Dear Tom and Ray: My wife and I live out in Southern California and have some ... well, to be polite, interesting neighbors in our condo complex. One couple in particular is very proud of the Porsche 911 Carrera they're leasing. The car probably is a 2007 (about a year older than the woman's face ... the rest of her is a 1950-something). Whenever they start up this car, or before they turn it off, they make sure that they rev the engine loudly, in case we all forgot that they have a Porsche. My question is this: Can revving the engine while the car is not moving damage anything? — Chris
TOM: Well, clearly it can damage relations between neighbors, Chris. Not that there's going to be anything left to damage after she reads your comments about her new kisser!
RAY: The answer is that damage can occur from revving, but it has nothing to do with whether the car is moving — it depends on whether the car is warmed up yet. So, in the case of your neighbors, they may be doing damage by revving it first thing in the morning, but not at night, after they've just driven the car home.
TOM: When you first start a cold engine, especially if the outside temperature is low, it takes the oil a few seconds to build up pressure and fully circulate. That means for those first few seconds, crucial parts of your engine are not fully protected.
RAY: That's why with modern, fuel-injected cars, you're not supposed to step on the gas at all when you start the engine. You just turn the key, and ba-da-bing, the engine starts and automatically idles at a nice, low RPM.
TOM: If you really stab the gas pedal the moment you start the car, and go VRRROOOM, VRRROOOOOOM right away, you will put extra wear and tear on things like the rings, the cylinder walls, the valves, the crankshaft, the bearings and other parts that absolutely require proper lubrication. And those parts are very expensive to replace.
RAY: Of course, your neighbors are just leasing this thing, so what do they care if it burns oil at 80,000 miles?
TOM: On the other hand, all they're really doing is enjoying their car. I mean, the engine of a Porsche does sound wonderful. In fact, I may buy one just so I can rev it up and listen to the engine.
Air dam removal
Dear Tom and Ray: So the air dam on my '91 Chevy C1500 has taken a beating and is starting to come off. Rather than try to rig it back on or replace it, I want to simply remove it and be done with it. The truck is my only vehicle, used primarily for driving to and from work. However, I do take it “off road” from time to time, even though it has two-wheel drive, and that is where the damage comes from. I've been warned that the air dam is not simply a cosmetic piece but that it serves several functions for the truck. Thanks! — Brad
TOM: You can tear it off, Brad.
RAY: It has three purposes. One is cosmetic, but I'm guessing that's not a major concern on a 1991 truck that you use on a farm.
TOM: The second purpose is that it decreases the turbulence of the air that goes under the truck as you drive, and therefore helps to increase the mileage a little bit — a very little bit. The dents in the side of the truck probably are doing more, these days, to disrupt your air flow and mileage than a missing air dam would.
RAY: The air dam's third purpose is to fall off after about 80,000 miles and create a road hazard.
TOM: In case you're interested, it would cost you about 14 bucks to buy a new one on the Internet. But I'm guessing you'd rather invest that in half a tank of gas these days, and you can do so with our blessing, Brad.