Choosing the right exhaust system for a VE or VF Holden Commodore

The Holden Commodore was Australia's best-selling car for 13 consecutive years, a run that lasted right through the VE's entire production life. By the time the VF rolled off the line at Holden's Elizabeth plant in October 2017, it wasn't just the end of a model; it was the last Holden ever built in this country.

That history is a big part of why so many VE and VF owners are still modifying their cars today. There's no more being built, so the ones still around have become prized possessions.

When we’re talking about performance or the sound of those glorious V6s and V8s, exhausts are one of the most popular upgrades. However, they’re not all the same, which is why we created this guide. It explains the most common types of exhaust upgrades for your Commodore, why you might choose one over the other, and some of the things you should consider before making a purchase.

Key takeaways

• A cat-back exhaust (everything from your catalytic converter back) is the simpler, cheaper upgrade, while a full system adds new extractors and high-flow cats ahead of it, offering some of the biggest performance gains

• Almost no VE or VF on the road is turbocharged, so a turbo-back exhaust almost always means a full system replacement, not a literal turbo-to-tailpipe setup

• Any exhaust upgrade needs to stay under Australia's noise limit and keep a compliant catalytic converter in place, or it risks an instant fail at a roadworthy inspection

• Getting the right system also comes down to a genuine fit for your exact model, the type of steel, how the pipe's bent, and buying from a retailer you can trust

• Perform-Ex Automotive stocks Redback, Pacemaker, Manta and XForce exhaust ranges for both VE and VF Commodores, with a vehicle search tool to help you find the right one

Common exhaust upgrade types

Before thinking about power and sound, it’s important to understand the most common terms when it comes to exhaust upgrades. 

Cat-back exhausts

A cat-back exhaust system replaces everything from your catalytic converter (the component that cleans exhaust gases before they leave the car) backward. That includes the mid-pipe, mufflers, and tailpipe. This type of package typically bolts straight onto the factory catalytic converter, so it’s a fairly straightforward job for a competent mechanic, and even a confident DIYer can do it if they have the right equipment.

Full exhaust systems

A full system, sometimes sold as an extractor-back or header-back setup, adds two things ahead of the cat-back: new extractors (also called headers) in place of the factory exhaust manifolds, and high-flow catalytic converters that perform the same job of managing emissions, while also letting gases flow through faster.

Because it reworks the exhaust all the way from the engine to the tailpipe, this upgrade almost always provides the greatest boost to power. 

Clearing up the turbo-back confusion

A genuine turbo-back system runs from the turbocharger to the tailpipe. Considering turbocharged or supercharged Commodores are rare, this expression is often misused.

When someone mentions a turbo-back exhaust on a regular V6 or V8 Commodore, they’re usually referring to a full system, as explained above.

Cat-back vs. full system: what’s the difference?

Both types of exhaust upgrade will change how your Commodore sounds and performs, just not by the same amount, or in the same way. Here's how they stack up.

Cat-back vs. full systems at a glance

Why choose a cat-back

A cat-back exhaust brings a fairly modest power gain, typically 5kW to 12kW at the wheels, because the biggest restrictions in a factory system actually sit further forward in the manifolds and catalytic converter.

Many cat-backs offer twin 2.5-inch exhaust piping, which suits a stock or lightly modified V8 with a deep, classic tone. You’ll notice a slight jump in power, but the biggest difference is often in throttle response.

It’s worth pointing out that cheaper cat-backs cut corners on the rear muffler and resonator, which can result in unwanted cabin noise. So, it’s worth spending a little more on a quality cat-back if you don’t want any intrusive, unpleasant sounds. 

Why choose a full system

A full system makes a much bigger difference to power. Workshop dyno testing on a VF's naturally aspirated V8, the 6.0-litre L77 or the 6.2-litre LS3, found gains of around 24kW at the wheels once you add an OTR cold air intake and a dyno tune, according to Oztrack Performance.

Full systems are usually paired with twin 3-inch exhaust piping to account for the additional flow, and they also sound louder and more aggressive. On a budget of around AU$2,000, you could buy a mild-steel full system with some spare change left over to cover fitting costs.

As full systems are designed to be louder, you’ll almost always hear more sound in the cabin. If that’s not something you want, a quality cat-back might be the better option.

5 things to consider when buying

Now that we’ve covered the two main types of exhaust systems, here are five things to consider before deciding what’s right for you.

1. Does it actually fit your car?

VE and VF Commodores span several years and variants, and they can have small differences in mounting points and pipe flanges (the bolted joins connecting each section). As a result, it’s important to confirm that the system is a genuine match for your exact model and engine.

