Quote:
Originally Posted by JSH
As to the idea that some tunes decrease emissions - LOL. Sure they do. If a simple tune could be used to reduce emissions OEMs would do it and book the emission credits.
|
The off the shelf tunes most people get that bump up some ignition timing and lean out the open loop AFR map do run cleaner though...for a while at least (maybe with marginally increased NOx emissions, esp with people who disable EGR). OEMs try to avoid running rich on the test cycle but in normal operation some cars dump a pretty good amount of unburned fuel out the exhaust.
The only problem I see is the guys who run without cats and force the emissions readiness monitors to pass. The number of people attempting lean burn is close to 0, mostly because of the widely held belief that lean burn raises EGT and doesn't help fuel economy.