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How To Select Appropriate Flywheel Part 1

April 15, 2021

Appropriate flywheel has considerable impact on vehicle’s performance, drivability and even safety.

There exist several materials for producing flywheel, namely cast iron, billet steel, billet aluminum and chromoly. Materials vary a lot in terms of cost and strength. Your choice is determined by specific model.

The following is what flywheel can do

1. Flywheel is installed to crankshaft and has a machined surface to engage with clutch disc which is between flywheel and pressure plate. It is critical for transmitting horsepower to manual transmission.

2. Flywheel also transfer inertia to drivetrain, which makes vehicle move from a stop when clutch is engaged.

3. In addition, flywheel has a ring gear on its edge, which engages the starter drive gear. In terms of externally balanced engine, flywheel is useful and helpful for engine rotating assembly balance.

NOTE: We ZNDmotor highly recommend you to replace flywheel fasteners as well when installing a new flywheel, since strength of bolt needs to match or exceed that of flywheel’s material.

How flywheel weight impacts engine performance

The selection of flywheel depends upon lots of factors, namely engine torque, vehicle weight, gearing and intended purpose.

Selecting appropriate weight is critical in improving driving experience.

The weight is relevant to flywheel’s diameter. Hence fewer cylinder an engine has, lighter the flywheel is.

Flywheel with standard weight can store more energy. As a result, it proves to be a good choice for moving stock-geared cars and heavier vehicles, like trucks, drag cars and rock crawlers. In addition, heavier flywheel can slow throttle response and maintain engine RPM longer when decelerating.

Lightweight flywheel can make engine response faster, when accelerating and decelerating. It is usually used for road racing and circle track, since it enables driver to drive deeper into turns with a sharper RPM drop when letting off throttle, and subsequently help engine recover faster into power band heading into the straightaway.

Lightweight flywheel also enjoys popularity among turbocharged drag racers, since it can help to spool the turbo and soften the launch with a high-torque engine.

Lightweight flywheel can deliver inertia of heavier flywheel. When at increased RPM, however, a slightly modified driving style is required to include more clutch slippage to make vehicle move.

In general, the lighter the flywheel is, the heavier the vehicle will feel. Of course, there remain exceptions, which depend upon specific model.