no improvements mate, the secondary air injection pump is a common failure on these cars, unsure why, but the car will run unaffected if removed, the later model of s3's ie amk and bam engines dont have these at all as audi realised they are pretty pointless
couple hours work to remove, see my guide as jojo posted if you going to have a go at it
SAI is there for controlling emissions (adds air to the exhaust on sold start), typically VAG approach with solonoid valves and rubber hoses that just split and leak all over the place. Typically its fine to remove but leave the solenoids etc electrically connected to stop fault codes etc...
tuffty, how exactly does the sai work, one pipe airbox to pump then another pipe pump to combi valve/block
it either draws cold air into the engine from air box, or pumps warm air into air box from engine?
cant see how its supposed to warm your cat up quicker?
Wasn't sure exactly so after a bit of googling, the secondary air system is an emission related system that injects extra oxygen into the exhaust pipe to burn off any extra fuel. The system only activates on cold starts (when the coolant temperature is between 15 and 35 degrees Celsius). The system consists of a large air pump, one or two combi-valves and a solenoid. The valves are controlled via vacuum lines that cause them to open and close.
Whats the n249 bypass mod its mentioned on the sai removal guide
Bypassing the N249 (known as 'deleting') improves the response time of the DV but 'can' lead to boost spikes particulary on smaller turbos...