One question...Where do you plug the manifolds at, and what do you use to do it? On my 95 Z28, it just had 1 outlet on each manifold, not 4 per...

Also, If I didn't want to get into removing the pump(no bloody room to maneuver below car with my POS jack and apt. complex-no garage), could I jsut clamp a rubber hose from the in to the out? I did this on my 95 Z28(for some reason, motor would not run with out pump hooked up...) without any problems?


Thanks all, I am still learning about TPI's...A lto different than my ole LT1....

 

its best to rip off the check valves and buy 8 pipe plugs from home depot, at least in my opinion

also, you should have NO problem at all removing the pump from the top, try it just a coupla torx screws

 

Are they bolt in, weld in, what?

Also, do you know what size, etc... so I can buy in advance so i can doo it all at once?

 

why would you want to remove it??? the pump is electric... it only operates for a short time onafter start up (and possibly in steady cruise situations)... I do not see any benifit from disabling the air injection system...

zroc

 

zroc, The small advantage to remoiving it is to clean up the engine bay. There's no noticable Hp gain at all. For me, it was all cosmetics. Besides, I'd rather not have that stuff there anyways since I want a cat and headers without the ugly air fittings.

murock, i belive they were 1/2" pipe plugs, screw em in w/ a wrench. there's only two sizes that most depots will carry and i'm pretty sure the other size i saw there was way too big by inspection. They'll be gold with square heads.

 

The smog pump on a thirdgen isnt electric.

Theres a tech article if you go to www.thirdgen.org and go to the tech articles section on taking the smog pump off.

 

Thanks, that is what I suspected, but I wanted to be sure!

 

Update: they are 3/8ths in size...Home Depot carried them for .79 apiece, galvanized. Going to install them tomorrow...

 

Actually they are all 1/2" black pipe CAPS, I used galvonized to prevent any rusting in case i want to put my smog pump back. I have no cat so i probably wont pass emissions.. I wonder if i will pass if i just put a cat back on it.

 

oops... I thought he was talking about the 95 z28...

zroc

 

What year is your thirdgen? Depending on the year it may have a V-belt or Serpentine belt system (or a combo of both). If you have V-belts then it is very simple. You can reach your pump from the top of the engine bay and get it out with only a couple sockets. Just take the belt out totally. If you have the serpentine setup then listen to madmax and go to the tech article on re-routing your belt to accomplish this. As far as the AIR tubes on the headers or exhaust manifold, what I did was take off my check valves, bring them to the nearest Home Depot, and pick up two threaded pipe caps to screw on in their place. No crimping, cutting, or other wise molesting expensive headers involved. It was an easy job and really cleaned out the engine bay. You can just unplug the little black canister and everything smog related, it won't throw codes or affect your driving. Removing the system will however increases your chances ofa clogged cat since it aids in catalytic combustion. So if emmissions isn't an issue I'd take this as an invitation to gut your cat (if it isn't already ).

 

Hi,

A lot of people I know remove their air pumps thinking they will get a gain, and in fact, they do immediately because it requires a few HP to pump air, believe it or not, and the air pumps usually go after a while, taking away more HP until they eventually freeze.

Now, heres the problem - the car. You know what happens to a cat when no air is supplied?? it melts. Really, it does. I have taken many out with melt downs, and showed them to people and explained "You need to remove the cats if you're gonna remove the air"..

Now, you know what happens sometimes when the cat melts down? it causes too much back pressure.. My buddies cat melted down, and ended up clogging his cat. Now gradually he lost power.. A few tenths, then a second at the track, ...

Then his car wouldn't run past idle. Not bad huh? This was a 2000 Camaro.

Once my Formula is tuned better, with the S/C, and I can run consistant 12.0's, I will most likely go with a high flow cat, since I live in Mass, and I run a race shop. (Fines out here are bad).

-- Joe

 

Good point Joe. To add to that, I had always planned to switch to a cat designed to work w/o the AIR fitting before I even took off the system. But just in case you've taken it off already, no need to panic. I had been running around w/ the system dissconnected since July, and my cat was fine. I fianlly got a chance to have it changed only last week.

 

My AIR pump has been seized up for just over a year now. I have not had any problems at all with the cat clogging up.

anesthes, are you saying that a high flow cat will not clog with the AIR disconnected?

--Jesse

 

Hi,

No I'm saying I'd re-hook up my pump eventually..

