1xsculler

I was told by a foreign car mechanic (especially Mercedes) I respect that there was no need to burn high octane fuel in my 2007 GL450 even after I sited that its compression ratio was 10.7:1 and the factory recommends it. He said if you were constantly driving on the Autobahn at 80,90,100 mph or otherwise pushing it then yes, you might want to burn high octane but for normal driving in the US there was no need to spend the extra $ on high test gasoline.

He bought a GL450 for his mother and he told her to always burn regular unleaded fuel in it.

Your thoughts.

BlownV8

I've been running.regular unleaded for over 100k miles. Check out some of my threads especially the on on sparkplug change at 200k miles.

alx

It will retard the timing a bit and you will lose power. Unless you hear audible knocking when pushing the engine- you don't "need" higher octane.

However what you do need is the detergent agent found in the higher octane fuel. Otherwise you will get carbon buildup deposits in the heads that will lead to various complications. So, but regular but put a bottle of chevron techron every now and then.

Do not try that on any force aspirated engine though (turbo/ supercharger). You will break things in a hurry especially if you push the engine