I thought those of us who read up on Nissan (there web site) should see some of the changes that they say will be in the the new 4 cyl. type. The combustion period has been shortened and thermal efficiency improved by strengthening the gas flow in the combustion chamber. Some of the world's most advanced technologies have been employed to reduce friction, including the use of a new machining method for the cylinder bores and the application of a mirror-like finish to the crankshaft and cam bearing surfaces. The load imposed on the engine to drive the air conditioner and other auxiliary units has been reduced by enhancing their efficiency and improving the control program.