Have EGR/AIR Removal questions
04-23-2004, 04:05 PM
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Have EGR/AIR Removal questions I read newbie exhaust guide and have heard before that Macs have trouble with fitment of emissions for 00 cars. The owner of the car doesn't need to meet emissions requirements. Should he just get rid of the air and egr, and will tuning be needed to make the car run right? If he goes with LT's, he may want the emissions removed anyways to make the engine bay cleaner and easier to work on. Thanks
04-26-2004, 06:16 PM
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Engine control systems and computers have come a long way since 1981. I removed my AIR (pump and all) and EGR and tuned out the associated trouble codes. My car runs just as well post-egr as it did pre-egr, which is to say it runs fine-so don't worry about it.
I would like to add, the function of the EGR system is to route a small amount of exhaust gas back into the intake stream, dilluting the air-fuel mixture and lowering combustion temperature-which decreases the formation of oxides of nitrogen. By removing the EGR, you are changing the air-fuel ratio under the conditions the computer opens EGR (part throttle, warm operation driving). However, the stock PCM will learn its way around this with short-term correction(aka the fuel trims) of the A/F ratio and timing advance (O2 sensor feedback), continually adjusting the base calibration of the engine. GM calls this "Block learning".
PCM experts correct me if I'm wrong, but I don't think simply turning off the EGR code does anything more than that-the computer dosen't default to some EGR-less fueling/timing tables?
I would like to add, the function of the EGR system is to route a small amount of exhaust gas back into the intake stream, dilluting the air-fuel mixture and lowering combustion temperature-which decreases the formation of oxides of nitrogen. By removing the EGR, you are changing the air-fuel ratio under the conditions the computer opens EGR (part throttle, warm operation driving). However, the stock PCM will learn its way around this with short-term correction(aka the fuel trims) of the A/F ratio and timing advance (O2 sensor feedback), continually adjusting the base calibration of the engine. GM calls this "Block learning".
PCM experts correct me if I'm wrong, but I don't think simply turning off the EGR code does anything more than that-the computer dosen't default to some EGR-less fueling/timing tables?
