RobertG

if you use low octane fuel instead of what the manufacturer call for,it will lead to serious engine problems down the road.
Preignition is going to damage the pistons, engine computer will retard the timing but not enough.
Low octane fuel burns faster then high octane, when the cylinder is coming up on it's power stroke, fuel is introduced and it ignites too fast causing the piston to rattle in it's bore(piston is still traveling upwards while the combustion is trying to push it down) as well as damaging the piston ring lands.
low octane fuel gives you less bang for your dollar as well ,by causing you to press the throttle little more to achieve the same performance using high octane fuel.

RobertG

no the were not the same engines.

ImInPA

I respect your opinion, but, you make the presumption that using a lower octane fuel is fatally bad to an engine in the same way as cigarettes are bad to a human. This is factually not the case. I agree that some engines MUST have the higher octane fuel. Most modern engines can accommodate a fairly wide range of octane ratings. So I respectfully disagree that using a lower octane rated fuel is always going to be bad. I think you just have to try it in your own vehicle and do what you feel is best. Personally, I always follow the manufacturer's recommendations.

hanjaya1

Hello nice people in this forum,

Why we need to discuss if W212 needs premium or not?
The premium gasoline with min of 91 octane is a requirment and not a recommnedation. Otherwise it will damage the catalytic converter. This is mentioned in your Operator's manual at several different places, stressed with "!" symbol (=Highlight Hazards that mayt result in damage to your vehicle) -TWICE! Please see post#7 attachment in this thread. I copy-paste from the actual Operator's manual for E-Class.

Have you guys read the operator's manual page 221 and 363 yet?

But... again, at the end is your car...
My two cents, Follow the operator's manual exactly.

Cheers!

RNBRAD

A good read taken from USATODAY article. As for catalytic converter damage, that's not octane related but specific to leaded versus unleaded gasoline.

The main advantage of premium-grade gas is that it allows automakers to advertise a few more horsepower by designing and tuning engines to take advantage of premium's anti-knock properties. But auto engineers generally agree that if you use regular in a premium engine, the power loss is so slight, most drivers can't tell.

"I go back and forth, and I'm hard-pressed to notice" whether there's regular or premium in the tank, says Jeff Jetter, principal chemist at Honda Research and Development Americas. He drives an Acura designed for premium.

Import brands, especially, use premium fuel to distinguish their upmarket models. Most Toyotas, for instance, are designed to run on regular or midgrade, while the automaker's Lexus luxury brand prefers premium. Same with Honda and its Acura luxury line.

"Generally, the more expensive the vehicle, the higher the expectation for performance and the more the customer is willing to pay for fuel," says Pete Haidos, head of product planning for Nissan in the USA.

Actually, the price debate is nearly worthless. At 20 cents more for premium, pumping 20 gallons of it instead of regular would cost $4 more. Annually, that's a difference of $171 for a vehicle that averages 14 miles per gallon — as some big sport-utility vehicles do — and is driven 12,000 miles a year.

Gasoline retailers and refiners like high-test because it's more profitable than regular-grade gas is. The retailer paid about 8 cents more for the premium you pay 20 cents more for — though that margin can swing wildly. Refiners make a few cents a gallon more on premium than on regular when they sell to wholesale distributors.

As long as it's clean

Profit is meaningless to the modern engine, which, regardless of what's specified in the owner's manual, hardly cares what you use — as long as it's clean.

Today's engines use highly evolved versions of a device called a knock sensor to adjust settings automatically for low-octane gas. And more engine control computers have adequate memory to allow separate sets of instructions for various octanes. The engine control computers keep pushing to maximize performance on whatever grade of fuel is used.

Extreme pressure inside the cylinders causes knock, which is the sound of the pistons literally rattling inside the cylinders. Too much too long can damage the engine. A little now and then won't.

The only modern engines that should really need premium are those with superchargers, which force-feed fuel into the cylinders. "You're driving along and just tramp the gas and the knock sensor cannot sense the knock fast enough in some cases," because the supercharger boosts pressure so fast, says Bob Furey, chemist and fuels specialist at General Motors.

