Convert a Car to Biodiesel

From Wired How-To Wiki

We've all heard stories about the wonders of biodiesel cars. Unfortunately, rigging a vehicle to run on this cheaper, more environmentally sound fuel takes more than a "Veggie-powered" bumper sticker. Here's the scoop on how to transform your ride into a petroleum-free, cash saving driving machine.

Contents [hide] 1 Diesel Vs. Biodiesel Vs. Vegetable Oil 1.1 Petroleum Diesel (petrodiesel) 1.2 Biodiesel 1.3 Straight Vegetable Oil (SVO) 2 Step 1: Get a Diesel Car 3 Step 2: Scout a Fuel Source 4 Step 3: Procure a Conversion Kit 5 Step 4: Choose Your Install Method 5.1 Mechanic 5.2 Self-Install 6 Step 5: Filter The Used SVO and Fill the Tank

Diesel Vs. Biodiesel Vs. Vegetable Oil

There's often a little confusion when it comes to the term "biodiesel." When one speaks of converting their vehicle, it's usually in reference to vegetable oil specifically. However, this confusion is compounded by the fact that most diesel engines can run on regular diesel, biodiesel, and some form of vegetable oil too. Here's the difference between the three:

Petroleum Diesel (petrodiesel)

This is the 'regular' diesel you'll find at a gas station. It's easy enough to locate, and ultimately what a diesel engine was designed for. In addition to supply advantages, petrodiesel is also better suited for colder temperatures than its bio cousins.

Biodiesel

Photo by skidrd on Flickr

Biodiesel is basically a non-petroleum variation of diesel that's been chemically modified through a process called transesterification. Though not nearly as available as petrodiesel, it's often sold in varying mixes of petrodiesel/biodiesel. A system called the "B factor" is used to denote the percentage of biodiesel contained within a petrol/bio mix. For example, biodiesel rated "B5," "B20," or "B100" contains 5 percent, 20 percent, and 100 percent biodiesel respectively. These percentages are worth noting because some stock diesel engines have problems running on pure biodiesel (B100) for extended periods of time.

Straight Vegetable Oil (SVO)

If you've stepped foot in a kitchen, chances are you've encountered straight vegetable oil. It's commonly derived from soy, corn, palm, hemp, or a number of other vegetable sources. Despite being the brass ring for biodiesel aficionados, the setbacks for this fuel source are numerous. For starters, it's extremely expensive if purchased off the shelf -- especially compared to petrodiesel. Also, since it hasn't been chemically treated like biodiesel, SVO tends to turn to gel at low temperatures.

Step 1: Get a Diesel Car

Bad news gasoline lovers. The cornerstone of this conversion is a diesel engine. Since diesel vehicles fell out of vogue for automakers during the 90's, finding a newer used car may prove a challenge. But on the bright side, automakers should be bringing diesel cars back into the marketplace in the coming years.

Step 2: Scout a Fuel Source

Waste Vegetable Oil: It's not clean. It's not pleasant. But it's cheap (and good for the environment).

What good is an eco-friendly car without eco-friendly fuel? Believe it or not, the best starting point for large amounts of vegetable oil is restaurants. Local fast food joints should have vats of used SVO (sometimes called waste vegetable oil) out back, and ripe for the taking. However, there's no guarantee you'll be able to waltz in and skim whenever you want. It's best to talk to the manager and get a feel for how much SVO the business generates and then try to hash out a regular pickup schedule.

A good balance is make an arrangement with a few businesses in the area to secure a rotating supply. Don't panic if you can't secure a solid source right off though. After all, you can still run on petrodiesel or even biodiesel in the meantime.

Step 3: Procure a Conversion Kit

A conversion kit is pretty much mandatory for SVO-only operation. Like any other large purchase, it's advisable to hit up online biodiesel communities before rushing out to make a purchase. Shopping around and compiling testimonials is crucial for two reasons: First, prices for equipment and labor can vary greatly. Second, it's likely there's a specific kit that works best with the make and model car you've chosen. Picking the collective brain of the local biodiesel community will likely bring details like this to light. Good sources for kit info can be found at greasecar.com and frybrid.com.

Step 4: Choose Your Install Method

Mechanic

Playing grease monkey not your thing? Finding a mechanic to do the install for you shouldn't be too hard. Just be sure to find someone who has some sort of experience performing the conversion. Chances are you're voiding the vehicle's warranty by undergoing this process, so it's best to have someone skilled in your corner if something goes wrong or additional maintenance is needed.

Self-Install

The sky's the limit with modifications. Just remember you're responsible for the upkeep. Photo by 300td.org on Flickr

Tackling a kit install isn't an impossible task, but it's definitely involved. Luckily, most kits are relatively user-friendly and designed with the eco-conscious DIYer in mind. Below are some of the the more common mods you'll have to install:

• SVO Fuel Tank

The difference in viscosity between SVO and diesel can be problematic given their different gel points. So, most kits employ a two tank system for keeping the fuels separate. This is usually achieved by providing a second fuel tank (typically stored in the trunk) specifically for the SVO. Any kit up to snuff should also supply a pumping system for getting the SVO out of the fuel system for once the car is no longer in use.

• Hose/Seal Overhaul for the Fuel System

Though diesel engines can handle SVO, it's a toss up whether the fuel system is compatible. Rubber hoses and seals from older vehicles are notorious for breaking down after prolonged exposure to heated SVO. If you're able to locate a kit specific to your make and model, it's not uncommon to see a new set of SVO-safe hoses, seals, and additional filters included for install.

• Heating System

One of the biggest setbacks of SVO is its need for heat. Conversion kits combat this by including a heating system to warm the SVO before pumping it into the fuel system. One of the most common setups is a system that pumps waste heat from the radiator into the SVO tank. If the kit doesn't include a similar system, take heed -- the cold will always be your enemy, and you're going to need some sort of heating solution to keep the SVO running smoothly through the fuel system.

Step 5: Filter The Used SVO and Fill the Tank

The filtering process can be long and messy, but it'll save your fuel system. Photo by Laboratorio en Movimiento on Flickr

With a used SVO supply and a converted vehicle, you're almost ready to get moving. The final hurdle is filtering the waste oil you've collected and getting it into the SVO tank. Although there are a number of filtration methods, one of the simplest is to heat the oil (a container as simple as a metal bucket can work) and then pour it through a series of cheap household filters. Large coffee filters or even mesh strainers should do the trick, but there's lots of room to get fancy if money isn't an issue. Just remember that the ultimate goal is to remove any visible leftover food particles and debris before loading it into the SVO tank.