Exhaust gas recirculation (EGR) is just a strategy used in petrol and diesel engines to reduce emissions, more specifically its used to reduce nitrogen oxide. Because the air entering your engine is 80% nitrogen and 20% oxygen, if you replace some of the air with exhaust gasses you can reduce the levels of oxides of nitrogen, counterintuitively EGR actually reduces combustion chamber temperatures under part throttle situations thus further reducing NOx.
What you'll find is the EGR strategy only actually comes into play once the engine is fully warmed, and even then it also only really operates at idle and during very low engine loads such as under cruise conditions. This is why on older petrol engines like the Duratec, Ford linked it's operateration to engine vacuum.
With internal combustion engines the idle condition is always very inefficient, volumetric efficiency is extremely poor at idle so not all the fuel burns resulting in a significant increase in the hydrocarbon gasses emitted from the tailpipe, reintroducing those fuel rich gasses into the engine to be reburnt before they're emitted to the environment is therefore definitely a good idea. However, EGR systems are not 100% reliable, failures are common with a faulty EGR valve resulting in a rough idle and performance issues including a loss of power, reduced acceleration and decreased fuel efficiency, ironically when it starts to play up it will also cause vehicle emissions to increase.
Because the EGR system is not in operation when the engine is under load and at wide open throttle, removing it will have zero effect on outright performance so don't expect an EGR delete it will give you another 10 horsepower at the dyno, because it absolutely won't, indeed it won’t even give you a 1 horsepower gain! However because the EGR valve is open at idle it will have a negative impact on throttle response, that is the moment you apply the throttle known as 'Tip In', but only for that split second you transition from idle to a driving state, in this respect EGR has an impact on throttle response much like the negative effects of a vacuum leak.
Blanking the path of exhaust gasses being reintroduced to your engine will definitely improve throttle response as you pull away off junctions, if you then combine this with a swirl flap delete the improvement will be even more pronounced, you'll also be removing a potential point of failure that is the ERG system.
Your NOx levels will increase though, in my opinion this is more of a personal choice thing as I doubt you'll have an issue at MoT time, if you do a lot of town driving where extended periods of idle are common and your exhaust tail pipe will come into close proximity to pedestrians you may choose to keep the EGR system out of respect for your fellow man, otherwise I'd blank it off and enjoy the crisper throttle response.
Also keep in mind a blanking plate can't be seen by your ECU, so as long at the valve remains connected and operational the ECU will continue to instruct it so no fault will be throw, remember the old Ford Visteon ECU used on our Duratec plus 4s is only sampling the oxygen content in your exhaust pre and post catalyst and it does so using very old tech narrow band lambda sensors that are only accurate around stoich (14.7:1 AFR), the ECU is not
directly measuring NOx so again you can be reassured a fault code is extremely unlikely.
If you're not driving around the city all day long, if you like crisp throttle response off idle and you want to eliminate a system that's known to fail from time to time, an EGR blanking plate is a nice cheap mod. I'd also recommend deleting the swirl flap system at the same time as it's just a massive inlet manifold restriction, better still fit a Fusion Fabrications long runner inlet manifold with internal velocity stacks and along with a big improvement in throttle response you'll enjoy a nice uplift in torque.
![[Linked Image]](https://i.ibb.co/fF9yB7x/FF-Inlet-7.jpg)
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