The owners manual tells me to use 91 octane in my (30,000 mile) 1995 E320 with the L6 engine. To date, it's all I've used. Great pickup, lot's o power, runs like a dream.
But...... can I use 87 octane?

Gas prices really hurt.

 

I had the same question so I collected data on my 2000 E430. 87 vs. 92. Let's assume for now that running 87 octane does not have any adverse affects on the engine, carbon build up, etc.

Long story short: The engine is tuned for the higher octane therefore will get higher MPG with the higher octane. My data showed a 2% $ advantage to paying the higher price for 92 octane in order to acheive the higher MPG. Relatively speaking, the cost savings for 87 was offset by the decrease in MPG. Therefore it makes economic sense to spend more for the higher octane and it's better/cleaner for the engine in the long run.

Matt

 

I would use the recomemded fuel. It may cost more but the car will wun longer. If you use the cheaper gas you will eventually have serious problems.

 

An extra $2.00 to $3.00 at the pump when you fill up really isn't that much of an impact when you consider that a cup of Starbucks costs more than that. I have strayed from the path of premium fuel in the past. I did not notice it when I was doing some state to state driving, however I really did notice it when I was in town and on entrance ramps. Even my wife noticed the irregular power surges that occurred when accellerating up the entrance ramps. After I put premium back into the tank the issue went away.

I will always use premium fuel in my Mercedes. The engine is tuned and programmed to run best on this particular type of fuel. Sure it has computers that will alter the timing etc... to compensate for lower octane fuel - all cars have that. But you will lose a degree of power and efficiency by running cheaper gas. Also, most mechanics will tell you that you have a greater potential to shorten spark plug life and invite fuel management problems if regular fuel is used.

Spend the extra few bucks at the pump and ensure that your engine is running like it should and in the long run you will come out ahead.

 

I always run regular fuel. The last mercedes I had, I sold it w/ 185,000 miles, always using regular in it as well. It is still running this day.

 

Glad I nor anyone I know bought it.Ever see a hole burned through a piston?You were lucky,don't tell people to gamble with a high compression engine just because you did.
ohlord

 

octane rating compression of your pistons selects the fuel you should run. Lower octane will predetenate at a lower compression. Too low of octane will ignite before your piston reaches top dead center= loss of power worse yet the piston has to continue compressing until it reaches top dead center before it goes into the power stroke of it's 4 cycles. This inturn put sever stress on the bearings, crank, rods, and pistons. light cases you may hear a pinging sound severe rap rap bang call a tow truck

 

Run the low grade fuel with acetone. It will improve your fuel economy by alomst 7 to 10 miles. I run it in all my cars includung my 2007. BEFORE running it read this site www.brightgreen.us
And if anyone wants to leave a comments make sure you have personaly tested acetone.

 

another person that has fallen prey to his hype.did you also purchase the 6-8hundred dollars of snake oil valves and plastic tubing they sell?

 

Why dont people just use the recomended fuel? If you cant afford to put the proper fuel in the car and it is costing you a lot of money then buy something more feul efficient or change driving habbits.