what is the point of this??? - Page 2

GoldieGoldie97 · 07-31-2007, 04:45 AM

but.. the air would be coming from the engine, not from the outside, so how would that work? it looks like the air would just circulate around and be deposited into the middle two exhaust pipes?

**Ssicarman** · 07-31-2007, 06:03 AM

Quote:

Originally Posted by GoldieGoldie97

but.. the air would be coming from the engine, not from the outside, so how would that work? it looks like the air would just circulate around and be deposited into the middle two exhaust pipes?

The air is injected/blown in from an external air pump. The air is sourced from outside the engine and is directed into the exhaust.

Joeybagodonuts · 08-03-2007, 11:21 PM

actually they were designed WAY WAY before we even had cat coverters tommy! air pumps were simply designed to lower emmisions, they pump fresh air in, yes, allot of people have been taught, or told that its to assist the cat, but its to assist in LOWERING EMMISIONS! LOL.
and truthfully,. the fresh air pump was around before emmisions even, it was designined i believe in the 40's but i forgot the original reason, in the early to mid 70's when car makers were scrambling to meet new and more stringent emmisions laws they started using air pumps,then the cat converter was invented and that helped reduce emmisions allot. saturns, never a precision motor to begin with, always were borderline emmision test passers here in the states, the cali cars got air pumps before the rest of the 48 states (cali ALWAYS has the toughest emmisions laws and hence the manufacturers always have to meet cali's standards...) then they all got the air pumps, but they were simply added to lower emmisions, pumping fresh air into the exhuast after its burned will always lower emmisions out the tailpipe...
on a sidenote, california is SO STRICT that the early gen saturns, the 91-94 vacuum motors, HAD to be swapped to electronic egrs! thats how we found out about the adaptor to make a vacuum engine work with electronic egr's, it was a california only part, but of course it assisted us and helped to use diffrent model engines throughout the saturns line up, but ALL 91-94 vacuum egr saturns had to be switched to the electronic version to make them satisfactory to calis standards. occasionally well see a car come in and itll have the adaptor and electronic egr, besides the adaptor for the head there was a sub harness that saturn sent to its cali dealers to add the egr system.
ps, as far as this post is concerned, on the factory manifolds the air holes were in the head and the manifold(four holes) from 2000+ but still, all it did was pump fresh air from the pump into the exhaust STREAM...

Artificialist · 08-08-2007, 02:00 AM

They helped on cold starts, because the engine was ran much richer than 14.7:1 because cold engines don't atomize fuel efficiently. That means that fuel quits burning due to a lack of oxygen, but since it is hot, adding more oxygen from outside air re-ignited the fuel. Catalytic converters don't work until they reach a specific temperature, so the combustion of the fuel in the exhaust raises the temperature, of the exhaust gas, helping the catalytic converter reach light off temperature earlier.

Also, some cars built before O2 sensors in the exhaust would run permanently rich, and then the air pump would introduce enough air so that the catalytic converter would not overheat. On many early emission control Toyotas (And many other cars) the air pump would fail, leading to a cherry red converter failure. This happened to my dad's 1979 Toyota Corrolla, and it put him in PERMANENT fear of parking a car over grass.