Catalytic Converter without an Airpump...
 

I've heard that if you remove your airpump the stock cat will clog. Does this hold true with aftermarket catalytic converters?

u dont' need the air pump if you have a midpipe tho

yes it's true with aftermarket cats it'll burn because without an airpump it can't catalyze

Yeah, but the smell is terrible... :puke:

Well, how do piston engine cars run catalysts wihout them clogging?

I e-mailed n-tech and asked them the same questions about their high flow cat... they said their cats last just as long with or without an airpump.

every one always says that about the smell...I really don't smell it.

if you have to pass emissons you will need your airpump. and your cat will not last long at all if you take the pump off.

Not quite right. The added air from the airpump aides the catalysis, but isn't a requirement. There are plenty of aftermarket high flow cats that come without air fittings and they function just fine.

All other things being equal the airpump will allow a more complete catalysis.

One person is saying the aftermarket cat doesn't require an airpump, another person says yes it does... what gives? I'm not concerned about keeping the airpump for emissions... they don't test here :D

if they dont test, then get a mp and you can drop the air pump and not worry about anything.

If they dont emissions test where you are, then why the heck are you wanting to put a cat on the car. If you are worried about boost creep, do like I did, cut a ss gasket with a 2.5" hole in the center and put it at outlet of the down pipe

HDP, poke around Magnaflow's site for more info

http://www.car-sound.com/03converter.htm

http://www.car-sound.com/universal/941.htm

I have a 94109 that I'm welding into a "midpipe" for my v8 converted car. Notice the lack of an air inlet tube. The cat is still perfectly functional, and WILL lower my emissions.

If you're not comfortable running with no cat you might want to consider picking up one of these high flows and having them welded into a midpipe for you. At least that way you can ditch the air pump under the hood.

Just so you feel a little more comfortable with the catalytic converter, it is a heat transfer device, similar to the intercooler. they are made in many different shapes and configurations but all of them have the same purpose, to gather heat, like a sponge, from the hot exhaust gases that flow thru them. Although these gases are hot enough to ignite by themselves, at this point in the exhaust, there is not enough oxygen to completely burn whatever hydrocarbons (unburnt fuel) that is left in the exhaust. Thats where the air pump comes into play, supplying the last thing you need to finish the combustion triangle........air/fuel/ ignition.
air: from the air pump
fuel: from unburnt exhaust gases
ignition: from a red hot rock of honeycomb ceramic coated with platinum, to help it absorb, and to preserve the ceramic

some of us have to pass emissions :D

I installed a 3" S/S MagnaFlow hi-flow cat converter on my MP and it really lowered the Exhaust Dbs. It has the The air tube welded on it (capped) but I've never connected it to the air hose. The air hose is capped.

My inspection tag expires this Month, so I'll find out soon if I'll be able to pass emmisions.

OMG!!!

what kind of made up baloney is this!!

wow....

i've read some pretty far off explainations on these boards before...but this pretty much takes the cake :)

you will not hurt your cat stock or other wise by running without the air pump, but it won't work quite as well because there is not enough oxygen in the exhaust stream to completely REACT(not combust) all the unbunt fuel.

that coating on the ceramics does WAY more that just collect heat.

john

"Your cat will clog without an air pump" is an old wives tale. Show me one person that has had their cat clog and can prove that it was due to lack of air pump. The pump adds O2 to the unburnt fuel in the exhaust allowing more complete combustion. Air pump will clean the exhaust gasses considerably, rx7's will not pass emissions tests without it.

See 8 posts previous to yours ...

See 9 posts previous to yours ...

Thanks, I'll look into this ...

I always wandered too if the cat would clog without an air pump. I have a hi-flo with an air pump hooked on to it, but it would be so much better if I could remove it.

Recen't I put a midpipe on, and It doesn't smell as everyone said it would. It is loud, but you get used to it after a while. My only problem is that i loose some of the low end power with midpipe, but I gained it when 2ndary turbo kicks in.

Amel

I've heard before from someone that airpump shuts off at certain RPM and that its not always on?? Is this correct?? if so, I would think you wouldn't need the airpump. I remember a discussion while back about the functionality of airpump and cat.. I think I said soemthing about how you don't need the airpump and others said you do.. it was nasty discussion.. Mahjik, do you remember which thread that was??

Yes, the airpump stops about 3250 or so RPMs (I think it also depends on engine load so I don't think it's active in 5th gear at 3000 rpms).