Today’s cars rely on a harmonic balancer, or crankshaft damper, to reduce torsional vibration typically found in the crankshaft when the engine is under load. While a technical innovation in its own right, it is still possible to improve over the OEM design. Thanks to companies like Fluidampr, you can now order up a lightweight, more efficient piece for your late-model or LS-swapped performance car. Below, we shared some insight with you, with the help of Fluiudampr, to help you better understand what a harmonic balancer is, what it does, how it works, and how a high performance version from Fluidampr can benefit you.

What is it?

A harmonic balancer reduces destructive crankshaft torsional vibration, which is the end-to-end twisting/rebound motion, that is naturally generated during each power stroke.  Harmonic balancers contribute to greater valvetrain and timing efficiency, plus they reduce the wear of critical engine components such as main bearings, oil pump and the crankshaft.  They often incorporate the main drive pulley for engine accessories, and they’re often overlooked as having no essential function to the life of the engine. As Fluidampr puts it, “If the drive pulley is incorporated with the harmonic balancer, removing or changing it to a lightweight design, or using a low quality product may be the single biggest costly mistake you can do to your engine.”

How Does it Work?

Performance dampers, like the ones from Fluidampr,  protect across a broad frequency range and can become more effective as magnitude increases throughout your RPM range, unlike that of a stock elastomer harmonic balancer.  Fluidampr specifically designs their performance dampers for the engine application it is intended for.
 
They consist of a free rotating inertia ring inside a laser sealed outer housing within tight tolerance of each other.  Both the inertia ring and the outer housing are computer balanced to exceed OEM specifications during manufacturing.  Between the inertia ring and outer housing, an area known as the “shear gap” is pressure injected with viscous silicone fluid.  This liquid maintains stability across an extreme temperature range and provides superior heat dissipation. 

 
As soon as your engine starts, torsional vibration is present.  As Fluidampr tells it, to damp an engine’s destructive effects, the outer housing turns at engine RPM, while the inner inertia ring immediately self-centers and is free to be ‘shocked’ by each torsional vibration event.  As the inner inertia ring moves in-and-out of RPM with the outer housing, the shearing force through the silicone transforms the vibration to heat, which rapidly dissipates through the housing.  Since the mass of the inertia ring is engulfed in a thin film of silicone and not directly connected to the crank, it can be calculated that only 2/3 of the total Fluidampr weight is rotating at RPM.  For example, a 7.9l pound Fluidampr for a Chevy LS1 only ‘feels’ 5.3 pounds at speed.

Why Do I Need a High Performance Damper?

When you install performance parts that increase torque (like an intake manifold, exhaust system, or a camshaft), it can cause an increase in torsional vibration magnitude, but it keeps the frequency the same.  If you need any clues that your OEM harmonic balancer is not performing adequately, it will be cracked, bulging, or missing rubber between the hub and outer ring.  This cracking is caused by excessive heat retention, over-stretching, and age.  A common failure will be the outer ring separating from the hub, causing damage inside the engine bay.  Most race sanctioning bodies require a SFI 18.1 spec damper as a safety precaution for just this reason.

Speed parts related to the rotating assembly – such as rods, pistons, crank, flywheel/flexplate usually change both the torsional vibration magnitude and frequency.  According to our friends at Fluidampr, “a stock harmonic balancer typically is only tuned for a 50 Hertz peak variance.  Move a stock damper beyond its parameters and it may leave your critical engine components unprotected when torsional vibration is at its peak.”

Since there are limitless combinations of performance upgrades that you can do to an LS engine, the simplest and more effective solution is to install a Fluidampr performance damper.  By design, Fluidampr protects across a broad frequency and can become more effective as magnitude increases.  The earlier a Fluidamper performance damper is installed, the more you’ll benefit from the protection, performance and durability in the long run.

Let’s be honest; even though you can pick up a used LS-Series engine from a junkyard for pocket cash these days, you don’t want to have to suffer from failed engines any more than necessary. Wouldn’t you rather be having fun at the track or on the street, rather than fixing a broken engine during your free time?