Monday, August 13, 2007

Greasecar TDI Edition: Part 1

After months of doing homework, research... and a lot of waiting... I'm finally converting my Volkswagen Golf TDI to run on waste vegetable oil. I did my best to educate myself on diesel engines before I bought the car about 2 months ago, and I also spent the better part of the last few months learning about the different conversion systems on the market. Now that I finally have my Greasecar kit and I'm ready to go, I'm going to keep a bit of a running diary for anyone out there who's interested in following along.

There are four companies that I looked at before making my decision - Greasecar, Frybrid, VO Tech, and Golden Fuel Systems. All of them are good guys with great products, and all of them were really helpful over the phone. There's a lot of different ways to set up a system like this, and no one really has it right or wrong. For anyone out there thinking of doing this, you really have to do as much homework as you can and just go with the system that sounds the best for you.

I went with the Greasecar kit for reasons you'll see throughout the posts. Without going into too much of the technical stuff (You can get tons of info about how these systems work on the different company web sites), vegetable oil has the same properties as diesel fuel when it gets hot enough - visualize heating vegetable oil in a frying pan and watching it get thinner - that thickness is called viscosity, and vegetable oil has to have the same viscocity as diesel fuel for it to inject properly into the engine. So the way the system works is you install a separate tank with separate fuel lines for the vegetable oil. You start the vehicle on diesel, and when the engine gets hot enough, bingo, you switch over to grease lightning. The tricky part is remembering to purge the lines and switch back to diesel at the end of your trip, otherwise the oil will cool in the engine and fuel lines and it will be a whole mess.

This is a photo of the ISI Solar company truck (In front of a 3 KW system we installed on a detached garage in White Plains, NY). It's a Ford F350 Powerstroke that my boss did the Greasecar conversion on about 2 years ago. Since my boss is also helping me install the system on my VW, part of why I went with the Greasecar kit is because I knew it would be familiar.

Back to the whole heating thing - in order for the vegetable oil to get hot enough, the system taps into the engine coolant and uses it to heat the vegetable oil in the tank and fuel lines. The first problem with the Greasecar kit that I wanted to remedy is that they use a copper heat exchanger in the fuel tank. Since copper can have an adverse chemical reaction with vegetable oil, I replaced the copper in the tank with 5/8" aluminum tubing. A lot of the other systems have done the same, and to be honest, I can't quite figure out why Greasecar hasn't replaced the copper.

The nice thing about the system is that the tank is designed to fit right in the spare tire well beneath the mat in the trunk. We ran the fuel and coolant lines under the heat shield beneath the car and drilled into the tire well to connect the tank.

After it's all done, the spare tire cuts into your trunk space a bit. I may end up trying to mount the thing along the side.

Next time we'll be mounting the valves under the hood, installing the computer system, and if all goes well, tapping into the fuel and coolant lines for the final connections.