The harmonic balancer that hangs off the front of your engine isn’t the star of the show when it comes to horsepower, however, it plays a critical role in making sure the engine remains happy. To learn more about this mysterious piece of metal that is essential to making sure an engine stays balanced we talked with Brian LeBarron from Fluidampr. LeBarron touches on how a harmonic balancer is made, how to avoid a balancer failure, and more!
Dragzine (DZ): What goes into the research and development of a harmonic balancer?
Brian LeBarron (BL): Development of a new Fluidampr harmonic balancer is customer driven. We encourage engine builders and the industry as a whole to help drive the process so we can exceed user needs. Once we know what users are looking for in a balancer, we can begin extensive research, including expert torsional vibration analysis and simulation modeling. Once a design has been approved, prototypes are additive printed for fitment verifications.
There is no replacement for validation testing. Functional prototypes are constructed next and thoroughly tested for fitment, vibration control, and durability. If it is a new design concept, the prototype is sent to SFI for independent approval. Quality takes time and in total, a new Fluidampr harmonic balancer may take up to six months before production begins. Our goal is to deliver the best viscous harmonic balancer available to professional motorsports.
DZ: How is a harmonic balancer manufactured exactly?
BL: Fluidampr is a performance viscous harmonic balancer. You’ll find non-racing viscous types on luxury and supercars from major OEMs. The design differs from common tuned elastomer harmonic balancers in daily drivers. Fluidampr is considered a broad range harmonic balancer because it is effective at controlling crankshaft torsional vibration across the entire rpm range.
Fluidampr performance harmonic balancers are proudly made in the USA. They are constructed from three main components; an outer housing, internal inertia ring, and viscous silicone fluid. The outer housing and inertia ring are CNC precision machined and computer balanced to tighter than OE spec. A thin layer of proprietary silicone fluid is then placed between the outer housing and inertia ring. The unit is sealed with a laser-welded cover to prevent contamination from dirt, oil, and solvents. Finally, the harmonic balancer is finished in RoHS-compliant black zinc chromate to prevent corrosion.
DZ: How can people avoid experiencing harmonic balancer failure?
BL: The harmonic balancer may be the least understood critical engine component. Its basic function is to control crankshaft torsional vibration. This is the end-to-end twisting and rebounding of the crankshaft caused by combustion. Reduce this vibration and you can improve engine efficiency and durability.
The most common, low-cost approach OEMs use for daily drivers is a tuned elastomer design. Engineers know where the worst vibration will occur and design the harmonic balancer for those conditions.
In motorsports, failure often occurs when we modify the engine. Increasing torque will overwork a stock harmonic balancer quickly and cause problems. Greater work generates more heat, which in turn breaks down the elastomer in a balancer. A simple preventative maintenance routine is to inspect a stock tuned harmonic balancer for signs of cracked, bulging or missing rubber. Upgrade if found.
Changes to the rotating assembly can also shift where the most destructive vibration will occur. That means your stock harmonic balancer is no longer ‘in-tune’ to do the most good. In this case, you will want to upgrade to a broad range harmonic balancer, such as Fluidampr, at the time of those changes.
DZ: When does someone need to step up to an aftermarket harmonic balancer?
BL: The harmonic balancer is a fundamental engine building block to achieve efficiency and durability so we recommend upgrading early in the build process. If you’re modifying in stages it’s typically next in line after a cold air intake, exhaust, and tune. Anything above that, or changes to the rotating assembly, and you’ll want to include it in your initial package.
Investing in a Fluidampr performance harmonic balancer is one less thing to worry about. It is designed to last the life of the engine with no maintenance or future tuning required. Plus it helps you to get the most out of all the other fun power adders.
DZ: How do you select a harmonic balancer for a power adder application?
BL: Fluidampr makes the process very straightforward. Due to its premium viscous style design, it is effective across the entire rpm range. Another advantage is there’s no setup, maintenance or future re-tuning is required. They are designed for specific engine applications so ordering is as easy as knowing your year, make, and model.
In Fluidampr’s line for 396 – 427-inch Big Block Chevy applications we do offer 6-1/4-inch, 7-1/4-inch and 8-inch diameters. In drag racing applications the 8-inch is the most popular to handle the straight out power … that’s simply popular preference. You can use a 6-1/4-inch in drag racing but the tradeoff comes in durability and performance. Most Fluidampr harmonic balancers offer provisions for drive pulleys and/or custom mandrels as well.