The Demo Site

Franz Kafka's Garage

Send questions to "Franz Kafka's Garage,"1585 Eisenhower Place,Ann Arbor,MI48108or e-mailFKG@CARandDRIVER.com.

CIRCULAR LOGIC

August 2008, page 62, yellow box: "Power oversteer is possible on left-handed skidpad." Um, is there more than one skidpad? Is there a right-handed skidpad? An ambidextrous skidpad? If there's more than one, do all cars get skidpadded in all directions? If not, why not? Do some cars oversteer in one direction and not the other? Inquiring minds need to know.

Kevin WhitakerSomewhere in Texas

Cars are driven around the skidpad in both directions, and the results are averaged. In terms of left-to-right weight balance, the driver is on the inside half of the car in a continuous left-hand turn and the outside half when turning right. In some cars, that difference in side-to-side weight is enough to change the steady-state cornering behavior of a car. In other words, yes, some cars oversteer in one direction and not the other.

WATER-BENT METAL

What is hydroforming, and what are its benefits over the "old-fashioned" way of metal forming?

Brandon IrvingLos Angeles, California

Hydroforming uses high-pressure fluid (typically water) to force a metal into a shape as opposed to stamping the metal with a press or casting molten metal in a mold. One advantage of hydroforming is that it can create much more complex shapes, increasing design flexibility. The drastically curved front fenders of the Pontiac Solstice are good examples of this. Also, a hydroformed part such as an engine cradle can be made in fewer pieces than with conventional stamping, which reduces the number of welds, increases the strength, and cuts assembly time.

YAW MO B THERE

What exactly is yaw control? I know that some of the newer sports cars have it, but I've never known what it really does.

Joshua D. RatliffHilliard, Ohio

Yaw control limits a vehicle's rotation around its vertical axis (imagine a line pointing straight up through the sky) by applying individual brakes. Basically, it's intended to keep a car moving in the direction the wheels are pointed and prevent the car from spinning. All stability-control systems provide yaw control.

READER SIGHTING

The option will cost you maybe $1700; the Y goes for $7.50. Steve Patterson saw it in spicy St. Paul, Minnesota.

TICKING SOUNDS

I've had two neighbors ask me if direct-injection (DI) engines are noisier than port-injection engines. Then I did the Short Take on the Cadillac CTS with the base engine [April 2008], and I drove it back to back with the direct-injection car. I swear the DI engine makes a low, rumbly kind of ticking that isn't evident in the regular V-6. As I recall, nothing showed up in our noise measurements suggesting one was louder than the other. Maybe I'm just hearing things, but what was that ticking noise?

Keep Reading: Skidpads, Hydroforming, Yaw Control, and Direct-Injection Ticking Noise