Slant Six Forum :: Canadian pulse air injection vs. US belt driven AIR pump

The van has no A/C and only one catalytic to begin with, not the mini-ox pre-cat, so I think I may end up ordering a new three way catalytic converter.

The other problem is that there is no line for direct injection into the converter.

Should I plumb it so that it injecct at the cylinder head full time?

There is a capped off port in the exhaust line directly downstream of the exhaust manifold that looks like it might have been the air injection port

will I have to run a line all the way back to the cat for direct injection?

I also might be converting it to a two barrel and dumping the Holley 1945.

Okay, here's another question: If I am only going to run one catalytic converter, do i have to get a cylinder head that has the air injection passages in it?

One doesn't follow from the other. Cylinder head air injection is primarily to handle cold-start emissions. If you want to avoid head swapping, go ahead and run your air directly (and constantly) to the catalyst, which is placed as close as possible to the engine, and never take the van in for a smog check unless it's thoroughly warmed up! I would also use that Thermo-Tec heat wrap to insulate the headpipe between the manifold and catalyst, and maybe even to insulate the manifold itself. Getting the catalyst up to temp, and keeping it up to temp during idling and low-speed runs, is the key.
Take a look at This photo for a visual on manifold-wrapping (wrapping the intake is unnecessary, and you'd want to wrap the exhaust clear down to the collector, but this'll give you the idea).

Author:	Reed [ Thu Apr 06, 2006 12:47 pm ]
Post subject:	Canadian pulse air injection vs. US belt driven AIR pump
Okay, I am in the middle of getting my brother's van road worthy again. It is a 1983 Dodge shorty van with a slant six. The van originally had an air injection system but the motor was toast, so we replaced it with a rebuilt motor from another van. Here's the problem. The rebuilt motor does not have air injection passages in the cylinder head, nor did we bother to keep the original AIR pump that was on the engine, but the catalytic converter is still plumbed into the exhaust line. My brother says he had a hard time getting the van to pass emissions last time, which I attribute to the lack of an air injection system and most likely a clogged catalytic converter. I am in the process of obtaining a smogged cylinder head, but I need to know if I should put the pulse air injection system I already have on the engine or if I should go scrounge in a boneyard for a true AIR pump. Opinions?

Author:	SlantSixDan [ Thu Apr 06, 2006 1:30 pm ]
Post subject:
Pump-type air injection is more effective at reducing emissions. Pulse-type systems work only at curb idle, and even then not as well as pump-type systems.

Author:	Reed [ Thu Apr 06, 2006 2:28 pm ]
Post subject:
Gotcha. Pump type it is then. Now its off to the boneyard to find a system that will bolt up in the van and clear the firewall...

Author:	SlantSixDan [ Thu Apr 06, 2006 2:30 pm ]
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I'm pretty sure the air pump bracketry is more or less the same for most all slant-6 applications so equipped. A/C or lack thereof may affect this. You'll want to find a system that has upstream + downstream injection and an intact air-switching valve system if you can. If you can't, just run downstream (catalytic converter) injection, a good converter, and pray hard!

Author:	Reed [ Thu Apr 06, 2006 2:44 pm ]
Post subject:
The van has no A/C and only one catalytic to begin with, not the mini-ox pre-cat, so I think I may end up ordering a new three way catalytic converter. The only slant air injection system I saw during my last trip through the boneyard was a pulse air injection system on a 79 Volare. The other problem is that there is no line for direct injection into the converter. Should I plumb it so that it injecct at the cylinder head full time? There is a capped off port in the exhaust line directly downstream of the exhaust manifold that looks like it might have been the air injection port, should i try to tap into the exhaust line there? Or will I have to run a line all the way back to the cat for direct injection? Arrrrrrgh. Oh yeah, I should mention that this engine was rebuilt to 1976 specs and is a solid lifter motor. I also might be converting it to a two barrel and dumping the Holley 1945.

