Considering performance upgrades for your ride, but don’t know where to start? If you ask the experts, tuning and power upgrades are done in stages. Start by adding parts that push more air into the engine for combustion, follow up by balancing fuelling and timing and wrap things up with strengthened internals to maximise power delivery. For stage one, you’ll be looking at revised air intake systems, uprated exhausts, and an ECU tune to balance things out. This sets the stage for all mods down the road.
Why Go Aftermarket?
The tuning scene is populated by hundreds of specialised aftermarket brands, each building on the shortcomings of original equipment parts with bettered designs, superior materials and extensive real-world testing to verify results. Specifically for exhaust systems, you’re looking at straighter and wider tubing, strengthened metals, and parts that deliver on all fronts. Buyers get more power, substantially more torque and improved throttle response, and an exhaust that should outlast the car no mater how hard you’re on the gas. The modular design is also straightforward to install, fitting in the recesses reserved for the stock system.
What you Get With a Performance Exhaust
Stock parts with narrower and winding tubing limit airflow, the basic ingredient for more power. This can increase backpressure, or how long the spent gases linger in the piping and exert pressure on the internals. They’re also made of thin-walled piping in crush-bent mild steel that struggles under higher temperatures (and generated pressure) at faster engine speeds, leading to possible ruptures or dents and hindering airflow even more. To get more power down to the wheels, more air in (with a performance air intake) and more spent gases out with a custom racing exhaust does the trick.
If you’re still wondering what qualifies for a performance exhaust system, ensure that it ticks all points below, before parting with your cash:
- More power and torque – half an inch makes a difference, and with wider exhaust tubing rounding out at 3″ in most cases, there’s more leeway for faster exhaust flow. Engines breathe easier and can get onto producing power with faster combustion cycles resulting in higher horsepower and torque figures. Estimates for full systems average 10 per cent of overall output. Something you can definitely feel when on the pedal.
- Better throttle response – power comes on earlier, with higher low-end torque spinning wheels instantly.
- Faster acceleration – improved combustion efficiency results in faster 0-100 times, and better in-gear acceleration. For street use this means easier overtaking with less pedal work, and on the track, the edge over the competition.
- Durability – strengthened mandrel-bent stainless steel (in 304 or 409 grades) fares better with higher temperatures, increased pressure, impact and corrosive environments. This is the entry point into higher durability at sane prices. A full-specced racing exhaust though can be optioned in exotics like titanium, hardened alloys (such as Inconel) and carbon fibre, with matching price tags. The combination of parts is considerably stronger than any type of steel, and will endure more abuse.
- Lower weight – tuners go to extraordinary lengths to shed weight where possible. A full turbo or header back exhaust can shave off 20 kilos or more. Not a number to downplay, especially when opting for other race components.
- Custom sound profiles – the beauty about performance systems is that they sound and look the part. Not only is there more power, but the higher volumes belting out of the tips is a joy to listen to. And this gets louder and deeper the faster you go, especially in valved exhausts. Of course, you can opt for ‘quiet’ systems with included resonators and mufflers with higher sound insulation and included baffles to lower decibels, but still get some roar.
Going With Compatible Parts
Power gains can be achieved with exhaust separates compatible with the engine layout and type, or complete systems with different goals in mind. Separates like downpipes for turbocharged cars, downpipes and extractors for aspirated engines, high-flow catalytic converters and cat deletes for petrol track cars, or uprated DPF filters for oil-burners all produce extra power by improving exhaust flow and velocity. Headers and extractors are also involved in scavenging or the pulsating vacuum effect of drawing spent gases out of the combustion chamber. The good thing about racing separates is that can replace stock parts without any additional work, provided you get compatible components for the vehicle.
Most buyers though choose packaged configurations. Axle-back systems swap out factory parts from the rear axle to the tips, with the focus on improving sound and adding resonated or non-resonated silencers and mufflers, and giving the tips more visual dazzle. Cat-back and GPF-back variants on petrols, and DPF-back systems on diesels, additionally include wider mid-section tubing from converters and filters for a tangible power gain. The power gains though come from header and turbo-back performance exhaust systems. These throw out all the old piping, and slap on a new exhaust from the manifold to the tips.
When buying, set a realistic budget and see if this meets your goals. Axle-back systems are affordable, but won’t bring more real-world performance. For that you’ll be shelling out more cash, opting either for cat-back systems, or a full header-back exhaust. Where possible choose from the growing number of specialised Australian exhaust parts brands, which offer unmatched workmanship, advanced production methods and materials, and some interesting proprietary tech, particularly with the sound.
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