I've always thought that EGR was necessary on some engines to keep the combustion temperatures below a certain level, and by disabling the EGR the temperatures would become high enough to cause detonation. So how is it that some people are totally disabling their EGR?

From what I have heard, the valve overlap and exhaust scavenging somewhat acts like EGR. True?

Even more, when there is boost present, how does EGR still work effectively? Isn't the factory EGR valve too small to provide enough recirculation for the increased airflow? And because the engine would run hotter anyways with a turbo, wouldn't it be twice as bad to remove the EGR system?

Thanks everybody

 

hi

You are right on high overlap cams, also remember in a FI engine you blow intake right out exhaust a bit too which lowers exhaust temp some, you generally don't need high overlap cams on turbo engines.

In OEM turbo cars the EGR is only on a part throttle conditions, its off totally in WOT and idle.
thats very general explanation that should hold true on Honda too.

PS: I wouldn't disable EGR unless you are sure of ignition timing and fuel maps are good with proper exhaust temps at part throttle.

 

ya what he said