2. Type of steel

A mild steel exhaust system is the cheapest option, with a slightly deeper, warmer tone that some V8 owners actually prefer. However, these are more prone to rusting, especially if you live in a coastal area.

Stainless steel costs more upfront and resists corrosion for much longer, sometimes even outlasting the car itself. The least expensive is 409 stainless, while 304 usually sits at the top of the range.

3. How the pipe's bent

Mandrel-bent piping is shaped with a rod, or a chain of ball bearings, that supports the pipe wall as it bends, so it keeps its full internal diameter around every curve. Press-bent (or crush-bent) piping is bent without that support, pinching in slightly at every bend. This can slightly restrict the flow of exhaust gases, which can affect ultimate performance. 

Generally, those seeking maximum performance gains will be looking for a mandrel-bent system, while those on a budget are usually happy to accept the compromise of a crush-bent pipe.

4. Staying road legal

Every state in Australia applies the same 90 dB(A) noise limit for exhausts. It’s measured at a set rpm for every car built from the early 1980s, which includes the VE and VF Commodores. Reputable aftermarket exhaust brands are usually designed to sit under that limit, while cheaper, straight-through systems sometimes fail roadworthiness checks.

Emissions are another reason upgrades can run into problems. From 1986, new cars sold in Australia had to run on unleaded fuel and carry a catalytic converter as standard, a rule that covers every VE and VF Commodore. However, that doesn’t stop some people from removing them in the relentless pursuit of performance.

Unsurprisingly, a vehicle without a cat is also a near-certain fail in any roadworthiness test, unless it’s been certified. A better option is to replace the factory cat with a 200-cell metallic converter, which allows gas to pass through with less resistance, while also staying compliant.

5. Buying online or from a shop

Buying online is usually the cheaper route, and it gives you access to a far wider range than your local exhaust shop might have in stock. The trade-off is that you're relying on the retailer's own information to get the right part, so it’s important to use a reliable site.

Some indicators that a website is reliable include a proper vehicle search tool, allowing you to filter results by your exact model and engine. It’s best to avoid any site listing products that “suit most Commodores”. You should also check if they carry the stock themselves, or if they’re shipping to you from a third party (which could include overseas suppliers), and whether they have a technical support number you can call.

How to get started

Perform-Ex Automotive has supplied Aussie car enthusiasts and workshops since 1976, and we stock comprehensive ranges from top aftermarket brands, like Redback, Pacemaker, Manta and XForce. We’re a proudly 100% Australian-owned business and A Capricorn Preferred Supplier, meaning we’re trusted by automotive repair businesses across the country.

If you’re looking for a high-quality aftermarket exhaust for a VE or VF Commodore, our vehicle search tool allows you to find parts for your exact model and engine type, and our team of experts is always on hand if you need some advice.

FAQs

What is a cat-back exhaust system?

A cat-back exhaust system replaces everything from your catalytic converter to the tailpipe, including the mid-pipe, mufflers, and tailpipes. It bolts straight onto the factory catalytic converter, leaving the manifolds and cat untouched, and it's the simpler, cheaper of the two main upgrade paths for a VE or VF Commodore.

Will a twin 3-inch exhaust cause a loss of low-end torque on a naturally aspirated V8?

On a stock or lightly modified engine, a twin 3-inch system can feel slightly softer low down, because the extra pipe volume reduces exhaust gas velocity at low rpm. It usually makes up for that with better flow and more power higher in the rev range, which is why it suits modified engines more than stock ones.

How do I stop exhaust drone on an automatic VE or VF with Active Fuel Management?

Choose a system built with a proper rear muffler and resonator rather than a straight-through design. These components are specifically built to cancel out the resonant frequencies AFM creates when it shuts down cylinders at cruising speed, and getting this right is the single biggest factor in avoiding drone on an automatic.

Can I pass a roadworthy inspection with a 3-inch performance exhaust?

Yes, provided it stays under the 90 dB(A) national noise limit and keeps your catalytic converters in place. A quality branded system with high-flow cats is built to meet both requirements. An unbranded straight-through system is the one most likely to fail.

Should I choose 304 stainless steel or mild steel for my Commodore exhaust?

Choose 304 stainless steel if you want the system to last the life of the car without rusting, especially anywhere near the coast. Mild steel costs less and has a slightly deeper tone, but expect to replace it sooner.

Will fitting a full exhaust system need a dyno tune afterwards?

A cat-back on its own generally doesn't need one. A full system with extractors and high-flow cats changes how much air and fuel your engine is working with, so booking in for dyno tuning is worth it to get the power gains you're paying for and keep the air-fuel ratio correct.