Catalytic Converter replacement

Mines got a hole it it ... the sound is driving me nuts . Time to replace it , any suggestions on a size / replacement that others have used ?
Im gonna take the whole exhaust out and bring it to my welder friend to repair .

thanks ...

3" High flow from Magnaflow, sold by ZZPerformance.com for $50, something dollars.
Then have your friend weld the flanges on to it to bolt into your system.
Just an idea, don't know how it will work with everything else being stock, but I welded one in when I put the headers on and left the rest of the exhaust stock and have had no issues at all.

EDIT: Cost of CAT

Or just not replace it at all, and use straight pipe.. *cough*

BrianEsser wrote:

Or just not replace it at all, and use straight pipe.. *cough*

Unless of course, *cough*cough*, New York requires smog tests to renew your registration...

(and if you have a cat, we won't be coughing so much )

BTW, it appears this thread duplicated itself... You may want to go back and kill the other one before someone posts to it.

Im not spendin 450 thats for sure will straight pipe throw a code , Icould go that route , got a Aeroforce to clear the code , unless it comes back all the
Im looking at a MagnaFlow Spun Stainless Steel Catalytic Converter
its ilke 80 bucks , but do i get 2.5 or 2.75 or 3 ? I measured the pipe after the cat ... its 2.650 or so O.D.

I keep forgetting not everyone is as lucky as some of us in the sticks.

Just run an O2 sim and it won't kick a code.

BrianEsser wrote:

I keep forgetting not everyone is as lucky as some of us in the sticks.

Just run an O2 sim and it won't kick a code.

And it also won't pass the tailpipe test...

Surely Magnaflow or someone similar sells cats with the correct fittings to do a drop-in replacement?

True , Brian , that would work .... When they put the sniffer in my backside i wonder what they'll smell , and if they will be offerded ? lol

Even a drop in will have to be welded on our cars ... before the resonator ... so i might as well go cheaper and weld X2

You can 100% pass a tailpipe test without a cat, and even with a carb. completely depends on your tune.

If it's that big of a concern, make it where you can just swap in a flanged "test pipe" and a cat when it's testing time.

im not worried about them looking so thats cool . i might go this route ...
whats an o2 sim like 15 if i recall ?

No idea on cost, haven't looked lately. But, if you have access to HPT, you can simply delete it.

Hmmmm seems no one sells o2 simulators anymore ... clean air act ... seems caspers even had to pay fines ...

" Today's settlement, the first of its kind, requires Casper's to stop selling electronic devices-known as oxygen sensor simulators or "O2 Sims"-recall the devices, and pay more than $74,000 in civil penalties to the United States. An O2 Sim tricks an automobile engine's computer into sensing a properly functioning emission control system, even when the catalytic converter is missing or faulty. These "after-market" sensors are considered illegal "defeat devices" under the federal CAA. "

o well ... guess ill get a 2.5 in ? 3 will be toooo big ... id like to have a 3- 2.5 that would fit on my D?p i bet ...

heres a link on how to make one ...
http://www.mkiv.com/techarticles/oxygen_sensor_simulator/

link to EPA settlement ...
http://www.epa.gov/Compliance/resources/cases/civil/caa/casper.html

Quote :

You can 100% pass a tailpipe test without a cat, and even with a carb. completely depends on your tune.

I would like to know more about this 'tuning out the cat' concept. Information I found says:

"Many states and localities have legislated annual automobile emissions testing that checks the actual emissions content. The exhaust emissions test checks for the absence of a converter or a malfunctioning one during an inspection."

If the tailpipe test detects actual emissions content, how does a tune do the job of a cat? And if it could, why would modern cars even have a cat? Couldn't the manufacturers just "tune out" the emissions?

Probably if i took my mini afc and leaned her out some ....
wouldnt detect all the unburned gas ?
Not goin that route either ...

