In particular, I’m thinking of Redex, but I don’t know if it’s sold under that name in the U.S., and that there are comparable products. The label claims that it helps increase fuel economy, cleans injectors, helps restore performance and reduces emissions.
I know what you’re thinking - just Google it. I did, and found a minefield of anecdote and contradiction. Some claim it does work, some say the effect is negligible, some claim a placebo effect, some even claim it can harm a car’s engine.
Dopers, please sweep away the cloud of ignorance and confusion with the fresh breeze of knowledge. Is this stuff worth the money?
Most auto manufacturers recommend against adding anything to the fuel.
That being said, I’ve had some cars that tend to build deposits in the fuel injectors over time (probably because I do mostly short trips). I use MMO (Marvel Mystery Oil). It smooths the idle out and is very cost effective. But it will only do something on an engine that has deposits. There is no additive I know of that will improve anything on an engine that is clean.
I added a “horsepower booster” product to the gas of my motorcycle once. There was a noticeable increase to the punch of the throttle. I was quite impressed and very surprised it actually worked!
They’re almost all useless in today’s modern engines.
If you’ve got an old 70’s era cruiser with years of buildup on the valves, and a host of other issues, then sure, burning out some gunk with an additive may help. It also may break up the “glue” that holds the old engine together. (meaning the dirt…holds it together…cuz it’s old)
Newer vehicles just don’t require that crap. At best you’ll get a temporary gain that will confuse the car’s onboard sensors and computer, at worst you’ll ruin an injector or destroy the o2 sensor or gum up the catalytic converter. Most of the time, you’ll get no effect whatsoever beyond what you dream up in your head.
Point is, if it ain’t broke, don’t “fix” it, and if it is broke, “magic fluid” won’t help.
Moth balls will do the same thing. Grain alcohol will too. Anything that is more violently combustible than gas will seem to give you more pep. However it is at the expense of longevity and stability. Plus if your engine isn’t tuned to accept the new a/f ratio provided by the increased combustion needs of the “mystery fuel”, you’ll just run lean or rich and lose any temporary gains real quick.
I guess I can’t say this for sure about over there, but in the US the gas that comes out of the pump already has additive packages that should be all you need for most cars and most driving conditions. If you get some contaminated gas or let the gas get too old in the tank, you can sometimes get some fuel system problems that might be helped by this stuff, but there’s no need to use it preventatively.
Chevron’s Techron additive has had a good reputation for decades. It is one of the few additives of any type endorsed/used by auto manufacturers (as in, sometimes private-labeled under the car maker’s name). It is extremely difficult to get that type of approval.
I work for an auto manufacturer as an engineer (although not in powertrain). Our official position is that you should follow the recommendations in the owners manual. In the United States, this means using gasoline that’s approved, and that happens to coincide with government standards for additives, etc., meaning that there’s no unapproved gasoline available in the United States.
