The first time I heard someone talk about an emissions delete diesel truck was at a welding shop in 2016. My coworker talked about how fast and how much better the truck ran after the “delete”. He was boasting about how his 2015 Denali hit 152 mph. Roughly two weeks later, he, myself, and my boss all went out for lunch and I could tell he was visibly upset. I asked him how the truck was running, which started a conversation that took a very bad turn. During the conversation, I learned that his Duramax had a catastrophic engine failure. Unfortunately, the torched engine was not the worst news for the one-year-old truck. 

After putting all the emissions pieces back in place, he had the truck towed to the dealership. He was hoping to “beat the system” for warranty work. That experience could have gone better. After taking the truck to the dealership, one day he got a phone call from the dealer. The caller stated that the warranty was void. This was due to emissions tampering and ECU tuning he tried to hide. Needless to say, this was a lesson learned.    

It all started with a little (EGR) valve. (seen on the very top of the intake.)

Emissions System Over The Years

Anyone who knows about diesel trucks has heard of “emissions delete.” But what does that actually mean? To understand more, we need to go back to the ’90s, when the Exhaust Gas Recirculation (EGR) valve was incorporated into light-duty diesel trucks. The EGR valve would reroute exhaust gas back into the air intake, through the engine, and out the exhaust. This process is done to reduce emissions output. The EGR valve would be the only emissions system on a passenger diesel truck until 2008.  

In 2008, new regulations for diesel trucks were introduced, and the Diesel Particulate Filter (DPF) was mandated on light-duty diesel trucks. The DPF acts as a filter in the exhaust system to keep emissions down to help with the ever-tightening emissions regulations from the EPA.  

Then in 2010, the EPA mandated that all diesel trucks have an emission-reducing device using Diesel Exhaust Fluid (DEF). Entry of this new regulation would cause diesel enthusiasts to become furious with the addition of another liquid added to the diesel engine and the hassle of dealing with it. 

What Is The Meaning Of Emissions Delete

Whenever you hear someone say emissions delete or “deleted” in the diesel truck world, they are talking about removing part or all of the emission systems like the DEF, DPF, and EGR. So why would you want to delete the emissions on a diesel? One of the reasons is purely personal and is done simply to have a perceived performance benefit. Let’s use the 6.4-liter Ford Power Stroke as an example. The emissions systems on this engine have a bad reputation for clogged DPF units, and the internet is abuzz with people wanting them off their trucks. But it is not just Ford owners. many diesel enthusiasts with Ram and GM diesel trucks want to eradicate emissions devices whether they work well or not. The only problem is the EPA does not like that.

According to the folks at Calibrated Power, “If you take a late-model Cummins that has been deleted and tuned and pit it against a  non-deleted and tuned Cummins, the numbers are extremely similar.  Many people believe that the exhaust flow restriction caused by the DPF filter is robbing them of power. In actuality, the factory calibrator and bean counters are the horsepower criminals! After a decade of emissions-equipped custom tuning, we can confidently tell you that any nominal cost of horsepower from the DPF can be offset with good tuning.” You can check out their testing results by clicking here.

Emissions Delete, Think Again…

If you are thinking about deleting your truck, please reconsider. The main reason is that, first and foremost, it is highly illegal. Removing any emissions device on a diesel engine or adding a non-SMOG-compliant product carries a punishment of up to a $5,000 fine per unlawful part installed. The EPA cracking down harder than ever and you will eventually get caught. 

The resale of a deleted diesel truck is also a punishable offense, and the EPA can, once again, press charges. It’s no secret how hard the EPA has been looking into emissions deletion during the past few years. We’ve seen it all, from full-blown raids on diesel shops and tuning companies, and then throwing the book at them, much like they did at PPEI Tuning. That has not slowed down to this day. They are actively going after companies that are not complying with regulations. 

Oh, So Sneaky

If you think you can be sneaky when building an emissions delete truck, the odds are probably not in your favor. Let’s say you have a brand new 2022 Duramax and decide to delete it. But at 25,000 miles, you fill up with lousy diesel and the CP4 pump grenades. Guess what? You will have to be towed back to the dealership to get expensive repairs. However, a few days later, you get a call saying that the tuck is not covered due to emissions tampering, and you will have to fork over $20,000 for the L5P repair bill. That sounds like a fun time, right? Try explaining that one to your wife.

Ain’t Technology Wonderful

There is definitely a stigma surrounding emissions devices, with these devices choking engines which reduces power and overall performance. But there is a flip side. New technologies and advancements in tuning have made diesel engines more powerful and fuel-efficient than ever. Take a look at the 2023 Ford Super Duty, for example. It’s an excellent platform that makes 500 horsepower and a monstrous 1,200 lb-ft of torque with emissions devices doing their job.

Emissions repair jobs are usually not very fun, we get it. However, it keeps the wolves at bay. Special thanks to the engineers that bury them in the engine like on this 6.0-liter Ford.

Many comments found on the internet, tout a substantial mileage increase and power bump after deleting a new truck. When DPF filters were first installed, that might have been the case. However, advances in technology have changed things and these filters are more efficient than ever. It has taken many years to create emissions devices that work seamlessly with our diesel trucks and not choke them. Had more research and development been done on those early diesel trucks, perhaps we wouldn’t be headed down this road. But, unfortunately, many enthusiasts read comments about how deleting the emissions equipment of older trucks helped performance. Unfortunately, they equate that to also be true with new trucks. That’s not the case.

Ask Questions First, Modify Second

If you want to modify your truck, first you need to check out the laws in your state. Emissions tampering is a federal offense and no emissions devices can be altered or deleted. But, most states will allow you to alter specific components of your vehicle as long as all emissions remain intact. Take for instance our Project WorkHorse. This 2019 Ram 2500 frequently tows and hauls through different states. That is one reason we are upgrading this truck using only emissions-compliant parts.

With the help of only emissions-compliant parts and upgrades, we are proving that we can live with these mandated items and have powerful trucks at the same time. For starters, we installed a Bully Dog GT tuner on the truck and realized a definite increase in fuel mileage with this 50-state-legal “tuner.” Next, we tested an Advanced Flow Engineering (aFe) cold air kit and a Magnaflow DPF-back exhaust. You can see the results of that testing right here.

We have plans to test many parts on our Ram that do not alter any emissions devices. Remember, it is not illegal to modify your diesel truck. All we are saying is, when you do so, do not remove or alter the emissions devices. Make sure that all of the aftermarket parts you install will not void the warranty if you have one. If you do, you could cause the EPA to go into a convulsive fit. 

Are ready to add a few upgrades to your rig, follow along with the legal parts we add to WorkHorse. Hopefully, we will realize some serious performance gains while remaining emissions legal.

If you want a great-running EPA-compliant truck, emissions system maintenance is essential. Keeping up with this will ensure everything is functioning correctly and does not cause any damage to the engine. However, if you want to avoid putting DEF into your tow rig, buy a pre-emissions truck and STOP deleting our industry.