air injection delete thread
 

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!

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.

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.

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

Some pictures:

The removed air injection piping:
http://forums.pelicanparts.com/uploa...1222820564.jpg

The plugged heads. Pelican sells these plugs. P/N: PEL-BRC-02, they are $2.95 each and you need six of them:
http://forums.pelicanparts.com/uploa...1222820735.jpg

Mark

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

http://farm3.static.flickr.com/2166/...ef6df574_b.jpg

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

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

Mine was rusted through from condensation.

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?

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.

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

http://pic20.picturetrail.com/VOL86/...6/97495617.jpg

http://pic20.picturetrail.com/VOL86/...6/97495606.jpg

http://pic20.picturetrail.com/VOL86/...6/97495582.jpg

http://pic20.picturetrail.com/VOL86/...6/97655732.jpg

Yasin

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):

http://forums.pelicanparts.com/uploa...1222875343.jpg

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.

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

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.

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.

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

first of all you shouldn't need threadlocker if using the right style plug, second, I don't think it will help anyway due to the high exhaust temps.

No...they should be the same ones the sponsor sells..NOT those damn pipe threaded ones....they call them grub screws and they have an allen head on them. They resemble a small grub, hence the name...I haven't seen the ones that Pelican sells....I got mine from a Porsche indy who in turn got them from a Mercedes dealer...and like I said before, they have locktite embedded in the last 1/8th inch or so of the threads so that they stay in. Nathan from UK used some that had a nut type head o them with a lip, and his fell out too. I originally used the SAE allen head pipe threaded ones, and that was a BIG mistake....they started falling out even after I re-torqued them...they still backed out after a couple hundred miles. Since I have the SSI heat exchangers, they cover access to two of the grub screws...so I ended up having to take off the damn heat exchanger to get to the point where I could replace the grub screws. Make sure you use locktite...or you'll end up like I did...extra work and embarrassment....one fell out when I was 50 miles from home so I drove home with it sounding like $hit all the way. It's always nice to be at a stoplight and having folks look over at your nicely shined up and spiffy Porsche that sounds like a lawnmower. You just look straight ahead and pray for the light to change.

RSmike: It does help to use locktite. I agree that the extreme temps do affect them, but the locktite seems to keep them from falling out. The grub screws go all the way in flush....and are tapered to fit tight.

I haven't drove my car yet but I fitted the ones from IA. They have to be fitted with an allen key (I have a 3/8" drive set) and they have the shoulder. I was told by Stephen to use new sealing rings that seal the injectors to the heads.
A lot of people have had problems with there bungs!

Stephen should know...but I've heard that even the ones with the shoulder on them have come loose...they're really no big deal UNLESS they end up being the ones under the heat exchanger if you have an exchanger that covers them.

someone even posted a method for locking them in by drilling the lip and putting wire thru it like a sort of cotter key and wound it around a stationary post...dunno...these have been the most recurrent PIA for me. I'm hoping these mercedes grub screws do the trick. The indy i go to swears by them....and he mostly works on the turbos. Hope springs eternal....

Chuck, does your car pass emissions with the air pump & air injector lines removed?

Here may be a stupid question, or a simple option. My 930, when I purchased it several years ago, came with an "air pump in a box". In other words, it had been removed by the previous owner and I'm using it as a boat anchor. But, the injection piping was left in place (see the picture) and simply plugged at the end of the spider. Saves all that effort of dropping the heat exchangers, finding the correct plugs for the heads, etc. Plus, re-installing back to stock would be much easier.
For me, it all seems to be working fine in this lazy-man configuration. Now don't tell me I've got a disaster about to happen!!!

The thread was called "those dam air injector plugs" and it covered a lot of ground on the plugs side of the air injection delete subject.
(I tried my hand at putting a link here but it didn't look correct.)

My solution was to lock-wire the plugs in place.
This is quite easy if your heads are off but not really practical otherwise.
I drilled 1.5mm hole through the head of the plugs and a 2.5mm hole through head fin close to the port then used some 1mm tie wire.
There are "proper" ways of lock-wiring when you are dealing with fasteners on critical joints, but for our application you don't need to be too fussy about following the rules. The main issue is to stop this little fkrs from unwinding and falling out.

The plugs I used are from our host ...
PEL-BRC-02 at $2.95 each "Air Injection Smog Pump Port Plug, sold per each, 911/911 Turbo 1975-83". They come with copper washers and fit all models, not just up to 1983.

http://forums.pelicanparts.com/uploa...1222992160.jpg
http://forums.pelicanparts.com/uploa...1222992174.jpg
http://forums.pelicanparts.com/uploa...1222992185.jpg

Pass emissions?.....Ummmmm....let's see...where did I put that copy of the Constitution that has the 5th Amendment printed in it?

