Lude Generation

PerformanceAutoworks wrote: The EGR system was brought into play through increasingly stringent emissions regulations, not just carbon monoxide but nitrogen oxide (NOx) as well. The EGR is focussed towards the NOx reduction part of the equation but also aids with reduction of hydrocarbons or unburnt fuel.
NOx is an inert gas it does help with the reduction of cylinder combustion temperatures but at a sacrifice to some power. The cooler cylinder temps have the knock on effect of producing less NOx and so the cycle continues. This is obviously good for the tree huggers but not so desirable for the power hungry petrol head as valuable cylinder capacity is being taken over by unwanted inert gasses.
The argument that without the EGR system the combustion temps will be too high and cause problems is unfounded tbh. The EGR will never be open at WOT, the ecu will be in "open loop" fixed map mode Honda use oil squirters to cool the piston undersides and over fuel the higher rpms to control cylinder temps.


If using an OEM ECU
Earlier systems like the 4th gen Prelude are pretty dumb meaning that there are no significant changes to the ecu map while the EGR is in operation. These can be blanked off with an alloy plate sandwiched between the EGR valve and the inlet manifold. The egr is in place and still connected so the ECU "sees" it is working. No problem here and no detrimental effect. MOT emissions tests won't be affected so no worries there either.

The 5th gen is pretty similar althgough being a later spec OBD2 system it is a little more sensitive so can throw up an error code even if left connected. For the most part you can get away with it though.

ATRs suffer alot with EGR related faults as these are very sensitive and will throw error codes for EGR flow problems. Simply blanking these off will throw an error code.

If running with a Hondata or other aftermnarket ECU you can simply remove the EGR valve and blank the manifold completely, remove the assosiated EGR lift solenoid and purge valves etc as well.


In all honesty the gains you make by simply blanking it off on a stock ecu are negligable as the ECU is mapped with the EGR system in mind. Removal and full re-map then yes it definately helps to maximise what you have.
The peak power gains will be marginal as the EGR is not open during this period (of WOT and high rpms) however there will be some carry over of contaminated intake charge. Most gains will be made through midrange/partial throttle conditions where usable power can be improved.

I'm not saying that gains are all down to the EGR, quite clearly it's not but the fact remains that EGR does inhibit the potential of an engine to produce power as it will contaminate the intake charge