The exhaust gas recirculation (EGR) valve is among the most important components of your car’s exhaust management system. It’s part of why your car operates at its current fuel efficiency and why it can pass an emissions test and stay on the road.
The EGR valve is also a key component in one of the most popular upgrades and modifications people perform on their vehicles. It is known simply as “EGR Delete”. In today’s blog, we are going to try to answer all the most common questions about 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 is and what it does. The valve connects the exhaust and intake manifolds and can be controlled using either a vacuum or an electric stepper motor. The main function of this component as part of the overall engine management system is to control the exhaust gas flow that is recirculated through the system depending on the current engine load and to reduce the level of NOx gases. Generally speaking, there are 5 types, with vacuum operated valves being used on older vehicles and computer controlled on modern vehicles:
- Diesel high pressure EGR valves
- Diesel low pressure EGR valves
- Gasoline EGR valves
- Vacuum operated EGR valves
- EGR digital valves
By doing this recirculation task, the EGR fulfills its secondary function of increasing the engine’s overall efficiency. Some engineers have also used EGR to their advantage when designing gasoline and diesel engines that can operate with lower pumping losses and higher combustion efficiency and knock tolerance.
How does the EGR valve work?
Nitrogen is the main constituent of our air, making up about 78 percent. By itself it’s inert and harmless, but when you apply extreme heat, things change. The nitrogen inside your car’s engine combustion chamber is heated to 1370 degrees Celsius, after which it becomes a reactive and noxious gas known to us as nitrous oxide, or simply NOx gases.
In older cars, these NOx gases simply passed through the exhaust and were pumped into our atmosphere, which in the days of mass production cars was extremely bad news. The EGR valve was installed to allow an amount of this exhaust gas to be recirculated back into the combustion chamber, where it would burn at a temperature approximately 150 degrees lower than previously, thus removing some of the NOx gases to help clean the exhaust. .
The EGR valve itself works either fully open, fully closed, or somewhere in between. It closes when you start the engine and requires no power. It opens when you are idling or at low speed. As you accelerate, more oxygen is needed in the combustion chamber and so it closes.
What is EGR deletion?
An EGR delete is among the most common vehicle modifications/upgrades. It’s an aftermarket kit that strips your vehicle’s EGR system, for which those who use it expect to get some performance boosts.
Everyone recognizes the importance of the EGR system in street cars. NOx gases are not only harmful to the environment in general, but also directly harm human respiratory health. The fact remains, however, that by recirculating the exhaust gases back into the combustion chamber, an amount of oxygen is displaced in the process, which negatively affects the overall performance potential of the engine.
An EGR Delete is simply designed to remove the EGR system from the equation, thereby removing exhaust gas recirculation and allowing 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 get the job done. Your typical EGR Delete kit usually comes with the following parts:
- EGR tube
- Barbed couplers (usually 2)
- hose clamp
- boot gauge faucet
- Disable push touch lock
- Screws, hose, washers, spring washers
Some kits may differ from this, but generally speaking, this is what you’ll find. Tools needed include a wrench and set of sockets, some pliers and a screwdriver. Below we will list the basic steps required to perform an EGR delete. There’s a lot of stuff removed in the first few steps, so proceed with caution:
Step 1: Disconnect the battery and electrical harnesses first. If the engine has just been run, allow it to cool before starting.
Step 2: Remove the MAP sensor and disconnect the inlet tube. At the same time, you need to remove the air intake filter and disconnect the point where the intake pipe and turbo connect. To do this, remove the staples that you find there.
Step 3: A few more disconnects follow. First, the vacuum line that connects to the EGR solenoid. Remove the solenoid clips and pull the solenoid out. Then disconnect the blue, red, and black electrical connections.
Step 4: Then drain about a gallon of coolant by removing the coolant reservoir cap, then take out the coolant lines in front of and behind the EGR.
Step 5: Remove the EGR flange bolts so you can access the tube and remove it.
Step 6: The next thing to come out will be the EGR cooler. Locate the screw behind the EGR cooler assembly and remove it. Then loosen and remove the screws holding the bottom bracket in place and remove that as well. Finally, remove the cooler manifold so that you can disconnect the entire cooler assembly.
