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lear31a driver · 02-23-2006, 10:03 AM

I'll be one of those bold enough to admit that I use Regular fuel in both my E and S 500's. I use the fuel not because I am "cheap", I use it because I know what my engine really needs based on my driving habits. Let me tell you folks a bit of information that isn't commonly known. I'll back my information up with my background, I routinely work (rebuild from ground up) high performance engines, mostly those in aircraft. My company has been doing this for 10 years and subcontracts for primarily the racing sector.
The non supercharged engines in M/B, at average operating RPM's don't develop the combustion chamber pressures that require higher octane fuel. IF you are the type to apply full power at almost every start, or run your engine in the 5000+ rpm range for continued periods .. then you are the types that need the 91Octane or higher. Keep in mind that you'll wear down or break other internal assemblies long before you pit your pistons from engine knock.
Supercharged engines do develop higher internal pressures so the above does not apply. If your M/B wears the AMG badge .. buy the higher octane fuel along with the $400.00 tres, $3500.00 insurance, ect.
Bottom line is this, I have seen what prolonged engine "pinging" does ... and know the cause. I doubt few of you run your cars at 100% power, run down the freeway in 3rd gear or try to defeat the traction control at every stop. For those of you that do .. pay the extra for premium, but also start a side fund for repairs for wear parts (crankshaft bearings, camshaft bearings, transmission bearings, ect) that are assured to fail.
Fuel companies will continue to sell higher octane fuel, because it sells. Not their fault, the public simply needs to be fairly educated. Mercedes stpulates premium fuel so that their STATED horsepower/torque ratings are valid and can be sustained without severe engine damage. I have yet to use the 300+ HP in either of my M/B's, and usually cruise along using about 20%of whats avalable.
I do use 110 octane in my turbocharged Beech, no skimping there. The engine puts out its rated horsepower (310) and is required to do so every time I roll down the runway.

02-23-2006, 10:03 AM	#17 (permalink)
lear31a driver BenzWorld Senior Member Date registered: Jan 2006 Vehicle: 07 E63 AMG Black on Black Location: California Posts: 446	RE: Premium vs Regular Gas I'll be one of those bold enough to admit that I use Regular fuel in both my E and S 500's. I use the fuel not because I am "cheap", I use it because I know what my engine really needs based on my driving habits. Let me tell you folks a bit of information that isn't commonly known. I'll back my information up with my background, I routinely work (rebuild from ground up) high performance engines, mostly those in aircraft. My company has been doing this for 10 years and subcontracts for primarily the racing sector. The non supercharged engines in M/B, at average operating RPM's don't develop the combustion chamber pressures that require higher octane fuel. IF you are the type to apply full power at almost every start, or run your engine in the 5000+ rpm range for continued periods .. then you are the types that need the 91Octane or higher. Keep in mind that you'll wear down or break other internal assemblies long before you pit your pistons from engine knock. Supercharged engines do develop higher internal pressures so the above does not apply. If your M/B wears the AMG badge .. buy the higher octane fuel along with the $400.00 tres, $3500.00 insurance, ect. Bottom line is this, I have seen what prolonged engine "pinging" does ... and know the cause. I doubt few of you run your cars at 100% power, run down the freeway in 3rd gear or try to defeat the traction control at every stop. For those of you that do .. pay the extra for premium, but also start a side fund for repairs for wear parts (crankshaft bearings, camshaft bearings, transmission bearings, ect) that are assured to fail. Fuel companies will continue to sell higher octane fuel, because it sells. Not their fault, the public simply needs to be fairly educated. Mercedes stpulates premium fuel so that their STATED horsepower/torque ratings are valid and can be sustained without severe engine damage. I have yet to use the 300+ HP in either of my M/B's, and usually cruise along using about 20%of whats avalable. I do use 110 octane in my turbocharged Beech, no skimping there. The engine puts out its rated horsepower (310) and is required to do so every time I roll down the runway.