I wish I still had the box of bad cats in my shop to show you guys some picks. The honeycombs just melt inside, its kinda kewl.

For a while I was keeping them to hollow out for people but then I crapped 'em all.

-- Joe

 

I dont buy that at all. First, everything I hear is that the air supplied to the cat makes it run hotter. Secondly, there are plenty of OE cats that do not have air supplied to them. Even the aftermarket ones the manufacturer will tell you it can be run with or without air.

Mines been disconnected since day 1, not melted yet.

 

Honestly, i wouldn't go through the trouble of removing the AIR pump on a serpentine equipped car ( i didn't on mine), the gains are negligible, and there is the *risk* of melting the cat down.
If you don't have to worry about the visual, i will highly recomend you remove the AIR tubes off the manifolds though. It makes spark plugs and absolute gravy job. I would still leave the diverter and AIR pump on, and this is why....

The cats on our cars are *designed* to use AIR. Cars with no AIR use cats designed to not use AIR, thats why they get away with it. Our cats can tend to get a build up of HC in them w/o the extra air to keep it working properly and clean, especially with a lot of short trip driving. Eventually this build-up will burn and *may* melt down the cat. In practice, it usually doesn't cause problems. Hell, even my old LG4 grand prix (with a removed AIR pump) never clogged it's cat in winters of short tripping it, so if a choke on carbed car doesn't foul the cat, then TPI should be that much better.
As to the diverter valve, i considered removing it on mine and just running the AIR line straight off the pump to the cat. This creates a new problem. You see, the cat does not want the extra AIR during super rich warm up, that can cause the cat to melt as well. The diverter valve only switches AIR to the cat once in closed loop and the corect AFR is being sent (note, no AIR during WOT for the same reason), which ensures that everything is burning at the right rate. With only the 2 - 10mm bolts holding the diverter to the AIR pump outlet it's easier to just take it out when you need to rather than risk screwing wth functioning cats IMO.

It's called an emmisions *system* for a reason. If you don't understand the *system* you're not gonna be ready for the problems you might cause if you just start hacking into it.

 

Why does everyone insist that if theres an AIR tube, the cat needs it? Have any of you called the manufacturers? I have. Stop guessing and take it from the horses mouth.

 

Well, i never called the manufacturers, but i have read more than once over the years (in real tech docs, not online posts) that their is a difference in the construction/chemistry of an AIR injected cat. Makes sense to me (though i'll admit, chem is my most hated subject) The catalyst material is designed to react most efficiently at a certain A/F ratio in the exhaust gas. Injecting fresh air directly onto the catalyst bed must be factored into the chemistry of the reaction. If the catalyst is expecting (as it was designed) to have more O2 + exhuast gas to complete the reaction (isn't there a term other than combustion for what the cat does in converting HC and O2 into H2O and CO2), then if you take out the extra )2, the catlyst material will not be operating as efficiently. If it's not operating as efficiently, build-up can occur. More than one person has melted a cat (even turned them literally cherry red) over the years with a faulty choke on carrb car loading up the converter until it decided to burn. Why then is the same principle not true (albeit on a smaller/slower scale)....
Thats about as good an explanation as my non-chem e *** is gonna give you. My last retort is, if the AIR truly does absolutely nothing, why would the maufacturers ever have bothered with them? Even the AIR into the manifolds serves a purpose, to add some more O2 to the rich exhaust from warm up to help complete combustion in the exhaust, reducing cold start emmisions It's only pointless in that this is a very limited time of operation and will never affect an e-check.

I'm not refuting what the manufacturers told you. I'm refuting the education level of the rep you spoke with. To me it seems basic science that if you tinker with a catalyzed reaction, you will screw it up.

edit, just wanted to add, i am NOT saying that you WILL clog/melt your cat running no AIR to it. I am saying that you are increasing the likelihood that this will happen. As i already said, one of my old GPs did just fine with no AIR to the cat. On a V belt car, i would definitely axe the entire AIR system as it is ugly and in the way. On a serpentine car, the pump is out of the way, and the diverter assembly is a 15 second operation to remove when you need to, therefore, why INCREASE the risk of clogging your cat, for NO real increase in power, looks, or ease of maintenance?

 

They all said the same thing, the air injection aids in reduction of pollutants but is not necessary to prevent the cat from failing.