Two and a half hours is all it takes to unlock 10-15% more power and low-down torque from your engine. How? By replacing your restrictive factory exhaust with a high-flow system customised specifically for your 4WD.

[blockquote cite=”” type=”center”]”Unlock 10-15% more power and low-down torque in just 2.5 hours with this Scotts Rods exhaust install”[/blockquote]

To show just how easy it is, we’re going to replace the exhaust on our 4WD Action Triton with a 3in mandrel bent system made by the experts at Scotts Rods. Scotts Rods have customised our system with a 3in dump pipe, 200 cell high-flow catalytic converter and resonator combination to achieve the precise sound and performance gains we wanted.


A quality exhaust system not only makes your 4WD sound better, but it also lets it breathe better therefore improving power, torque and acceleration. And because your engine makes power more efficiently, every time you take off from the lights or power up a hill, you’ll be up to speed faster and off the gas sooner – meaning you’ll save on fuel consumption, too.

First up, we’ll need to remove the old exhaust. Start by jacking the vehicle up and setting it down on rated vehicle stands then soak all exhaust flanges, hangers, nuts and bolts with penetrating spray to make removal super easy. If you can, do it the night before so it’s got a chance to set in.

It’s usually easiest to start from the rear and work your way forward when removing the old system. Start with the rear muffler by undoing the flange just above the diff and prying off the rubber hanger. If you find the hangers to be a bit stubborn, give them a soaking with soapy water and gently pry them from behind with a lever bar.


With your socket on the nut or bolt, give it a short sharp tap with a hammer to break up fine rust particles and prevent treads from binding as you undo the fastener.

Lubricating stubborn fasteners with penetrating spray will loosen seized threads and prevent them grabbing. If they do, try working the nut or bolt backwards and forwards gently, spraying the thread regularly.

Never use a shifter. Instead, use single hex sockets and spanners of the right size. There are small differences between metric and imperial sizes, making it easy to round off a fastener if you use the wrong size.


Can’t decide between aluminised steel and a 409 stainless steel exhaust system? Here are the benefits of both systems to help you decide.


  • Cheaper purchase price
  • The aluminised coating inside and out slows down corrosion


  • 409 stainless steel is heat tolerant, meaning it’s specifically made for exhausts to cope with extreme changes in temperature
  • It’s the same grade of stainless manufacturers use for standard exhaust systems
  • It’s only around 20% more expensive than aluminised steel kits but lasts significantly longer

Now it’s time to remove the old centre muffler and the front engine pipe. To avoid overloading the dump pipe and flex joint once the rear hanger is removed, support the weight of the exhaust with a floor jack. From here, it’s much the same as the rear section; simply undo the flanges, the three dump pipe nuts, disconnect the O2 sensor (if fitted) then slide the rubbers off the hangers. Here you can see the old dump pipe and cat side-by-side with the new 3in dump pipe and high-flow diesel specific catalytic converter.

This is the exciting part – installing the new exhaust. Apply a small amount of anti-seize paste to the studs before inserting the gasket, fitting up the dump pipe and tightening the nuts.

You’ll notice the new dump pipe is bigger than the old one. The 3in dump pipes used in Scotts Rods kits have been designed to help the turbo spool up faster which improves acceleration and engine responsiveness.

Fitting the new centre section is often easier than pulling out the factory one because you’re working with all new components. On top of that, Scotts Rods precision manufacturing jigs mean every exhaust system is an easy fit, first time. 

For the next section, fit the new centre flange gaskets to the bottom of the engine pipe, lift the centre pipe into place, insert the flange bolts (but only do them up finger tight at this stage) then slide the hanger mounts into place. If the hangers need a little encouragement, soak them in soapy water and they’ll slip right on.

For the rear tail pipe section, use your jack to support the exhaust while fitting the new gasket and bolting the flanges together, and again, leave the nuts and bolts finger tight. We’ll double check the alignment next before finally tightening everything up.

Replacing your old exhaust with a larger diameter unit naturally means you’re going to have to make sure it doesn’t fowl on anything before you finally tighten it all up. Check for adequate clearance between the exhaust and the chassis, cross-members, firewall, gearbox wiring harnesses and the rear diff to ensure nothing’s too close. Then, working from the dump pipe back, tighten each flange and hanger ensuring there is adequate clearance around these surrounding components.

It’s important to note that each flange is designed with a small amount of adjustment which means any clearance issues can be corrected at this stage. This is particularly important if you’ve got aftermarket accessories like long-range fuel tanks fitted.

Last but not least, it’s a good idea to do a quick leak test. With the motor cold and running at idle, hold a rag firmly (but carefully) against the end of the exhaust pipe to restrict the flow of exhaust gas. Blocking off the exhaust creates backpressure within the system, exposing any leaks in the process. Just remember, breathing in exhaust gas is hazardous to your health so only do this in a well ventilated area.


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