Cummins Exhaust Upgrades

The below products are popular exhaust options for your Cummins. However, to see all exhaust options, please select your vehicle application from the top menu and navigate to the appropriate category.

Do you consider yourself a Cummins aficionado? Well, maybe not necessarily an aficionado, but an avid supporter at the very least, right? Either way, if you can differentiate a Cummins rolling down the highway before you can see it, you're scoring some points, but if you can tell what generation of engine it has (12 valve, 6.7L, etc), consider yourself a pro. One thing is for sure, the sound of a Cummins is unlike any other diesel engine, which is why one of the most popular upgrades on a Cummins is in regards to the exhaust system.

Over the years, Dodge has done a relatively good job of designing the factory system to support the factory power levels and create a system that would suit the masses in terms of aesthetics and sound level. That being said, there are numerous reasons to make the upgrade to a higher flowing, performance exhaust kit no matter what year Cummins you drive. In general, you can expect an increase in power, a bump in fuel economy, lower EGT's (Exhaust Gas Temperatures), and of course, a sweet new sound.

In particular, lets dive into each model year range of truck to give you an explanation of why an exhaust upgrade is beneficial starting off with the first model year range, the 1989-1993 Cummins, sometimes referred to as a 1st Gen. The first generation Cummins featured a three inch diameter exhaust coming right off the turbo all the way to the tailpipe. Due in part to the diameter as well as the massive muffler, this system does not flow very well for anyone that has made any type of fueling enhancements, such as an upgraded VE Fuel Pin or larger injectors. For many, the stock exhaust has simply rotted off, and no better time to upgrade than when you absolutely have to!

The 2nd Gen Cummins covers all 1994-2002 Cummins, and these trucks also featured a 3" diameter system, however with the addition of a resonator in front of the muffler to further aid in reducing in-cab resonance. These trucks are where the performance game really started, most notably the 1994-1998 models that featured a 12 valve, mechanical Cummins. Because of the simplicity in adding power to the 12 valve with simple pump modifications, as well as the 24 valve through performance programmers, exhaust gas temperatures can quickly become an issue. The simplest method to dissipate heat in the exhaust is to increase the size and reduce the amount of bends. For most, an upgrade to a 4" single outlet exhaust system is the most practical. However, 5" and even dual outlet systems are available. Five inch systems typically will be substantially louder than a four inch and will not deliver any noticeable gains over a four inch system until you reach higher power levels.

In 2003, Ram unveiled their 3rd Generation iteration with an entirely new body style, engine, transmission, and basically everything. Specifically talking about the exhaust, this truck features a four inch discharge directly out of the turbo, but then bottlenecked to 3.5" in the cast elbow coming directly out of the turbo. The exhaust would remain at 3.5" going into the factory muffler, and then discharge at four inch. Sound complicated, right? Well, its not terribly complicated, but it definitely has room for improvement. The biggest gain is to upgrade the muffler, but because of the offset inlet versus outlet, you can't merely install a new muffler into the stock system. The best and simplest method is to upgrade the entire system, which will also deliver less bends for a full upgrade. For those that are planning to keep the factory turbo will even replace their bottlenecked turbo discharge cast elbow with one from a 2004.5-2007 Cummins (we'll get to this in a minute) that does not feature the bottleneck to gain a complete four inch turbo back exhaust kit.

The next model years are classified under the 2004.5-2007's. This truck is similar in certain fashions to its predecessor, but does have some unique differences to even the exhaust. As we eluded to earlier, the cast elbow turbo discharge does not bottleneck like the 2003-2004 model years and maintains a full four inch turbo back system. However, this truck did receive a catalytic converter located at the base of the tailpipe followed up by another massive muffler with an offset design. So, the good news is that Dodge opted for a full four inch system from the factory, but the bad news is there's a catalytic converter and still an inefficient muffler. To upgrade this system, there are muffler upgrades that include an offset pipe which are a great way to save some money on upgrading the system and still get many of the benefits to a complete system. However, for maximum benefit, there are numerous four inch and five inch kits available in both turbo back and catalytic converter back configurations. Heck, you can get a single outlet, dual outlet, axle dump, stacks, you name it, somebody's probably made it. For the most part, all of the aforementioned will deliver relatively similar results. What it boils down to is the style and you're after. A four inch is perfect for most, but some prefer the deeper sound of a five inch kit. And while some may argue this point, dual exhaust really is just for looks. We'll admit, it does look pretty cool, so don't let the fact that it won't benefit performance dissuade you in any way.

Up next came the 6.7L Cummins released in mid model year 2007. This exhaust is entirely different than its predecessors as it brought about the introduction of a Diesel Particulate Filter, or DPF for short. The DPF is used in controlling emissions output by creating chemical reactions during what is known as regeneration cycles. We won't go into the details of how all that works here, just know that its complicated. Starting at the turbo and working backwards, this system is four inch diameter and immediately forces exhaust through a catalytic converter located in the downpipe. At the base of the downpipe, another catalyst called a Diesel Oxidation Catalyst, or DOC, is inline, followed by the DPF. Leaving the DPF you'll find a chunk of four inch straight pipe that leads into a small muffler immediately before the axle. From there, its pretty standard, four inch over the axle and to the tailpipe. Phew, did you follow all of that?! There are numerous methods to improve upon this system, but the best and most logical method for most is to install a five inch DPF-back system. Now, if you were paying attention earlier, you learned that we did not recommend a five inch kit for most. While that's true on a 5.9L that does not have all of these restrictions, a 6.7L will benefit as anything you can do to free up these restrictions post-DPF the better off you are. This basic exhaust system was used all the way through 2012 model years.

For the 2013 model years through current, emissions regulations were again tightened down and we saw the introduction of SCR, or Selective Catalyst Reduction system utilizing urea injection. Overall, the rest of the exhaust is quite similar to that of the earlier 2007.5-2012 models, but with this new addition. In terms of making this better, the same principles hold true. A 5" DPF back system will be your best friend to extract every bit of power, fuel economy, and sound out of your mighty Cummins.

Overall, there's an exhausting amount of options when it comes to upgrading the exhaust on your Cummins (did you notice the pun!). For some, the decision comes down to sound, to others its about the style, and others performance, but for most its a mixture of all the benefits.

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