plug boss cooling. These approaches did not require a high-conductivity copper insert, but did not preclude its use. Ford tested a Wankel engine with the plugs placed in the side plates, instead of the usual placement in the housing working surface (, 1978). Torque delivery Wankel engines are capable of high-speed operation, which means that they do not necessarily need to produce high torque in order to produce high power. The positioning of the intake port and intake port closing greatly effect the torque production of the engine. Early closing of the intake port increases low-end torque, but reduces high-end torque (and thus power), whereas late closing of the intake port reduces low-end torque, whilst increasing torque at high engine speeds, thus resulting in more power at higher engine speeds. A peripheral intake port gives the highest mean effective pressure; however, side intake porting produces a more steady idle, because it helps to prevent blow-back of burned gases into the intake ducts which cause "misfirings", caused by alternating cycles where the mixture ignites and fails to ignite. Peripheral porting (PP) gives the best mean effective pressure throughout the rpm range, but PP was linked also to worse idle stability and part-load performance. Early work by Toyota led to the addition of a fresh air supply to the exhaust port, and proved also that a Reed-valve in the intake port or ducts improved the low rpm and partial load performance of Wankel engines, by preventing blow-back of exhaust gas into the intake port and ducts, and reducing the misfire-inducing high EGR, at the cost of a small loss of power at top rpm. Elasticity is improved with a greater rotor eccentricity, analogous to a longer stroke in a reciprocating engine. Wankel engines operate better with a low-pressure exhaust system. Higher exhaust back pressure reduces mean effective pressure, more severely in peripheral intake port engines. The Mazda RX-8 Renesis engine improved performance by doubling the exhaust port area compared with earlier designs, and there have been studies of the effect of intake and exhaust piping configuration on the performance of Wankel engines. Side intake ports (as used in Mazda's Renesis engine) were first proposed by Hanns-Dieter Paschke in the late 1950s. Paschke predicted that precisely calculated intake ports and intake manifolds could make a side port engine as powerful as a PP engine. Materials As previously described, the Wankel engine is affected