no coughing necessary rutnick, the resulting emmissions would still be legal up here,

and way bettter than the gas rich crud im sending though

 

OK
so yorue talking about essentially hollowing the cat out? instead of removing it and replacing it with pipe?

ok ive been reading on fouled cats and the symptoms are generally poor performnce and ***** gas mileage, which i have.

it then also says that it will act as a rev limiter because of too much backpressure buildup, which i don't have...

 

why not just remove it and put in a straight pipe? granted its illegall but i don't know of to many cops that like to crawl under the cars

 

Sorry for the momentary hijack there, guys.
My fault.

Lou, if your cat is already clogged you have nothing to lose by gutting it. A steel bar pounded through the core will do the trick. Make sure you get as much of the core broken loose (and removed) as you can, and you're good to go. Good luck with it. -Mike

 

Removing the airpump adds about 1-1.5hp to your rwhp and reduces some weight. The pump's purpose is to a add oxygen to the exhaust flow at low engine speeds when the mixture is still part unburnt. The theory is the unspent fuel will then be mixed up flowing through the cat, which is in effect a static mixing device, and some will burn off due to the heat. The idea is the burnt mixture with the added air flow will reduce the parts per million pollution measured from the exhaust so the car will pass emission controls where they are strict.

There is very mixed evidence about removing the air pump other than low speed emission control. Some cars have run for over 10 years without the air pump and not suffered. Removing the cat which now serves no real purpose is the way to go, marginal hp increase and loss of weight, but illegal in many places. A few people attempt to hollow out the cat and pass visual inspection.

The later 12A was set up to be more efficient in terms of fuel burn, so the impact of the air pump/cat is only marginal, as against the thermal reactor.

The conclusion is not to worry about replacing the airpump unless there are strict emmission controls. You can also think about replacing the cat with a presilencer, or modify the cat to reduce its impact. Keeping the engine tuned and with clean spark plugs should limit any adverse impact of deleting pollution controls from the engine.

 

so modifying you mean like taking a hammer and a broomstick to its innards?

 

Yes!

 

Just leave the clogged cat on....

The worst that can happen, is you'll be driving about 90mph, passing a semi, and the exhaust will EXPLODE making the car bounce up about 6", making you almost spin out and go underneath the trailer.

 

oh yeah
theres no way in hell iim doing that again

 

(Don't know if I'm the guy with the yellow RX in my avatar, so I guess I better add something, huh?!)

Thermal reactors act much like catalytic converters to reduce pollution in the form of unburned hydrocarbons, but use a different action. I'll attempt to explain a bit about each, and then you can make your decision about keeping the airpump...

The Thermal Reactor (TR) was present in 79 and 80 models before catalytic converters or 'cats' became popular. Back then, they wanted the hydrocarbon output to be legal according to US standards, so they added the heavy, cumbersome, (and did I mention heavy?) TR. This is basically an expansion chamber that both exhaust ports exit into with some tubing to help guide the exhaust flow toward the collector at the rear of the TR. There is an internal wall within the TR that the airpump feeds with cold air so that the air gets superheated and helps to cool the exhaust (heat transfer from TR to air) which is then pushed down to the header pipe which connects the TR to the tailpipe. This bypass air is blended with the exhaust gases to help burn off any unburned fuel coming out of the TR. Within the TR is a large chamber that allows mixing of air (again, from the airpump) with the exhaust gases. The oxygen rich fresh air gives more O2 for the unburned gases to combust with, which also helps to reduce emissions. This incoming air stream is controlled by the Air Control Valve located behind the airpump and attached to the lower intake manifold.

Catalytic converters (cats) work by using a platinum core which is highly reactive with hydrocarbons when in an O2 rich environment. This O2 is provided by the airpump and ACV which routes fresh air to the cats during most driving conditions, and the platinum mesh (or 'brick') causes any unburned fuel to be ignited almost immediately, reducing emissions. A byproduct of combustion is H20, which is often why you'll see water dripping from mufflers during colder weather when the water vapor isn't picked up by the ambient air.

Anyway, the platinum core of a cat is expensive but effective in reducing hydrocarbon emissions and unburned gasoline that could otherwise make it to the atmosphere. A clogged cat is due to residue from unburned fuel and hydrocarbons in the exhaust building up to an extent that the brick will no longer flow air smoothly, increasing emissions and backpressure and decreasing performance and fuel mileage.

