Emissions: help me not kill my new cats!

[kishy]

Hey folks
So, '84 Townie is getting new exhaust, consisting of Magnaflow direct fit cats, Walker H pipe, mufflers I'm taking off my 97 Vic (crossing my fingers they're stock dimensions so they'll direct fit), and Walker tails. Going to paint the pipes with VHT Flameproof so hopefully they will last longer than the usual aluminized steel junk does. Crush bends and stock size piping shouldn't be a meaningful restriction on a stock CFI engine especially since it's going to dual exhaust, so this choice should be the right one. I hope.

Anyway, the cats. I do not want to kill them prematurely so let me know if there's anything I should do in preparation of this project...

The car does have a functioning air injection system. Diverter/bypass thing does seem to work properly. Computer opens it to add air to the exhaust when throttle blade closes, which seems to be correct on CFI. The new cats do have air injection tubes so running the smog pump is a good idea I think.

Thing is, my current cats are badly rusted out and there's a bit of a popping effect going on when the throttle closes. What I'm worried about is that the popping represents the exhaust having too much unburnt fuel which in turn will kill my new cats.

Any thoughts?
(and no, I will not run the car catless even though it doesn't need emissions testing)

[Kodachrome Wolf]

Is it running rich at any points in time? Are the fuel injectors leaking or do they seem to be operating properly?

As long as the car isn't send a bunch of unburnt fuel down the exhaust, you should be fine. Admittedly I prefer catalytic converters remaining fitted since the fumes from an un-catted system aren't that great, and that's coming first hand since the '87 lacks them.

Since all of your emissions stuff is in good order, you should be good.

[kishy]

It occurred to me that I should pull the codes and see if the O2 sensor has reported any weirdness. I know it used to indicate lean from time to time, back when I was troubleshooting my nightmare problems.

Cars without cats absolutely stink. Completely intolerable to be around. Given that (I'd estimate) over half the exhaust of my car is escaping the cats untreated, it's smelling that way, and it's really unpleasant. Also, regardless of the direct impact on me, there's that whole environmental business. Cats and air injection have proportionately massive effects on pollution reduction relative to the (negligible) power they absorb to do their jobs. But, this isn't a soap box so I suppose I'll stay off it lol.

The Magnaflow direct-fit cats are stainless and price-wise, I consider them worth it knowing the part should bolt on, no welding or bending required, so it's totally doable in the driveway.

[DerekTheGreat]

If they're running rich they do. Port fuel injected stuff smells much better when warmed up. I am 100% pro cat though, all of my stuff that has cats will continue to have cats.

[gadget73]

A lot of those modern converters don't actually need the air injection. Something to do with the way they work, one section generates oxygen and the other section uses it.

Proper fuel mix and not burning oil or coolant pretty much takes care of keeping the converters working for an extremely long time. Basically when you pump more crap into them, they have to work harder and they get hotter inside. Too hot and it melts and thats all she wrote.

Understand wanting the converters. I run them too, don't actually have to anymore. Not a fan of the smell. Properly working they're such a minimal loss of power that its not much of a talking point there either.