Why Diesel Owners Remove Emission Control Equipment—And Why You Don’t Need To

• November 5, 2023
• Story By
  Mike McGlothlin

Before we pull the curtain down on our emissions-friendly diesel parts series, we’re wrapping up with a conversation on the industry’s hot-button issue: the removal of emissions control equipment. It’s a topic virtually no one, inside or outside of the diesel segment, wants to discuss. However, without a shadow of a doubt the issue of “deleting” emissions equipment is the elephant in the room for all current and prospective late-model diesel owners. The emissions removal problem simply cannot be ignored forever. So, why not tackle the issue of deleting head-on?

Because we’ve already offered you fun, legal and clean paths to making more horsepower with your diesel-powered Ford, Chevy or Ram, this time we’re explaining why so many diesel owners delete parts from their trucks—as well as why you shouldn’t. We’ll also touch on the biggest disadvantages associated with deleting, the most common misconceptions about factory emissions equipment and remind you that The Big Three have gone out of their way to make the latest emissions-scrubbing equipment attached to heavy-duty pickups as reliable as it’s ever been.

Why Diesel Owners Delete: Reliability

It’s no secret that the exhaust gas recirculation (EGR), diesel particulate filter (DPF), and selective catalytic reduction (SCR) systems on modern diesels come with a myriad of failure points. EGR valves stick, EGR coolers rupture, DPF’s fill up, pressure differential sensors fail, SCR doser valves quit working, DEF heaters stop functioning, and on and on. From simple sensor issues to complete component failure, the owners of these modern day, 1,000 lb-ft of torque workhorses—many of which depend on them to make a living—understandably don’t appreciate any downtime incurred on account of an emissions equipment issue. Eliminating failure points is the biggest reason emissions system deletes occur.

Why Diesel Owners Delete: Fuel Economy

Another factor that plays a part in a diesel owner’s decision to delete boils down to fuel economy. However, while removing the emissions equipment from a late-model diesel can provide a bump in fuel efficiency, it’s nowhere near as noticeable as it was in the 2007-2010 era. Back then, when only EGR and DPF technology was employed on diesels, fuel economy was dismal—like 12 to 14-mpg with an empty truck dismal. However, after SCR debuted (’11 model year for Ford and GM, ’13 model year for Ram pickups), as well as other aftertreatment system improvements, fuel economy received an immediate shot in the arm, with many ¾-ton model trucks capable of achieving 20-mpg empty.

Common Misconceptions About Modern Age Diesels

A lot of diesel owners are under the notion that the DPF is a ticking timebomb. Again, much of this line of thinking stems from the early days of the technology’s existence, when failure was more prevalent. Additionally, many (and we would argue most) diesel owners believe the DPF is a restriction that costs you horsepower. In lower horsepower applications (i.e. street-driven trucks), this has been disproven time and again. Another familiar misconception is that the EGR system will kill the engine. While the carbon trap that is an EGR system can eventually hinder performance, proper maintenance (namely cleaning) goes a long way in both keeping its components alive and ensuring peak engine performance is always on tap.

The Disadvantages Of Deleting

For starters, it’s illegal. By reducing complexity and removing failure points in an attempt to gain reliability and some fuel economy, you do so at the expense of technically making your truck illegal for street use. But beyond the fact that it’s illegal to tamper with federally-mandated emissions equipment, no manufacturer will honor your truck’s warranty upon realizing the hardware is missing. Worse yet, a dealership could actually use the fact that your truck is deleted to get out of performing other, non-powertrain-related warranty work. And if the absence of emissions equipment is detected by law enforcement, you could face steep fines and/or a fix-it ticket.

The Reality Of Emissions Equipment

While still not without their faults, present day diesel emissions components are more reliable than they’ve ever been. As the EGR, DPF and SCR systems—all of which have to work in conjunction with each other—continually improve, each piece within these systems will likely enjoy a longer service life. And, as was previously mentioned, proper maintenance plays a huge role in the durability of any modern diesel engine. Timely DPF cleaning intervals (including allowing regeneration intervals to be completely carried out without interrupting them) and EGR system cleanings should be performed at the specified interval(s). And don’t forget about your engine oil. With all the soot contamination that takes place in any EGR-equipped engine, running the right engine oil has never been more important.

Why You Don’t Need To Delete

As we alluded to above, the components forced to live in the harsh environment that is a diesel engine’s exhaust tract aren’t perfect by any means, but their longevity has improved tremendously since first being introduced. Stronger electric actuator motors, better EGR cooling, DPF quality improvements and more precise regeneration functionality have all made this possible. Now, an EGR system that receives proper maintenance (cleanings) can be made to last 100,000 miles or more and a DPF can live twice as long as that. As a bonus for horsepower junkies, the DPF isn’t as much of a restriction as most think it is. In fact, for anything under 650 hp to 700 hp it isn’t a bottleneck at all.

CARB E.O. Numbers: The Future Of Diesel Performance

When a manufacturer is awarded an Executive Order (E.O.) number from the California Air Resources Board (CARB), it means that its product has been proven to not increase vehicle emissions when in use. And because CARB often enacts emissions standards that are more stringent than what you’ll find in the other 49 states, if it’s clean enough for CARB (California) it’s clean enough to run anywhere. And as our emissions-friendly diesel parts series has illustrated, E.O. numbers aren’t just reserved for cold air intakes and tuners. Companies are making CARB-compliant performance turbochargers, injectors and high-pressure fuel pumps, too. Make no mistake, CARB E.O. numbers are the future of street-legal diesel performance.

Off-Road: Where E.O. Numbers Need Not Apply

Of course, true off-road use vehicles are a different story, so don’t expect dedicated diesel sled pullers and purpose-only drag racers to become extinct. On the contrary, vehicles that only see competition use on the track, and that aren’t licensed and plated for street use, are exempt from emissions regulations—at least for now. Just make sure your tow-rig stays up to snuff on the street. Embracing new, emissions-friendly aftermarket diesel products will only help the market continue to grow.