consumer reports cars: Cheap Cars

Showing posts with label Cheap Cars. Show all posts

Monday, November 7, 2011

Ever Wonder How Brakes Stop Your Car?

The braking system for present day automobiles has benefited from repeated improvements for well over 100 years. Disk brakes in front make up the standard braking system, while the back includes either drum or disk brakes. A network hoses and tubes connect the brakes, linking to the master cylinder from each wheel. The power brake booster, the anti-lock system and parking brakes also link into the braking system.

Brake fluid jets through a network of hoses and tubes at each wheel when your foot contacts the brake pedal through a plunger located in the master cylinder. Brake fluid, which is a hydraulic, lacks compressibility and is akin to pushing a steel rod through a pipe. Fluid however, unlike a steel pipe allows for direction and therefore, it arrives with the same precise motion and intensity as its beginnings. It is imperative that the fluid consist of pure liquid without air bubbles.

Air is compressible and creates a spongy feeling in the brake pedal while hindering the brakes effectiveness. At each wheel cylinder and caliper, you will find bleeder screws. The screws serve the purpose of bleeding the brake lines of compressed air. The two types of brake systems, disk and drum brakes, operate just a bit differently.

The disk brake uses fluid from the master cylinder forcing the fluid in the caliper, pressing against a piston. This piston, then presses the brake pads snuggly with the disk rotor fixed to the wheel. This causes it to slow or come to a stop. The function compares to bicycle braking which involves two rubber pads pressing against the rim of the wheel applying friction to slow down and stop.

Drum brakes on the other hand jets fluid into a wheel cylinder and in turn forces the brake shoes in an outward motion, applying pressure against the drum fixed to the wheel and bringing it to a stop. Whether it is the surface friction of pads or shoes on the drum brake, forward motion of the car creates heat. Heat supplies the driving force behind the friction surface of shoes and pad, wearing them out over time and demanding replacement.

In modern automobiles, the disk brake has the best performance. From trains to airplanes, disk brakes are the preferred choice. Disk brakes simply last much longer, are less prone to disruption from water, can adjust independently, and can clean themselves. Disk brakes seldom grab or pull and are by far the superior system.

Yet, you might wonder why we still use the drum brake system. The cost factor always plays a role in the production of an automobile. In the front of all vehicles in production, manufacturers make use of disk brakes. However on the back wheels, drum brakes represent a significant cost savings.

The parking brakes presents as the main culprit. Drum brakes only require installation of a lever. However, on disk brakes, an entire mechanical system and sometimes a mechanical brake drum assembly requires attachment in the disk brake rotor. Parking brakes do not make use of hydraulics, but instead rely on mechanics.

Pontiac G6 Review

Until Pontiac bit the dust in the wake of GM's 2009 bankruptcy fiasco, the Pontiac G6 was the company's go-to midsize car. In a constant battle to steal sales from the class favorites, the G6 offered unusually tactful styling by Pontiac standards, solid performance from its V6 engines and the availability of a four-seat retractable-hardtop convertible body style. Volume-selling models were the five-passenger sedan and four-passenger coupe.

Unlike the Grand Am that it replaced, the Pontiac G6 had considerably more flavor than a generic rental car. Still, the traditional class favorites topped the G6 in the areas of engine refinement, driving dynamics and cabin materials. The G6 may still hold appeal for used-car shoppers, especially given its likely cut-rate pricing. GM has pledged to continue supporting Pontiac products in its service departments, so a used G6 isn't necessarily a bad idea.

Most Recent Pontiac G6
Based on General Motors' lengthened "Epsilon" platform, the Pontiac G6 was produced from 2005-'09 as a sedan, coupe and retractable-hardtop convertible. For '05, only the sedan was offered; the coupe and convertible debuted a year later. Three main trim levels were offered on the sedan: base, GT and GTP (which became the GXP in '08). Coupes were either GTs or GTP/GXPs, convertibles GT only. Plenty of standard features, such as air-conditioning, full power accessories and CD audio, came on the base model. The GT added niceties such as an upgraded Monsoon audio system. The GXP topped the range with items like sporty exterior styling tweaks and automatic climate control.

At the time of Pontiac's demise, the G6's engine lineup included a base 2.4-liter four (164 horsepower), a 3.5-liter V6 (219 hp), a 3.9-liter V6 available on the convertible only (222 hp) and the GXP's 3.6-liter V6 (252 hp). Four-speed automatics were standard with all except the GXP's V6, which got a six-speed; however, the four-cylinder got an optional six-speed for 2009 that raised highway fuel economy to a laudable 33 mpg. Some power ratings were a bit lower in previous years, notably the 3.5-liter V6, and a manual transmission was available on a limited basis until '08.

In reviews we found that the Pontiac G6 offered generous room for those riding in back, no matter the body style. And we noted that after years of enduring criticism about its overstyled exteriors and gimmicky interior designs, Pontiac stepped up its efforts with the G6. Outside, the G6 had a crisp and sleek look; inside, there was a restrained and attractive layout with none of the traditional dull gray plastic switches. Even so, the G6 still had a few too many cheap plastic surfaces for our tastes.

On the road, we appreciated the low and midrange torque of the 3.5-liter V6, and the ride was smooth. The convertible's optional 3.9-liter V6 should be avoided if possible, though -- it was barely more powerful than the 3.5-liter V6 and got worse fuel economy. Handling was respectable, but we disliked the electric power steering, which was too light and offered virtually no feedback. GT models from 2007 and up had an improved hydraulic steering setup, which we preferred. Along with the enhanced feature content of the later models, we'd recommend focusing your used Pontiac G6 search on the '07 or newer models.