purpose of flywheel

i was just wondering what exactly does a flywheel do y do we need it and y dont car makers put on light weight flywheels on teh cars they build if the lightweight flywheel is better.

thanxs

It is used primarily today as a means to connect the engine to the transmission. With automatics, many manufacturers simply use a very small flexplate in lieu of a full size flywheel. The starter ring gear is incorporated on the torque converter.

There are light weight flywheels available for some manual shift applications. The problem you encounter with a clutch is having a place for the starter to engage the engine. This is done on the flywheel. You also must have a metal/alloy stronge enough to take the stress of engaging the clutch between (for example) a 160 hp engine and the transmission to move a 2800 lb car. And everyone doesn't drive like grandma.

In many years gone past, the flywheel was used to help balance the engine. It had to be indexed properly to the crankshaft.

For a good case study of your questions, do a little research on a racer called the winged outlaw. Here, they push start the car, eliminating the starter. They use a coupler to engage the engine to the trans. You are either in or out of gear with an engine producing between 600 and 800 horsepower.

damn that fool sounds smart. believe what he says