How To Drive a Mazda\Mercury Capri Turbo Car
Owners of turbos in many cases need to be aware of how to drive their turbo engines in daily driving. Turbos have changed since the 60s, 70s, 80s. It varies with the size of the turbo also and the haunting question for most owners is do I need to wait in the parking lot to allow the turbo to slow down to idle?
For bigger turbos than those in the Mazda or Mercury Capri XR2 1.6L engines, the answer is that it won't be a bad idea if you been cruising at 70 mph for any length of time and then park, to wait until the engine is idling. Turbos spin at a tremendous RPM and rely on the oil pump to provide necessary lubricant to the turbo bearings. Typically, if you just cruised down your street at 35 miles an hour for a couple of minutes or more it is not much of an issue. But, if you just got off the highway or perhaps just climbed a tall hill, turning off the engine immediately leaves it wound up, but without an oil feed to keep it cooled and to provide the lubrication. The effects of which could affect the lifetime of the turbo, which is why some fail early before 100K.
Whether or not it is something your should fear is debateable, espically as turbo technology has advanced. But, if you are in the habit of putting your foot to the metal every chance you get, it is certainly worth the additional 30 seconds to a minute to allow the turbo to wind back down to idle speeds before shutting her down. A turbo timer is a very cheap alternative to waiting in your car to shut her off. They can be had for anywhere from $25-100. Some people don't mind sitting and relaxing, as others like to get on their way and let the turbo timer handle the cool down and shutting off of the car. Also, the turbo timer will automatically dictate how long the car needs to cool down by how hard you've been driving (i.e., after 80mph highway driving, the turbo timer might read 2-3 minutes before turning off). Most owners don't need a turbo timer unless you're boosting, then quickly stopping and turning off the car. Taking it easy 30sec before you park will be enough time for things to cool down. Mazda confirms it, timers are are waste on these small turbos and have even said that if the turbo is not babied after driving, they will last a long time.
However, Mazda mechanics will tell you that these turbos are so small in boost, there is no need to wait for cool down, in fact, the owner manuals do not even mention this. So, if you are commuting 40-miles and doing 70-80mph the whole way on the highway, but the last 5-minutes is 30-mph down the back roads, and the last 2-minutes is below 15 mph through the company driveway and parking lot, do you still need to sit there for 30-seconds once I get to my parking spot? No, because the cool down is happening once you get off the highway and gradually drive slower and slower.
Finally, simply as a safe rule of thumb, if you have been doing highway speed driving of any length, get off the highway and into a gas station, let the car idle for 15-30 seconds before shutting it off. If the scenario is like the one previously noted, where you get off the highway, and go through a series of stop lights, your cool down pretty much has occurred by the time you stop the car.