stevenross

Hello everyone.


I have a 14 E350 and recently filled it up with premium as the car calls for premium and it acted very different and aggressive. I am curious as to what everyone is putting in their cars.

I understand a Porsche or an M3 calling for premium. I don't really get it on a 6cyl E350.

Would love to here some feedback.
TIA

Steven.

paking

Congrats on your new car. I always put premium gas in my E, at a minimum 91.

BACnMercedes

Always use premium. It should say the minimum allowed on the refuel door. Never go below that.

chrisvr6

Octane rating goes up accordingly with the compression ratio of the engine at hand.

GregTR

In Europe where they use RON (Research Octane Number) to describe their fuel the minimum required is 95 which is their "Regular Unleaded". This equates to about a 91 in the US where we use AKI (Anti-Knock Index which is the average of RON and MON) to describe fuel's octane rating.

In the US "Regular" fuel is 87 AKI which is about 91 RON and it is seldom sold in Europe nowadays. In Europe you can get 98 RON (93 AKI) and even 100 RON

In the US not everywhere they sell 91 AKI so you have to get 93 which is probably higher RON than the required 95.

So in Europe these cars run on "Regular" while in the US they run on "Premium" simply because in Europe they sell higher octane fuels, at much higher prices mind you!

But worry none, these engines all have anti-knock sensors and electronics and the only thing that will happen if you fill it with lower octane fuel is that they will have higher fuel consumption with lower performance making your savings negligible.

ghstudio

while premium is recommended, if you are in a flat area and don't make pedal to the floor starts, plus (89) octane fuel is likely not going to be a problem. Good news for those in south florida or Kansas...but not so good if you drive in Vermont, etc.

mr e350

In my 2005 e60 BMW I used 89 in it for 6 years and never had a problem or a loss of power. I continued this octane in my 2011 e350 which now has about 20 k on it and again have not had any problems or any loss of power when I needed it.

zibby43

The engine will retard the timing and you will suffer minimal but real performance loss.

If you paid for a luxury car, why not put the proper, better gas in it (which it by the way calls for)?

zibby43

How do you know you didn't lose power?

Did you dyno the car using 89 and 91+ octane?

Or were you judging by the seat of your pants? Just curious.

Couldn't have said it better myself.

stevenross

It's not about a luxury car or better gas. It's about putting a higher octane performance fuel in. 6cyl moderate performance engine.

I'm not downgrading our engine - I just didn't think it warranted 91 octane.

As mentioned earlier its not an M3 or a 911.

zibby43

I'm not trying to sound like a dick when I say this but why do you think MB advises 91 octane if it didn't detrimentally affect the engine (however marginal the performance decrease may be) to put a lower-octane type of fuel in the tank?

Don't equate an engine's power output to it's level of sophistication. That would be a mistake.

It's not a Honda Accord or Toyota Camry either. I'm not telling you that you should put race gas in it or anything like that.

stevenross

Agreed. Its funny you say that. My family used to be in the racing gas business and we used to mix a few gallons into our old S Class. It was awesome to watch the engine react.

Thank you for the input everyone.

zibby43

I wish they were still in the business! I could use some come the Spring!

In any event, enjoy your new E350 in good health. It's a beautiful car and it runs even more beautifully when you feed it 91+ gas.

El Cid

All gasoline sold at gas stations in US is unleaded and has been for decades.
The car REQUIRES premium to operate. If you use less than Premium, the MPG will be lower and the performance will be lower.
It can operate on regular, but just not as well. Sort of like using cheapest oil you can find and then only changing it every 20,000 miles or so.
If the car could operate on regular, MB would say that because regular is a big marketing plus.
All 6 cylinder engines are not created equal.
If you can afford an MB, you can afford the appropriate fuel for it.

Cao Black

Octane is basically gasoline's resistence to preignition or "knock" (detonation of the gaso/air mix by compression rather than spark). Higher compression engines (like your MB) are subject to creating "knock" if lower octane gasolines are used. They pre-ignite. Or they were, at least, back in the day.

Many sources will argue that paying the extra cost of Premium grade is a waste of money since laboratory test demonstrate that Regular and Premium have about the very same energy content.

On the other hand, if you do use Regular fuel, and, if the car's knock sensors do their job and tell the engine computers to change the engine timing to overcome the knocking you may not even be aware of it. You will likely lose performance and probably fuel economy. It could even do more harm that good over the long haul.

I would go with the manufacturer's recommendations to be on the safe side.

FastE

Depends whee you are located. Here, all but premium fuel has Ethanol mixed in by law. So, I only buy premium. No ethanol for me thanks!

stevenross

Thank you Zibby..

Munich77

I am jealous - even here they have ethanol in premium fuel. I only put 93 octane into the car. To me it seems silly do put any fuel other than the recommended in there - especially at the price tag. If you an afford an $60K car then you can afford to buy the premium fuel. While the engine software adjusts to lower octane rating, why risk the potential of any engine damage (highly unlikely).

Cao Black

That's really a good point. Most gasoline sold in the US now contains some ethanol, whether it is labeled as such at the pump or not. Ethanol doesn't have the energy value of gasoline, so that might be another reason to stick with using Premium grade per the manufacturer's recommendations.

And then there is always the "mid-grade" option. Does anyone use it?

El Cid

In S.C., all gas, including premium, has ethanol and my understanding is that this is a federal requirement. There are a few independent stations that sell premium which does not have ethanol, but it costs about 50-75 cents per gal. more than premium at other stations.
BTW, gas in SC is 87, 89 or 93 octane.

FastE

Well, I can only get 91 where I am. I doubt there is any ethanol in your 93 octane gas - just because it brings down the octane too much.

I used to use silver in my Acura MDX - but then I got some knocking. Most people say it doesn't need it, but I am convinced it relates to driving style. If you drive "sporty" you need the higher octane.

I had a Murano when they first came out. Had knocking after a few months on regular - until I switched to premium. A few tanks later it stopped. My wife now drives a newer Murano - same generation. She has no problem with regular gas. She doesn't drive as "sporty" as I do.

Premium also includes more cleaning products which could be related. That is another reason to buy it - or additives.

stevenross

Premium it is. Thank you ladies and gents

Arrie

Someone with facts to present can shed little more light to this but I think one of the reasons ethanol is used mixed in the gasoline is to boost the octane rating up. Ethanol has octane rating over 110 and it can actually increase gasoline octane rating and is much cheaper chemical for it than the other "non-lead" components that are used.

El Cid

1. All gasoline sold in U.S. has ethanol, even premium except those specifically sold as not having ethanol. Non-ethanol premium is going to cost considerably more than premium and most "branded" stations will not sell non-ethanol fuels.
2. Ethanol does not raise the octane. The sole purpose of ethanol was to add something to fuel to lower imports of petroleum. Sort of like watering down beer or liquor.
Now its purpose is to provide income for corn agribusiness, refineries, distributors, transporters, and politicians they support.
If ethanol was so good, the US would cancel the embargo on Cuba and import sugar to make higher grade ethanol.

instantfob

I rather have them put sugar tasty regular Coke.

http://www.latimes.com/food/dailydis...#axzz2pdYRIaCW