jctevere

The fact is that it has nothing to do with being a Ferrari, Toyota, Bently or Honda. It hsa to do with the compression ratios. Heck, cadillac's new cts run on 87 octane, and they are very luxurious. But with such a high compression our N/A engines use, the octane becomes more important. Now is it going to cause your engine to explode or force a piston through your cylider wall? No, at least not today with knock sensors that retard timing. But your car will not run as efficiently, there is always a trade-off for your decision, otherwise there wouldn't have been specific instructions to use premium fuel.

Acapulco Bill

@RLE: You are absolutely correct, only the automatic transmission C300s are Flex Fuel compatible. Sorry to be a source of bad information on E85 premium. The rest, though, stands.

envyxc350

Hey guys I was wondering if it's ok to put Cheap no name 87 fuel in my 40,000 Mercedes-Benz? I mean I always did with my Honda..what's the difference? Engine ping? What's that? I thought the CEL was suppose go be on all the time... Seriously don't put us other Benz owners to shame at the gas station by being cheap and using 87. Only fools use 87.

jadewombat

My wife drives our C300 (leasing) most of the time and she was a life-long cheap gas buyer (87) up until we got married a few years ago. We had to reach a compromise so we've been running 89. I put 91 or 93 in when I go autocrossing. Notice a slight difference in the power, have seen no difference in the mileage at all going from one to the other though, oddly enough.

NJBNZ

I'm sure others will disagree with me and that's fine...but...I have found that as long as you always use regular grade gas you will be okay. It's when you start with premium or super and then drop down to regular that you will notice a difference ans have problems with pinging.

When I had my corvette (owned not leased) I always used super. My fiance accidentally put regular in it one day and you could definitely notice the difference. With my '05 Jag and '07 C280 (both leased) I used regular from the beginning and never had any problems

NJBNZ

Only fools think using a certain kind of gas makes a person look bad

blue00r6

What is the compression ratio in these engines? I'm a skeptic, but I would be surprised that a N/A engine would knock on 87.

NJBNZ

Exactly. Once you bring a supercharger or a high performance engine into the discussion then people may have an argument...but with today's modern engines and sensors, using regular grade gas will not harm your car. It's all marketing hype. Sure using Super may get a little better performance...maybe half a second faster from 0-60...but how many people can actually notice that small of a difference unless we're talking drag strip cars. It's just a placebo effect

Acapulco Bill

@blue00r6 - the C300 engine´s compression ratio is 11.3:1. It used to be that anything over 10:1 was 90+ octane territory. Not anymore, now many current engines with 10.5:1 recommend regular gas. (Nine of my other cars use regular, only the Merc and the V12 use premium).
The BMW 328i has a 10.7:1 compression ratio and specifies premium unleaded. For this truly refined Mercedes engine with an 11.3:1 compression ratio, that´s high enough for me, so I will keep using the 93 octane rated Pemex Premium, the only premium unleaded available in Mexico (I´m sure its true octane is lower, though).

C300Sport

Don't be so sure of your self. It is true that advanced electronics and knock sensors do a great job of retarding timing and keeping an engine from destroying itself. The fact remains that there has to be some amount of premature detonation occuring before it can be sensed and adjusted for. If you plan on keeping your car for a many years or many miles or simply plan on driving the hell out of it on low octane fuel, you will end up having issues from premature detonation.
Of course, if you plan on passing it along to some one else on a two year lease, I guess Karma will have to take care of you...

NickCats

I filled up my car after work and it made me think about this thread...

My car took about 15 gallons of premium. General price difference between regular and premium here in Illinois is $0.20 a gallon.

If I chose to fill up with regular I would have saved a whopping $3.00 - now let's say I fill up once a week - that's $150 a year in total savings for putting the WRONG octane of gas in your car.

If you are that concerned about spending an additional $150 a year on gas, you should not be driving a Mercedes Benz in the first place !

Nick

lamonsas

u still dont get it, the BIG question here is for a LEASED CAR, not an owned car, the question is since the car is leased is it still worth to fuel it with premium or regular will do for fine the 36 months that it will be used for, after that its the dealer's problem.

If the car is owned there is not a single doubt in my mind it should be fueled with premium.

C300Sport

After that last sentence, I think I do get it now. Of course, if that is how you think about things, you are pretty pathetic. It's sad that people have no problem taking a big crap on the next guy down the line just because they can.

lamonsas

Considering dealers try to screw costumers in every possible way , i dont see why i need to take care of the dealer problems.

When u lease a car, the car is not yours , u just pay to use it , then u return it to the dealer, its the dealer's car. My salesman himself told me to fuel whatever i want in the car since its a lease and it doesnt really matter, i told him that in the manual it says premium REQUIRED and he just smiled at me and said to just relax because its a lease. he knows what a perfectionist i am since its the salesman i BOUGHT my 06 C230 from and i ONLY put premium in that car.

Now thats what the dealer told me and it shows that they really dont give a damn about how the car is maintained as long as its returned in a good condition.

Besides , u have a couple of ppl above me that said they used regular and they are just fine so dont go around calling people pathetic because if you do then you are pathetic yourself. I wont even go down to that level with you if thats how you chat on forums.

