The Tornado Fuel Saver has been around for years now, claiming to give you an increase up to 24% in gas mileage.
The theory behind this device is that is will swirl the air coming in from the intake, which when mixed with gasoline will increase combustion and make the combustion more complete. In theory this means you have to use less gas to achieve the same speed and power, resulting in higher miles-per-gallon.
Many independant magazines and websites have tested this device over the years, which have all concluded that this device will not work, especially on modern fuel injected cars.
Even though Consumer Reports, the Department of Energy, the E.P.A, and countless other resources have tested this and other similar products with no positive results, people still convinced that this item may work.
Below is a review of the Tornado Fuel Saver from amazon.com
The Tornado Fuel Saver is a great idea for the patent holder and anyone else making money from its sales.
As an automotive technician I have encountered many devices that claim to improve performance or gas mileage. The Tornado is nice and shiny and makes an excellent paperweight or doorstop.
The theory of swirling the air/fuel mixture into the combustion chamber is nothing new; many modern vehicles are able to attain this with intake valves that open at slightly different times. There is very little doubt within the automotive industry that the better atomization of fuel within the combustion chamber yields better performance and as a result efficiency (mileage) for each unit of fuel and air that is taken into the motor.
However the Tornado Fuel Saver does not work for most modern cars and here is the reason: <br>
When the tornado is placed before a Mass AirFlow Sensor, otherwise known as a MAF, all that swirling air will be turbulent once again after passing through the sensor. Most MAFs have screens protecting the fragile wires (Hot Wire MAF) inside. If you have a Vane style MAF, then your airflow is even worse. No help from the Tornado before the MAF.
Stock intakes these days have a whole lot of ridges and baffles built into them, some are for strength so the intake piping doesn't collapse under vacuum, some are there to help quiet the roaring sound of the intake. If you place the Tornado after the MAF, but still within a stock intake, you are unlikely to see any improvement as the ridges and pockets will cause turbulence.
A modern vehicle with Sequential Fuel Injection will not see much benefit. Usually the fuel injectors are pointed towards the intake valve(s) meaning that fuel is squirted on top of the valve seat. This is where the swirling is the most important; however this is well into the intake manifold where a Tornado cannot be installed.
Fuel injectors on a modern day vehicle are designed to atomize the fuel as efficiently as possible. The atomization of fuel is in the design of the intake manifold, the fuel injectors, valves, and head.
The vehicles that it may have a positive effect on would be the older carbureted cars with an air filter that sits directly atop the carb. The swirling may help atomization a minute amount as the air passes through the carburetor's venturis. However, the benefits in that case are still minimal and not worth the lighter wallet.
Tornado Fuel Saver's infomercial mentions commercial vehicles while showing large 18-wheel big rigs. The mention of using one of these on a Diesel engine is laughable. Diesel engines compress the incoming air before fuel is added to it, once again the gains are minimal, assuming there are any gains using this product in a Diesel engine.
Some vehicles these days, especially European cars, are equipped with turbochargers (Kompressors for you Mercedes folk). A turbocharger unit forces more air (measured in Cubic Feet) and pressure to the engine. That extra pressure, commonly called "boost" helps atomize any fuel that has collected at the valves. (Fuel injectors running at a low 50% duty cycle are still spraying on a closed valve about half of the time). The "extra" air forced into the engine allows for more fuel to be burned during the combustion process. This creates an engine with a higher volumetric efficiency, meaning more power/liter for that particular engine. If you have a turbocharger, you don't need a Tornado, because you already have something much better.
The mileage gains that people see are likely to be from driving habits. This claim is backed up with anecdotal evidence, someone explains that their first tank of gas with the Tornado went a long way, but after a while it dropped back down. How can this happen? Its the right foot.
When gas prices jump, everyone is easy on the gas. Mileage is on your mind every time you pull away from a stoplight, the same happens when you install the Tornado. The first few days you are easy on the gas, improving your mileage, after a week or so you get back to your normal driving habits and your old gas mileage.
The bottom line is that if such a simple device really worked, it would come pre-installed on all vehicles from the manufacturer. If you insist on spending this money on your vehicle, you would be much better off getting new tires or perhaps buying a bicycle to use instead of your car.
As the review from Amazon states, swirling air fuel mixtures is nothing new. I just thought I'd add this tidbit of information:
During the gas crisis of the 70's with increasingly stringent EPA emission standards coming out, Honda motors was developing a technology called Compound Vortex Controlled Combustion, or CVCC [yes, this is where the name for the beloved Civic comes from]. A more appropriate name for the technology they were developing would be 'Stratified Intake Charge, Compound Vortex Controlled Combustion.' The idea was to create a cylinder head with a pre-combustion chamber right next to the spark plug electrode and a regular combustion chamber. The smaller pre-combustion chamber was filled with a richer air fuel mixture [actually, closer to a regular AFR found in most cars] than the regular combustion chamber, which was filled with a larger but leaner mixture during cylinder intake [hence the 'stratified intake charge']. The small rich charge was easy to ignite, and the flame could then propagate across and ignite the leaner charge. This allowed for overall leaner fuel mixtures to be used, hense better gas mileage and lower emissions. Honda tried to introduce a compound vortex into the mix, but found it difficult to control, and abandoned attempts, especially since the stratified charge worked so well.
The idea of managing the turbulence of the intake air flow first appeared to me when I was shopping around for Motorcyles (great gas mileage...) in the early 80s. Most companies offered a standard butterfly valve to manage the air/fuel mixture enterig the carborator, however the competition offered a Constant Velocity alternative featuring a clam shell design of two plates converging in the shape of an eye. Imagine what water would look like being poured over a butterfly value. It would be all over the place. Now imagine it being poured into your cupped hands, and then seperate them in the middle. Smooth huh? Why would I want to "swirl" my airflow if it was going to be directed at a butterfly valve, which would mess it up again? The Tornado device would have to be mounted AFTER the butterfly valve which would require cutting most intake plenums in half! Gotta be a gimick. :|
Well, if you want proof it's not a gimmick go to basically any forced induction section of any serious forum (h-t por ejemplo) and ask if it's a good idea. I may say whatev popular mechnics tested may be crap, because FI people spend hundreds on these kits. But they do indeed cool the charge, allow for leaner burn conditions, more ignition advance, and suppress knock. So bleh.