My son and I did a little experiment to try to get better milege on his 2011 Honda Civic Hybrid.
First we ordered a "Fuel Genie" for $103.00 from the internet. It was a plastic bladed device that fit into his air intake, install was a snap, and the instructions said it would make a noticable difference within 2 tanks of gas.
Then we got a Platinum Gas Saver ($248 for two, free shipping) including tubing and a plastic reservoir containing a "special" liquid. The National Fuelsaver Corporation claims the device is guaranteed to increase fuel mileage by up to 40 percent. It was a bit harder to install than the Genie, but we got it working.
We added a pint bottle of Bio-Performance Gas Additive to the fuel tank, it says on the label 5% better mileage, but the company that sells it here in the USA (it's Made In China) claims 20% or more!
We changed his oil to fuel saving synthetic, and installed 4 new tires that touted low rolling resistence, added 4 new spark plugs plugs different from a Standard plug because they go thru a freezing process called cryogenics that give a 25% better efficiency,
as well as a brand new K&N air filter that is advertised to give a 2.5 mpg improvement.
And finally we thru in a few ounces of Eviro-Mat Plus...35% better mileage and better performance too.
We picked a closed road (part got washed out in the last rain storm we had), filled up the Honda to the top with premium Shell gas, and added all the above gizmo's and additives to the tank.
Then we locked the gas cap, zeroed out the odometer, and the driver (who is a cop friend of mine) and I as a passenger started to drive the 2 mile stretch of closed road.
Right at the 2nd mile marker, we had to stop. The smell of Gasoline was strong, and we were afraid we had sprung a leak.
As we walked around the car...we saw that the overflow tube from the gas filler pipe had gasoline coming out of it....
We had done better than we thought we would...we had saved so much fuel during the test drive that the gas tank had overflowed.
Just pointing out that a major Consumer Magazine found to no one's suprise that even $400.00 worth of "gas saving devices" won't help any more than just driving slower!
The above are all real things you can buy that claim better mileage. The names on some have been altered because I didn't want to advertise them!
And these plus more usual gas saver scams are making the news right now and being pitched like crazy. And a sucker is born every minute!
According to European and US fuel mileage studies that sweet spot speed is 56 mph!
Isn't modern science great!