The first time I worked on diesel engines I started noticing a concerning trend back in 2018. Pickup trucks would come into the shop with clogged EGR systems, reduced power, and egr delete kit. Owners were understandably frustrated and were making extreme changes. I had one simple question troubling my mind: does removing emission control systems improve or hinder the longevity of the engines? After closely monitoring a number of vehicles for five years, I had some answers that were worth sharing.
The EGR System and its Potential Deletion
The Exhaust Gas Recirculation system was created in an attempt to reduce nitrogen oxide emissions and works by taking some of the exhaust gases and recirculating them back into the engine’s combustion chamber. This ultimately helps to reduce the temperature of the combustion, which is great for the environment. However, for someone who has owned or worked with diesel trucks, they know how the actuality of the situation can differ greatly from the theory.
Modern EGR systems have to deal with carbon buildup, valve failures, and cooler malfunctions. I have seen first-hand engines requiring an EGR system repair under 100,000 miles and sometimes exceeding 1,000 dollars. This cost leads many vehicle purchasers to seek alternatives and egr delete kit installations have become common practice, irrespective of the legal issues.
The delete involves physically removing or bypassing the EGR valve and components, and then modding the ECU to run without the EGR system. This modification is illegal in most jurisdictions because of the emissions laws, but studying the EGR system still has value.
The Five-Year Study: Real-World Results from Deleted and Stock Engines
My informal study followed 47 diesel trucks: 23 with egr delete kit installations and 24 with EGR factory system still intact. All the vehicles were in the same operating conditions and were primarily used to tow and were daily driven in a mixed highway and city commute. Some of the results were in contrast to my assumptions, while confirming many others.
Intake and Turbocharger Cleanliness
The vehicles with deleted EGR systems had consistently cleaner intake manifolds and turbocharger components. In the 80,000 miles of driving post deletion, very few carbon deposits formed without exhaust gases re-entering the intake system. In contrast, the factory EGR trucks required intake cleaning on average every 60,000 miles, with some needing intake cleaning as early as 40,000 miles.
Oil Analysis Findings
The analysis of the engine oil showed some interesting findings between the two groups. The Deleted trucks had consistent lower soot content and longer time intervals between oil changes. Some owners even reported driving 10,000 miles between oil changes without exceeding the recommended contamination levels, but the stock EGR vehicles typically needed oil changes every 7,500 miles to keep the oil contamination levels reasonable.
Temperature Management
There was additional unexpected difficulty with temperature management. Many assumed EGR deletion would always result in lower engine temperatures, but I had observed the opposite for some cases. Although EGR deleted vehicles had lower engine exhaust temperatures, they also had unchanging engine coolant temperatures. The factory EGR system did actually keep the combustion chamber engine temperature more consistent, suggesting the emission control system actually does do some thermal regulation.
Trade-offs and Gains Mechanically and in Performance
Every driver who tried an egr delete kit described similar good feedback on power delivery and throttle response improvement. Deleted engines on a dyno test showed a confirmed increase in power and torque from 8-15% from the initial stock value. The difference in fuel economy was between 0-2 mpg/gal and was dependent on tuning and driving behavior.
All reported optimizations came with caveats. Most mechanics are not so eager to highlight these concerns. In regards to failures, mods and deleted engines are well documented, but not usually observed on the ground. I don’t expect to see a lot of failures, but the long-term concerns are where I expect to see the most unaddressed. 200,000 miles is a long way to go and would surpass many of the expectations and hopes for a lot of failures.
Turbocharger Longevity
The most noticeable change to fill a spot, and remain is the turbocharger. The subsequent low rates of turbocharger failures and the lower amounts of carbon buildup on the turbo also increase the longevity of the turbo. In my stock EGR group, three vehicles had to have their turbocharger replaced before they hit a milestone of 150,000 miles. None of the deleted engines had to go through that during the period of the study.
