Ty Martin estimates he gets about 100 miles per gallon of diesel out of his old Dodge truck.
And he's not joking.
"I've done some extensive road testing and had great luck," the Lawrence resident said.
Martin is one of a small but growing group of drivers who are skirting rising gas prices and taking what they see as a more environmentally friendly route by fueling their cars with used restaurant grease.
"It's something that's really taken off in the last two years," said Josiah Cuneo, production manager for Greasecar Vegetable Fuel Systems, a Massachusetts-based company that sells the kits to enable diesel engines to run on vegetable oil.
For Martin and his co-worker and fellow grease guzzler Marcos Markoulatos, it's more than just a way to run the car - it's a way of life.
The two, both automotive technicians at Kansas City Auto Sport, started using grease in their vehicles last year. They both drive Dodge trucks built to run on diesel.
Markoulatos bought a $1,000 kit to convert his engine to use vegetable oil.
The process involves essentially adding a second fuel system to the vehicle to accommodate the vegetable oil.
"You keep diesel in the main system, vegetable oil in the added system and then you have a switch where you can switch between the two fuels," Markoulatos said. "It took me a very leisurely weekend to install."
Martin, who converted his engine a bit later, chose to convert his truck from scratch, using a mixture of salvaged parts.
In the winter, Martin will use diesel fuel for the first 10 minutes of his drive until the grease, which thickens in cold weather, warms up along with the engine. Then he'll flip the switch to grease for the remainder of the trip until just before the end, when he switches back to diesel to purge the oil from the engine.
Regardless of whether he drives to Topeka or Denver, he'll use the same amount of diesel to get started and to end his trip. That makes long-distance driving with grease particularly economical, the drivers said.
Fill 'er up
For these drivers, local restaurants take the place of gas stations.
Martin and Markoulatos have built relationships with downtown Lawrence restaurant staff members whom they visit regularly when they pick up leftover oil that was used to fry french fries, onion rings and other foods.
Martin declined to say where he gets the grease because he didn't want to inform others of his resources and lose out on the grease. Not all grease is considered equal and the drivers prefer quality restaurants that use quality oil and change it regularly, he said.
Using grease can be time-consuming, but Martin and Markoulatos say they don't mind.
After gathering the grease, the drivers must take it home, where they let it settle in a large bucket. Then they pass it through a filter and into another bucket where it stays until it's pumped into the trucks.
Markoulatos said he gets about 20 miles per gallon when using grease and about 22 miles per gallon on diesel.
"You lose a little bit of economy and a little bit of power - I'd say less than 10 percent of either," Markoulatos said. "I bought the truck to haul a trailer with my Jeep on it. And I've never had any issues with that. There's never any time when I wish I had more power running on vegetable oil. It seems like an even trade-off."
Clean Air Act
Cuneo, of Greasecar, said the company has sold 3,000 conversion kits since the company started in 2000 and this year has been the busiest so far.
Cuneo attributes rising sales to the spike in fuel costs as well as increased concerns about global warming.
"One of the first questions we always get is 'What is the difference between what we're doing and biodiesel?'" Cuneo said.
Biodiesel is a fuel made from vegetable oil that can run in any unmodified diesel engine.
Cuneo admits that vegetable oil is more time-consuming to process and use than biodiesel, which is available at some gas stations.
But with vegetable oil, "the benefit is you're going to be paying essentially nothing for the fuel that you're using," he said.
While grease users point to the fuel's ecofriendliness, the Environmental Protection Agency sees it differently. Using vegetable oil fuel is a violation of the Clean Air Act, according to the EPA.
"The Clean Air Act requires they use only registered fuels," EPA spokesman John Millett said. "If you're making your own fuel, then it's not a registered fuel."
Millett said drivers that use vegetable oil fuel run a few risks, including creating more pollution than diesel or biodiesel, damaging their engines and the legal risk of using an unregistered fuel.
"There are compounds in vegetable oil that create a soot," Millett said of the pollution concerns.
And, he said, working with fuels in a home or garage can be a fire hazard.
But vegetable oil fuel drivers point out it's a renewable resource and say it's "carbon neutral" because vegetable oil plants absorb more carbon dioxide from the air during their growing cycle than is released when the oil is burned. It also uses a restaurant waste that otherwise would be disposed of.
They also don't mind another unique aspect - the smell.
Sniff the exhaust and you'll likely get a whiff of french fries or onion rings.
"It smells pretty much like Burger King," Martin said of his exhaust. "I don't know what that says about Burger King."