air injection delete thread

[9dreizig]

Ok so I"m almost back to tackling my vacuum leak problem so I figured I'd eliminate a bunch of the potential leakers.. Hence I think I"m going to get rid of the air pump and everything associated with it..
Has anyone done this and documented it ?? Pics and direction are appreciated!

[AFM744]

No pics (yet), but if you stop by here on your way to/from Tahoe I can show you the whole system piece by piece since my engine is totally apart. I'd be glad to make a local acquaintance too.

[911nut]

I've done it but no pictures.

The removal is in two phases: Above the engine tin and below.

The above portion is easy; cut the drive belt to the air pump and remove it. Then remove all the plumbing. I'm not sure about the 930 cat but on my 965 I already had removed the cat and just needed to find a fitting for the cat bypass air port. I found on on the internet. Also, there's a port coming off of the throttle body. I plugged mine with a simple cap I bought at the local auto parts store.

The under tin work is a little more challenging.

First remove the air distribution header from the injector fittings. Next, the injector fittings need to be removed from the heads. To do this, the left heat exchanger must be dropped, which means the whole exhaust system must be removed up to the crossover.

The best way to drop the heat exchanger is to heat each nut with an oxyacetylene torch to red hot and immediately turn the nut off. To get the nuts off while still extremely hot is a three handed job. Do not attempt to do this by yourself. Find a competent assistant (in my case my 17 year old son was competent enough to assist) and have an 13 mm swivel head socket and a 13 mm regular socket that you will have to cut down to get it to fit between the exchanger and the nut. You will also need a 10 inch extension that fits through the access hole in the heat exchanger. Failure to remove the nuts in this manner will result in multiple snapped studs, the purchase of a drill guide from A Quiet Boom for $150 and a two week delay (ask me how I know).

After you have dropped the heat exchanger, soak each air injection fitting with PB Blaster or Kroil overnight. If you don't use a good penetrant the fittings may gall as you back them out, destroying the thread in the head (once again, ask me how I know). Back them all out and plug with the Weltmeister kit plugs and torque them to 20 ft-lb so they don't back out.

Re-assemble the exhaust system and you are done. This job removes approximately 20 lb of dead weight from your car.

[lucittm]

Paul,
I just finished my air injection delete and your tips were right on the money. I can't add anything.

However, can you tell us where you sourced the proper metric cap for the cat/cat bypass? I need one of those.

Thanks,
Mark

[lucittm]

Some pictures:

The removed air injection piping:


The plugged heads. Pelican sells these plugs. P/N: PEL-BRC-02, they are $2.95 each and you need six of them:


Mark

[willtel]

Does anyone know if exhaust removal is necessary with aftermarket headers? Specifically Powerhaus with heat.

[lucittm]

I cannot imagine getting behind those heat exchangers to hold the air injector fittings with a 12mm wrench while you turn the supply line caps with a 14mm wrench. You could potentially cut the lines near the fittings and then use a socket, but that would prevent you from returning to stock and the pipe line costs $535.50.

Good Luck,
Mark

[911nut]

Originally Posted by lucittm

Paul,
I just finished my air injection delete and your tips were right on the money. I can't add anything.

However, can you tell us where you sourced the proper metric cap for the cat/cat bypass? I need one of those.

Thanks,
Mark

I found it on the internet. I don't remember where. It is either a 22 or 24 mm - 45 degree female cap. Sorry

[911nut]

Originally Posted by lucittm

but that would prevent you from returning to stock and the pipe line costs $535.50.

Mine was rusted through from condensation.

[im4duke]

Yasin documented his steps on the other forum.

http://forums.rennlist.com/rennforums/showthread.php?t=204196&highlight=injection

[911nut]

Originally Posted by im4duke

Yasin documented his steps on the other forum.

http://forums.rennlist.com/rennforums/showthread.php?t=204196&highlight=injection

No pictures, however Doesn't help much. What was your point?

[krasuskyp]

I recently scrapped mine - tho opted to leave in the "spider" line underneath even tho I had the plugs ready to go in.

Figured the few oz's weight wasn't worth the hassel of exhaust tinkering IMHO. If / when exhaust work being done, then tackle.

The real weight is in that air pump (crazy heavy!), then the other plumbing and valves are nice to loose too.

[911nut]

Originally Posted by krasuskyp

I recently scrapped mine - tho opted to leave in the "spider" line underneath even tho I had the plugs ready to go in.

Figured the few oz's weight wasn't worth the hassel of exhaust tinkering IMHO. If / when exhaust work being done, then tackle.

The real weight is in that air pump (crazy heavy!), then the other plumbing and valves are nice to loose too.

That was my original plan too. Cut the feed end of the spider, crimp it closed and braze the crimp shut. When it crumbled in my hands the plan changed. It had been leaking exhaust gases, which was bypassing the turbo for God knows how long.

If anyone need to add the spider back for, say, to meet Cali emissions, it should be easy to get a used one for cheap, IMO.

[slow&rusty]

Originally Posted by 911nut

No pictures, however Doesn't help much. What was your point?

Be nice...Maxx was trying to be helpful, here are my actual pictures and here is the two page thread:.

http://forums.rennlist.com/rennforums/showthread.php?t=205489&highlight=air+injection









Yasin

[David]

When I had my heads off, I made plugs that went into the port so I could shape them smooth (I also safety wired the plugs to be safe):

[zbph10]

Forgive my ignorance but what's the air pump for (assuming emissions) and why other than weight do people get rid of it.

I'd like to eliminate the cat on my 964 and go with a bypass pipe so I'm again assuming the air pump could go since they don't test for emmissions here in Iowa?

Sounds like a good winter project.

[lucittm]

I'm moving to Iowa...

Actually, the air injection system added air to the unburned exhaust gases in the six exhaust ports and the cat when the engine was cold to reduce emissions. This is because the cat does not work until it is warmed up. The air injection system has check valves that are supposed to prevent exhaust from leaking back through the system, but they often fail after years of use.

A failed check valve in the exhaust port side allows back flow of exhaust pressure that would otherwise be directed to the turbocharger resulting in a loss of boost for a given rpm.

The air pump body is made of cast iron and is quite heavy. I have to ensure that my car is up to operating temperature and that the technician will not look too closely at my engine when connecting the emissions computer to the spark plug wire.

Mark

[911nut]

Originally Posted by lucittm

Actually, the air injection system added air to the unburned exhaust gases in the six exhaust ports and the cat when the engine was cold to reduce emissions.

After a set amount of time (one minute I think) the air feed gets switched to the cat.
There's an small HP loss from turning the air pump, 15 lb of dead weight and the issue I had with a rotten spider.

[Chuck Jones]

Make sure when you put those grub screws back into the air injection threaded holes that you use some locktite on them. I've had them fall out one at a time even after they were cinched in hard....finally ended up getting the ones from Mercedes that have blue locktite on the last 1/8 inch of threads so that they dont' back out. They're a PIA if they back out on you while on the road....makes your car sound like a 67 VW with a cracked manifold. Embarrassing to say the least....and depending upon your heat exchanger...several can be hard to get to.

[lucittm]

Chuck,
The screws you are referring to that backed out, were those the same that our sponsor sells under P/N PEL-BRC-02, or were they the pipe plug type?

I was thinking that the included flange and the copper washer of the ones I used would keep those plugs in. But I may pull them and use blue loctite or even safety wire them in. I sure don't want them coming out when I am on a hot date.

Thanks,
Mark