Aftermarket Commodore Exhausts: Benefits, Types and What to Look for When Buying

New cars may have that new car smell, but most lack character or defining traits to single them out of the slew of look-alikes. Holden didn’t have such issues, with homegrown legends like the Commodore enduring some of the longest best-selling runs in Aussie car history. Big, burly and with roaring engines, the car vied with the Ford Falcon in one of Australia’s longest and best-remembered rivalries.

While both brands shuttered local production, Commodores and Falcons still roam the streets in large numbers. And they’re regarded as real cars, not marred by downsizing, emissions standards or high profit margins. If you’re lucky enough to have your hands on a decent-condition Commodore and a V6 or V8 engine workhorse engine, there’s quite a bit of kit to bring the legendary car back to the limelight. Rebuilders, tuners and regular Commodore owners get more out of the car with aftermarket Commodore exhausts.

Why Consider a Performance Exhaust in Your Commodore?

With a production stint lasting nearly half a century, Holden manufactured quite a few Commodores in numerous badges, series and engine variants. Especially popular was the VL series from the mid-1980s with a 3.8-litre V6 or a bigger 5-litre V8 in higher tune, the VS and VT cars of the 1990s, and the VE and VF Commodores produced between 2006 and 2017.

The base engines provided the foundation for tuned Calais and SS models, and were the main ingredients for all HSV cars and their hugely powerful 6 and 6.2-litre mills. Any of these cars benefit from a Commodore performance exhaust.

Regardless of which Holden Commodore you drive, a performance exhaust system lifts stock power numbers for a livelier driving experience. Compared to the stock exhaust, this results in a long list of accompanying benefits:

• Improved airflow – aftermarket exhausts go at least half an inch wider. The added space results in smoother exhaust flow, with spent gases exiting the car faster. This prevents common problems like backpressure in the stock tubing, which effectively chokes the engine and blocks the next combustion cycle.
• Faster acceleration – a more efficient engine and a less restrictive exhaust system translate to faster acceleration and higher top speeds.
• More power – a full exhaust adds over 50hp in the high-spec V8 cars – a substantial boost for a more responsive car.
• Durability – the crush-bent mild steel, especially in the third-gen cars, resulted in punctures and leaks that hurt engine performance. A performance Commodore exhaust is built from more durable, mandrel-bent stainless steel that better handles higher temperatures and pressures, handles direct hits from road debris, water and mud without rusting or staining.
• Improved engine longevity – improved airflow, reduced temperatures and no backpressure limit the impact on vital engine parts, including the cams and exhaust valves, resulting in lower maintenance needs, and engines that last longer.
• Better sound – the 3, 3.6 and 3.8-litre V6s couldn’t quite replicate the sound from the bigger V8s. Change this with the sound tuning options of a bespoke Holden exhaust. Parts like revised headers, bigger extractors, wider mid tubes, and different muffler and resonator layouts help get a bigger and bolder sound. There are also options to quieten things down or reduce exhaust droning in older cars.
• Customisation – with modular parts, Commodore owners can mix and match to get the results they want.

Exhaust System Configurations

System builders offer Commodore exhausts in three “complete” configurations. Choose an axle-back exhaust with new parts from the rear axle to the tips if you’re looking for a full-bodied sound. This involves fewer parts, is the most affordable complete system, deals with muffler punctures, and adds style with interesting tip designs.

Upgrade to cat-back systems for real power gains and livelier throttle. This builds on the benefits of axle-back systems to include wider mid-pipes that help with exhaust flow. Full header-back exhausts go the whole hog with completely new parts. Revised header tubes and extractors improve exhaust scavenging to create vacuum and pulsation to draw spent gases out the valves faster; high-flow catalytic converters aid exhaust velocity and result in fuller burns for lower emissions, while muffler and resonator combos tune the sound. There are also turbo-back variants for the 6.2-litre engines with improved downpipe designs resulting in smoother turbo spooling.

Materials, Widths and Compatibility

Stainless steel does well against the higher heat in tuned engines and has the strength to resist road obstacles like speed bumps and potholes. Advanced production processes also help. Mandrel bending ensures the piping has uniform diameters throughout the length, optimising flow and exhaust speeds. This also adds strength and prevents kinking. For overall value, stainless steel is the material to beat, balancing performance, durability and price.

Buyers can save some cash when opting for aluminised mufflers, or spend more on high-end materials like Inconel, titanium and carbon fibre. These surpass steel for overall strength, heat and impact resistance and come at a lower weight. The catch though is the much higher price and low availability.

Also, consider how pipe diameters affect performance and sound. Choose between 2.5 and 3″ piping. Bigger diameters get more character in the exhaust note and ease spent gases faster out the tips. Lastly, ensure parts, piping and mounting hardware are compatible with the engine and your Commodore badge and series for a clean, leak-free fit.