Often times, people will upgrade their flywheel while replacing the clutch. If you have a clutch that needs to be replaced but you’re debating on whether to upgrade to a lightweight flywheel, this list of pros and cons might help you reach a decision.
Pros of Lightweight Flywheels
This mod is popular for many good reasons, the main ones being:
1. Faster Engine Acceleration
This is the main reason people upgrade to lightweight flywheels (and a clutch rated for above stock horsepower, such as this lightweight flywheel/clutch kit for Audi B8 models with a 2.0T engine). As a lower mass flywheel spins more freely, the engine will accelerate a bit quicker than normal. The difference isn't large, but the sooner you can get your engine up to the higher RPMs, the more power it can produce. People who track their vehicle will definitely notice an improvement with a lightweight flywheel. Street drivers? Not so much.
2. Low Cost
While lightweight flywheels can range between $150 and $350, you can find a clutch kit with a lightweight flywheel included. Many of the clutch kits we sell (such as this one with a JB Racing single-mass performance flywheel included) include a high-quality lightweight flywheel in place of an OEM-spec flywheel at no real additional cost. That means you don’t really have to pay extra for a flywheel upgrade while replacing your clutch with the right kit.
Cons of Lightweight Flywheels
A lightweight flywheel may cost next to nothing and boost your engine’s acceleration. But it comes with a few drawbacks, including:
1. Reduced Off-the-Line Performance
If you want to maximize performance from a standing start, a lightweight flywheel might not move you in the right direction. It depends on the type of vehicle you have, but often times reducing flywheel weight hurts 0-60 times. It typically helps in the quarter mile, however, and definitely helps at the racecourse.
2. Rough Engine Feel
With a lightweight flywheel, the engine will feel rougher while running. One of the main reasons major automakers make their OEM flywheels fairly heavy is because a heavy flywheel has more inertia. If there's a random misfire, for example, a heavier flywheel will basically compensate for that as a result of its inertia. If the flywheel is lighter, any sputter or unevenness in the engine will be easier to feel.
3. Gear Rattle
If the lightweight flywheel is part of a dual mass flywheel conversion kit, than the vehicle will have some 'gear rattle' or 'gear chatter' after the conversion. This is normal, though. The gears make noise when they're good and hot, as they expand at slightly different rates. This is true of all manual transmission vehicles. To minimize this problem, auto manufacturers put dual-mass flywheels into their vehicles, as these flywheels basically absorb this chatter/rattle sound. So when you go with a single mass lightweight flywheel, the sound is more easily heard. This issue varies from car to car.
Again, no harm comes to the gearbox. If the gear rattle annoys you, however, you can buy a lightweight flywheel that’s designed to eliminate the noise (like this performance flywheel & Sachs clutch kit that fits most late-model BMW 3-series).
The Bottom Line
Adding a lightweight flywheel to your performance car has advantages and disadvantages. There’s a way to enjoy the advantages while minimizing the disadvantages, however, and it is to get a flywheel that’s specifically designed to eliminate certain problems.
Looking for a lightweight flywheel that solves a certain problem? Please contact us. We’ll be happy to help you find the right lightweight flywheel for your car!