We know few things will boost the mpg like:
1)Top tier gasoline. 91 or more octane, Synthetic oil
2)Good driving habits, Good car condition

3)How about some things/additives/chemicals
Anyone has any experience with devices like: Tornadofuel saver and any other.
Chemicals: Enviromax, Enviroplus, Power MPG gas caplets, powerplus mpg,Auto RX,Techron..... so on.
Are they OK(safe for the car and engine in short/long run)?
Do they work as advertised?
Please post.

 

Surely if they gave a calculable benefit, it would be a no-brainer and everyone would use them.

Isn't that the power of advertising?

ABC

 

If, and I say if there is any measurable effect, it would never be offset by the cost of the additives.

 

Item #2 above will outweigh any possible benefit from additives (if you assume they do work). Underinflated tyres can alone can cause a decrease in fuel economy by as much as 10%. Gasoline with modern detergent additives (like Techron) will only improve fuel economy if your fuel system is suffering from deposits.

 

The "tornado" is always something that intrigued me.
Will that metal thing even fit in a BMW air hose?

 

Proper tire inflation (more is better for mileage) will impact your fuel economy the most.

 

Tornadofuel saver :thumbsdown:

99.9% placebo effect. If any of the crap for sale out there that puported to increase fuel savings was cost effective, it would have been adopted by the manufacturers by now. They have significant incentives of all sorts to maximize individual vehicle and fleet fuel efficiency.

 

That is debatable from my understanding. Top Tier is essentially more detergent additives which MAY make your engine cleaner than other major oil company gasolines but no mpg impact unless you spent years filling up at Sam's. Other majors will argue that they have the optimum detergent in their gasoline and that the Top Tier is overkill; just a marketing ploy. I could argue that the extra additives (possibly unnecessary) displaces gasoline and could even marginally reduce your mpg! Something to consider. Fred

 

I kept a spreadsheet for all my fillups and mileage for the first year and a half or so of ownership. I noticed a small increase in economy when I started using Toptier.

I think your argument would be fine if you could rely on regular gas not being unpredictable garbage - but unfortunately, that's exactly what most gasoline is.

 

Trust me, Top Tier is just a marketing ploy. Seriously, do you really think that Aloha Petroleum, Tri-Par, Kwik Trip, et al have higher quality standards than Exxon, Mobil, Hess, BP, Amoco, etc.? And half those brands on the list don't even have refineries or propriety additive systems at terminals, rather they just buy on the spot from any number of gasoline companies. I'm not saying that the Top Tier retailers are worse than those I listed, but certainly not any better. They just made a marketing decision to "advertise" with BMW and the other car companies listed.

In terms of regular gas being unpredictable garbage, what do you mean? How would you know? There are some pretty stringent standards in place from the Refinery to the terminals and at the stations. The only thing that would make gas "garbage" is an individual retailers operating standards (doesn't check for water, contaminents get into tanks, etc.), but in my experience those are few and far between.