Premium fuel? - BMW Forum

teebee · 07-13-2011, 04:11 AM

Okay, so I bought my first BMW a few weeks ago, and let me start by saying that I'm a woman who really doesn't know a whole lot about cars. I'm not a COMPLETE idiot, I just need some info. I have a 2006 325i, I know, nothing THAT special, but I need to know about fuel, in LAYMEN'S terms.... Do I REALLY need premium? I've read about how it doesn't perform 100%. If you use regular, performance is decreased by about 5%?? Basically, what is the bottom line? Will I be damaging the engine by not using premium? This isn't a money issue, gas is expensive either way.. I've read that in the long run it will end up costing more by using a lower octane. Is this true?

Just want a subjective answer from someone (perhaps a mechanic??) Is the engine in an '06 325i really that evolved that it NEEDS higher octane fuel? I read something saying that the only engines that really need it are those with superchargers... I respect the advice and opinions on this forum as people seem to know what they're talking about. Thanks

jimmythepie · 07-13-2011, 06:23 AM

welcome tb,i also know nothing about cars,but some of the others do,im certain your problem will be solved soon.

brettski · 07-13-2011, 06:31 AM

Welcome to the Werkz.

Again, not a mechanic. What I'd suggest is to try using a tank of each in your usual travel routines, and see how they stack up from two perspectives,
a) how you feel the car performs.
b) the mileage that you get from the fuel that you use.
I don't think that this sort of test is likely to cause any damage to an engine, but it will give you something to work with. The engine management system in your car should adjust for the octane of the fuel that you are using (at least to some extent).

Put up some photos of your car when you have a chance, and hang around a while.

Jack Dabsy · 07-13-2011, 02:20 PM

Just to add...
The PLANET(except China) and his dogs build petrol cars to use standard unleaded (92-95 oct), this has been a consensus between manufacturers since the mid '90s...
If you feel that your power is down then there maybe another issue involved, like for example, airflow or fuel pressure !

bighorns · 07-13-2011, 10:37 PM

My understanding is that you can use regular if you never put your foot in it. I didn't buy my Bimmer to drive it like a Camry, so mine's always full of premium.