do you really need the air pump on a 928?

 

ONLY if you still have cats....

 

Legally, yes. Really.... mine doesn't have one.

 

Only if you still have cats that require a source of atmospheric air.....the new ones don't....so when you replace your original Cats, off come the air pump and assorted paraphenalia....

 

Early cars 78-86 it is the idler pulley for the belt driven fan.

 

I thought the air pump was only there to add fresh air to the exhaust so that it would "dilute" the ppm of polutants. Whats this about the cats needing an air pump?

 

Some cats have a rear chamber that requires extra oxygen to complete the conversion of gases. They have a stainless tube that comes out the side of the cat between the two chambers. Most newer or aftermarket cats don't need that. Some after market cats have the tube capped so that you can use them on a car with or without a smog pump.

On 78-86 cars you can use a 21" long 1/2" V-belt to drive the fan if you remove the air pump and don't install an idler from a Euro/ROW car.

 

if you have an early Euro there would be no factory smog pump...
those early cars are now EPA exempt, as such you only need to comply with local emission laws