Depends on the area and their acceptable emissions levels. A visual inspection is easy to pass, a split stock cat welded around a straight pipe takes care of that.

Maybe the acceptable standards have changed since we last went through the process. Then again I know in Virginia, many places don't even do an honest inspection.

Consider getting a "Walker" cat from Advance - the standard Riv cat was a high flow cat and the Walker matches. Walker will fit exactly and weld in.

Probably should not get an 'Eastern' they will work initially but use lower spec substrate and metal.

As for passing smog without a cat, depends on your state and how they run the test. If your car is tuned to run efficiently and all the sensors are working then after it warms up it probably won't fail smog during a drive cycle that does not 'floor' the accelerator for any appreciable length of time. I don't know more about this though and I don't know about the visual inspection.

Albertj

mr riviera wrote:

Probably if i took my mini afc and leaned her out some ....
wouldnt detect all the unburned gas ?
Not goin that route either ...

sorry but it's nowhere near that simple. AFC is only for correcting fuel trims and WOT adjustments. Any change you make will be 'corrected'. The O2 sensor will make the amount of fuel at idle consistent unless you really break your tune, which you can't do with an AFC.

Found tha walker for 150
the magnaflow im looking at is rated for 564 cfm wonder how much we flow .... says it good for up to 5.2L
idk the walker would be easy though ....

Looks like albertj is the winner lol , thanks from a fellow NY'er
150 isnt bad ill just order it and be done

Quote :

If your car is tuned to run efficiently and all the sensors are working then after it warms up it probably won't fail smog during a drive cycle that does not 'floor' the accelerator for any appreciable length of time.

I don't know why the test procedure would even require WOT during testing for emissions, as this richened condition would put the cat outside of its efficiency range. You see a lot of carbon monoxide and hydrocarbons even with a cat under WOT. I'd think they would test for average driving conditions (cruising and medium throttle, keeping A/F near stoich 14.7:1 so cat can do it's job.) A cat blocks emissions better with A/F near stoich, while no cat would allow them to pass.

albertj wrote:

Consider getting a "Walker" cat from Advance - the standard Riv cat was a high flow cat and the Walker matches. Walker will fit exactly and weld in.

Albertj

mr riviera wrote:

Found tha walker for 150
the magnaflow im looking at is rated for 564 cfm wonder how much we flow .... says it good for up to 5.2L
idk the walker would be easy though ....

That would be my choice... As Albert confirmed, I always thought we had a hi-flow cat as stock, and anything is better than the pellet-type cats that GM used for 10 or 15 years!

As far as the actual testing, I know that many states with high concentrations of either smog or liberal do-gooders have started copying California's stricter-than-Federal emissions standards.

Depending on your 'zone', they might only do an OBD test (where the sensors and computer have to be happy, with no codes set and all the Readiness Tests complete,) or an actual tailpipe test. Ours are on a dynomometer, and while my car runs perfectly, and has a catalyst, the unburned HC limits are wicked low. I smogged my car a week ago, and I had a comfortable cushion on CO, CO2, NOx, etc, but the HC limit was only in the double digits to start with - 50 PPM higher and I would fail. In that kind of test, you're not gonna' get away without the cat...

I made an error on my first post.
I'm surprised nobody went to ZZP site to verify.
The Cat I bought from them was $50 something dollars. Cheap and works good if you are going to do a weld in or weld flanges.

I came across the printout from my California smog-test on 5/14/10...

Just FYI, I thought I'd post the limits that apply to my '97 S/C motor in this urban area:


At 15 MPH on the dyno, you're only allowed

HC ------ CO
49ppm 0.47%

And at 25 MPH,

HC ------ CO
33ppm 0.44%


The NOx allowances are quite high, but with my fully functional emission-control systems, I was putting out:

HC ------ CO
11ppm 0.05%
and
14ppm 0.16%


Not bad, but in the great scheme of things 20ppm is not much, and that much more hydrocarbons would have flunked me...