Nobody fiddling around with Toyota's all-new C-HR and its 2.0L engine with its belt-driven transmission expects to be setting records on the dyno, and that includes us. But that doesn't mean there aren't improvements to be made, and to prove that, we turned to longtime exhaust maker Borla, which turned out one of the first performance-based exhaust systems for the C-HR.
Never mind the C-HR for a moment; for Borla, exhaust development starts with knowing which applications to go to the trouble of making something for in the first place. And according to the company's VP of sales and marketing, David Borla, that decision's based on obvious things like requests from consumers, Borla distributors, the media, and even vehicle manufacturers. It's also based on less obvious things, like intuition, or the sort of experience to know which applications might be hits and which might be misses that only a company doing this for 40 years could have. "When we see something new that lines up well in the right areas with something we've had success with in the past, we're more likely to take the risk of developing parts for that application," Borla says.
Speaking of development, Borla's R&D process begins with its people knowing what its end users might actually want. For example, the guy with the C-HR and the guy with the Super Duty Ford pickup care about entirely different things. According to Borla, if the company can fulfill those specific needs and at a price that works for everyone, then R&D will move forward. From there, a prototype is made up that's designed to meet whatever parameters that, say, the guy with the C-HR might care about.
No matter the application, that prototype process is more involved than you might think. Before a single tube is welded up, whatever car that prototype is meant for-in this case the C-HR-has to be dyno-tested in stock form to understand its powerband, and its exhaust flow-benched in order to, as Borla puts it, get an understanding of its flow characteristics. "Once we have those baselines, we use scientific formulas to come up with the first few iterations of our product," Borla shares. "Those initial prototypes are tested on the vehicles and then dialed in even further with real-world experimentation, which is all verified through our dynos, flow benches, and other diagnostic equipment."
If you think every one of Borla's exhaust systems are just reworked versions of whatever the company last made, you couldn't be more wrong. Aside from each system's unique shape that has to allow clearance for all of the same things the original exhaust did, Borla's R&D team has to consider all sorts of other things, the most important of which is tubing diameter. "In most cases, the best diameter is smaller than what end users believe, but we won't allow that to change our process," Borla says about those mandrel-bent tubes. "You'd be surprised how much power is lost in the [low-to-mid] rpm ranges with oversized tubing."
Borla goes on to explain that tubing diameters arrived at by way of specialized tooling and diagnostic equipment leads to you ending up with the most power possible throughout the entire rpm range. "So many enthusiasts are driving around with 3-inch exhaust systems that are killing their power, but they don't know it," he says. He goes on to warn about some competitors' dyno sheets that highlight peak horsepower figures but little else. "If you want to go fast, you want to know what happens everywhere in the rpm range," he says. "Those large-diameter systems that quote a peak horsepower number are losing power down low where you drive most."
For Borla, it's the mufflers that make the company's exhaust systems so unique. Here, there are no universal mufflers compatible with everything from that Super Duty to your Civic. Instead, this exhaust maker relies on mufflers specific to each application, which leads to the best possible performance and sound quality, every time. "While this may seem obvious," Borla says, "the reality is that we're one of the rare exhaust brands that doesn't use universal mufflers."
From there, successful prototyping leads to things like building production fixtures, creating 3-D CAD drawings, and then addressing all sorts of business concerns on the back end so people like you can eventually buy that exhaust system, even if you're driving a C-HR.