Inside Look: Behind The Scenes With Borla Performance Products

We recently had the opportunity to visit the Borla Performance facility in Johnson City, Tennessee and we were given an extensive look at how this American-built company is building performance exhaust and induction systems for enthusiasts worldwide. Sitting on 100 acres in the mountains of east Tennessee is Borla’s 320,000 square foot manufacturing facility. This facility, which is a 1/4-mile wide, houses the company’s exhaust and induction manufacturing as well as their research and development center.

Exhaust components begin here where they are mandrel-bent and stamped.

Exhaust Systems

What Borla is most closely associated with is their high-performance exhaust systems. These systems are used prominently by aftermarket tuners and often also included in the performance catalogs of many OEM performance divisions.

The company offers everything from direct-fit systems for modern musclecars and classics to lightweight race applications for hardcore enthusiasts. Borla is also back in the motorcycle exhaust market and they’ve recently ventured into marine exhaust system offerings as well.

Borla’s exhaust systems are constructed from a range of high-end materials and depending on the application, anything from stainless steel to titanium can be used. These systems offer everything from mild tones that are just a bit more aggressive than stock, to a sound that will let everyone know you’re on the way. Improvements in exhaust flow also translate into more horsepower and often better fuel economy on nearly any application.

Muffler cans are stamped and welded. Next, they're stuffed and fitted with the end caps.

We go for an install time on most vehicles of around an hour. -Tim Lovelady

Every exhaust system is designed to fit the original equipment hangers and locations on a vehicle. This eliminates the need for enthusiasts installing the systems to have to move a hanger, or even bolt on or weld in a new one. “We go for an install time on most vehicles of around an hour,” says Tim Lovelady, Quality Control Manager for Borla. Maximizing efficiency is key to a successful manufacturing operation.

Borla produces their components in batches. What this translates to is that everyone involved in the production process is working on the same systems at the same time. This speeds the process up, and eliminates confusion. You won’t get a Mustang tail pipe welded to a Corvette muffler, because those parts wouldn’t ever be built at the same time. Quality controls throughout the production and post production processes also ensure such mistakes wouldn’t occur. Borla controls every aspect of the manufacturing process in-house, with the exception of sourcing the quality raw materials.

Building Exhaust Systems

Fixture Mock Up

All exhaust systems have a fixture set up. Each system is placed in the fixture prior to welding to ensure that all components are up to the correct tolerances and also that they align properly with one another. This ensures uniformity and consistency in the manufacturing process. It also helps Borla meet it’s goals of having many of their customers able to bolt on most of their muffler systems in an hour or less.

Steel arrives either as tubing, or sheet and is placed in a mandrel bender and embossing machines as necessary. Components are cut, bent and stamped to the specified sizes for the systems being built at that particular time.

Depending on the system, mufflers are then shaped with a large press and die and have their internal tubes or baffling installed. From there, end caps are installed and sound deadening material added as specified for that type of muffler. After this part of the process, each muffler is sent to final welding. While there is some automation to the machinery, most of this work is done by hand including the welding. Which means that each muffler is in fact still hand-welded.

In systems or components where mufflers are paired together or in headers where complex systems are installed, all the key components are placed into fixtures. Tim Lovelady told us “Everything goes in the fixture, and has to match up exactly.” These fixtures ensure that the exhaust systems or headers are consistently assembled the same every time. Even though the welding process is performed by hand, the fixtures ensure that each tube, flange, or hanger goes in exactly the right spot, every time. All tubing is then cut and any hardware or hangers are installed before the final finished welding is performed.

The last step in the process is the final polish, cleaning and inspection. What’s going to show on your car is brought to a beautiful shine in this step, again done by hand. At the same time all components are checked for quality, ensuring the welds are done properly and each component is assembled correctly. Once polishing and quality control inspections are completed the items are packaged and boxed. From here they go to the warehouse where they’ll be shipped to suppliers and customers worldwide.

Final steps in building every exhaust system include final welding. Once welded all parts are inspected by quality control, appropriate parts receive polishing and cleaning , followed by wrapping, packaging and boxing. Orders then go to the warehouse where they await shipping to the customer.


Recently Borla acquired TWM induction. “We have handled airflow at the rear of the car, it made sense that we should offer something on the induction side as well so we could offer our customer’s a complete line of products,” said Borla’s Tracie Percell.

These induction systems offer several options to builders, and enthusiasts. First is a conversion from carburetors to fuel injection. The second is an alternative over less attractive fuel injection manifolds.

This system installed on a small-block Ford equipped replica Cobra gives the engine an old school look and feel with the benefits offered by fuel injection like easier cold starting, better idle quality and improved part throttle acceleration and cruising.

The individual throttle body appearance offers a look that resembles old school multi carburetor or mechanical injection setups. With these systems, you get the ease of use and drivability of a modern fuel injection system. The intake systems offer increased hood clearance which can allow for a wider variety of engines under the stock hood, as well as clearance where other induction systems may not fit.

Building Induction Systems

We already handled airflow at the rear of the car, it made sense that we should offer something on the induction side as well so we could offer our customer’s a complete line of products.

The lower intake manifold component is cast at a different location but the rest of the hard parts and the final assembly of all intakes is done at Borla’s Johnson City facility.

Throttle bodies are built for aluminum extrusions and finish machined on a CNC machine. The same holds true for the system’s air horns. Borla builds components for the induction systems similar to how they build their exhaust systems in terms of doing production runs. Parts are then stocked and each intake is built to order.

