of the turbo as possible so it will have time to cool the airflow. It is controlled by the "Stand Alone" boost enrichment system. Most fuel injection computers will not two-stage, or control two different sets of injectors at different times. Be careful here, some say they do, but under closer investigation all the do is turn them on at a certain throttle position, or pressure. You want a system that controls "How Much" they're turned on at a certain boost pressure. This is why fuel management with computers works where carbs cannot.

For a sandrail, usually 2 1/2 to 3 gallons is fine. You only put it in under boost. The fuel pumps we use are the big Bosch units, out of the VW Rabbits. The place where we buy methanol is at the race track or go-cart shops. Here in Phoenix the circle track boys run methanol all the time, so it is fresh. As far as mixing 1/2 water with 1/2 methanol goes, it should work just fine as a boost enrichment detonation control, but, I would at no time want to see what happens to my fuel injectors if water goes through them, let alone the pump! The problem with water injection is the pumps and solenoids. This is why "Our" group runs two separate fuel systems, one for Av-Gas and one for the methanol.

 

Further Reading:


DIY Water/Alcohol Injection System

 

 

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