The new Isuzu D-Max has been racking up accolades from every corner of the globe. It’s been awarded Australia’s best dual cab for 2021, with improvements across the board over the outgoing model. Safety is high on the agenda, as well as the standard quality and reliability the brand is known for. It might be down on outright power and torque compared to rivals, but a few performance upgrades, like an aftermarket DMax exhaust system, brings the workhorse ute up there with the best.
The engine is the famed 3-litre inline four-cylinder turbodiesel, churning out 140kW low in the rev range. It’s known for being dependable, with few issues reported. The same engine features in the D-Max clones, the Holden Colorado and the Mazda BT-50. Tuned more towards frugality and durability, it has heaps of untapped power.
Benefits of an Aftermarket D-Max Exhaust
The previous gen D-Max and Colorado come with a restrictive stock exhaust. Restrictive in the sense that gas flow can be improved to allow the big diesel to breathe. The tubing is narrow, and the routing snakes its way in unnecessary bends. There’s more chance of increased backpressure, with more than expected exhaust gases making their way back into the cylinder head. Mind, the turbo feeds off exhaust gases, but too much, and the engine is deprived of new, cool air needed for the next bang. Allowing for straighter and wider tubes, while still fitting into the underbody recesses of the stock exhaust, is one way to bring more grunt into the picture.
Another thing to look for is the build quality and materials found in the stock exhaust. This is where most car makers cut corners to bring the final cost of the vehicle down. Mild steel is prone to rust and dents, even in everyday city driving, let alone in more demanding off-roading scenarios. Aftermarket exhausts use better materials, of high-grade steel alloys, that are also coated against corrosion. This is not only thicker, but built to withstand higher temperatures and rated for increased pressure. Individual tubing is mandrel-bent to ensure constant widths throughout the exhaust, and minimise typical areas of restriction. Quality, double braided flex joints help reduce vibrations, say when hitting potholes, and avoid cracks or ruptures along the entire length. High-grade flange plates connect the tubing to the exhaust manifold.
The use of better materials also means the aftermarket DMax exhaust sheds a few kilos. As mentioned, the tubing fits within the space reserved for the stock exhaust, without the need for any modifications in the underbody. Metal brackets fit in the vehicle mounting points to make things easier. Individual parts are quickly assembled as a pain-free bolt-on system.
And let’s not forget the exhaust sound. Buyers have the option of either including a resonator to mute out any noise. Or, as most buyers, go for a muffler delete, that brings out a more noticeable rumble, while also allowing exhaust gases to escape faster.
Types of Exhausts for the D-Max
With the diesel engine, D-Max, Colorado, and BT-50 owners can choose between a DPF-back or turbo-back exhaust system. There are also axle-back exhausts, but these just add a few decibels to the sound and not much else. A DPF-back exhaust changes all the stock parts from the diesel particle filter to the exhaust tip. The benefit here, besides the increased area for the gases to exit, is the reduction in toxic nitrous oxide and carbon monoxide. This helps in better fuel consumption for those with the environment in mind, while putting a few more horses in greener pastures.
The best Isuzu D-max performance exhaust is definitely a turbo-back. Here all parts from the exhaust manifold and the entire tubing are swapped out. You get a higher rated DPF filter, exhaust extractors and/or downpipe for better airflow and a choice of mufflers. This system allows the turbo to spool faster and push more air into the cylinders, in effect creating more horsepower. It also relieves any issues with backpressure. The only downside is the higher cost due to the additional parts.
Choosing an Aftermarket Exhaust for Your D-Max
Prices vary between makers. Look for Aussie-made, hand-built exhausts of high-grade steel. Coated or painted exteriors will last longer, and also look better. The current D-Max has stock tubing at 2.75 inches in diameter, so the minimum to go for to get any respectable performance gains is 3 inches or wider. The choice remains between the slight boost in speed and grunt with a DPF-back exhaust, or higher figures found in a turbo-back. If you own the latest generation Holden Colorado, or the recently released BT-50, the same exhausts also fit. Builders let you choose between different muffler options when tuning the exhaust sound. Systems with muffler deletes or only straight tubing will be slightly cheaper to buy than those with included resonators.
Installation is quick, regarding most aftermarket exhausts are engineered as bolt-on systems. You can save on labour costs by fitting the exhaust yourself. All mounting brackets, gaskets, bolts and nuts are included in the package.