So I see this infomercial on tv the other day for a device called the Tornado Fuelsaver. It’s a fan type device that is inserted either on the intake of a normally aspirated carburator or in the air intake hose of an EFI car. They claim an increase of sometimes as much as 15% in gas mileage. They also claim some vague increase in horsepower without giving any numbers, but have testimonials about how the care accerates more smoothly and easily. Without numbers to back it up, I routinely attribute testimonials to the placebo effect.
I see the claims being made, and I think, hey, an extra 10% gas mileage and possibly some small increase in hp for 10 minutes work and about $80 doesn’t sound bad. But I don’t buy anything of consequence unless I research it first. Consumer reports online had nothing, as did Consumers Digest. The only other listings I could find were Q’s on other message boards. I of course, do not trust other message boards.
Do these things work, and if so, how well? Are they worth the $70-80 they cost? I have serious doubts myself, but I’m not a car guy, so I thought I’d put it out here.
Doubly good for you - you recognized when you should doubt, and you asked at the right place.
In general, these sorts of doodads and devices (including the “Econo-mizer”, the “Platinum gas saver”, and anything whatsoever involving magnets on your fuel lines) do not work in the least.
I say “in general” because there are exceptions to making absolute statements. An old professor of mine once analyzed a “gas saving device” which did, in fact, save gas - it consisted of a “fuel line swirler”, which was supposed to create “combustive turbulence” in the lines (bullshit), and a set of special carburettor jets to go with it. The truth was, the jets were simply made to lean out the carb, and that was where the gas savings came from. Yawn.
I always am amazed at how much trouble and at what lengths people will go to to increase fuel economy and/or increase power, when they often steadfastly refuse to do the things which are guaranteed to help them out. Such as ensuring that the car is tuned up properly, or the tires are properly inflated, or that the air filter is changed regularly, or putting on a less restrictive exhaust…
When things really work, there is evidence from reputable sources (e.g., a legitimate independent testing lab) to attest to that. When they don’t really work, you get testimonials–some of which may be genuine, none of which reflect any accepted standards of testing.
If significant fuel mileage gains were available from something relatively cheap, the auto manufacturers would use it. They don’t use any of these “miracle” devices. That says a lot.
The other thing to remember is that, if there were a simple, inexpensive device (if someone’s charging you $70 for it, it can probably be manufactured for about $10) that would improve gas mileage and/or horsepower, don’t you think the auto manufacturers would do it themselves, rather than letting some aftermarket company do it? They’ve invested billions of dollars in research to improve gas mileage (under varying degrees of pressure from the gummint); if a piece of finned stainless steel could do the magic, they’d go for it!
I once heard an oil company exec make essentially that point about STP Oil Treatment. He said that if there were an easy way to make their product better, in a highly competitive market, they’d jump on it in a heartbeat.
So does putting on a “less restrictive exhaust” system really increase gas mileage and power? If that was the case why wouldn’t manufacturers do that on their own? How is it suppose to work?
I can’t believe this! Especially from Anthracite! I BOUGHT the same Tornado and it’s worked great for me. Back in 1999 I commuted to and from UMBC everyday. I was filling up every 330 miles (16 gallon tank). That’s travelling on I-70 and I-695 everyday. Now I go to a technical school in Baltimore that is an additional 10 miles away. This trip is I-70, I-695, and I-95. Since I’ve gotten it, I get over 370 miles out of a tank. BTW, I drive a 1993 Pontiac Grand Prix, 6cylinder 3.1L. YMMV obviously but it’s practically paid for itself since I got it 2 summers ago.
Good question of the day explaining how back pressure improves performance. Anthracite, I respect you a lot and I’m not trying to throw this in your face, but howstuffworks really know their stuff.
What Muldoon III is providing is precisely the kind of testimonial that Gary T is warning about. This is not a controlled test. Yes, he’s added the Tornado to his car, and he’s getting better gas mileage. But he’s no longer driving the same route he used to. There could be more or less stop-and-go, more hills, different cruising speeds for different lengths of time, etc., etc. He might be driving at different times of day, when outside temperatures are different, so he’s using the A/C less often. The list of possible causes for the changed gas mileage is very long.
There’s also the possibility of the self-fulfilling prophecy. Because Muldoon III spent good money on this device, he’s anxious to get some results from it. Without even being aware of it, he may be driving just a bit more gently, accelerating more gradually, laying off the accelerator when he sees the light changing a block ahead.