Burning regular when the owner's manual specifies premium won't void the warranty, nor damage the engine, even the most finicky automakers say. "You're giving up perhaps just a little bit of performance that a customer wouldn't really even notice, it's so slight," says Furey.

Automakers say they don't test premium engines on regular to check the difference, but some auto engineers estimate that power declines roughly 5%.

"We can't guarantee the vehicle will perform as specified if other than premium fuel is used," says Mercedes-Benz spokeswoman Michelle Murad. All U.S. Mercedes engines specify premium.

All Porsche engines are designed for premium, too, but it's not available everywhere. "Our cars must be able to drive all over the world, and so we are able to run on regular," says Jakob Neusser, director of powertrain development at Porsche's research and development center in Weissach, Germany. "You don't have to feel that a mechanical problem or anything else will happen" using regular gas, even in the highest-performance, regular-production Porsches.

Premium, in fact, sometimes is worse fuel than regular. It resists knock because it's harder to ignite than lower-octane fuels. As a result, some engines won't start as quickly or run as smoothly on premium, notes Gibbs, the SAE fuel expert.

High-test does have a potential fuel economy benefit. It is slightly denser than lower-octane gas, meaning there's a little more energy in a gallon. But the small difference is hard to measure in real-world use, and that same density can contribute to undesirable buildup of waste products inside the engine.

No data show that engines designed strictly for regular run better or longer on premium.

The Federal Trade Commission, in a consumer notice, emphasizes: "(I)n most cases, using a higher-octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner."

There is "no way of taking advantage of premium in a regular-grade car," says Furey.

"There is no gain. You're wasting money," insists Jim Blenkarn, in charge of powertrains at Nissan in the USA.

"No customer should ever be deluded into thinking there's any value in buying a higher grade of octane than we specify," says Toyota's Paul Williamsen, technical expert and trainer.

But premium retains a mystique.

Even Mayne, the sensible Subaru owner who has switched to regular, says she'll buy premium when her neighborhood station has a special price. "It's my perception that I might get better gas mileage or that it might be better for my engine," she says.

"I would stop driving rather than use a lower grade of gasoline," says Andrew Martschenko of Boston, who drives a 2003 Nissan Maxima. Nissan says premium is "recommended" for that engine — automaker code for regular is OK, but you'll only get the advertised power on premium.

If the price difference between regular and premium grew to $1, Martschenko says, "Then I might consider trading down" to regular.

Guilt plays a part

Some people feel almost guilty, as if they are abusing their cars, when they don't burn premium, says gasoline retailer Jay Ricker, president of Ricker Oil of Anderson, Ind., which operates 28 stations. "They go all the way down to 87 (octane), but maybe every fourth tank they put in the good stuff."

Sam Turner has seen the appeal, too. He's president of Favorite Markets of Dalton, Ga., which operates 139 outlets in three states.

He recalls visiting one of his stations during a price war with a nearby station, which had cut the price of premium to just 4 cents more than regular, instead of the usual 20-cent difference.

"A customer was waiting and asked me if I was going to match the guy across the street. I said, 'Yeah,' and he said, 'Good. For 4 cents, I'm gonna buy super.' "

Contributing: Barbara Hansen

mbuster25

I do think it is necessary and I do run 91/93 in my car depending on what is available.

g2k

if not then can you please tell everyone here on mb world the difference between the 2 since you seem to know so much about the year of trucks im talking about

davatk

Well, I posed this same question a while back in regards to my C Class. After fighting the battle diligently in the forums, I finally gave in to the fact that:

1. The engine is designed as a high compression engine and premium is what it was designed to run on.
2. Over the course of a few years it really doesn't make that much difference in price. Maybe $100-$200 per year.
3. If you really want to save a few dollars you can use 91 octane as opposed to the higher 93 that many of the gas stations have as their premium.
4. Get a Shell Gas Credit Card and you will save 5% which basically makes it the same price as regular.