I bought an almost new cat and muffler from someone on eBay....and I have to retro the car back to stock to pass emissions. This is a once every two year event....and it's no fun. The nonsensical part of this is that it runs better and somewhat cleaner with the upgraded parts, but without the cat converter....you're flat out of luck...

I left the air pump in place with the belt on it...a little less to put back together.

I'm going to attach a picture of the 914 caliper plugs (used as SAI plugs on 911 /930 cars) and the stainless version sold and branded as Weltmeister. I tried the 914 caliper plugs initially and was not happy with the hardness of the steel. They are mild steel plated with blue zinc. I decided against these after testing them out and ordered the stainless hex plugs instead. I'm much happier installing these into a 930 due to the harsh heat / exhaust contaminents they will see... Also, nothing against the way billjam did it but the plugs are not safteywired properly... The anchor point of the wire needs to be opposite the direction you turn the bolt or nut to unscrew it. This is a perfect example of using the right chemical for the job. Much like the right tool, the right chemical compound makes the job 100 times easier. Applying Resbond 907 Red Thread Locking agent / pipe sealer on the plugs will prevent them from coming out on their own.

Please click on the pic for full resolutuion.

http://img220.imagevenue.com/loc21/t...s_122_21lo.jpg

hope this helps those looking to make a decision on which plugs to buy.

Looks like I have the Weltmeister ones but I didn't get any copper washers with them. The factory used rings, not washers to seal the air injectors in.

I think Billjam just didn't want to lose the plugs.

Ok so I pulled a bunch of stuff off mine but won't get to the injectors until winter.. So my question is what do you guys plug the hoses with ? Seems like the easiest way to go..

Maryland metric sells the plugs....
 

for $0.50 apiece and $0.15 per copper washer.. I have had them in for two years...Note I dont track my car.

can anyone recommend another hi temp loctite to use on the plugs when removing the air injectors?

I'm sorry but 2100 degree loctite is probably the highest temp stuff I could find... Good luck trying to find anything that is higher temp! If you are confused try reading my previous post and clicking on the picture.:rolleyes:

Keeping the air injection?
 

Has anyone considering keeping the air injection for between shift anti-lag? My motorsports background is rallying. Many of Lancer Evo 5 & 6's (Toyota celica all-trac) had an air injection manifolds with a one way check valve connected to the dump valve. When the anti-lag was armed the ecu would use the dump valve connected to air injectors to dump all excess boost pressure to the hot of side of the turbo between shifts or throttle lift. The excess air would help burn excess fuel and keep the turbo spooled. Of course the rally car would also retard the ignition also so that unburned fuel would enter the manifold but just dumping the excess air works fairly well without destroying the exhaust like a full-on anti-lag does. I guess this might require EFI conversion, CSI may dump excess fuel.

Scott

Flame away, it was just a thought.

This came up on Rennlist and supposedly some of the turbo race cars were done this way. However it was thought to do nothing to help turbo longevity. I think the idea was abandoned for a streetcar.

dump valve
 

The longevity issue is not as big as deal in respect to longevity if you are only dumping the excess boost pressure without fuel enrichment and ignition retard. The main issue is if there is over-excessive fuel then there are some serious shock waves as in the full ant-lag. The full motorsports anti-lag retards ignition to past TDC, dumps enrichment fuel and dumps alot of air around the throttle plate making large explosions that would require hearty exhaust valves and ceramic turbine parts. The dump valve only method actually helps pump cooler air through the turbo when the motor coasts with the throttle closed.

Scott

re:
 

The best setup I think would be dual dump valves selected with a vacuum solenoid pressyre reference, so a person could select the traditional dump valve that recirculates and the one that dumps to air injectors for those just in case moments. It does make a substantial difference in acceleration times.

Scott

Where did you purchase the Resbond stuff. I am the original poster of the "dam injector plug" thread menstioned and this has been a recurring problem for me as well. I do track the car and it mostly happens at DE days. I looked into high temp loctites and there is no vendor that will sell it retail. Grainger and Loctite only sell wholesale and you aint gonna find this stuff at Autozone.
Safety wire is best but damn it is tuff to do with the engine in the car....plis drilling thru those small plugs aint easy either.
Thanks for any input.

Any reason why I shouldn't have the the air injection system permanently removed during my current engine rebuild? I have B & B headers/exhaust system and a K27/7200 turbo on the car now, and see no reason why I can't have the extra weight taken off and have the engine holes plugged. I'll have the mechanic put the parts in a box in case a future owner wants to "restore" the exhaust system.
______________________
Steve
1989 930S Factory Slant