I was looking into buying a 96-97 c220 or 280 and saw that it required premium fuel. Is it totaly necessary or can I get by with filling it with regular? I understand that if you want to drive in a sporty manner then yea, you need premium but if I just drive normaly would it be really necessary? Just wondering...

 

For the right performance and life of your car I would recommend putting in the recommended fuel. Actually, most Mercedes manuals say never fill your car up more than half tank with the lower octane fuel and you should not drive over some pretty low highway speed tha tI can't remember off the top of my head.
Let me try it from this angle. I heard of people trying to go regular on the fuel and ended up with all types of problems, like sluggish take offs, short life fuel filters and pumps, and things. But then again, my uncle has a 1990 300SE and rarely put premium in his car and he drives like a bat out of hell and the thing has over 310000 miles on it and still running strong. He had plenty of Benzes and know what he's doing.

A tank won't hurt and see what happens. If it starts to under perform, add premium and you have your answer but if it runs fine (as long as you're not full throttle all the time.), then more power to you. I asked myself the same question when I got my Mercedes but decided not to risk it.

I'm sorry if I didn't answer your question directly.

 

The worst thing that happens is predetonation, or "pinging." It's very hard on an engine and can blow out head gaskets and even pop the heads up off the block. You need to retard the spark advance significantly to prevent predetonation. A '96 or higher ECU should do it automatically, but depending on the actual grade of the gas, you may need aftermarket programming to do it effectively. It would be a dumb move, though. Not the programming per se, but retarding the timing. It really kills performance. Better to just buy premium gas.

 

At least everyone seems to agree on premium gas.[sm=icon_cheers.gif]

 

As Lugnut says, the ECU combined with the knock-sensor will avoid predetonation. However, by avoiding predetonation with lower octane, your car will get lower mpg. Any savings at the pump is eaten up by lower mpg.
Futhermore, if premium is $.20 more/gal. then you are saving $120/year if you drive 12,000mi. I don't think anyone wants to throw money away, but $120 over 12 months is not a budget buster and I'm not convinced there aren't other benefits to the fuel system using premium.
Ultimately, I'm not sure if it hurts your car or not, but I don't see an advantage either.

 

Thanks for the input. Much appreciated.

 

YES

 

This was a long argued question in the Cadillac CTS forum when the gas prices shot up last fall. The outcome was basically calculated that your savings of using regular gar over 12 months of driving is so miniscule when compared to other maintenance requiements on the cars, and possabilities of other things breaking because of the low grade gas. I put it simply with my post; if you can afford the car, then you should be able to afford to put the right gas in it. If you can't, then maybe consider selling the car...

For cars only requiring regular grade gas, putting premium in them does absolutley nothing, contrary to popular belief. It will not gain a single extra horsepower since the engine was designed and engineered to run at it's peak performance potential with the grade of gas recommended by the manufacture.

To sum it all up, use the gas you're supposed to, the engine was designed to operate and ignite the gasoline at that particular temperature, so to put anything else in could be damaging, and will negatively impact your cars performance.

 

There was a spot on Motorweek last night on SPEEDTV. One part said if you owners manual requires you to your high test, try a grad lower and if the car runs OK, it will not harm the car. the announcer when on to say this only applies to cars made in the last 10 years. They gave no explanation. But I strongly disagree and I strongly agree with your last paragraph.

 

I really think it's something silly for people to cause a fuss about on a luxury car forum. I mean, come on, it's slightly more expensive to buy premium gasoline, and the pros far outweigh the potential cons.

Like I last posted in the first paragraph, if one buys a premium car, but can't afford premium gas, then one must look at the big picture and realize that cheaping out on the gas isn't the most cost saving solution, selling the car and getting your priorities straight is.