PCM tuning questions

[ws6drbob]

I plan on ordering a PCM from madz28 and had a few questions about some of the options. I plan on running headers with no AIR or EGR fittings... so what I was wondering is are there any drawbacks to removing these systems that I should be conscious of? I also plan on running a y-pipe with no cats as well... Is there any reason besides emissions that I shouldn't disable the o2 sensors? Also, what is a carbon canister? Thanks for any help.

[Joe 1320]

I plan on ordering a PCM from madz28 and had a few questions about some of the options. I plan on running headers with no AIR or EGR fittings... so what I was wondering is are there any drawbacks to removing these systems that I should be conscious of? I also plan on running a y-pipe with no cats as well... Is there any reason besides emissions that I shouldn't disable the o2 sensors? Also, what is a carbon canister? Thanks for any help.

Removing the EGR will often have a negative impact. EGR is used , believe it or not.... to reduce the octane requirement of the engine at cruise and part throttle. Since EGR isn't active at WOT, unless the system is malfunctioning, I would leave it alone. By deleting it you could likely experience part throttle knock and a slight decrease in fuel mileage could result.

You cannot simply delete the front or primary 02 sensors, when warmed they are used to measure the oxygen content in the exhaust and fuel mixture is altered by the computer for ultimate fuel effeciency. While it is physically possible, I don't think it's the way to do it in this application. Heck, you could even tear out the whole ignition and fuel system, slap on an intake and carb, a distributer, and it will run pretty well. I still prefer computer control.

The carbon canister is used to capture exhaust fumes that in the old days simply vented from the tank into the atmosphere. Now the fumes are basically drawn out of the tank and absorbed in the charcoal canister.

[ws6drbob]

Ahh I really wanted the EGR system gone due to the fact that I have had to fix an intake related leak 4 times already and I figured that this would ensure that it doesn't happen again. Hmmm... is it possible for my intake manifold to be warped and thats why it won't seal properly? I followed Kens guide and make sure that I let it sit 24 hours before starting.

[fastTa]

I plan on ordering a PCM from madz28 and had a few questions about some of the options. I plan on running headers with no AIR or EGR fittings... so what I was wondering is are there any drawbacks to removing these systems that I should be conscious of? I also plan on running a y-pipe with no cats as well... Is there any reason besides emissions that I shouldn't disable the o2 sensors? Also, what is a carbon canister? Thanks for any help.

Like Joe pointed out, the AIR and EGR systems don't even operate at WOT, but I can definitely understand removing the EGR and AIR and disabling it via the PCM if you do not have EGR fittings and you are not going to run cats. Without cats and/or the need to pass emissions tests, the AIR system is useless.

As long as the EGR and AIR systems are disabled and the associated codes disabled you will not have any problems. You may have slightly more emissions, but it appears you are in an area where you don't have to worry about that. Texas doesn't have any emissions laws either.

Joe explained basically what the carbon canister does. It also allows the gas fumes to re-enter the intake manifold by means of the CCP purge solenoid.