The 5 Things To Know Before Doing An EGR Delete

An EGR delete is seen by many as an easy way to improve performance and efficiency by removing the EGR (exhaust gas recirculation), which is a component that helps in reducing the NOx that is thrown into the atmosphere, particularly in diesel vehicles. The EGR recirculates exhaust gases into the combustion chamber, thereby reducing emissions that go out of your tailpipe. 

The EGR controls the release of NOx, a harmful gas that can cause cardiovascular and respiratory diseases in humans, contribute to lung congestion and coughing, trigger asthma attacks, and lead to acid rain. The EGR, however, is often seen as a hindrance by many car owners, who believe it restricts performance, reduces fuel efficiency, and gradually causes engine issues due to the carbon buildup it produces, particularly in the intake system. An EGR delete, especially in diesel vehicles, is seen as a quick fix to extend its life, improve engine performance, and reduce service expenses by minimizing carbon buildup.

But, there are a few things that you have to keep in mind before you head over to your nearest tuner to begin work under the car.

Let’s get this out of the way: if you’re from the U.S., U.K., Canada, and several other countries, an EGR delete is illegal and could result in some severe penalties. An EGR delete goes against the EPA’s Clean Air Act, which means that cars that are used on public roads have to have an EGR. However, those used on private property or for off-road and track use can run their vehicles without an EGR. 

EPA regulations forbid the tampering of emissions devices in vehicles. But this hasn’t stopped the growing trend of “deleted trucks” — vehicles that run without EGRs, DPFs, or SCRs — in a bid to make them faster and, in some cases, more reliable. While a “deleted truck” may offer certain benefits, there’s a price to pay if the authorities get a whiff of the illegalities – up to $5,000 for owners. Tuners, meanwhile, may face far steeper penalties, sometimes in the millions, as some unsuspecting businesses have recently discovered.

Automakers go to great lengths to do a background check of your car — and the mods you may have done — before they entertain any warranty claims, evidenced by various tricks that manufacturers have in their back pocket. There may be some claims that are justified, but it’s quite certain that an EGR delete is a mod that they’ll quickly latch on to and not honor your warranty claims. The EPA has announced that any defeat device installed in a car will void warranty claims and will not be eligible for insurance coverage.

In fact, even exhaust modifications could lead insurance companies to deny coverage or require owners to purchase a custom policy, often with a higher premium. Cars that lack the required emissions equipment can also be harder to sell due to voided warranties and potential insurance issues, and many dealers refuse trade-ins for such vehicles. EGR-deleted cars will almost certainly fail emissions tests, which could prevent the car from being legally registered or driven.

Vehicle manufacturers take emissions control very seriously, particularly after the Dieselgate fiasco, which put the spotlight on car companies and their deceptive methods to manipulate emission tests. This means that they have put several safeguards to ensure that all of their emissions devices stay in the car, and the absence of one component would result in a check engine light. 

You will most certainly get a check engine light when you pull out the EGR, as well as several error codes. Some of the error codes include P0401, P0402, P0404, P0405, P0406, which are EGR flow errors, EGR voltage errors, and EGR circuit errors. This will require you to recalibrate your ECU to ensure that the car runs smoothly, sans the check engine light blinking continuously. The codes can be cleared through an OBD2 scanner, but they may not be a permanent fix. One option some use is an EGR simulator, which fools the ECU into thinking that the EGR is still connected to the car.

The EGR helps regulate engine temperature, as it includes a cooler that lowers the temperature of exhaust gases before they are reintroduced into the combustion chamber. Removing the EGR could increase combustion temperatures, and basic internal combustion principles suggest that higher engine temperatures can reduce efficiency. Some tuners have also noticed increased knocking in cars that have their EGRs deleted. 

The higher cylinder pressures resulting from an EGR delete, combined with increased combustion temperatures, can cause damage to pistons, piston rings, head gaskets, and cylinder heads. Over time, this stress may also contribute to premature wear of valves, turbo components, and other engine internals. After an EGR delete, the turbo is subjected to greater strain because hotter exhaust gases pass through it, which can increase stress on the turbine and compressor, reduce efficiency, and potentially shorten its lifespan. Before removing the EGR, you should ensure that your vehicle’s internals are in good condition, with particular attention to the engine having good compression, no knocking or leaks, and a properly functioning cooling system. It’s also advisable to check the turbo, pistons, and valves to ensure they can handle the increased combustion temperatures and pressures.

If you’ve weighed the pros and cons of an EGR delete and are convinced that it’s the best option for you, you have two options: blocking or deleting it altogether. Both options, though, will require you to reprogram the ECU and trick it into believing that the EGR is still functioning to ensure that you don’t have any warning lights.

In the case of an EGR delete kit, the whole EGR system will have to be removed, which will free up some space in the engine. On the other hand, there are options to block or blank the EGR system, which would ensure that the EGR is still in place, but blanking plates are fitted to prevent the exhaust gases from recirculating into the combustion chamber. Some owners have reportedly faced issues with blanking the EGR as pressure builds up against it, which could cause damage to the engine in the long run.