Can I convert an older vehicle to something more environmentally-friendly?

Converted plug-in Prius – Click above for high-res image gallery

Cash For Clunkers is officially over and helped put almost 700,000 new cars on the road. Now that the easy $4,500 are no longer available to buyers with low-mpg cars, we thought it'd be a good time to answer AutoblogGreen reader Adam's question that he submitted for our Greenlings series. Adam said he would like to know:
What efforts are being made via research & development that will convert existing vehicles to green vehicles? Is it not important to use the existing fleet vs. constant production of new and more vehicles? I am thinking of classic or special vehicles owners want to keep on the road once alternative engines / fuels are commercially available.
We tackle the question after the jump.

Photos copyright ©2007 Sebastian Blanco / Weblogs, Inc

There are quite a few conversion options available to turn dirty gasoline internal combustion engine (ICE) vehicles. If you have a hybrid, you can get an added battery pack and a plug to make your car a plug-in hybrid (PHEV). If you want to burn natural gas in your car or truck, you can get a CNG conversion. Greasecar kits will allow your diesel car to use straight vegetable oil (SVO). There are even cheap kits to turn your gas engine into one that can burn high concentrations of ethanol (E85 fuel) in a "standard" car. If you're ready to make a huge shift, you can even take out your ICE altogether and put in a bank of batteries to make a pure electric vehicle (EV). Here are some short descriptions of these conversion types and links to get more information:

From ICE to E85
This is the easiest conversion to make. At least, it sure loooks easy. All gas engines in the U.S. are probably already burning a little bit of ethanol (most gasoline is sold with up to 10 percent ethanol in it) and changing a gas engine to burn E85 is technically feasible and there are shops around the U.S. that will install E85 kits into your car. The problem is that the federal government has given its imprimatur to only one commercially-available kit. This kit is sold by Flex Fuels U.S. and works on Dodge Chargers, Dodge Magnums, and the Chrysler 300 2wd and AWD 5.7L Hemi. Cost? $1,295.

From hybrid to PHEV

More expensive than an E85 conversion, turning a gas-electric hybrid into a plug-in vehicle seems to be the leading consumer conversion going these days. The most popular conversion kits come from Hymotion/A123 and Plug-in Conversion Corporation. Depending on the pack that is installed, the converted hybrid will get something like 30 miles of electric-only driving (at speeds below around 35 mph) before the gas engine kicks in. The cost of most of these conversions start at around $10,000, so we had to ask recently: where is the government funding for PHEV conversions?

From diesel to SVO

Another popular conversion is to go veg with an SVO kit. SVO is vegetable oil and is also known as VegOil, waste vegetable oil (WVO) and virgin vegetable oil (VVO). For SVO, you need to start with a diesel car and then find space for a separate tank to store the veggie oil (say good-bye to your spare tire). You'll still burn a bit of diesel fuel with an SVO kit when the car starts up, but once everything is heated up, you can get off the petroleum completely as you drive. SVO conversions start at around $2,000. To learn more about SVO, read this.


Converting a vehicle to burn compressed natural gas or propane has long been the purview of fleet managers across the U.S. Roush offers factory conversions of many big Ford trucks, taking the vehicles directly from Ford and putting in their own propane systems. In Europe, liquified petroleum gas (LPG) conversions are popular and sometimes available with stylish looks. Costs for these conversions vary widely, but start at a few thousand dollars. As with all of these conversions, it makes sense to educate yourself and look out for cheap installers who want to cut corners. For more on natural gas vehicles, read this.


We've covered pure electric conversions in a previous Greenlings. EV conversions often fall into two categories: DIY home conversions done on the cheap and expensive conversions of expensive cars. In the first category, we can point you to previous articles about a teenager who converted his 1988 Mazda pick-up and these shade tree mechanics who lovingly reworked a 1936 Chevy sedan. There are also a lot of ways to learn how to do these conversions yourself. As for the expensive versions – and this would probably interest the classic or special vehicles owners that Adam was asking about – there is no lack of companies who will take your ride and put in batteries and an electric motor. We recommend reading EVAlbum and looking for local conversion shops through the Electric Auto Association to get started. If you don't want to convert your own vehicle, go ahead and order an electric Mustang (for $80,000) or a Shelby Cobra ($125,000). That's pretty expensive, but in the EV conversion game, prices range from $1,000 or so to as much as you want to pay for batteries. You get what you pay for.

  • Image Credit: click for gallery

These are just the most common conversion options out there. Other conversions – for example, to hydrogen power – are possible, but we don't see them too often. If you have a conversion story or a question about a vehicle you'd like to convert, let us know in the comments.

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