A properly functioning airpump is required to inject the fresh air into either a TR or cat system - disengaging the airpump will contribute to a clogged cat or a burned up TR. On the TR, once the internal wall collapses due to heat, it is toast and will no longer function correctly to reduce emissions - resulting in a failure in your next annual.

Hope this information has been helpful, and if your state requires emission testing like mine does, I recommend keeping it functional.

 

i don't mean to thread jack but, Longduck...where did you find that kit? aighty sorry again

 

thanks

the pump is long gone which is why i asked

that was a great post by the way, thank you

think it will probably be bye bye to the cat, as i dont know how much a working airpump would be , and i don't know if adding air at this point will cear the cat up

i generally support emissions controls compleetely, but in this case im glad we don't ahve any

 

punch that baby out!

 

Hang onto your spare parts - if you end up needing to pass emissions testing, I'm sure someone on this board has a spare airpump around that they'd get to you for next to nothing. HTH,

(also, to Rotofire - post a question in a separate thread and I'll reply there. I don't like to dilute these discussions in case somebody runs a search in the future - this way they don't have to wade through a bunch of unrelated stuff...)

 

LongDuck, does the brick cause a direct chemical or a thermal reaction?

 

the deicision is whether its fouled and the root of the problem or not its coming off since the consensus is it will foul up in time without the airpump.

so i'm cutting it out on the weekend.


I really hope its the major culprit, the mileage is brutal

and coming back on the highway the engine topped out at 150 KM/h

i don't know how much faster a 12a should go, but it must be able to break 160

160 km/h is 100 miles per hour for you imperial guys


Now, to find a cheap winsheild wiper motor...

 

Chemical reaction. A thermal reaction would be a heat transfer between the platinum core brick and the unburned gasoline.

In effect, you have the hot platinum core breaking down the unburned fuels that come out of the engine - you could accomplish this just as well by running the exhaust through a butane or propane powered heater (like an outdoor space heater), but you'd have to carry around that apparatus and the separate fuel for it...

Simple reaction using platinum as a catalyst to ignite anything that's not already burned up. HTH,

 

so we had a bit of a thaw and i got under my car.

the cat's there and its looking like cutting it out and leaving the brackets in place is the easiest thing.

Had a conversation about the airpump with an rx owner that likes things stock and he says its better to have it..

i don't agree from all i ahve read if its gone get rid of the cat and problem solved.

Speaking of problem solved, i did tests on my ignition wires, which i didn't change on purchase and they were totally FUBAR,
new 19.99 wires fron canadian tire and boom instant improvement.

set the timing as best i could, down where the mark is supposed to be has kind of rusted so i couldnt make it out all that great.

THen checked my cables, tightened the choke accelerator and the fourbarrel opener, and much more responsive now.

Played withthe idle, still cant get it to idle lower and it still "misses".

I am now thinking i have a vacuum leak somewhere. Its going to be a pain in the *** to find it, i am barely mechanically inclined as it is but given the halfassed look to the job the previous owner has done to the emissions removal i suspect that is where my problem lies.

Now to fine a mint version of an RX to race to see if i have most of the power i should, or if theres still more to be had just getting the stock running right.

the plan is getting good working order then doing upgrades

 

Update
so we had a bit of a thaw and i got under my car.

the cat's there and its looking like cutting it out and leaving the brackets in place is the easiest thing.

Had a conversation about the airpump with an rx owner that likes things stock and he says its better to have it..

i don't agree from all i ahve read if its gone get rid of the cat and problem solved.

Speaking of problem solved, i did tests on my ignition wires, which i didn't change on purchase and they were totally FUBAR,
new 19.99 wires fron canadian tire and boom instant improvement.

set the timing as best i could, down where the mark is supposed to be has kind of rusted so i couldnt make it out all that great.

THen checked my cables, tightened the choke accelerator and the fourbarrel opener, and much more responsive now.

Played withthe idle, still cant get it to idle lower and it still "misses".

I am now thinking i have a vacuum leak somewhere. Its going to be a pain in the *** to find it, i am barely mechanically inclined as it is but given the halfassed look to the job the previous owner has done to the emissions removal i suspect that is where my problem lies.

Now to fine a mint version of an RX to race to see if i have most of the power i should, or if theres still more to be had just getting the stock running right.

the plan is getting good working order then doing upgrades