Thing is, results will vary depending on the car and driver. Every now and then, oil companies will sponsor some fuel efficiency challenge comparing 2 of their products (i.e. FuelSave vs V-Power). But the difference are very small that you can't really pinpoint it to the fuel or if it's just a result of slightly different driving conditions. Even in tests where identical cars take identical routes in convoy of each other, the driver factor makes a big difference. If you use the same driver, the traffic condition could be different from one run to the other.

If you do the tests in a completely controlled environment, it won't be relevant to real world usage. C! magazine tries to do a lot of these controlled tests but even then, their results are still sometimes different from what real world owners get.

Bottomline, and this is something oil companies don't want you to know, is that fuels are much more identical than what the buying public thinks. Pero makukulit mga buyer eh.