The Exhaust Gas Regeneration (EGR) is currently used in both diesel and petrol engines. If the manufacturer of the engine isn’t able to drop the amount of emissions below a given threshold without EGR. EGR will be equipped to keep the tailpipe emission/particles below the threshold.
The Exhaust Gas Regeneration (further named as EGR) is there to lower the amount of NOx in vehicle emissions. Instead of filling the engines cylinder with fresh air (oxygen o2), exhaust gas (NO) is entered to lower the amount of oxygen. Oxygen helps to burn the mixture but with a high temperature as end result. The high temperature causes high NOx.
The downside of EGR is the following:
- The intake manifold, EGR valve itself, EGR cooler, intake manifold and other pipes connected can be clogged by time and mileage. The parts or cleaning of them that are necessary to get rid of the clogging or clear the error codes as a result of clogging can be expensive to repair or replace.

- Once the intake manifold is clogged it can restrict airflow to the engine cylinder(s) and thus restrict power output or cause smoke as a result of less air.

- It can cause a higher fuel consumption due to higher intake temperatures. Due to the higher temperature it is not possible to inject/start the burning process earlier (ignition efficiency).

- Due to the exhaust gas that enters the cylinder the oil can dilute and cause engine/turbocharger failure once oil refreshing limits are exceeded and driving conditions are mainly operated in an area were high EGR flow rates are used.

- Components in the manifold can be affected by high amount of sulfur and cause pre-mature failure which can lead to engine damage. These failures can be swirl flaps or other components that were tested in pre development with a lower rate of EGR than used in real life.

The upside of EGR is that it helps to reach the operating temperature sooner by entering hot exhaust gas into the cylinder. It can also help bringing up the total net efficiency of the engine. When an engine is filled with exhaust gas in part load conditions, it can cause a lower intake manifold vacuum which helps bringing the complete efficiency/work necessary for the engine*.

*This is currently only applicable for petrol engines with a throttle valve.

Intake manifold pipes which are clogged due to exhaust gas regeneration.
Karreman Engineering is able to completely or particial* remove those strategies that involve EGR. Also Karreman Engineering is able to remove error codes related to removed EGR components. With our EGR OFF service we can remove the EGR valve/cooler and piping from your car and/or algorithms inside the ECU (Engine Control Unit) that are used for EGR.
*It is also possible to enable EGR until a specific coolant temperature has exceed the threshold set in the ECU. Giving the fastest engine warmup (less fuel consumption and engine wear) and no EGR during an engine at operating temperature.
With the removal of your EGR valve/cooler/piping or functionality the following benefits can be fulfilled:
-Much less or no risk of clogged EGR related parts that could cause error codes.
-With less clogging risk there is less risk of parts that can failure due to clogging (example: swirl flaps)
-Sustained airflow from new with less clogging risk giving optimal engine performance over time and mileage.
-No more or less oil dilution caused by EGR
-Less fuel consumption due to cooler intake temperatures (only applicable for particial removal or long road trips).
Once the EGR is removed from your vehicle it is possible that it doesn’t meet your country emission regulation. Therefore it is forbidden to use a vehicle with EGR OFF functionality on the public roads there were this is not approved.
Karreman Engineering is not responsible for those who use this were not applicable. The user agrees the terms and conditions once the service is payed and the work is executed by our staff.