Why Choosing the Right Performance Exhaust Matters: A Cautionary Tale and Expert Tips
Many of our customers are first-time buyers of performance exhausts and free-flow systems. They often learn about these upgrades through friends, ads, or even a bumper sticker. Some customers dive deeper into the world of performance exhausts, researching the top brands, asking about pricing, performance gains, dyno test results, fuel efficiency, noise levels, and warranty concerns. However, they’re often met with a mix of accurate information and misinformation. Despite this, after gathering enough
details, they’re able to make an informed decision, knowing what’s available
and what they can expect to pay for the right performance exhaust system.
A larger percentage of customers, however, are often uninformed and tend to make their purchase decisions based solely on price. Unfortunately, this scenario happens all too often:
“Joe” calls to book an appointment for a repair on his aging performance exhaust system for his Honda 180i Ballade. When we inspect the system, we find that it consists of a branch manifold and a free-flow system, installed just 18 months ago. The branch is poorly designed, with four small 38mm pipes, only 300mm in length, pressed into a 4-1 collector. This merges into a 50mm knuckle joint that connects to a makeshift “free-flow” silencer system made from hot-rolled mild steel tubes, bent and welded into place with two silencer boxes. Unlike a proper setup with separate flanged sections, the whole system is a single welded piece from the knuckle joint to the tailpipe. To make matters worse, the rear box is not a true through-flow absorption type, and the mild steel rear silencer and pipe section have started corroding, leading to leaks and the need for replacement.
This highlights the importance of knowing what you’re buying when it comes to performance exhausts. Price shouldn’t be the only factor in the decision.
Joe asked me, almost like it was a trick question, “How much improvement do you think this system gave me?”
For context, the B18B is a fairly high-performance engine. It’s also widely known that not just any branch manifold will work effectively with this motor, and that using a silencer system with a diameter smaller than 57mm won’t optimize exhaust gas flow to match the efficiency of a proper branch manifold.
So, I replied with a bit of humour, “You probably got a minus 5% improvement!” To which he responded, “My car has never been the same since I installed this cheap system.”
It turns out Joe was a first-time buyer of a performance exhaust system, and unfortunately, he wasn’t very discerning. He didn’t do much research and assumed it was a straightforward process: “You want a branch manifold and a free-flow system, so you get one. My friend had a contact who gave me a good price…”
In the end, Joe’s story had a happy outcome. After some work, we managed to boost his Honda 180i’s power from a disappointing 52kW to 67kW (measured off the wheel at Gauteng altitude)—an 18% increase in power that he had been missing out on for nearly a year and a half!
There are two main reasons why people replace the stock manifold with a performance branch manifold:
- Cost-Effective Replacement:
Replacing a broken, cracked, or warped stock manifold with a factory-supplied original can be very expensive. A branch manifold, on the other hand, costs about half the price or even less, including installation. In South Africa, around 70% of branch manifolds are sold as replacement parts. Interestingly, in Australia, this number rises to approximately 90%, where most “extractors” are inexpensive press-bent items similar to the ones described earlier. In these cases, performance isn’t even a consideration.
- Performance Enhancement:
South Africa has more car enthusiasts per capita than almost anywhere else in the world. Fortunately, South Africans have access to well-designed, off-the-shelf branch manifolds that actually deliver performance gains at reasonable prices. When paired with through-flow silencer systems, these branches can significantly increase power, as proven on dynamometers. If you’re replacing a broken stock manifold with a quality branch, you’re not only saving money but also gaining power—especially if you opt to upgrade the stock silencer system to a matching performance setup.
That’s all for now!
Abel dos Santos
