Hi there,
I've been toying with the idea of removing the smog pump and forced air system on my 1981 Corvette, 5.7 liter. It runs great now, can anyone tell me what else must be done to once removed? I've told you need to rejet the carburator and HEI ingition work?
Thanks,
roxyvette
The smog pump blows air up stream to the exhaust manifolds when the engine is cold. This adds oxygen to the hot exhaust, which has a lot of unburned fuel left due to cold operation. The hot fuel and oxygen meet, then burn, cleaning up the leftover fuel before it comes out of the tail pipes. This also creates an 'afterburner' effect and heats the exhaust manifolds. This helps the engine to warm up faster, but not much. A few choke adjustment can be made to allow for the warm up time.
If the air is supplied upstream on a warm engine it can cause vapor lock, pinging, and overheating.
When the engine is warm, the air blows downstream to the cat converter. This supplies oxygen to the cat so it can do it's job better and more completely.
Without the smog pump or A.I.R. ( Air Injector Reactor ) pump, there is a increase in emissions.
Now what other than a slightly extended warm up does this do for driveability? NOTHING. It will not affect the way the car runs at all. Removing it will make no difference in performance, fuel mileage, or anything else. The EPA does not care for it, but Oh Well Too Bad. Over 25 years it does not matter to the Feds. Removing the pump is a no harm, no foul operation. If you like the look, go for it.
The only caution is you MUST seal the holes or tubes that the air pumped through. Otherwise air will get into the exhaust when it's not wanted, and the oxygen sensor on 81 and 82 C3s will pick up the O2 content, and drive the system rich trying to correct for the O2. Nothing else has to be done.