Step 7: Remove rear EGR tube and lower coolant lines
Step 8: Finally, we come to an installation stage. Here you will install the turbo lock plate by placing the seal plates and gasket from the EGR exclusion kit into the turbo manifold and then locking it into place with the screws from your kit. Finally, assemble the block off the support.
Step 9: In this step, you replace the coolant lines. Start by connecting the front coolant line to the now assembled block support. Place the lower coolant line into the hose and secure it with the clamp from your kit. Do the same with the upper coolant line and connect the line to the block support.
Step 10: Put back all the parts you removed earlier and test run the engine to see how it went. The main thing you are looking for here is coolant leakage. There must be no refrigerant leakage.
What is the typical cost of an EGR delete kit?
Buying the kit yourself will cost between $40 and $50, depending on your vendor. If you install it yourself, you only have to cover the costs of the tools involved and dedicate a little of your time. If you have EGR Delete professionally installed, chances are it will cost you $200 or more. If you need to tune the ECU after installation, it can add more cost to the process.
Do you need to tune/map ECU after deleting EGR?
Not all cars will require the ECU to be tuned or remapped after installing an EGR Delete, but some do. The reason for this is that some cars will start to emit error codes when you discover that the EGR is no longer working as it should in the vehicle’s original specification.
If you are unsure about the potential effects of EGR deletion on your ECU, it would be best to work with a professional who can advise on whether or not an ECU remapping would be necessary.
What are the benefits of EGR deletion?
There are several key benefits to performing an EGR delete on your vehicle:
1. Cleans the Exhaust System
This first benefit is felt mainly in diesel engines, where the use of the EGR valve over time causes a buildup of soot, which blocks the air flow. Performing an EGR Delete therefore prevents this from happening, allowing the exhaust to run cleaner and preventing any soot from reaching the engine or combustion chamber.
2. Potential gains in fuel efficiency
Cleaning the exhaust system in this way allows it to work more efficiently. Without the “drag” of soot and other contaminant build-ups that are a natural result of exhaust gas recirculation, the engine can run much smoother and thus offer an increase in fuel efficiency. It has been known to achieve an increase of up to 20 percent.
3. Reduces engine temperature
Another positive result of smoother engine operation is an overall lower engine temperature. When blockages begin to occur, however small they may be, the engine has to work harder to compensate and overcome them; So bypassing the EGR valve means the engine can remain running at a constant rate, thus maintaining a constant temperature.
4. More power and throttle response
Another part of the system that ends up being obstructed by the EGR is its intake, as well as its turbo. Keeping it free of these build-ups allows maximum potency to be maintained. You’ll also find that it offers improved throttle response thanks to maximized oxygen flow.
Is it illegal to delete EGR?
In all US states, it is illegal for street cars to operate with an EGR override performed on them. The act of erasing the EGR itself is not illegal, but it becomes illegal when you perform it on a tram that is used on public roads. If you want to perform this action on a car that you only drive on your own terrain or off-road, then it’s cool. It is merely illegal for use on trams.
Are there any other downsides to using an EGR delete kit?
The main downside is that it makes a car you have illegal to operate on the streets, as we mentioned above. Beyond that, however, the main downside is that your car becomes a NOx spewing machine again. Not only is this bad for the air and the environment in general, but if you are parked near such a vehicle and its fumes, it can also be bad for your own health or that of your family members or others close to you.
Another problem with performing an EGR override is increased temperatures in the exhaust gases. EGR uses coolant to help cool the exhaust gases before they return to the engine, but without it, the gases can heat up and remain hot. This can – but not always – damage your car’s cooling system.
Can you reinstall an EGR after deleting it?
In short, yes you can. It’s not as simple as pushing a button, but with a few parts, tools, and time, you can restore your car’s EGR valve to its original function if you’d like. To reverse the process, you may have to use an EGR cooler and may need a new riser section for that cooler if you replaced it with a different type when performing the EGR delete.
Conclusion: is an EGR delete worth it?
If you have a vehicle that doesn’t need street legal and whose off-road performance you want to boost for your own amusement, an EGR Delete is a great project. It is relatively easy to perform and not an expensive modification in the broadest sense of vehicle modification. Furthermore, it is technically reversible and therefore does not permanently render the vehicle unusable.
On the other hand, if you only have one car and you perform the EGR delete without knowing the legality of it, you could end up canceling your street car and being stuck for some time without a roadworthy car. Consider the implications before performing this modification.