Should I !EGR?
 

Hey guys,
I'm thinking about doing the !EGR mod on my ZZ4-cammed TPI 355. I remember the LT4 motors came without EGR from the factory since the cam had enough overlap, it was kinda like a built-in EGR. I think the ZZ4 cam is a touch bigger than the stock LT4 cam so would it hurt to !EGR? Any pros or cons with getting rid of it? I have Collector registration on the car, so no worries about emissions.

If it ain't broke.....

Well, I dunno if it's broke; the car has a nasty vacuum leak and won't idle when it's cold until the ECM kicks the idle speed up to compensate. I'm hoping to track it down tomorrow afternoon with the propane torch (not lit, don't worry!) and checking to see when the idle smooths out. Might be the EGR valve or solenoid, an injector O-ring, upper/lower plenum gaskets, clogged PCV, who the heck knows. I was just thinking of getting rid of it to eliminate some excess wiring and vacuum lines.

ditch it. It'll look a lot cleaner w/o it.

the only real advantage is weight savings and thats minimal at best...makes for a cleaner engine bay too. just make sure your computer isnt going to freak out when its removed, with my mustang i had to leave the position sensor hooked up to avoid the computer going weird

True enough guys. Oh, don't worry 'bout the ECM, I can burn a new chip to take care of the missing EGR. :)

Find you vacuum leak first. I would leave the egr alone. It helps lower combustion chamber temperatures. The EGR solinoid only gets vacuum at part throttle cruise from the port on the bottom of the throttle body. The best way to see if the egr is at fault is to disconect the line from the egr valve and atach a vacuum pump and watch to see if the valve moves when vacuum is applied and returns to it closed position when vacuum is released. then try it running at idle. apply vacuum to the egr valve. If the car stalls or get near to stall then the egr is working properly. Plus the egr valve is under the plenum so no one really sees it, so you not really cleaning up anything.

the EGR is a tube from your car's a$$ right back up to its mouth.

actually... EGR is on the intake manifold on tpis under the plenum. it has nothign whatsoever to do with the cat or tubes off the exhaust manifolds. thats the AIR system.