RobertG

Lincoln used dual overhead cam engines.(DOHC)intech
Ford pickups did not(SOHC)triton

RNBRAD

I say if the cars owners manual recommends premium fuel, then by all means use it. If you think that using anything less than premium will damage your motor, I say you don't know motors very well. You could honestly run 87 in this car from now on and never hurt the motor. PERIOD!! Does anyone remember the days of bad gas where your old cars would knock and ping? Those days are history. That was generally gas that sets for a certain amount of time. An FYI, gasoline looses around 1 to 2 octanes per month. So we are really never sure how long it's been setting and what octane it really is. So there are in actuality, many variation possibilies even with the same rating of gas that was purchased at the pump. The good thing is that our cars are ready for anything we throw at it and you will never hear a ping or a knock. Like the article above stated, the car doesn't care about the octane, just whether it's clean gas or not.

I know our cars are designed to eek out the benefits of premium and there is gains to be seen but that doesn't mean using a lower octane will damage this car in any way shape or fashion. That's just pure ignorant speculation and is honestly proved quite the contrary every day.

golfster

I would prefer to use 93 octane if I could find it, but only see 91 as the premium around here.

Firestopper0383

I have seen so many threads about premium versus regular gas and almost every time the big question arises, "Do I really have to spend that extra money for Premium 91 octane if I don't have to?".

Sorry if I touched a nerve but, that's my opinion and I am entitled to say it.

El Cid

Wasn't this topic discussed extensively about 4-6 months ago?
Regardless, if you use less than M-B states, you WILL have decreases in MPG and Performance. They and others have done too many tests confirming that. Even Japanese manufacturers will recommend premium, but state you can use regular, BUT you will experience loss of performance and MPG with regular.
BTW, it is almost impossible for an individual to really compare MPG using regular vs. premium fuels. Way too many variables, such as weather, temperature, tire inflation, time of day, etc. Add to this almost impossible to drive exactly same speeds over exactly same road surface for same distances.
A more important concern is that E15 (15% ethanol) has been approved by EPA for nation-wide sales. Consumer Reports conducted MPG tests and E15 was 27% lower than gasoline without ethanol.
Living near a major distribution point for gasoline, there are 100-150 railroad tank cars per week loading ethanol into the trucks going to the stations. Can't be sure, but I doubt any leave the terminals without ethanol in them.

LawRens

If they want to run 87 octane in their $50k+ cars to save a few dollars a week, let them; nothing to get mad over. Just laugh or "i told you so" when they post a new thread on the forums a few months or years later when they have problems that will exceed the savings from lower octane gas, like catalytic converter failure, knocking, etc...

But honestly, if you can afford a great luxury car, can't you afford the gas? Just saiyan.

K-A

Exactly.

Also, as has been said, power has nothing to do with Octane requirements. Many other factors do however, such as Compression (bingo for the E350), and F/I, etc. etc.

Just use what is recommended, M-B puts it there for a reason.

There a LOTS of people who won't even buy a car that requires the expensive stuff, so why would M-B put it there? Shouldn't they be more concerned with selling cars to out Lease-generation, and saying "yes, it's okay, use 87"?

It's only a few bucks at the pump, and you'll have a minimal increase in MPG, a minimal decrease in emissions, and a minimal increase in power and engine health (i.e, your Computer won't be retarding timing).

If nothing else, have some respect for the poor sap who'll own your car after you, considering he/she may be an enthusiast who will want to take care of their car to a "T", putting in the recommended fuel, etc. whilst never knowing the previous owner raised it on 87.

I'm all for saving money, and I'm all for not being "scammed" by automakers, but if anyone can prove to me that MPG is exactly the same with the cheaper stuff, and power is exactly the same, and the computer WILL NOT retard timing to avoid from pinging, then I'll be on board, happily.

Tjdehya

I agree with you but for me I would have to change your sentence.

K-A

Exactly, works either way for me as well.

If they tell me to do it one way, I'll stick with it. Only time I'll question what they say, is if they're trying to sell me an M-B Product to use on my M-B, and even then, I'd have to do a lot of research to get real proof as to whether a cheaper alternate approach would be equal to, or better than M-B's product that they're recommending.

