wireless200

Just found out that nearly every station in NC has 10% or more ethanol.

I have one station not too far from my house. It offers one pump w/o ethanol gas. Just got a new C350 and it says use 91 or greater octane. The station offers only non-ethanol BP silver with 89 octane. Which one to go with? Put in the silver this morning. I figure it's better than 93 Octane with 10% ethanol.

You can check your state - at least five or ten states don't require any labeling. NC's labeling law expired in 2009. They passed a new law to require it but it's dragging slowly because of various outside-their-control factors.

http://pure-gas.org/

http://pure-gas.org/extensions/map.html

I am Jeff

You have nothing to worry about. MB engines are designed to be able to run on 10% ethanol. All gas stations in NY and NJ have at that 10% ethanol in the gas. It does not lower your octane rating.

Ethanol will reduce your mpg rating as ethanol has less energy content vs. gasoline.

RLE

That's correct. Expect a 10% loss in gas mileage using E-10.

global33

Ditto nothing to worry about. Ethanol actually has a higher octane rating but lower energy density, but it will not hurt the engine at 10%. My C300 is even allowed to run on E85 but I'll never put that in my tank.

Glyn M Ruck

You should use the higher octane fuel. The car is designed & adequately mapped to run on it. Modern materials & lubricants will ensure no wear issues. While the ECU has a very conservative map that would allow running the lower octane fuel (can be altered with Star) it would mean that the engine was frequently running with retarded timing.

The energy value of the alcohol portion of the blend is lower than the petroleum fraction which has a slightly adverse effect on fuel consumption. The counter to this is that running retarded every time the knock sensor detects the onset of knock on the lower octane fuel will also be detrimental to consumption. The slight differences would require some very sophisticated dynamometer testing to quantify.

haykf1

My car was running really bad with Synoco, was down on power. Now I swithced to Shell and what a difference, like adding more HP completely different. Both have 10% ethanlol, NVA area does not have gas stations with no ethanol.

Scat01

I have used Sunoco Ultra 94 since purchasing my car (it is only 4 cents more than Premium 91 at my corner station) and it runs perfect (faster than a 335i with the Sprint Booster on Red - just kidding). Probably no advantage running 94 over 91 octane, but mentally it satisfies something within me...

Your sig says "M3 Couple"...do you have more than one or is it a "Coupe" ? ha.

kostas86

I just use Shell VPower all the time

LILBENZ230

Actually, I found a station close to my house selling 0% ethanol gasoline at 90 octane. I'm gonna try it. I've ran 87 in my 05 C230 numerous times with no noticeable loss in performance or economy.