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Author:	SlantSixDan [ Thu Apr 06, 2006 3:13 pm ]
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Quote: The van has no A/C and only one catalytic to begin with, not the mini-ox pre-cat, so I think I may end up ordering a new three way catalytic converter. This '83 probably doesn't have an O2 sensor, so the NOx reduction portion of a 3-way catalyst would operate with limited efficiency. Nevertheless, some NOx reduction is better than no NOx reduction, especially if it gets you past the test. Place it as close as you can to the engine without causing clearance of fire-hazard issues. Quote: The other problem is that there is no line for direct injection into the converter. But there will be, when you're done! Quote: Should I plumb it so that it injecct at the cylinder head full time? Naw, that'll prevent the catalyst working well and torch your exhaust valves. Quote: There is a capped off port in the exhaust line directly downstream of the exhaust manifold that looks like it might have been the air injection port Possibly with an old 2-way catalytic converter, but more likely that port was a test port for an exhaust gas CO meter used for diagnosis. Not much point to injecting air that far upstream of the catalyst and that far downstream of the ports. Quote: will I have to run a line all the way back to the cat for direct injection? You really should. Quote: I also might be converting it to a two barrel and dumping the Holley 1945. Not a bad idea. Keeping the computer?

Author:	Reed [ Thu Apr 06, 2006 3:33 pm ]
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This van was ordered in the time when you could get a whole host of computerized/non-computerized emissions crap. As it sits right now, it has no lean burn or spark control computer, never had an O2 sensor, and is running a Holley 1945. If i can piece together a decent condition BBD and kickdown linkage I want to swap it to a Super Six. After all, this is supposed to eventually be my brother's "band van" so it must be capable of hauling five adults and their musical gear. So it sounds like my best bet is to install a new three way catalytic as close as possible to the exhaust manifold and to plumb a direct air injection line into it?

Author:	Reed [ Fri Apr 07, 2006 11:28 am ]
Post subject:
Okay, here's another question: If I am only going to run one catalytic converter, do i have to get a cylinder head that has the air injection passages in it? If all io am going to do is route the AIR pump to a direct injection line on the catalytic, are injection ports in the head necessary? I'm just trying to save myself some time and expense in swapping out the head.

Author:	SlantSixDan [ Fri Apr 07, 2006 12:48 pm ]
Post subject:
Quote: Okay, here's another question: If I am only going to run one catalytic converter, do i have to get a cylinder head that has the air injection passages in it? One doesn't follow from the other. Cylinder head air injection is primarily to handle cold-start emissions. If you want to avoid head swapping, go ahead and run your air directly (and constantly) to the catalyst, which is placed as close as possible to the engine, and never take the van in for a smog check unless it's thoroughly warmed up! I would also use that Thermo-Tec heat wrap to insulate the headpipe between the manifold and catalyst, and maybe even to insulate the manifold itself. Getting the catalyst up to temp, and keeping it up to temp during idling and low-speed runs, is the key. Take a look at This photo for a visual on manifold-wrapping (wrapping the intake is unnecessary, and you'd want to wrap the exhaust clear down to the collector, but this'll give you the idea).

Author:	Reed [ Fri Apr 07, 2006 7:00 pm ]
Post subject:
Quote: One doesn't follow from the other. Cylinder head air injection is primarily to handle cold-start emissions. If you want to avoid head swapping, go ahead and run your air directly (and constantly) to the catalyst, which is placed as close as possible to the engine, and never take the van in for a smog check unless it's thoroughly warmed up! I would also use that Thermo-Tec heat wrap to insulate the headpipe between the manifold and catalyst, and maybe even to insulate the manifold itself. Getting the catalyst up to temp, and keeping it up to temp during idling and low-speed runs, is the key. Take a look at This photo for a visual on manifold-wrapping (wrapping the intake is unnecessary, and you'd want to wrap the exhaust clear down to the collector, but this'll give you the idea). Thanks. I didn't know what the functional difference was between the head injection and the direct injection into the catalyst. I really would rather avoid the hassle of swapping the cylinder head, so I think I am going to go with just a straight injection into the catalyst and maybe the manifold wrapping. The emissions test station closest to my house is aout five miles away and I get on the highway to get there, then there is the 20 minute wait in line, so the catalyst should be good and hot by the time the sniffer goes up my pipe. Now its time to swap to the Super Six, install the AIR pump, and make my exhaust manifold look like a mummy! Thanks for the input Dan! I really appreciate it!

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