Can one use Regular gas in a Mercedes ?

You won't save any money. You will see a drop in MPG due to the lower power output. Also, you are likely to hear some "pinging" and such. My

300E was run on regular unleaded for about 2 months (by my father). It ran like crap (lost about 20hp) and pinged under hard accelleration. Plus it got horrible milage.

"Can one use Regular gas in a Mercedes ? Mercedes C220 1995 model. in California "

Why don't you just read the owners manual? That should specifiy the minimum octane rating for the car. Then you'll know.

But can't one simply go to a cooler plug to resolve this?

Collin

maybe for the pinging, but the drop in HP (wich will cause a drop in MPG) will eat more than the $.20 per gallon savings. Not to mention the havoc it could wreak on the timing and emissions equipment. California is pretty strict on emissions, I would be surprised if it could pass on regular.

My neighbor mistakenly put regular fuel in his mid-90's C and the check engine light came on. Seems that the computer could not compensate for the lower octane. He ran a tank of premium and it cleared the error.

Josh

i have ran regular and mid grade on my 95 E320 (2 of them) without any noticible issues other than 1 mpg drop.

Don't, especially in warm weather. Higher octane fuel ignites at higher temperatures and so doesn't preignite or "knock".

Knock occurs before the piston reaches the very top of its compression stroke; the piston is trying to compress the exploding fuel = knock. The engine is working against itself in those instances. Manufacturers add knock sensors to detect knock; the engine's computer then retards the spark in an attempt to avoid knock and that retardation cuts the engine's power and fuel economy.

Try mid grade fuel during the winter but go exclusively to premium in hot weather.

Only 1 MPG over an entire 16 gallon tank can be almost 1 gallon of gas. With the current prices, you save maybe $.50 per tank? Not worth the risk, IMHO.

Here in New York premium is 40 cents more a gallon. If your tank is 16 gallons:

16 x .40= $6.40 per tank. If your losing 1 mile per gallon per tank @ 16 miles per gallon the loss in performance is 1 gallon per tank. At $2.40 per gallon the total savings is $6.40 - $2.40= $4.00 per 16 gallon tank. Maybe not worth the risk, but not $.50.

NO.

If the car REQUIRES higher octane this is due to compression ratio. This is a REQUIREMENT.

On the other hand, if the car doesn't need it, then you are wasting your money and polluting as well, for no reason.

Try running some regular octane and see if you hear pinging under load. If you do then it's not for your engine.

The "your mileage will drop" is easily tested. Still if the engine really is a high compression one, you are on the hook...

Marty

Ridiculously wrong.

How?

My car get 2mpg better both highway and city with Premium vs Regular. (a fact I proved to myself when I took possession of the car from my dad, who ran regular in it.) It IS cheaper for me (not by much) to run premium rather than regular. Mfgrs do not randomly pick the octane level for the motors, what they recommend is best for the motor. Any more (higher octane=waste), any less "could" cause problems, some expensive. I run Premium in my van (that only needs regular) once every two months just to clean the injectors rather than add a fuel additive.

I had never heard of plugs being "cooler", so I wasn't sure, hence the "maybe".

I've been running regular or more often medium grade fuel in my 300e with no ill effects whatsoever .... I've never heard any pinging, period. all this talk about 1 or 2 miles / gallon loss is surely meaningless when one takes into consideration driving style. You should see my milage go down big time when I drive a bit more ahhh, 'spirited' by shifting myself.

cheers, guenter

ps oh, yes, I've driven the car in a 'spirited' way when it was filled with regular ..... no pinging, the computer appears to adjust quite well.

"I run Premium in my van (that only needs regular) once every two months just to clean the injectors rather than add a fuel additive. "

This is another urban myth. I have never seen any evidence that premium gas has anything to do with cleaning injectors, valves, or anything else. Premium gas simply has a higher octane rating, which is measure of it's ability to resist pre-detonation which is a function of the compression ratio for a particular engine. Provided the fuel has a high enough octane rating to avoid pre-detonation, anything beyond that is meaningless.

As far as getting better mileage with premium, I'm skeptical of that as well. I suppose it's possible, but if it were in fact true, it would be a great way to market the higher price premium fuels. Yet, I don't recall seeing gas companies doing that.

I uses Amoco for my premium fillups of my van, exclusively. Why? Because it contains MORE detergents than the government regulates. It is cheaper than a fuel additive when you take into count that my van's tank is 37 gallons. All premium gas does not have extra cleaners, but Amoco does, which is why I use it. I do not get any better mileage in the van, nor do I see increased power, but it does run smoother for the next couple months.

Note, you WILL have less power on regular than premium (In a high compression engine that requires 91 octane). The Knock sensor retards the timing, which causes the "maximum gas expansion" to happen when the piston is farthur aling in it's down stroke. This reduces the peak cylinder pressure. It eliminates the knock, but WILL reduce power and and give you poorer mileage. Drop the compression level of a engine from, say 9.5:1 to 8.5:1 to compensate for the lower octane gas, and you will drop HP.

In the UK Shell, for example, implies more additives in its high-octane fuel Optimax, though from the website it is not exactly clear whether Optimax (98 octane) actaully has more or 'better' ones than the standard 95.

(95 = 91 US)

BP is not much more informative about its 98-octane Ultimate:

DAS

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