ArchetypeZ28

iTrader: (3)

Can anyone tell me all about the egr system on an ls1?- I removed mine long ago to put on a ls6 intake and have not had the money yet to get a tune to removed the codes. Some techs at my work (Toyota) saw that I had pulled my egr and started saying how dumb I was for doing so. Well I can think of any real bad reason for pulling it, but was hoping someone could enlighten me about all aspects of the egr system.

5_02ls1

iTrader: (20)

you said it all when you said toyota.on forein vehicles it can cause trouble but on your car no.setting the dtc is the only thing it does.

Cld069

iTrader: (2)

All it does is aid in emissions. EGR=exhaust gas recirculation. It takes unburnt exhaust fumes and circulates it back into the intake which means your not just getting fresh air but exhaust gases as well. I beleive I read on here that it helps in highway mileage but I can say for sure. Dont let techs at toyota tell you that its stupid or going to cause problems becuase it wont. I had a manager at a muffler shop tell me that I would have to be dumb to delete my rear o2s because its going to make me run really rich and mess up in closed loop. I just smiled and said ok. Whenever you get a tune just get the code deleted.

LS1Aggie09

iTrader: (25)

interesting...not to hijack but hows the AIR system related? i hear its all just emissions as well

SladeX

If your mileage hasn't been affected drastically then I wouldn't worry.

The EGR only works at part throttle.

Stated above, it circulates exhaust gases back into the intake stream. This has the benefit of "cooling" the combustion chamber a few hundred degrees. This is significant for emissions because it helps combat NOX.

This also has a second benefit. At highway speeds in order to save gas the car leans out the fuel AND advances timing. Well there's only so far it can do it before detonation occurs. Cycling exhaust gas back into reduces the temperature, but it also doesn't do anything for burning the charge. In other words, more timing, less fuel and detonation prevention = better highway mileage.

Now here's the catch. Depending on the fuel quality and the condition of your engine, you may or may not see that extra timing at all. If you pulled it and mileage went down, well now you know why.

Also, LPE sells a piece that lets you use EGR. I installed it with my LS6 intake and it looks completely stock at the moment.

Cld069

iTrader: (2)

The AIR system is just an air pump. What it does is this: It injects air into the exhaust manifold in hopes of lowering hydrocarbon levels. The engine is not completely efficient so there will be hydrocarbons left in the exhaust manifold. There is sufficent heat already present so with the addition of some o2 you will get combustion. Thus resulting in lower HC levels.