Another question about header work.

I finally ordered my headers for my LT1 and they came today. They look awesome. However, I feel that I am not going to be satisfied until someone here can answer this question for me. Is there a way that I can fully remove all of the pollution pumps (A.I.R. and EGR) from the car? I think I would rather not have those on there to make it a completly free emissions exhuast. I basically just want to cut out all of the AIR and EGR pipes and valves.

Can this be done?

Thank You, I know someone on here will have the answer, you guys are very helpful on here

sure it can, it will clean up the engine bay, you will be able to see intake, valve covers, shiny headers the way a hot rod motor suppose to look. but if you live in a strict emission check state your gonna have a ##### of a time passing emissions. other than that is very straight forward on a 94 lt1 removing the air pump wont throw a ses light but the egr will, best thing is to have your pcm flashed to delete the egr.
for the egr you just need to buy a block off plate for the manifold where the egr valve is and your headers are off road so you dont need the second block off plate that would go on the header flange.
for the air pump it also straight forward held by a few bolts and a bracket the only pita is the pipes, some of it is rubber but most of it aluminium and yanking the section that bends under and around the timing cover behind the balancer up to the pass side header.- if the front end is not disasembled for it to come off clean then you pretty much have to twist bend and cut and destroy it to take it out.,
but all in all, all this is about a 6 pack worth off work.

Ooops, ya got that backwards (sort of)--removing the A.I.R pump will set a DTC, becuz it is run by the PCM. Moreover, so is the EGR. The EGR runs on a 400 Hz modulated DC signal from the PCM--lose the EGR controller and another DTC will be set.

Here's the fun part...the A.I.R pump only comes on for 2 minutes on a cold start. It is there to burn off any unburned exhaust gasses within the exhaust headers and not in the CAT...to prevent The CAT from blowing up. The EGR is there to prevent not only NOX but to cool down the combustion chambers and prevent detonation which will cause the PCM to yank bank the timing and and richen the mixture. If this happens, the PCM does it really fast and then straightens everything out really slowly. That means, if the knock sensor senses any kind of pinging or detonation, the engine will run like crap for quite awhile.

Moral of the story pull both the A.I.R and the EGR at your own risk.

Actually, I purchased the ones with the AIR and EGR. I was concerned about removing the AIR and EGR because I do not want the car to run like crap. It is my everyday car. I was thinking that if it was possible to remove the AIR and EGR without any complications, then I would have exchanged my headers and got the ones without the spots for the EGR. I just dont want to have to change anything else besides the headers. I dont want to upgrade the knock sensor or anything like that. Besides, I cant gain that much power from the AIR and EGR being eliminated right? Just changing from the stock manifolds to the LT's should be plenty i think

The A.I.R does not take any hp from the engine, it is there as a kind of safety for the muffler and CAT. The PCM is programmed to start the engine with a "bark". You've noticed that?! It does this by relaxing the timing to take the strain off of the starter, and then instantly richens the mixture and advances the timing in conjunction with setting a high idle speed using the TPS and IAC. On a cold day, this means that it is possible for some unburned gasses to to make their way into the headers and settle in the CAT, where they can be dangerous when the CAT finally lights off. The A.I.R injects fresh air directly into the headers to burn those gasses off before anything happens.

Bear in mind that for top end hp, nothing beats a good set of long tubes--nothing, period. That's just the way it is. However, what LT1 can actually hit those rpms? If the owner adds the AFR Hydra Rev Kit, and 1.6 roller rockers, then ports and polishes the heads, even with the stock cam--the LTs will be utilized to their full extent.

The EGR is a pain in the butt. It really does take some hp from the engine--theoretically. However, it only comes in during a programmed sequence of events--namely low vacuum, low rpm and when the engine is required to pull stumps out of the ground or when the throttle is mashed at low rpms. During that time, any hp that is made would go up in pinging--that's when the EGR comes in and stops the pinging. Under normal use, the EGR doesn't even work and costs zero hp.

Not to mention the fact that your in for more work by removing them both than if you leave them alone. AND,the expense of having the ECM reprogrammed.

on obd 1, disconnecting the air pump should not throw a code. my 94 didnt throw a code when i disconnected the air pump

if you ordered lt with emissions hook up and its your dialy driver best bet is to leave them on. most people eliminate the air and or egr on off road vehicles or to clean up the engine bay, if eliminating them is not a concern.

The DTC that will be set will indicate an over rich condition on the HO2s (oxy sensors). If they indicate an over rich condition for more than 1 second, and this does not return to normal, then a DTC will be set. However, if the condition does not occur for something like 40 cycles, then the DTC will be cleared.

Again, the A.I.R pump helps to clear unburned gasses from the exhaust manifolds. If the owner is not concerned about this, then the A.I.R pump can be removed and it will not harm emissions readings when the engine is warm.

Also, the EGR can be removed if a cam with enough overlap and small enough centerline is used. For instance, a cam with a 114 centerline and duration of at least 210 degrees. A cam such as this will allow what is referred to as "natural" exhaust recirculation and makes the EGR redundant.

The big problem again is that SMOG testers have a complete list of what is supposed to be in the engine compartment and they visually look for it. If SMOG testers do not see an A.I.R pump or the EGR, then this would cause a failure.

Hope this clears this up. It's better to think of all the gear on the engine as parts of the engine managment sensors and not as SMOG stuff--it is there to make the engine run better and does not cost hp.

I"d like to add something to this posting. IMO, I don't care for this SMOG stuff either--I'm old school. However, the engine mgmt stuff is there to help the owners achieve max hp and stay within the SMOG laws. I have never seen an easier engine to tune for anything from mild to wild and still retain drivability, gas mileage and stay within the law as the LT1 and LS1 engines. So, I put up with the stuff, and accept the fact, that when the SMOG stuff is properly maintained, any owner can drop in a hot cam, mod the heads, add different CAT back exhaust systems, make tons of hp and still pass the SMOG tests with flying colors--that's amazing! Try doing that with a Holley carburetor.

--there to make the engine run better and does not cost hp.

I"d like to add something to this posting. IMO, I don't care for this SMOG stuff either--I'm old school. However, the engine mgmt stuff is there to help the owners achieve max hp and stay within the SMOG laws. I have never seen an easier engine to tune for anything from mild to wild and still retain drivability, gas mileage and stay within the law as the LT1 and LS1 engines. So, I put up with the stuff, and accept the fact, that when the SMOG stuff is properly maintained, any owner can drop in a hot cam, mod the heads, add different CAT back exhaust systems, make tons of hp and still pass the SMOG tests with flying colors--that's amazing! Try doing that with a Holley carburetor. --



i agree with above, having or removing wont cost hp. i removed my air pump cause it didnt throw a code and i wanted to clean up the enigne bay a bit plus i dont have a cat on the exhaust. and egr is still on, cause that one will throw a code plus it dosnt bother my eyes since its way it the back of the engine.