Topic: AIR Smog Pump
in Forum: C3 Engines
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What is the procedure to remove the smog pump and where do the extra hoses ETC go??? The pump sounds like it need new barrings. This is on a 1980 Vette 305 .
Pewter 2000 2006-11-20 09:46:51
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Duncanville, TX - USA
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
You can remove the pump by simply un-bolting it. The hoses for the check-valves will need to be removed, and the valves capped, or the air "manifolds" removed and the holes in the exhaust manifolds capped. The other vaccuum lines to the system can be plugged, or removed, and plugged at the source.
Why not just have the pump repaired, or replaced?
Why not just have the pump repaired, or replaced?
Joel Adams
C3VR Lifetime Member #56 
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
I can replace it ,I see that some of the C3's have had there's removed ""installed newer engine's""and was wondering if it makes any difference in performance.
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
It makes no difference in the performance of the engine, just the enviroment! The real purpose of the AIR pump is to allow the cat. convertor to function properly by squirting air into it when needed, to promote the complete conversion of the exhaust gasses.
On the earlier cars, without the cats, it added air to the exhaust in the manifolds themselves, to promote the complete burning of the exhuast gasses.
Ken(kstyer) can explain this stuff mooch better than I, but that's a general overveiw.
On the earlier cars, without the cats, it added air to the exhaust in the manifolds themselves, to promote the complete burning of the exhuast gasses.
Ken(kstyer) can explain this stuff mooch better than I, but that's a general overveiw.
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Thanks for the info ,Darn thing is noisey. I might replace it someday.
There is a very slight performance difference. But it is only the amount of horsepower that it takes to turn the air pump. This at very most is probably less than a 2 horsepower difference with out the pump. Trivial.
The air pump pumps fresh air into the exhaust at two different point, or diverts it to the atmosphere depending on engine temp and driving conditions.
With the engine cold, it pumps air into the exhaust manifolds. A cold engine runs rich, and leaves a lot of unburned fuel in the exhaust. By pumping air into the exhaust at the manifolds, oxygen is supplied to the fuel in a very hot area. The result is combustion which consumes the fuel instead of pumping it into the air. This has the added benifit of creating a lot of heat at the engine, helping it to warm up faster, further reducing emissions.
Once the engine is warm, the air at the manifolds would cause the engine to get too hot. In addition, 1981 and newer cars have oxygen sensors that the extra air would reak havoc on the sensor function. Both are severe negatives in operation. So instead, the air is pumped to the catalytic convertor. Here it mixes the air with the exhaust to allow the convertor to operate more efficiently. Without oxygen, it can't convert fuel or carbon monxide.
During hard decelleration all carbs go rich due to high engine rpm and closed throttle operation. During this time if oxygen was introduced in the exhaust it would backfire due to the heat and rich condition. To prevent this the air pump volume is dumped back into the atmosphere.
At no point does this affect the rest of the engine running system. It will not affect power or economy, or anything else. When working properly it is ONLY going to affect emission output from the tail pipe.
Once removed from the car, there is not noticable effect on operation. Only the EPA cares. And for feds, only if it's 25 years or newer. After that they don't care. California and a few others do care. So check with you local folks first.
Granted, with the stuff out of the way, it is a bit easier to work in the engine.
Now let's see if I can find a negative to removing it. Other the keeping it 100% OEM, and you can put that back so that doesn't count. Nope, nothing.
in Forum: C3 Engines
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