For U Solution

The rotary engine is a highly unusual and very rare power plant. Its sole application in road legal passenger vehicles is found in Mazdas RX-8 sports car. The compact dimensions and low weight of the engine allow Mazda to keep the RX-8s center of gravity near the ground and weight quite low, making it one of the best handling cars on the road today.

Basic Specs

Rotary engines have radically different designs than conventional motors and use a "rotor" (hence the name) instead of cylinders. The rotor is a triangular, lightweight piece mounted on a circular lobe. The rotor compresses the gas/air mixture simply by rotating on the lobe and therefore does not need pistons, camshafts or rods. Concepts such as bore and stroke do not apply to rotary engines. The capacity of a rotary is defined by the maximum volume it can compress and ignite per cycle, which for Maxdas rotary is 1.3 liters.

The compression ratio is 10:1, with multi-port electronic fuel injection igniting the mixture during the compression stroke. The rotor is housed in an aluminum chamber with chrome-steel liners. Exhaust gasses flow into stainless steel headers, which then connect to a low back pressure main muffler. Transmission options for the engine are a six speed manual or six speed automatic

Power and Torque

In addition to its light weight and compact dimensions, a chief advantage of the rotary engine is its ability to reach very high engine speeds. The Mazda rotarys redline is a stratospheric 9,000 rpm when mated to a manual transmission, and 7,500 rpm when combined with the automatic, as the later transmission is unable to cope with higher speed and torque. Due to the restriction in engine speeds, the maximum power also varies based on the choice of transmission. While the engine makes 232 horsepower at 8,500 rpm with a manual transmission, with the automatic it produces 212 horsepower at 7,500. This difference is solely the result of engine speed restrictions, as evidenced by the fact the the motor produces an identical peak torque of 159 pound-feet at 5,500 rpm regardless of transmission type.

Performance

This fast-spinning engine propels the RX-8 from zero to 60 miles per hour in six seconds flat when paired with the manual and six and a half seconds with the automatic transmission. Fuel economy is relatively poor in either case however, especially considering the 3,000-pound weight of the whole car, which is very light for a four-seater. Both the manual and automatic vehicles achieve 16 miles per gallon in the city. While the manual version gets 22 mpg on the highway; the automatic can squeeze one more mile from each gallon, due to its longer final gear ratio. Although both transmissions feature six forward speeds, the manuals final ratio is 0.79 while the automatics tops at 0.58.

Excess fuel consumption is practically unavoidable with rotarys and is the main reason these engines are not more commonly used in modern automobiles. The unique design not only allows a significant amount of unburnt fuel to escape the combustion process, but also results in a good deal of energy being wasted as heat.

Rotary is a brand of vehicle service lift produced by the Vehicle Service Group and distributed throughout the world. The lifts are available in several configurations, including small mid-rise lifts, two-post lifts and heavy duty four post truck lifts. Each lift has a set of requirements that must be met when it is installed. Because Rotary lifts often raise several tons into the air, these installation requirements are an important factor in keeping operators safe.

Concrete

Rotary lifts must be installed on a quality concrete floor that is free of cracks and defects. The minimum anchor depth for Rotary lifts is 3 1/4 inches. The total overall concrete thickness must be at least 4 1/4 inches for two-post lifts, or 5 inches for heavy-duty four-post lifts. The concrete must be rated to withstand 3,000 pounds per square inch. Rotary lift concrete anchors must be torqued to 150 foot-pounds.

Bay

Standard two-post Rotary lifts must be installed in a bay of at least 12 feet inch length and 24 feet in width. For heavy duty two-post lifts, this requirement increases to 12 feet by 26 feet. Low rise Rotary lifts must be installed in an 11-foot-by-24-foot bay, while four-post lifts require a 15-foot-by-23-foot bay size. The minimum ceiling height for a Rotary lift is 10 feet. Heavy duty four-post lifts require approximately 5 feet of additional ceiling clearance.

Electrical

Rotary lifts can be installed using several different electrical sources. The required electrical breaker size changes depending on the input voltage. For single-phase 100 volt installations, lightweight Rotary lifts require a 15 amp breaker, while larger lifts need a 25 amp breaker. Single-phase 220 volt installations must have either a 20 amp or 40 amp breaker, depending on the capacity of the lift. This breaker requirement drops to 20 amps if three-phase wiring is used. Installations using 400 volts and three-phase wiring require only a 10 amp breaker.

Hydraulic

Rotary lifts require Dextron III automatic transmission fluid, or a similar International Standard for Organization specification fluid for use in the hydraulic system. Standard two-post Rotary lift installations must have 19 quarts, or 17.98 liters, of fluid. The lightweight mid rise lift requires only 6.5 quarts, while the heavy duty Rotary lift must have 22 quarts.