Every throttle body is tested on a flow bench to ensure quality, and that they all flow within a relative percentage of each other due to Borla’s high QC standards .

Each intake system is hand assembled by one individual technician at the Johnson City facility. This technician carefully inspects and sets up all the individual components. He is also responsible for adjusting all the components of the intake system’s billet Capstan linkage. This ensures all the throttle blades operate in unison, opening and closing together.

Top Left: Throttle bodies are machined on the CNC machine. With the exception of the lower intake casting, nearly every component of the intake system is built by Borla in-house at their Johnson City, TN facility. Top Right: All throttle bodies are vacuum tested and must pass within a specified parameter to ensure even performance across all cylinders. Bottom: A single technician is responsible for assembling all induction systems. This includes installing and adjusting the linkage systems.

The fuel pressure regulators are also completely assembled in house and are included with each induction system. The regulators rely on a vacuum signal and can be adjusted, however they are preset by Borla for the specifications of the engine and induction system to be used.

Vacuum ports are also provided with each intake manifold. There is a -6 available for vacuum boosters, as well as a vacuum accumulator which will provide an accurate signal to a MAP sensor.

Each system uses a single throttle position sensor to relay information back to the computer control system on the position of all the throttle bodies. Since the system is preset from Borla there is no need to adjust each throttle body, keeping the TPS signal accurate and airflow consistent across the board.

The fuel rails are also included with each intake system. These high volume rails come with -6AN fittings, and have a standard mirror polished finish. These means you won’t have to try to source or build your own rails for the system.

Induction systems are available for a wide variety of applications from four cylinder VWs to small- and big-block Chevy and Ford engines including the LS. Borla is also offering systems for the new Chrysler Hemi, and is constantly researching new applications.


This optional carbon fiber air cleaner assembly fits over the air horns and allows for the use of a conical style air filter if a customer would prefer to run that over the mesh screens included with the throttle bodies.

Borla offers their customers a wide variety of options for their induction systems depending on each application’s individual requirements. The systems themselves are designed to work with a FAST self learning XFI ECM, although they can also be setup to work with advanced sytstems from FAST, MOTEC, or ACCEL. Borla can provide the XFI system and engine specific wiring harness as an option on each order. “Most customers will choose a variety of options for these systems,” says Garry Polled, Fuel Injection Manager for Borla Induction.

Other options on the induction side include:

  • Bosch fuel injectors, sized for the application
  • Bosch electric fuel pumps, also properly sized for the application
  • Idle air control valve for higher cold start RPM and smoother operation
  • Powdercoating on the intake, throttle bodies, and/or any combination
  • Polishing of the intake or throttle bodies

There’s also an optional carbon fiber air cleaner which could be used on four or six cylinder applications. This air cleaner goes on over the air horns and allows customers to run a standard cone style air filter. The throttle body screens will likely do enough in most applications, however under some dusty circumstances this could be a prudent option.

Induction Performance

The beauty of the Borla induction system is it can be optioned to meet a variety of customer needs and support a wide range of engine capabilities. The eight stack style injection system offers excellent throttle response.

If you’re switching from a carburetor to this particular system, you may not see a change in horsepower. As Polled explains, “If a guy is changing from a 750 or 850 CFM carburetor, he’s likely not going to see a change in his horsepower,” good news for those who are afraid the switch may cost tons of engine power.

Borla tells us this cross ram design for the Ford 351 Windsor engine gets the most attention at trade shows and events where it is shown. Currently it’s only avaibale for the 351w, however they are working on other possible applications.

Other gains can also be had, as Polled expalins, “It will fatten up the torque curve and offer better drivability than a carburetor.” The fatter torque curve translates to better mid range power and better drivability over the carburetor it replaced. Most fuel injected engines are going to run leaner and smoother at idle, and offer better cold starting characteristics as well.

Power capability of these systems depends entirely on the engine and build. As Polled told us, a typical small-block Chevy setup could be configured to handle in the 500-600 hp range. The system is setup primarily with street driven vehicles in mind, though you could in theory also use it in some street/strip or racing applications where allowed.


While the cross-ram is pretty trick for the 351w, we also really like the layed in look of this Chevy LS manifold.

Borla offers these induction systems for a wide variety of applications. These include four, six and eight cylinder engines. During our visit we saw many of the systems shown and not yet appearing in their online catalog, including small- and big-block Chevy and Ford, GM LS series engines, Chrysler’s new Hemi, Honda and VW four cylinders, and even a Porsche system.

Borla’s Chris Robertson told us, “Research and development is continuing on a variety of systems, with the main focus on those engines that are currently most popular in the aftermarket.” After talking with Robertson about all the possible future options, needless to say we’re excited to see what’s next.

The biggest piece of eye candy we saw during our visit was the cross-ram design for Ford 351 Windsor engines. The cross-ram is currently not available for any other engines, however it offers some real appeal and old school flavor. We’d definitely like to see this one under the hood of more cars at the local cruise nights and shows.

From the induction side to exhaust, Borla now offers products for a wide range of vehicles and applications. This company is continuing to innovate, and expand it’s offerings to meet the demands of today’s performance enthusiasts, while proudly designing and building their products here in the USA. Stay tuned for more!

About the author

Don Creason

Don Creason is an automotive journalist with passions that lie from everything classic, all the way to modern muscle. Experienced tech writer, and all around car aficionado, Don's love for both cars and writing makes him the perfect addition to the Power Automedia team of experts.
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