Boost Balance: Why You Need An Aftermarket Balancer For A Turbo LS

When we decided to switch power-adders from nitrous oxide to a turbocharger on Project Red Dragon, we knew there were going to be a lot of things that needed to be addressed. Since we were swapping engines and adding horsepower, it was the perfect time to beef up a few things, including the harmonic balancer. In this article, we’re going to speak to the benefits of an aftermarket harmonic balancer in a turbo LS application.

The LS engine has become one of the most popular powerplants for boost — they’re cheap, readily available, and can take plenty of abuse. These engines are capable of making astounding horsepower with a turbo in stock form, but that doesn’t mean you shouldn’t upgrade parts like the harmonic balancer, even if you’re on a tight budget.

An OEM harmonic balancer is designed to function at stock horsepower levels while operating within the RPM levels the manufacturer intended for the engine. Can the stock harmonic balancer function outside of those constraints? Absolutely, however, you’re entering dangerous territory when you push the stock harmonic balancer past those limits. The torsional loads that increased horsepower will put on the rotating assembly will quickly exceed the stock unit’s ability to control them…add a turbo into the mix and you have a timebomb waiting to go off in your engine bay.

The harmonic amplitudes created by adding boost to an engine will cause a host of problems, including causing a stock balancer’s rubber ring to delaminate, or even worse, the OEM balancer could shatter under the increased stress. There have been documented cases of each of these instances occurring — not only will this damage an engine, but spectators can also be injured. That’s why aftermarket companies put so much research and effort into creating harmonic balancers: they have to deal with a rotating assembly that’s literally trying to shake the entire engine apart.

Now, just because there are people who have been successful at using the stock harmonic balancer doesn’t mean you should. Nick Orefice from Fluidampr explains why you should upgrade your harmonic balancer when adding a turbo to your LS build.

“The stock harmonic damper is not built to hold the power and deal with the torture a modified engine puts them through. The stock damper is tuned to a specific frequency determined by the team that designed the engine — this is usually in a narrow range. Fluidampr viscous performance dampers have a broad range of damping ability. This allows the damper to tune in real-time to the harmonics of the engine throughout the entire RPM range.”

If you plan on going to the track with your boosted build you will definitely need to ensure you have an aftermarket harmonic balancer. All of the major sanctioning bodies have implemented rules that highlight what’s required when for a harmonic balancer, based on how quick your vehicle is. These rules were created through very stringent testing methods to keep racers safe and minimize engine failures that can cause downtime.

“An organization will get random dampers through a vendor or other unknown source so they can test the durability and integrity of the product. This is done by tests at 12,500 rpm for long durations to see if the dampers can deal with the stress of a high-performance engine. The NHRA and other racing sanctions require a safety standard from SFI; the certification is 18.1 which pertains to harmonic dampers/balancers. Fluidampr performance dampers are all SFI: 18.1 spec certified,” Orefice explains.

Project Red Dragon’s new heart is your standard stock bottom end 6.0 liter LS engine with an upgraded valvetrain. By using better valvetrain parts, we’ll have the ability to spin the engine to a higher RPM than stock, which will work perfectly with the 80mm turbo from VS Racing. Even without the turbo, that extra RPM would put some stress on the engine, so having an aftermarket balancer would be required. The balancer we’re using from Fluidampr (Part # 740111) is specifically designed for the LS engine. This means it won’t have any problems dealing with the additional horsepower our new boosted combination is going to produce.

Usually people associate having an aftermarket harmonic balancer with a high-horsepower naturally-aspirated build or a supercharged engine. So, do you really need to use an aftermarket harmonic balancer with a turbocharged LS build? Yes, you absolutely need to use one if you want to avoid having issues as you turn up the wick.

“Any power adders like turbos increase torque, and therefore also increase the torsional vibration amplitude on the crankshaft. The stock elastomer-style damper will wear out faster from the additional heat created from the torsional harmonics. This will cause the rubber bonded material to weaken over a shorter period of time and could allow the inertia ring to fly off while the engine is running,” Orefice says.

An engine is going to produce the most horsepower possible when it’s working at peak efficiency. There’s a substantial amount of locations you can unlock efficiency within an engine, and some of them are much cheaper and easier than others. Using the right harmonic balancer is one way to create some more efficiency while making sure your engine will have the ability to function at its highest level possible without any issues.

“Performance dampers are built to handle the additional power — many are tuned to cover a wider range of RPM. Fluidampr performance dampers are built to handle the extra power and load turbo engines produce. All builds start with a solid foundation, and a good harmonic damper is one of those key components needed to ensure your investment is protected,” Orefice explains.

Before you decide to just “send it” with a stock harmonic balancer on your turbo LS you might want to think about upgrading to a more robust unit. The cost savings of just using the OEM harmonic balancer might make sense initially, however, the consequences of a failure could wipe all of that out in an instant.

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About the author

Brian Wagner

Spending his childhood at different race tracks around Ohio with his family’s 1967 Nova, Brian developed a true love for drag racing. When Brian is not writing, you can find him at the track as a crew chief, doing freelance photography, or beating on his nitrous-fed 2000 Trans Am.
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