Performance Exhaust Systems Guide: Improve the Performance of Your 4WD - aLittleBitOfAll
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Performance Exhaust Systems Guide: Improve the Performance of Your 4WD

Performance Exhaust Systems Guide: Improve the Performance of Your 4WD

Utes and large SUVs still make up the majority of new car sales in Australia, and that trend is here to stay. Buyers need space, versatility, and the ability to come back from the bush in one piece. Here no other cars come close. What is lacking is a bit outright speed. Diesels feature in almost all the top sellers.

They have good low-down-pull and something you’ll need when fully laden, or towing. But from a standstill the 2+ tons of metal aren’t really brisk to pick up a good dose of speed. Even the bigger 5 and 6-cylinder engines struggle to break under 10 seconds when going for 100kph. If you want the wheels spinning faster, consider doing a few upgrades. You don’t even have to lift the hood. Nor dip into the rainy-day piggy bank.

Bolting on a 4×4 performance exhaust can make a whole lot of difference. This frees up more air in for the engine, while pushing combusted gases out that much quicker. Both petrols and diesels, as well as older and newer cars will feel livelier. You won’t be rivalling hot hatches or luxury sedans down a straight stretch of road, but the time you save reaching your destination can be better spent doing something more worthwhile.

4x4 performance exhaust


What do Performance Exhausts Offer?

The short answer is more power, better acceleration, cleaner emissions, and a longer lasting engine. And, if you’re not too hard on the throttle, a slight saving in fuel, something welcome now more than ever. A performance exhaust is designed for freer airflow straight from the exhaust manifold to the tips.

It reduces the buildup of pressure acting on the tube walls, maintains optimal heat levels, and redirects the right amounts of gases to work the turbines. Efficiency and more power rolled into one. Power is increased with wider tubing. This is directly related to the speed at which the exhaust gases exit the vehicle. Wider tubing, without the numerous bends found in stock exhausts, makes this possible.

The benefit here is that for a new combustion cycle to happen, first the gases in the exhaust need to be expelled. Otherwise, there is a buildup of pressure and what is known as backpressure, with part of the exhaust gases making their way back to cylinder, and in effect robbing the engine of new air.

Power is also increased with modified turbo downpipes that help the turbos set in quicker, and spool faster. Since most new utes and 4WDs are single or twin-turbo diesels, turbo downpipes add a significant bump in horsepower, and that’s evident from earlier on. Acceleration is faster as a result.

Performance exhausts also have uprated filters that clean toxic particles more effectively. For diesels this is the DPF filters, and for petrols a GDF filter. Changes to catalytic converters (within the filters or as separate units) means emissions are further improved. Then, there is better fuel use and engine longevity.

With the engine having more space to breathe, drivers need to rev it up less to get to optimal RPMs until the turbo kicks in. Less fuel is therefore used in building up speed (just mind your right foot in mid and high rev ranges). And lastly, an engine that needs to work less will definitely last longer.

4wd exhaust systems


Exhaust Types for Your 4WD

Depending on how much more you want to get out of the engine, there are different types of exhausts. A 4×4 performance exhaust will provide the biggest gains. These are usually turbo-back exhaust systems that replace all the factory parts of the old exhaust. From the exhaust manifold exiting the engine, to the exhaust tips at the back. If you want something milder, you have the DPF and Cat-back exhausts that bolt on the tubing leading to the particle filters and catalytic converter.

These are designed wider than the stock tubing, so gas flow is increased. Performance gains are less evident in the cheapest type of exhausts, axle-back systems, which have modified piping in the extension tubing leading to the muffler, and may have changes to the tailpipes and tips. Axle-backs are for those that seek a change to the exhaust sound, and most buyers go for exhausts that are louder.

What to Look for in an Exhaust?

All performance 4×4 exhaust systems are built better and will last longer than the one that came with the car. Instead of inferior grades of steel and cheap production processes, here there is the use of high-grade steel alloys with trace elements that increase strength, durability and resistance to higher pressure and temperatures.

Exterior coatings prevent rust, and quality connections reduce vibration. In addition, the use of mandrel bending when forming the tubes allows for piping to maintain strength, width and consistency, which is what’s need for optimal gas flow. Exhausts built locally endure stringent testing so as to comply with ADR and emissions regulations. These are what you should look for when buying.

Lastly, this goes without saying, but get the exhaust that’s compatible with the engine, and MY of your make and model. Most aftermarket exhausts are bolt-on variants that need minimal work during assembly and fitting. A professional fit will yield the best results.

Ian Tompson