unleaded or permium gas?

[SEBZX79]

The only modern engines that should really need premium are those with superchargers, which force-feed fuel into the cylinders. "You're driving along and just tramp the gas and the knock sensor cannot sense the knock fast enough in some cases," because the supercharger boosts pressure so fast, says Bob Furey, chemist and fuels specialist at General Motors.

Burning regular when the owner's manual specifies premium won't void the warranty, nor damage the engine, even the most finicky automakers say. "You're giving up perhaps just a little bit of performance that a customer wouldn't really even notice, it's so slight," says Furey.

[Jesda]

My opinion is typically to ignore the manual and go by what a professional technician says based on experience. And for the Q, the technicians say to change your oil frequently and use premium fuel.

Of course, if you're leasing a car, driving 75k and dumping it, that changes everything.

I talked to a NICO member whose father owns a 99 BMW 5-series (or 7? I'll have to ask him again), which is struggling to keep running with barely 60k on the odometer because his dad religiously stuck to the 18,500 mile oil change interval.

Looks like BMW found a way to increase sales -- destroy existing vehicles.

-Jesda