That’s why you just can’t rely on the testimony of a “satisfied user.” You need a controlled test.
I do all of those things religiously with my old car, and plan to do them with my new car. I’m not enough of a car guy to tinker with the exhaust, so I’ll just leave that alone.
For every other question I usually have about cars, I’ve been able to find the answer at Consumer Reports (their basic advice: follow the owner’s manual). Their advice closely matches Gary T’s and Early Out regarding other infomercial type products (slick 50, oil treatments, etc.) which is, if you follow the regular maintenance schedule and maintain your car properly, these products make no difference.
Muldoon: Thanks for the link to How Stuff Works. I’ll likely be spending some time there.
Both your links say back pressure is bad, which is correct. As Anthracite said a A free flowing exhaust will improve power and mileage. Improving the exhaust flow does not necessaily have to be loud but to make smooth bends in an exhaust pipe can be expensive.
Every post about the Tornado air on the car board I frequent says it is crap.
The 99 Nissan Maxima California emissions model does have a ‘swirl valve’ that is located just before the intake valves. They activate at low RPM to help mix the air and fuel better for more complete combustion. At higher RPMs when more airflow is necesary it deactivates. However this is stricly for emissions, it has no effect on fuel economy and this model is known for having less power than other models. I belive Hondas VTEC system is designed to do something similer, by only opening one valve (per cylinder) at low RPMs turbulance is added to the air and fuel for more complete combustion and cleaner emissions. Both these systems allow a full unrestricted flow of air at higher RPMs, where the Tornado would just be a restriction in the intake path.
In most cases power can be increased by enhancing exhaust flow, in some cases it might also increase gas mileage. The idea is to more efficiently scavenge exhaust gases out of the cylinders so that a bit more fresh air and fuel can get in.
The reason it can help on many cars has to do with compromises. Auto design engineers have many things to consider–power, economy, comfort, cost, controllability, sales appeal, etc., etc. Often a feature which betters one aspect will worsen antoher. Maximum exhaust flow tends to improve power, but at the cost of more noise and higher price. They decide what is most appropriate for the typical driver in the car as a whole, rather than trying to maximize every aspect, which is impossible anyway.
Not every car will see a significant power increase with freer flowing exhaust, it depends on which particular comprimises its design entails. To the extent that better exhaust flow improves efficiency, it can help with gas mileage, but having more power generally means using more gas, which may offset any mileage gains. Depends on how it’s designed and how it’s driven.
Could there be any more mis-information in so few posts?
Ummm…they do, when the need arises. The downside is 1) cost and 2) more difficult plumbing for dual/multiple exhausts under the car, and large more free-flowing mufflers and catalysts. These all cost money, but can increase performance.
No, you damn well don’t understand. Putting a less restrictive exhaust on a car is not inherrently illegal, provided you do not remove completely the catalyst, and/or exceed your local emissions and noise ordinances, or barring some crazy-assed State’s vehicle laws. You cannot possibly make a blanket statement like you have. And while it is true that a more open exhaust can be louder in volume, it can also have its noise shifted to a lower frequency as well, which can make it less offensive to the ears, all other things being equal.
There is a difference between a well-intentioned personal testimonial and a scientific study of effectiveness with well-bounded control parameters.
For those reasons, it would make no difference if I “tried it” or not. As a scientist, I know that to judge the effectiveness, I would need to have some very controlled conditions and static boundaries to properly test such a device - unless said device produced an huge differential savings which overhwhelmed the error bands of the instruments and the experiment itself. By your own admission you are not driving the same route anymore. That alone throws your entire testimonial’s control out.
I said “less restrictive exhaust”. I didn’t say open pipes. I didn’t say “no exhaust”. I said “less restrictive”. I am well aware of pressure-wave supercharging and exhaust scavenging, but that’s not what we are talking about here.
But the links you linked to say I am correct anyways, and only discuss reducing exhaust backpressure, and don’t even go into pressure-wave supercharging or gas scavenging. What links did you intend to link to?
Both your links say back pressure is bad, which is correct. As Anthracite said a A free flowing exhaust will improve power and mileage. Improving the exhaust flow does not necessaily have to be loud but to make smooth bends in an exhaust pipe can be expensive.