Update on my own car Mazda 2; went to the official Mazda dealer to have an oil change and specifically asked for synthetic. Learned that Mazda uses their own "brand" in stead of

Mobil/Shell etc.

New service interval is set at 10.000 km as the sticker attached to the window shows.

Curious to know if the synthetic oil reduces friction in a way that is noticeable regarding fuel consumption.

Anybody saw a difference in that respect or just theoretically?

The answer is NO and NO. Many peoples opinions on google ... more than you will get here... I hope.

However have a read of this

www.consumerenergycenter.org/transportation/consumer_tips/vehicle_energy_losses.htm in your thirst for knowledge ...could be a topic starter ... How to get more Km/L from your Mazda2 or what ever.

Also I've never seen a topic about switching your engine off at traffic lights ... especially the ones with countdown. Some are over 2 minutes long

Enjoy