NHRA requires the use of an SFI 18.1 harmonic damper for any car running faster than 10.99 in the quarter-mile. A performance harmonic damper that is SFI certified is calibrated for performance usage, and the SFI certification means that it has been tested to pass the containment standards in the event of a failure. A stock damper is calibrated for a specific power level and rpm range, and as you go beyond that point, the stock-bonded rubber damper becomes less effective and can fail with the damper coming apart. For example, the SFI certified Pro/Racer dampers range have been spin tested to 18,000 rpm, well in excess of SFI requirements.”Ĭhris Rose, of Innovators West, added, “As the power levels and rpm range increase on an engine, the harmonic waves being generated in the crankshaft can become an issue. That is why racers must consider a high-performance damper that is fit for purpose. Most OEM harmonic dampers are not designed to cope with the rpm and BHP levels experienced in competition. The function of the harmonic balancer is to reduce the amplitude of the torsional vibration peaks to an acceptable level. The peaks of this back and forth motion are measured as amplitude. This causes a deflection or twisting motion that is known as torsional vibration. An increase in gas pressure in the combustion chamber equals an increased twisting force on the crankshaft throws. Withers also mentioned, “When building a race motor, the engine builder needs to consider the targeted rpm and BHP. Both the Pro/Racer and Pro/Sport range of Dampers marketed by Pro/Race are SFI certified for competition and undergo annual testing for continued compliance.” The differences between an OEM and a high-performance harmonic damper would be clearly seen on a dynamometer. “Uncontrolled torsional vibration also robs an engine of valuable brake horsepower. Examples could be rapid wear on the camshaft lifter lobes, stretching of the timing chain, grooving of the timing chain sprockets, through to causing the flywheel to come loose on the crankshaft. Uncontrolled torsional vibration can damage and reduce the life of engine components. Graham Withers, president/owner of Pro/Race Performance Products, added, “Gas pressure in the combustion chamber has a direct relationship to the amplitude of the torsional vibration. That means you can modify the engine and not worry if your harmonic balancer is properly tuned.” It is engineered to protect over a wide band of frequencies throughout the entire rpm range, including high rpm. A Fluidampr performance damper removes the guess work. With every change made, the harmonics of the engine change with it. Constantly changing and tuning race engines is what keeps teams competitive. “You need a damper that will perform like it should in the most extreme conditions that stock dampers cannot do. “High-performance balancers are necessary to prolong the life of your engine,” said Nick Orefice, of Fluidampr. Lastly, friction-style dampers rely on internal clutch discs to quell harmonics. Viscous or fluid type uses fluid to absorb the flexing energy.
The elastomer type uses a rubber material, which controls much of the vibration. There are three major types of balancers: elastomer, fluid, and friction. So, with that, as the name implies, a properly designed harmonic balancer will absorb harmonics and vibration and keep your bottom end alive. Over time, the effects can lead to cracks and/or a failure. This twisting, followed by the metal rebounding, causes harmonics, even on robust aftermarket crankshafts. Because of this extreme force, the crankshaft is subject to torsional deflection. Now, imagine your legs firing as pistons rather than the smooth flow of a human pedaling.Īs you can imagine, the force within a race engine is far greater than what you can generate with your legs, and at times, it’s much more abrupt. In this case, you’ll be applying maximum force for only a short period (in degrees of crankshaft rotation) as you push past TDC, however, the power seems to be applied seamlessly. For example, imagine pedaling a bicycle briskly.
#HARMONIC BALANCER SERIES#
And while your engine provides continuous power through the rpm range, it’s actually a series of power pulses that keeps the crank moving. While we’d like to think the crankshaft spins 100 percent smoothly, that’s not always the case.Ī V-8 fires every 90 degrees of crankshaft rotation, so the power is applied in short, continuous bursts. Found at the front of the engine attached to the snout of the crankshaft, harmonic dampers are used to quell the harmonics of the crankshaft. A common part found on all high-performance engines is a harmonic damper (or harmonic balancer, as they are often called).
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