Is it “normal” to expect a Turbo equipped car to consume oil? How much is “normal” and is the A3 or 328i any worse than most turbo charged cars? (is turbo therefore a bad idea?)
A turbo car may not necessarily be more prone to burn more oil, but they certainly are harder on oil. They can subject oil to some pretty high temps and if run hard and shut down immediately can actually cook the oil in a process called “coking”. I usually reccommend to people that drive their cars in a “spirited fashion” to run a quality synthetic oil that can handle higher temperatures a bit better, and be less prone to viscosity loss.
Overall, turbo motors offer the potential to be fuel efficient and powerful.
I just want to add that while the turbo engine in the BMW 1 & 3 series is an excellent motor (I actually tested one out last week) that they should be serviced more often that BMW recommends. The 15,000 mile service interval is too long and I’d cut that in half to 7500 miles. Actually I recommend it with all BMW’s, but emphasize it with the turbo engines. The initial oil analysis work peope have been posting would suggest that these motors are brutal on oil and can run super hot.
They consume no or less than a natural aspirated engine. I own two turbo Subaru’s (WRX & Legacy GT) and have 0-0.5QT consumption over 4000 miles.
Some consumption is normal on vehicles whether turbo or not. It varies. For example my wife’s old golden on this board Honda Civic(1996) that had regular oil changes(4k) in its life burned a quart every 2000 miles.
I concur turbo’s are harder on oil so pay specific attention to the oil change interval and type of oil required. On my Subaru turbo cars that means every 4months or 3750 miles but they only require conventional engine oil. Idle down is not needed unless you run the vehicle hard and immediately stop/shutoff which is atypical. Usually you park or go normally through a parking lot or neighborhood which is idle down. Lastly many turbo’s cool themselves by convection designed into the coolant/oil lines after shutdown.
The 15k service interval is the maximum based on running the engine in optimal conditions. However there is an oil life monitor that uses an algorithm to compute oil change interval based on how the vehicle is being driven. A close friend who lives in Boston has their oil life monitor go off at around 6000 miles instead of the 15k as she mainly drives 90% city over a year.
Turbos have a very weak link in the lubrication system. The turbine bearing and seals is between the turbine wheels and subject to the worst of the exhaust heat. The heat deteriorates the seal on the hot side of the turbo, and if the engine is shut down immediately after high speed operation the accumulated heat and high rpm of the turbine is more than the residual oil can deal with, and, it ‘cokes’ up. This hastens the wear of the bearing, giving the turbine free play, which furter hastens the seals deterioration. But isn’t minute of idling before shutting down a turbo engine SOP? I recall dash placards stating such on turbo-diesels I drove some years ago.