Michael Benno

My 1988 S4 5spd has the cats deleted. I have straight-pipes to GT resonators and Magna flow muffler. However, I do still have the air pump system and it seems to be plumbed normally.

In researching the function of the air pump, during warm-up and low RPMS it sends additional air to the cats to facilitate old school CAT function. Since I have no cats, should I set up the system to always be sending air to the airbox? Does it even matter?

I know some of you will tell me to remove the air pump, and or install modern cats. I will consider the air pump delete with a TB job.

Thanks MB

Dave928S

Just cut the belt to disable it until you get around to removing it.

MjRocket

Install an SC and use it for an intercooler pump.

That was a joke of course!

Michael Benno

Thats a reasonable approach as it would ease load on the engine.

Does having it pump air in to the airbag provide any reasonable benefit.?

Dave928S

I assume you mean the air filter housing ... and there would be no benefit in doing that.

vsalvato

What do you mean??? what should the air pump do to the ABG's??? I guess it is a joke...

Adk46

The airbags on this forum don't need any encouragement, so no.

Michael Benno

Typo, "airbag" should have read airbox.

RKD in OKC

Left my plumbing hanging when went to x-pipe and sports cats. Later cut the belt because the pipe that was supposed to go into the cat would get against belly pan and make a farting noise. Later when I did the valve job, didn't put pump back on when put everything back together.

Speedtoys

This provides no chassis measurable load..

Leave it connected until you're done..then it wont freeze up.

Be nice to your air pump. Just a matter of time before people W/O them, are scrambling for them.

There's no usable HP lost in emissions, just a painful future finding parts when you suddenly need them.


The smart money is on keeping them and maintained, or stockpiling them for future Ebay retirement income.

Adk46

I threw caution to the winds and took my air pump out last winter. I blanked off the input to the diverter valve. This winter i took out all the plumbing and blanked off the pipe underneath the car. I also removed the sampling tubes. Reinstalling the cam covers was a lot easier after doing this.

All the air pump stuff will be preserved in a box sold with the car.