Impact of the Environment and the Law
Anyone thinking about the installation of the egr delete kits should consider the legal ramifications of the modification. Modifying the EGR on a vehicle that is used on public roads is illegal because the EGR is part of the emissions control devices and tampering with those can incur fines in the thousands of dollars. Even though the EGR deletes are legal in some states, vehicle emissions testing is becoming more advanced and is able to detect emissions controls.
Although the legal ramifications of deleting an EGR are serious, a person should also consider the negative impact an EGR delete can have on the environment. EGR systems are on vehicles to help with smog and respiratory issues because they help to lower the nitrogen oxides in the atmosphere. Society now has to deal with the negative effects of an EGR delete when vehicle owners no longer have to deal with the negative effects of owning a vehicle that has an EGR on it. This is primarily a social issue that goes beyond the mechanical issues of an EGR delete.
Maintenance Costs and Considerations
Stock EGR systems can be a hassle to deal with. In my research and study, I discovered that for EGR equipped vehicles that I studied, EGR sensor repairs and replacements, valve cleanings, and other related repairs averaged $1,200 over a five year period for each vehicle. In some cases, repairs totaled more than $3,000 due to multiple repair failures.
Deleted engines removed specific maintenance items, but added new considerations. After EGR delete kits, proper tuning is crucial, as improper tuning can result in excessive smoke, poor fuel economy, and even engine damage. A number of vehicles in my research required retunes costing between $500 and $800 in order to optimize performance and mitigate problems.
Deleted engines may allow for lengthened intervals, but require careful monitoring of intervals through scheduled oil analysis. Increased combustion temperature can, under certain conditions, lead oil to breakdown faster, making vague recommendations about extended intervals untrustworthy without individual testing.
What Five Years of Data Really Shows
Tracking these vehicles through a variety of situations and a wide range of mileage accumulations, my findings defy simplistic analysis. EGR delete kit installations showed engines experiencing fewer intake system issues and maintaining cleaner components, and showed fewer emissions system specific maintenance issues. These savings resulted in tangible cost savings and less downtime for customers.
However, claiming deletion universally lengthens life is an oversimplification. Increased combustion temperature, changes in emissions, and the possibility of improper tuning are all potential variables that seldom manifest until mileage exceeds the range of my analysis. Some engineers suggest that modern EGR systems, despite the issues they pose, promote overall engine longevity by optimizing combustion and temperature management.
The most honest assessment involves the fact that egr delete kit installations come with definite mechanical advantages in the short to medium term, but also come with legal concerns and long term questions regarding the future. Vehicle owners have to consider all of these issues and evaluate their own individual circumstances, habits, and level of comfort with breaking the law.
Final Thoughts
To those wondering about my holistic perspective after five years of watching, my recommendation is for anyone exploring this modification to consider regulations, consequences, and mechanical pros, while also understanding the considerable legal and ethical factors operational beyond performance.
Frequently Asked Questions
Does deleting the EGR system void the manufacturer warranty?
The answer is almost assuredly yes, since the deletion of any piece of the catalyst system is always going to breach the warranty of any part of the system, and in fact may breach the warranty on the entire powertrain.
Can a vehicle pass inspection after EGR component deletion?
The answer is no, because the EGR system is the most commonly checked system during the diagnostic portion of the inspection, and if these components are not present, the vehicle is going to fail in any state or country that has any sort of emission testing, even if factory parts are put back on.
Is the modification worth the legal issues, warranty concerns, and potential negative environmental impact?
If the modification is worth the legal issues, warranty concerns, and potential negative impact on the environment, the 8-15 percent rise in power and slightly enhanced fuel economy of the egr delete kit is an individual question. People tend to place emphasis on the issues that matter most to them.
How does EGR deletion impact vehicle resale value?
Many buyers seek deleted vehicles, but many legal issues are kept with the vehicle, which may constrain the available market, and will affect the vehicle’s ultimate price in an unpredictable manner as a result.
Disclaimer:
EGR delete kits are illegal in many regions due to emissions laws and may void warranties. The effects on engine performance and longevity can vary. Modifying your vehicle may lead to legal and environmental consequences. Always consult with a professional mechanic before making modifications. Consider local regulations and potential risks before proceeding.
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