The following is quoted from Mark Miller's Lifetime Maintenance Schedule for BMW owners concerning the care of turbochargers.
"Lifetime turbocharger warm-up and cool-down procedures
Many of my readers who own BMWs powered by turbocharged engines ask how they can help the turbochargers last longer. They are concerned, and rightly so, with the cost of post-warranty ownership of the modern BMW and want to know how to approach it. If you want to keep the car past the warranty the best way to prolong turbocharger bearing life is to do two things:
First, use very high quality full synthetic oil in a viscosity that can withstand tremendous heat, and change it at an interval appropriate to the product, verified by oil analysis. Second, practice traditional turbocharger warm up and cool down procedures. This means allowing the engine oil to reach operating temperature before spooling up the turbos (keep the rpms low), and allowing the turbos to cool down before shutting off the engine by driving gently at low rpm for several miles before reaching the destination.
Now, anticipating your follow up question, "Why doesn't BMW recommend this?" Here is why:
Back in the olden days, every car manufacturer with a turbocharged engine (BMW, Ford, GM, Mercedes Benz, Porsche, SAAB, Renault, etc.) detailed this warm up and cool down procedure. But those cars were bought and driven exclusively by driving enthusiasts who knew their way around cars. Car buyers have changed and today’s oil is better, but engine oil lubricated turbocharger bearings have not changed. The nature of turbocharged cars has changed as well. Back then, only sports cars, executive limousines like BMW’s E23 745i, and diesel-powered sedans had turbochargers. People who owned those cars could be counted upon to have a certain degree of automotive knowledge. Nowadays, the family sedan has two turbos to go along with the automatic transmission and the baby seat. If BMW told today’s turbo car buyers they had to follow warm up and cool down procedures first off few would understand it, secondly few would do it, and third-wise a lot of them just wouldn't buy the car.
All that being said, every turbocharged engine shares one thing in common, which is that if it is in service long enough it will eventually need a new turbocharger -- two in the case of some BMW engines." Mark Miller
In simple terms, I take this to mean don't run the car hard right after you leave the garage and don't run it hard on the way back into the garage.
"taken from
www.f30post.com
