Nissan equips many of its newer vehicles with a dual-mass flywheel to control a portion of the engine’s torsional vibrations, which causes various types of gear rattle noises. A dual-mass flywheel exhibits unique damping characteristics that cannot be replicated with a single-mass design.
When converting from the heavy, original dual-mass flywheel to any lighter, single-mass, aftermarket flywheel, much of the original torsional damping is defeated (with a partial exception when also using a spring-centered or damped clutch disc). As can be expected, the result is an increase in gear noise. In general, the lighter the flywheel is, the louder the gear noise will be.
During testing, ACT found two types of gear noise that commonly occur when using a lightened flywheel on the 350Z or G35: 1) idle mode rattle (also called neutral rollover noise), which occurs when idling in neutral with the clutch engaged, and 2) burst rattle (or start-up rattle), which is heard when accelerating heavily at very low rpm. Although annoying to some drivers, the additional gear noise should pose no harm to the transmission.
ACT manufactures flywheels in both Streetlite and Prolite versions. Each version is manufactured with integral ring gear that allows a greater weight reduction and eliminates the chance of gear breakage. ACT heat treats the entire forging for strength and durability. All ACT flywheels provide safety, improved throttle response, better feedback to the driver and increased acceleration. ACT flywheels are able to be resurfaced, if needed, which can save from having to purchase additional parts, as is common with any two-piece units.
ACT flywheels meet SFI Spec. 1.1 and are legal for competition in all racing organizations where SFI certification is required.
Installation note: The alignment hole in the flywheel must be lined up with the crankshaft dowel. It is possible for the flywheel to be mounted in a misaligned position. If the alignment hole is not positioned properly, the car will not start or run properly because of incorrect timing of the crankshaft, speed triggers machined into the flywheel.