Hey all! Been a minute since I posted about running E85 in my 2009 MB C300, well now its been a good 21 months and ~15k miles of which I would say was ~98% on E85 so figure I could give some long term observations of using the alternative fuel. Why I switched: - I am a huge proponent of alternative fuels (biodiesel, E85, CNG, etc.). While there are so many differing opinions on the "green" value of E85 I am happy knowing a large % of my fuel is sourced locally. While the carbon cycle of corn->fuel is up for debate it does burn cleaner and personal experience it most definitely reduces soot buildup on my white car ~85%. - Cost. C300 requires premium so even with the loss of mileage ~20-27%, depending on the price spread I am typically slightly ahead by running E85, now if I drove another FFV that only required regular unleaded it would be harder to swallow as that would probably put into loss territory by running E85. The spread between E85 and 91 is enough to keep E85 as a savings for me despite the more frequent fuelings. Pros: - More performance. After switching back and forth between Premium and E85 ~5-6 times there is definitely a noticeable performance difference using E85. Would love to put her on a dyno and see what the difference. - Cleaner. I can't really provide any concrete facts on actual emissions reductions, all I know is the soot buildup on the rear of my white car is WAY less running E85 vs 91. One tank of premium and the tail has a nice layer of soot on it, E85 it will be many tanks of fuel and the regular dust and dirt build up faster than the soot from E85 can build up. Anecdotally when I first switched to E85 after prior owners probably ran Premium for 62k miles the tail would soot up immediately, think there was a bit of a clean out period of the exhaust system as it was extremely heavy for a good 3-4k miles and has since subsided. - Eligible for Alternative Fuel tag in Georgia. Just learned this last night while renewing my tag, E85 vehicles in Georgia are eligible for an Alternative Fuel tag which gives you access to HOV lanes in Atlanta with only 1 person and I believe the HOT lanes for free (don't quote me on that part). It is a ~$225 annual fee ($200 to make up for gas tax loss and $25 special tag fee) to have the tag so doesn't make sense for me, but if I was slugging out the daily commute on the various HOV freeways around here daily I would spring for the fee. Cons: - Stations are few and far between. I am fortunate to have lived the last 21 months with a station within 1 mile to me. Trips to Florida last year were a challenge and required some planning to try to stay on E85 as much as possible. - Fuel Economy. The big Achilles heel of E85 is that you will lose MPG. C300 is rated as 18/25 hwy on premium and 13/19 on E85. My experience has been that the most loss is in steady state cruising on the freeway at ~27% (19 MPG vs 26 MPG), in stop and go city driving the loss narrows to ~20% (13 MPG vs 16 MPG). The hwy spread is a good representation of the loss, the city commute one is not so much as I have really only run one dedicated tank of premium on my city commute so it could possibly well be the same 27% as highway cruising. - Cold starting performance. Drop below 40 and starting starts taking a few extra "cranks" as E85 does not light up as well in cold weather. Now a chicken or egg problem I did encounter this past winter that I can't pin down to either my "new" station not blending down for winter or my worn out spark plugs. ~3 months ago during 25-40 degree days my car would start just fine but then sputter and misfire badly for a good 3-5 seconds before smoothing out, this went on for a few weeks before I got a misfire CEL which was misfires on 5 of 6 cylinders . This was at 77k miles and I was told by dealership back at 65k I needed new plugs based on "time" so I kept skipping it as I believe the MB interval is ~90k. As I was coming up on my required annual required emissions check I decided to spring for new plugs and asked for old plugs back, none were fouled but the electrodes were nearly gone. Dealer checked compression and did a "smooth idle test" and it passed both so they replaced plugs. Had a few 30-40 degree starts with new plugs and misfire was gone. I am pretty certain had I run premium for the winter I could have limped the plugs along another season but hindsight is 20/20 so she has new plugs now. Filling station observations: - E85 is quite popular at the city Atlanta locations, either that or the lack of stations causes jams at the pumps. Quite often I am lining up and waiting for the one E85 pump in a sea of GM and Ford cars. Makes me feel better that the tank gets cycled quite often for a "boutique" fuel. Pumps are typically yellow bagged every 1.5-2 weeks due to being exhausted so at least I know the fuel isn't just sitting there collecting water. - Yes my car is FFV capable from the factory - I have been stopped at the pump ~6-7 times with other FFV drivers trying to stop me from filling up my car with E85. Have had a few express shock that MB made FFV cars after I point out the sticker in the door and the yellow fuel cap. Overall: While I am not saving a boat load of money (I think it is to the tune of $50-75/year @ ~4500-5000 miles year depending on spread price variance) I will continue to use E85 mainly because it is most likely keeping my engine internals and emissions systems cleaner than E10, then there is the side benefit that a large part of each of my fillups was sourced from a farmer somewhere in the Midwest vs. oil sourced from who knows where.