BPhillyBenz

Thanks for posting the article and opening up the question...some of the responses are pretty funny. The Money article linked another article to Car and Driver. This pretty much said it all for me. Thanks again.

"Our tests confirm that for most cars there is no compelling reason to buy more expensive fuel than the factory recommends, as any performance gain realized will surely be far less than the percentage hike in price. Cheapskates burning regular in cars designed to run on premium fuel can expect to trim performance by about the same percent they save at the pump. If the car is sufficiently new and sophisticated, it may not suffer any ill effects, but all such skinflints should be ready to switch back to premium at the first sign of knock or other drivability woes. And finally, if a car calibrated for regular fuel begins to knock on anything less than premium or midgrade, owners should invest in a tuneup, emissions-control-system repair, or detergent additives to solve, rather than bandage, the root problem."

bzliteyear

why does same V6 engine in Honda say "regular unleaded-87 octane" but in the Acura, it says "premium 91-octane" required?
PL

fromthebeginnin

I had a 92, 2000 and 2002 S class cars always put regular in them no issues in also 20 years. In the Porsche and the E550, I use premium for the extra they deserve. If I had 350 I would use regular.

Read this you may find it interesting, especially the comments from Porsche!

All Porsche engines are designed for premium, too, but it's not available everywhere. "Our cars must be able to drive all over the world, and so we are able to run on regular," says Jakob Neusser, director of powertrain development at Porsche's research and development center in Weissach, Germany. "You don't have to feel that a mechanical problem or anything else will happen" using regular gas, even in the highest-performance, regular-production Porsches.

BTW, I do think quality gas with the appropriate ingredients, Chevron, Sunoco, etc vs costco, Arco is waranted.

http://www.usatoday.com/money/autos/...emiumgas_x.htm

K-A

I think that pretty much sums it up. The savings in price will cost you in efficiency, leveling all out (more-or-less). Taking the "cheapskate" route, you end up not only saving nothing, but you diminish your engines performance, increase emissions, decrease efficiency, and give your engine less than it requires. I see no gain in it.

ALSO, and this is obviously a huge long-shot, and mostly unrealistic, but let's say that something happened to your motor during your Warranty period (unrelated to Gas, even). You know if M-B found less Octane than required in the motor, they'd use that against you in voiding engine Warranty.

Pntblnk

FTB - thanks for the link. There are certainly a number of high profile contributors quoted in that article and it seems that there are an equal amount of supporters / non supporters on the forum.

I have burned 87 or 89 most of my cars over the past 12 years ( fatherhood shifted my buying habits to SUV's rather than sports cars) but always burned premium in my Harley's. My bikes were mostly stock with stage I or II kits and probably would have run fine on 89 but at 3-5 gallons per fill-up the jump to premium never bothered me.

I plan to burn premium in my 550 but not sure I can conclusively support my decision other than it is recommended and just doesn't feel right to burn anything less in a 380hp engine. Just don't press me for hard facts in a debate cause I run out pretty quickly after referencing the owners manual.

Getting 21-22 MPG in mixed driving so VERY happy with the performance and the mileage. If it ain't broke, don't fix it!

pmb600

This entire thread is comical and each time another one of these pops up I have to laugh. Don't drive a $60,000+ car if you can't afford $4 more per fillup in gas. I'm not a wasteful person with money, but when you're driving a luxury car which is REQUIRED to use 91 or higher octane to run, just spend the money and do it.

g2k

I agree

fromthebeginnin

Pnt, I'm coming to visit you for driving lessons, I'd like to average 20-21. I just got off a tank where I babied it (only jumped on it twice) and I could only get 18.1 with 1/4-1/3 freeway driving (6k miles). Even when I made a trip to Sacramento a few weeks ago I only averaged 23 on the Freeway. But it really doesn't matter because I love driving the car!

Off to the golf course, 69 in NorCal today!

Go Packers!!!!