928newb

Hello everybody, i have noticed that many on here have removed the air pump from their 928.

What is the benefit of doing it?

17prospective buyer

Maybe a couple HP, maybe. Less cluttered engine bay.

Alan

Makes room for a vacuum pump.

Its quite likely that many older 928's have a pump that doesn't pump much anymore, or a vacuum diverter valve that doesn't operate when it should anymore.

Newer cats may not need air injection and many 928s don't really need it to pass emissions anyway (and are likely in fact passing with a non-functional pump every year).

Worn pumps can get noisy...

Alan

LT Texan

I just removed mine when it broke as opposed to replacing it.

I don't think I'd do it as a stand alone project.

928newb

Thanks for the responses. Ho much of a hassle is this?

LT Texan

Block the hose from the pump (I don't even remember how I did this) and get the fan belt that fits needing no tensioner from crank to fan pulley.

When I rebuilt my engine I ripped all related stuff out and plugged the rear cylinder head holes with the same fittings/sealing rings used on the front.

GlenL

It doesn't make noises if it's removed.

It depends on the car model as to what it does.

On my Euro S cars it simply pumps air into the exhaust and there are no cats. That's an old, crappy emissions trick. I'd be likely to leave it in place on a stock car with cats.

Removing all the pipes, hoses and the filter are benefits as well.

928newb

I`m not sure what holes...

If I understand correctly, one of the hoses from the air pump goes to the cats, the other (blue one) to that bypass valve on the passenger side.

Did I miss something?

LT Texan

There are threaded holes in the front and back of the heads.

Use the same threaded plugs as are used in the front to plug the rear holes when ripping out the plumbing.

Alan

It depends on year as to how the air injection is plumbed. For some years its just a single pipe from the diverter to the cats to block/cap. This assumes you remove the (now no longer needed) diverter valve. If you leave the diverter valve in place you only need to plug the line feeding it.

Alan

928newb

Thank you for the responses, gents.

Out of curiosity, what would be the consequence of leaving the holes unplugged?

SteveG

More trouble than its worth in hp. You have to loosen the tensioner bracket.

SteveG

dupe

Crumpler

I deleted mine because the bearings failed.
I'm also in a state with no smog testing!!!!
While I was in there I deleted the belt driven cooling fan as well, and went with electric.

There is a vacuum line that runs from throttle to diverter valve, so I would cap everything if you delete.

Big Dave

Deleted mine when I deleted the cats for an x-pipe.