Fuel Question

[jlfarley]

My sister has a Volkswagen Beatle that requires 91 octane, but she was told if she put Chevron in she could get by with 87. Is that true, and if so, would this be true of a BMW as well?

 

[epj3]

No it's not true, bad idea. (I'll let someone else post the reasons why, becuase it'll undoubtedly happen)

 

[Militant-Grunt]

When a manufacturer sets a certain octane level requirement, it is there for a reason. Lower octane fuel has a lower compression rate, therefore it explodes earlier during the otto cycle, causing engine knock. Most engines these days have "Retarded timing" incase lower octane fuel is put in. The engine is timed differently to compensate for the lower compression, it does this so there isnt harm done to the engine. BUT THIS DOESNT MEAN YOU COULD PUT 87 IN, ITS A SAFETY PRECAUTION. Respect the requirement, or expect gigantic repair bills in the future.

On these kind of engines putting 87 = crappier fuel economy, lower performance figures, and engine harm.

 

[MrElussive]

My sister has a Volkswagen Beatle that requires 91 octane, but she was told if she put Chevron in she could get by with 87. Is that true, and if so, would this be true of a BMW as well?

Is it the 2.0 liter 4-cylinder engine? If so, VW recommends using premium 91 octane fuel, but you can run on regular 87 octane just fine, you will just take a bit of a performance hit.

Always run your BMW with premium fuel. Premium cars need premium fuel, don't be cheap.

 

[I love my 5 Series]

If it is a 1.8 turbo, DO NOT use 87 octane. Preignition on a turbo running at high load/high rpm will kill the engine. You can actually melt the piston if this happens. A non turbo 2.0 can be run on 87 octane safely - this is the recommended fuel. Read the owner's manual and pay attention to the type of engine you have.

 

[ThatOneGuy]

Any car built in the last 10 years has a sophisticated ignition system controlled by the cars computer. The 'knock' sensor will retard the timing and prevent engine damage. However, your performance will suffer and the car will not run optimally. Performance cars & turbocharged cars will be most effected. It's not a good idea to run lower octane fuel than the manufacturer specifies for long periods of time. Best case the car runs poorly. Worse case, damaged catalytic converters. Penny wise, pound foolish.

 

[Bmw 325i 7803]

Reminds of a dumb woman in a 323i I saw while filling up at BP putting 89 octane into her car. She took $20 of gas which amounted to about 9 gallons, premium is only 10 cents more so she saved less than 90 cents by putting in the cheapest mainstream-name-brand 89 octane fuel possible... Some people don't know how to take care of cars.

Thats just insane to put 87 into a 330...

 

[jammer]

Or maybe it's just leased and she doesn't give a rat's ass! Don't own it, don't care!