The exhaust gas recirculation (EGR) valve is among the most important components in your car’s exhaust management system. It’s part of the reason that your car operates at its current fuel efficiency, and why it can pass an emissions test and remain on the roads.
The EGR valve is also a key component in one of the most popular upgrades and modifications that people perform on their vehicles. It’s known simply as the “EGR Delete.” In today’s blog, we’re going to try and answer all of the most common questions surrounding the EGR valve and specifically the EGR Delete modification and how it works.
What is an EGR Valve? What Purpose Does it Serve?
The name of the EGR valve — exhaust gas recirculation valve — is actually very appropriate for what it both is and does. The valve connects the exhaust and intake manifolds and can be controlled using either a vacuum or an electric step motor. The primary function of this component as a part of the overall engine management system is to control the flow of exhaust gas that is recirculated through the system depending on the current engine load and reduce the level of NOx gases. Broadly speaking, there are 5 types, with vacuum-operated valves being used in older vehicles, and computer-controlled ones in modern vehicles:
- Diesel high-pressure EGR valves
- Diesel low-pressure EGR valves
- Gasoline EGR valves
- Vacuum-operated EGR valves
- Digital EGR valves
In doing this recirculation task, the EGR fulfils its secondary function of boosting the efficiency of the engine overall. Some engineers have also used the EGR to their advantage in designing both gasoline and diesel engines that can operate with lower pumping losses and greater combustion efficiency and knock tolerance.
How Does the EGR Valve Work?
Nitrogen is the chief constituent of our air, making about 78 percent. On its own it is inert and harmless, but when you apply extreme heat, things change. The nitrogen inside of your car engine’s combustion chamber gets heated to 1370 degrees Celsius, after which it becomes a reactive and harmful gas known to us as nitrous oxides, or simply NOx gases.
In older cars, these NOx gases simply passed through the exhaust and were pumped out into our atmosphere which by the time of mass car production was extremely bad news. The EGR valve was fitted to allow a quantity of this exhaust gas to be recirculated back to the combustion chamber where it would burn at a temperature roughly 150 degrees lower than previously, thus removing some of the NOx gases to help clean up the exhaust.
The EGR valve itself works by being fully open, fully closed, or somewhere in between. It’s closed when you start the engine, and no power is required. It opens up at times when you are either idling or travelling at low speeds. As you speed up, more oxygen is needed in the combustion chamber and so it closes up.
What is EGR Delete?
An EGR Delete is among the most common vehicle modifications/upgrades. It’s an aftermarket kit that takes away the EGR system within your vehicle, for which those who use it hope to gain some boosts in performance.
Everyone recognizes the importance of the EGR system on street cars. NOx gases are harmful not only to the wider environment but also directly detrimental to human respiratory health. The fact remains, however, that in recirculating the exhaust gases back into the combustion chamber, an amount of oxygen is displaced in the process, which does negatively impact the engine’s full performance potential.
An EGR Delete is simply designed to remove the EGR system from the equation, thus removing the recirculation of exhaust fumes and allow the maximum amount of oxygen to enter the combustion chamber.
How to Delete EGR with an EGR Delete Kit – Can You Do It Yourself?
You can perform the EGR Delete yourself if you have the right kit, the right tools and enough confidence to take on the job. Your typical EGR Delete kit will usually come with the following parts:
- EGR pipe
- Barb couplers (usually 2)
- Gasket
- Hose clamp
- Boot gauge tap
- Boost tap block off
- Bolts, hose, washers, lock washers
Some kits may differ from this, but broadly speaking this is what you’ll find. The tools you will need include a wrench and set of sockets, some pliers and a screwdriver. Below we’ll list the basic steps required in performing an EGR Delete. There’s a lot of removing of things in the first several steps, so please proceed with care:
Step 1: Disconnect the battery and electrical harnesses first. If the engine has just been running, allow it to cool before getting started.
Step 2: Remove the MAP sensor and disconnect the intake pipe. At the same time, you need to remove the air intake filter and disconnect the point where the intake pipe and the turbo connect. To do this, remove the clamps that you find there.
Step 3: Some more disconnections are next. First, the vacuum line that connects to the EGR solenoid. Take the solenoid clips away and pull the solenoid out. Next, disconnect the blue, red and black electrical connections.
Step 4: Next, drain about a gallon of coolant by removing the coolant reservoir cap, and then take out the coolant lines in front of and behind the EGR.
Step 5: Remove the EGR flange bolts so that you can get at the pipe and remove it.
Step 6: The next thing to come out will be the EGR cooler. Locate the bolt behind the EGR cooler assembly and remove it. Then, loosen and remove the bolts holding the lower bracket in place and then remove that, too. Finally, take the cooler manifold out you’ll be able to detach the entire cooler assembly.
