Bottom Line
Pills, magnets & stickers

By Paul Abelson
senior technical editor

I've been accused of inconsistency. Some industry suppliers and potential advertisers have gone so far as to call it favoritism, or worse.    

Why? Because before writing about some products that claim to dramatically improve fuel mileage, I insist on seeing verifiable, independent testing done by independent testing facilities. Yet, I write about other mpg-improving products without insisting on those tests.

The Society of Automotive Engineers and the Technology & Maintenance Council jointly developed recommended practices that objectively eliminate all variables - such as weather, speed, terrain, drivers' skills and practices, etc. - leaving the item under test as the only variable. There are ways to test items that immediately make a difference and test procedures for items that need long-term break-in or conditioning, such as oil treatments or slow acting system cleaners.

There are two credible tests designed by SAE/TMC to evaluate products. One is for products that can be moved from truck to truck. The other test is for products that are truck specific. Both tests are accurate within plus or minus 1 percent.

Suppliers resist running these tests for two reasons: The tests are extremely expensive and sometimes suppliers know their products won't pass. One full test sequence can cost from $30,000 to more than $100,000. For a small supplier earning only 5 percent on sales, that means selling as much as $600,000 to $2 million worth of additional product, and that's just to pay the testers. Supplier time and travel are extra.

Another reason some suppliers avoid having independent testing done is because they know their claims are exaggerated and their products don't work - at least not as well as they say.

So, why do I insist that some products be SAE/TMC tested and others not? Because if products apply known principles of physics to trucking, or adapt technologies from other modes of transport, I evaluate whether they make sense.

Examples are some of the aerodynamic devices made for tractors, trailers and truck bodies. Vortex generators have long been used on aircraft to smooth airflow and reduce drag. If they work on aircraft, where everything that goes on an airplane must be approved by the Federal Aviation Administration, reason says they'll work on ground vehicles, too. Trailer skirts and cab extenders fit this category.

I wrote about doublewide tires before formal testing was completed, because logic said they would save fuel. It is widely accepted that much of a tire's rolling resistance comes from its sidewalls flexing. By eliminating one-half the sidewalls from each set of duals, wide-based singles were bound to increase fuel economy.

The only question was, "by how much?"

Unlike products based on sound science, other products defy logic. Like most of us, I would love to find that magic bean that enables Jack to climb the beanstalk to find fame and fortune, or at least the fortune part.

But every year at every truck show, new products appear, and disappointed buyers find that all they've done is enrich the sellers, not themselves.

The wonderful pill that dissolves in the fuel tank to increase fuel mileage and reduce emissions is one of the latest. How does it work? When asked, the sellers say, "It's a secret. We can't tell you. But trust us, it works." I'd love to see such a thing, but if I had the patent rights, I'd approach a major oil company and offer them exclusive rights.

Wouldn't you line up for a premium fuel that gave you 10 percent better mileage than the other guy's fuel? That would be the way to sell it. Don't tell me that big oil won't want it sold and will conspire to keep it off the market. Competitive advantage is far more important to oil companies than concerns about market size.

Magnets and other devices that clamp onto or splice into fuel lines always amaze me. Have you ever tried to magnetize fuel?

Here's a little experiment. Put a little bit of diesel fuel on a clean glass or ceramic dish. Paper will absorb the fuel, and plastic may react with it. Now hold a magnet near, but not touching, the fuel. If it were magnetic, it would be attracted to the magnet. It won't be.

Molecules in diesel are random, and no magnets will ever change that. Some devices claim to alter the molecular structure of diesel, implying that they cut apart long chain molecules. If you could cut diesel molecules, it would no longer be diesel. Shorter molecules such as octane and heptane are components of gasoline or gases, not diesel. They would totally screw up burn rates and injector timing, and would likely damage a diesel engine.

A dozen years ago, there was a press conference at the Mid-America Trucking Show about a fuel-line device. The gadget spliced into the fuel line. Inside was a triangular-shaped ceramic bar that the presenter claimed had "a proprietary blend of noble metals that conditioned the fuel" before it entered the injectors.

Some noble metals, mainly platinum, are catalysts that improve combustion. But a catalyst - a substance that assists a process but is not consumed by it - must be in contact with the reaction, in this case combustion, inside the engine. But passing fuel over a specially shaped substance containing who knows how much or how little platinum? I don't think so.

One of the most outlandish claims was a sticker with a hologram on it. Placed on the outside of fuel tank, "the hologram captured the son's energy and changed the molecular structure of the fuel inside." Huh? What kind of physics is that? By the way, the product info really said "son's energy."

Controlled, turbulent airflow can assist carburetors to mix fuel under controlled conditions. But we don't have carburetors any more, certainly not in diesels. Placing a vane system that twists the air in a diesel intake accomplishes nothing. By the time the air goes through the turbo, the charge-air cooler and the intake manifold, any turbulence has disappeared.

Chemicals, of course, are always proprietary secret formulas, I believe in fuel treatments for winter operations, for water and organic control, to improve lubricity and to clean injectors or keep them clean. Cleaning dirty injectors will restore fuel economy, but any chemicals otherwise claiming improved mpg need to prove it to me.

Now you may better understand that I do have a double standard about devices and products that claim fuel economy improvements. I readily write about those that seem to make sense, products based on known science. But those that make claims bordering on the impossible can't expect me to accept their claims with only testimonials. I insist on industry-recognized, independent testing.

Those are my standards, just for writing about products. The manufacturers are asking you for your hard-earned money. Shouldn't you be at least as demanding before you part with it?

Paul Abelson may be reached at