porsche911targa

Hi,

I'm posting this here because it has to do with gasoline and BMW cars in general and not just E90 series.

I have a slight issue with my 2008 E93 where I detect a little shaking in the morning until it warms up and then it's nothing but smooth engine until the next morning.

The dealer went as far as testing the gasoline in the tank and they detrmined that I use 15% ethanol gas and they stated that their cars are warranted only up to 10% ethanol gas.

Now, I use a top-tier gas (Shell) and I only use premium and I had no idea about this 10% vs. 15%. Digging in a little deeper, I found out that the EPA mandates that cars MY2007 and newer must accept 15% ethanol.

Does anybody know if this also applies to BMW or if they were given an exemption? What would you do at this point? For the record, I'm going to start looking for 10% ethanol, but what am I supposed to do when the government mandates that all gas stations sell 15% ethanol gas?

What top-tier gas do you use in Massachusetts with 10% ethanol?

Thanks for listening.

ADD

There's not much you can do about it.

Here in NY, gas stations have stickers that state, "contains 10% ethanol", but I've had my dealership say they've pulled more than that % out of my tank as well. The problem, as I understand it, is that the ethanol is blended in/mixed/whatever at the point of delivery, so you would need to rely on the competence of the delivery chain to measure it properly. Yeah, okay.

I have found one place locally here that sells NO ethanol gas, and let me tell you, the line is around the corner at this place. According to them, gasoline is stored at the airport, but because of the corrosive properties of ethanol, they can't blend the ethanol in until it hits the delivery truck. (Makes you wonder, huh) So all the gas is stored without ethanol. They just order it without the ethanol, and pay more for it. It's made a world of difference in my car's performance. See if you can find a place around you. You'll know which ones... they are usually very passionate about no ethanol, and they advertise as such.

AUSaxon00

Ethanol corrosive? In most situations, that is patently untrue. There are no chemical compatibility issues with ethanol and carbon steel, any stainless steel, or any metal that would be used for a storage tank or delivery vechicle. Ethanol does have poor chemical compatibility with a variety of rubber and some polymer materials, especially polyurethane.

You will definitely see a performance benefit by eliminating ethanol, as it has about 50% less combustion energy than gasoline.

E60_550i

You can go on www.pure-gas.org and they have lists for every state that tells you where there are gas stations that sell ethanol-free gas.

pukka

In GA gas stations are allowed to mix up to 15%. I think the mixture varies throughout the year because during the colder months I notice slight hesitation during startup but in the warmer months the car starts up fine.

AUSaxon00

The ethanol content is "supposed" to be constant throughout the year. Winter-blend fuels have a higher vapor pressure (ability of the gasoline to vaporize which makes it easier to ignite), in part, to combat the cold weather hard starting issue. Typically butane is added at higher levels to achieve this effect. Vapor pressure increases as temperature increases, so whenever it is warmer it will be easier to combust the fuel. Summer-blend fuels have a lower vapor pressure to avoid excessive vaporization which leads to air pollution. The summer-fuel season starts around May-June timeframe (now!) and the winter-fuel season starts in September. This is all mandated by the US EPA. Also, in the US, there are many different fuel blends that vary by region.

NoQuarter

ethanol isn't always a performance killer and it isn't near 50% less energy (more like 30%) but it is cheaper so the less miles/gallon isn't as bad as it may seem.

Many guys seek out E85 for the performance benefits of it (85% ethanol) which include a slower burn, higher octane than 93 gas, cooler combustion. These benefits are notable in power adder applications like our 335/535 turbo charged, high compression engines as long as you have a tune that can take advantage of it.

OP - Stick with top tier stations like Shell, Marathon, Phillips 66 for a few tanks and see if you notice a difference. Also, search on topics for intake valve cleaning - our cars can get pretty bad due to the direct injection and bad idle is a common issue. Whatever they are telling you about ethanol%, etc is just detracting from whatever the real issue is.

AUSaxon00

Unless your engine is specifically tuned to take advantage of ethanol, it is definitely a performance killer. If you run E85 blend you can expect about 25% lower fuel efficiency (miles/gallon), and this has been verified by the EPA. The main reason ethanol is added to consumer gasoline is because it is very cheap dilutant subsidized by the US government. Initially it was thought that ethanol could replace some fraction of gasoline to produce a "cleaner burning" fuel and reduced petroleum dependence. In reality, the combustion of the ethanol produces about 20% more CO2 than that for gasoline. So, if you believe in AGW (that's a big IF), then ethanol is actually worse than gasoline.

Also I meant to say that gasoline is roughly 50% more energy dense than ethanol. Based on the LHV (Lower heat of combustion):

*LHV (ethanol) = 76,330 BTU/gal
*LHV (gasoline) = 116,090 BTU/gal

% Difference = (116,090-76,330)/76,330 = 52.1%

This is not a trivial amount and results in the very real fuel efficiency differences.


* Reference: American Petroleum Institute (API), Alcohols and Ethers, Publication No. 4261, 3rd ed.

e60oholic

Im running a 40% mix of e85 and 60% 93. My 335i loves it

wtlb

I just checked www.pure-gas.org and it seems as though there are only 5 gas stations in the state of California that have non-ethanol infused gas. Wow!! Very interesting topic. Thanks for the input.