Step 7: Remove the rear EGR pipe and lower coolant lines
Step 8: At last, we come to an installation step. Here you will install the turbo block off plate by putting the EGR delete kit blanking plats and gasket on the turbo manifold and then locking it in place with the bolts in your kit. Finally, mount the block off bracket.
Step 9: In this stage, you replace the coolant lines. Start by connecting the front coolant line to the now-mounted block off bracket. Put the lower coolant line into the hose and clamp it with the clamp in your kit. Do the same thing with the upper coolant line and attach the line to the block off bracket.
Step 10: Put back all the parts you previously took out and test the engine to observe how it has all gone. The main thing you’re looking for here is coolant leak. There shouldn’t be any coolant leak.
What is the Typical Cost of an EGR Delete Kit?
To buy the kit yourself will cost between $40 and $50 depending on your supplier. If you install it yourself, then you only have to cover the costs of the tools involved and give up some of your time. If you have the EGR Delete professionally installed, it is likely to cost $200 or more. If you need to tune the ECU after installation, then that might add further cost to the process.
Do You Need to Tune/Map the ECU After Deleting the EGR?
Not all cars will require the ECU to be tuned or remapped after the installation of an EGR Delete, but some do. The reason for this is that some cars will start issuing error codes when it discovers that the EGR is no longer working as it should in the original specification of the vehicle.
If you are unsure about the potential effects of the EGR Delete on your ECU, then it would be better to work with a professional who can advise on whether an ECU remap would be required or not.
What Are the Benefits of EGR Delete?
There are several key benefits to performing an EGR Delete on your vehicle:
1. Cleans Up Exhaust System
This first benefit is felt especially in diesel engines where the use of the EGR valve over time causes a buildup of soot, which blocks airflow. Performing an EGR Delete, therefore, prevents this from happening, allowing the exhaust to run cleaner and prevent any soot from finding its way to the engine or combustion chamber.
2. Potential Gains in Fuel Efficiency
Cleaning up the exhaust system in this way allows it to run more efficiently. Without the “drag” of the soot and other contaminant buildups that is a natural result of recirculation of the exhaust gases, the engine can run a lot more smoothly and thus offer a boost in fuel efficiency. It has been known to achieve an increase of as much as 20 per cent.
3. Lowers Engine Temperature
Another happy result of the engine running more smoothly is a lower overall engine temperature. When blockages start to occur, however minor, the engine has to work harder to compensate and overcome them, so bypassing the EGR valve means the engine can remain working at a steady rate, thus maintaining a steady temperature.
4. More Horsepower and Throttle Response
Another part of the system that ends up getting clogged by the EGR is your intake, as well as your turbo. Keeping it free from these buildups allows maximum horsepower to be retained. You’ll also find that it largely delivers an improved throttle response thanks to maximized oxygen flow.
Is it Illegal to Delete EGR?
In every US state, it is illegal for street cars to operate with an EGR Delete having been carried out on it. The act of deleting the EGR itself is not illegal, but it becomes illegal when you perform it on a street car that is then used on public roads. If you wish to perform this action on a car that you drive only on your own land or off-road, then it is legal. It is merely illegal for street-car use.
Are There Other Drawbacks to Using an EGR Delete Kit?
The main drawback is that it renders a car that you have illegal to operate on the streets, as we mentioned above. Beyond that, however, the chief downside is that your car becomes a NOx-spewing machine once again. This is not only bad for the air and the environment in general, but if you are standing near such a vehicle and its fumes, it could be bad for your own health, too, or that of your family members or other bystanders.
Another issue with performing an EGR Delete is increased temperatures in your exhaust gases. The EGR uses coolant to help cool exhaust fumes before they go back to the engine, but without it, the gases are just allowed to heat and stay hot. This can — but not always — do damage to your car’s cooling system.
Can You Re-Install an EGR After Deleting It?
In short, yes you can. It’s not as simple as just flipping a switch, but with some parts, tools and time you can restore the car’s EGR valve to its original function if you want. In order to reverse the process, you might have to use an EGR cooler, and you might need a new section of up pipe for that cooler if you had replaced it with a different sort when performing the EGR delete.
Conclusion: Is an EGR Delete Worth It?
If you have a vehicle that doesn’t need to be street-legal and the off-road performance of which you wish to boost for your own private amusement, then an EGR Delete is a great project. It’s relatively easy to perform and not an expensive modification in the wider sense of vehicle modification. On top of that, it is technically reversible and so doesn’t permanently render a vehicle useless.
On the other hand, if you have but one car and you perform the EGR Delete without knowing the legalities of it, you could end up just writing off your street car and then being stuck for some time without a roadworthy car. Consider the implications before you perform this modification.
