EcoTube is a fuel-saving gadget produced in New Zealand by BiosFuel. Like other gadgets we've reported on in the past, it uses the radiator hose to warm fuel before combustion.

According to EcoTube's website, "EcoTube works by preheating the fuel while applying a vortex. A vortex is a complex scientific phenomenon so let's keep it simple: If you have ever experienced the acceleration of going on one of those roller coaster corkscrews you will have some idea what is happening to the fuel. By the time it reaches the engine the heated fuel is in a state that naturally produces better combustion than without an EcoTube. The result is a faster, cleaner and more complete burn - which translates to more power on less fuel and cleaner emissions."

A vortex isn't really a complex scientific phenomenon. It's what happens when water goes down a plug hole. It doesn't affect the fuel in the combustion process, but EcoTube's makers get pretty excitable about vortexes and their mysterious powers.

BiosFuel director Cam Feast is emphatic that the vortex creates a whole new kind of molecular excitement.

"This describes in simple terms how the fuel molecule is excited by creating a vortex using fuel line pressure and the internal coil of the EcoTube. Steve Ryan, the inventor of the EcoTube, maintains that this is significant, above heating of the fuel in terms of delivering better combustion, fuel economy and reduced emissions."

EcoTube showed us test results suggesting the device may reduce emissions. It may also decrease fuel consumption, but the test results are generally over a short period (two tanksful) and drivers knew when the devices had been fitted.

We believe any results are due to a placebo effect and fuel warming. We don't fall for the vortex/excited molecules theory for one minute.

And if you do want to warm your fuel, there are cheaper devices on the market.

We examined the Jassco fuel economiser - designed for warming diesel - last year. We believe fuel heaters work by making the fuel expand and have a similar effect to lifting your foot off the accelerator slightly.

A scientific response

Consumer asked a physics professor from Victoria University's School of Chemical and Physical Sciences what he thought of the information on EcoTube's website.

"Even if a vortex were induced in the fuel line, this seems to me completely irrelevant to the processes which matter. The temperature of the fuel delivered might make a slight difference to the rate of fuel flow, but you're completely correct in saying that this effect could be equally achieved by changing the pressure of the foot on the accelerator. Hence, a placebo effect is likely to be at work, if the device actually produces some economy. Only a successful double blind test would start to arouse any serious scientific or engineering interest."

Enriched water

EcoTube inventor Steve Ryan isn't constrained by conventional science. Apart from his interest in excited molecules, he also claims to be able to run a motor bike on enriched water.

From the BiosFuel website: "Through years of committed research and development Bios Fuel founder Steve Ryan has developed an unprecedented water-based fuel. The fuel allows hydrogen to be housed safely in water and released on demand for numerous applications. Unlike electric and hybrid transportation - a bios fuelled engine requires dramatically less energy input, leaves a much smaller environmental footprint and is significantly more cost effective over its economic life."

The website does not give any evidence that these claims have been independently tested. Until we see some we'll take his claims of enriched water with a grain of salt.

We say

We don't accept EcoTube's claim that a vortex excites your fuel molecules. The device will make your fuel warmer, whatever benefits that may have.

And the very fact you've spent $300 on a fuel saving device will keep your foot light on the go pedal - but you can do that for free.

More information

• Fuel saving devices

Got a question or comment on this topic? Share your views and experiences with other Consumer members...