C300Sport

You posted in black and white that you would not do that to your own car(not leased) but would to a leased car. You know damn good and well that someone else will own and drive that car after you have finished with it. The fact that you are happy to knowingly damage it and then pass it down the line speaks poorly of your character. It's not that I am trying to insult or upset you, it is how your comments came accross.
If you don't like that, maybe your should re-evaluate your position on what you are comfortable doing to others.

lamonsas

you still dont get it do u, using regular doesnt damage the car lol, people told u in this thread a couple of times already, it gives lower mpg and slight performance decrease and yes if the dealer itself doesn't care then i wont stress myself over it.

Regarding with you biting on people's words in this thread, i still havent decided if im going to use premium or regular, something inside me tells me to use premium just for the heck of it but something else tells me to do what the dealer told me it doesn't matter what fuel i use because its a lease.

envyxc350

Why not just pay the extra 20c? Why treat the car like crap just because your not keeping it? Id treat any benz being a rental, lease, purchase, like my own. 91+, oil change every 6000, etc. Leave things better off then how you found them..

NJBNZ

Ding Ding Ding! Ladies and gentleman we have a winner! Def not worth it if you have a leased car...end of story

Some of you guys really crack me up...DAMAGE a car by putting regular gas in it?! The worst thing that can happen is slightly poorer performance or fuel economy...YOU WILL NOT DAMAGE THE ENGINE BY USING REGULAR GAS IN THIS CAR! You know how the next owner can "fix the damage" when they get it? By putting a higher grade gas in the car...problem solved!

As for being pathetic...uhm sorry it's the rest of you that are being pathetic...OMG I HAVE A C CLASS MERCEDES I HAVE TO PUT PREMIUM GAS IN OR I'M MAKING OTHERS LOOK BAD! Give me a break. If you want to **** money away by putting in a higher grade when you don't have to...be my guest. But to try to bash others that realize it's not a necessity is showing your ignorance...not mine

NJBNZ

Oh yea...one more thing...for those of you worried about the person that's going to end up with my car once my lease is up...how many times have you floored it from a dead stop, or accelerated too aggressively, or slammed on your brakes too hard? One could certainly argue that you are "damaging" your vehicle just as much...if not more...than I am (which I don't believe I am...nor has research shown that I am)

I am Jeff

Guys...If the Troll wants to use regular, let him. It's his choice. He asked our opinion and he didn't like what we had to say. He thinks it helps his case by stating that it's a lease. If that .20cents is too much for you, you shouldn't really be driving a benz to begin with.

jctevere

I don't really have any idea if it harms the car or not. But for me, its not worht saving a possible $150 a year to drive a car that feels sluggish and underpowered on regular and puts a smile on my face with premium. I definitely feel the difference between regular and premium, and sometimes I can feel the difference between fill-ups of gas brands. Heck, I can even notice a difference at my next fillup at the same station.

Also, it doesn't help that the one time I put regular in my c300 and went to start it, the engine misfired and the cel was blinking. I had to turn it off and turn it back on and all was fine. But apparently accoding to my service advisor this can happen where the pistons and the crank become out of sync. He seemed to think that the knock sensors or the misfire from regular gas has caused this. But I'm no mechanic.

C300Sport

Since you obviously do not know what you are talking about, you should probably stop trying to sound like an automotive authority.
It's funny how you are the only one that brings up the fact this is some sort of almighty Mercedes that we want to over maintain...it's simply a car...and like any other car, there are recommended ways of maintaining and caring for it.
Post 35 explains how and why low octane fuel can damage an engine. If you disagree, tell me just how the pistons, valves and rings like those premature ignitions that need to occur before for the computer acts to retard the timing.

NickCats

From the owner's manual :

To maintain the engine’s durability and performance,
premium unleaded gasoline must be
used. If premium unleaded gasoline is not available
and low octane fuel is used, follow these
precautions:
- Have the fuel tank only partially filled with
unleaded regular gasoline and fill up with
premium unleaded gasoline as soon as
possible.
- Avoid full throttle driving and abrupt
acceleration.
- Do not exceed an engine speed of 3000 rpm
if the vehicle is loaded with a light load such
as two persons and no luggage.
- Do not exceed 2/3 of maximum accelerator
pedal position if the vehicle is fully loaded or
operating in mountainous terrain.

navyjetmech

I do use Premium in my c300. My best friend has a Nissan Armada. I also have a Infinity QX-56. Same engine in both SUVs. Nothing is different from one to the other except the engine cover. Nissan requires 87 octane Infinity requires 91 octane. The reason is, better performance and better gas mileage rating and some hype. Things that make you go HMMMMM. To each your own. Use whatever gas you want. It's your money. But in the big picture you are saving what? 87 octane where I live is $3.39 91 octane is $3.69. So you are saving about $5.22 per fill up assuming your tank is completely empty. So is a $5.22 savings worth it to you. Only you can answer this question. Not us. No one here is an Idiot, We did buy a Mercedes.

C300Sport

Along with that engine cover comes a few extra horsepower. I don't know for sure how they get the extra HP but wouldn't be surprised if it was from a bump in the compression.