Valvoline.com

The Speed of Light

Installing a shift light for peak performance

There are those happy to go through life letting the planetary gears, lockup clutches, vacuum modulators, and associated computers of an automatic transmission do the gear shifting for them. And there are those who believe this is a pity.

Without a thought about the supreme privilege of driving, no less being able to truly participate in the process, some people motor down the road, happy to have one hand free for reading the newspaper, fussing with the cell phone, text messaging, or applying makeup. Some deprived drivers will never know nor understand the joy of rowing though the gears on a straightaway then listening to the beautiful music an engine makes upon execution of a perfect heel-and-toe downshift into a rapidly approaching corner entrance.

Spinning Round

Squeezing the last bit of available performance out of an engine is half the fun of banging through the gears of a manual transmission, but one must be careful. Over-revving an engine on a regular basis can and most likely will cause catastrophic engine damage. As an engine spins ever faster, the forces acting on the mass of the parts sometime overcome those same parts' ability to hold the engine together. The parts of the engine want to break out of orbit, such as it is. Damage can manifest itself instantly in the form of a connecting rod exiting the engine block, or show up in the longer term in spent engine internals. Tensile loads at higher than recommended engine revolutions place great stress on the connecting rods and crankshaft as well as valvetrain components. That piston moving up in the cylinder wants to keep on going—and will if the connecting rod shears.

Blink of an Eye

For these reasons, most of us who engage in regular, spirited driving keep our eye on the tachometer more often than the speedometer. Driving in this manner will help keep the engine together but can often result in unwanted conversations with members of various law enforcement agencies. Fortunately the solution is simple. A shift light installed in the driver's line of sight alerts the driver with a bright light as to the best time to shift, when the maximum revs have nearly been reached.

Today's shift lights are not only exceedingly easy to install, they're also programmable and compact. Despite what most drivers think, wringing out an engine to the RPM redline doesn't necessarily produce more power. Most production engines will run out of juice before the rev limit, with a "sweet spot" in the powerband well below the redline where all action is. Hitting that spot consistently is what installing a shift light is all about. Saving your engine and your driving record are but secondary benefits.

Resource

MSD, www.msdignition.com