GENTLE DRIVER WANTS TO BRING THE HEAT

Dear Car Talk:

I drive a 6-speed 2012 Mini. I pride myself on being a gentle driver. My goal is to drive so smoothly that you’ll fall asleep in the passenger seat. This means I shift early; I try to keep the engine speed between 1,800-2,500 rpm. In the winter, could I heat up the car’s interior more quickly by waiting longer to shift into a higher gear? I have the winter package (heated seats and side mirrors), but it would be nice to warm up the air a little faster. Thanks! -Mary

Have you considered buying a hibachi for the passenger seat, Mary? Or heated underwear?

I’ll be upfront with you: I don’t know the answer to your question. Not that that’s ever stopped me from providing an answer before. But the answer’s not obvious.

You would think that by creating more friction (at higher rpm), you would generate more heat and would heat up the surrounding coolant a little faster. That would be my intuitive guess.

But, on the other hand, we know that one of the reasons lugging the engine (accelerating from too low an rpm) is bad is that it causes overheating. Which suggests that you might create more heat by shifting earlier.

So you’re going to have to run an experiment for me, Mary. Use the stopwatch on your phone. When you get into the car, record the outside temperature, the weather (overcast; sunny) and the amount of time the car has been sitting since it was last used. Any of those factors can affect engine warmup time, so make sure you’re comparing apples to apples.

Then start the stopwatch when you start the car. Set the heat on full and the fan switch on high so you’ll feel the first blast of real heat when it arrives, and you can note how long it took. Try shifting at 3,000 rpm one day, and try shifting at 1,800 on other days.

My guess is that there won’t be a big difference in when the heat arrives. If that’s the case, I’d advise you to drive in a way that’s best for the car -- which is exactly what you’ve been doing, by the way. By driving smoothly, accelerating and braking gently, and shifting at reasonable rpm, you are doing precisely what you should be doing to make the car last longer.

And as long as it’s only the person in the passenger seat who falls asleep, you should be able to enjoy this car for many years. I look forward to seeing your results.