What is your favorite mod?

[sfkjeld]

Originally Posted by thstone

Removal of the Secondary Air Injection system.

The SAI is an air pump that injects air into the exhaust for about 90 seconds at cold start up to help the catalytic converters get up to temp faster and to reduce cold start emissions.

The air pump itself is on the passenger side of the engine compartment above the intake manifold. It kind of looks like an alternator but without a pulley.

When you start your car cold, listen for a motor whine in the background for a short time. That's the SAI pump working.

Thanks. Why remove this pump if only used the first 90secs? Weight?

[particlewave]

Originally Posted by sfkjeld

Thanks. Why remove this pump if only used the first 90secs? Weight?

Because the system (air pump, vacuum valves, electronic valves) is prone to issues that trigger a CEL and will cause cars to fail inspections in some states. Even when it seems to be working properly, the system may not show "ready" status in the monitors and cause it to fail.
Ironically, I actually had my system working flawlessly after years of tracking down and fixing issues when I decided to ditch it.