Running two catalytic converters in series

[xvxax]

I figured this is a safe enough place to ask this question. My car is due for emissions in May up in Northern Virginia. Two years ago my car had a bit of trouble passing emissions (my car is obd1 which means it gets put it on the rollers and tested at idle, 15mph and 30mph) and I have not changed anything since then except now I have cams and a different chip. My current setup is two OEM cats running parallel. In the event that I do not pass would running two cats in series help me pass emissions, or does running a second cat have little or no effect? Why? I am not sure if I have the room to run them far apart. I would probably run them back to back, with maybe a foot of pipe between them at the most. Have you heard of anyone doing this successfully? I do not want to register my car in Harrisonburg or pay someone off. I am a tree hugging hippie on the inside, but don't tell anyone.
I am however open to other emissions tricks (race gas helps, right?) so if you have any suggestions I'm listening. I do not remember which part of the emissions test I almost failed, if I can dig up the test I will share. I think it was the PPM section.

[CaptainHenreh]

The test would help.

My guess is that you failed HC due to your cams and chip. Two cats running in a series would help, and the further upstream the better. I mean, the WRX has a cat before the turbo for pete's sake. On the other hand, considering your cat is 17 years old, my guess that neither of them is working very well, and a new cat, even if it were just one, would probably be sufficient.

[D_Eclipse9916]

Hey peter what piping do you haev? I have a real 3-inch cat thatll make you pass, its almost brand new.

Aside from that...some tricks are to run a little bit of e85 in your tank to help you pass, and also, go to advance auto and buy a thing called Gauranteed to Pass. If that doesnt make you pass, then your car is in the serious shitter.

[.RJ]

go to advance auto and buy a thing called Gauranteed to Pass

Dont put any of that in your oil if you intend on keeping your car for any length of time...

[CaptainHenreh]

and also, go to advance auto and buy a thing called Gauranteed to Pass. If that doesnt make you pass, then your car is in the serious shitter.

For the record, Kaan put "Guaranteed To Pass" in his CRX and it didn't pass...so he put on a "Catalytic Converter" and it passed. AMAZING! Anyway, the "Guarantee" means you need to send them a copy of your failed report with your receipt and in 4-6 you'll get a check back for the amount that you spent on Guaranteed To Pass.

[BLINGMW]

so he put on a "Catalytic Converter" and it passed.

:lol: ..... do you just pour that in the tank?

[D_Eclipse9916]

and also, go to advance auto and buy a thing called Gauranteed to Pass. If that doesnt make you pass, then your car is in the serious shitter.

For the record, Kaan put "Guaranteed To Pass" in his CRX and it didn't pass...so he put on a "Catalytic Converter" and it passed. AMAZING! Anyway, the "Guarantee" means you need to send them a copy of your failed report with your receipt and in 4-6 you'll get a check back for the amount that you spent on Guaranteed To Pass.

Lol thats why I said serious shitter, I assume if you want to pass emissions you have a catalytic converter? Why would you attempt to try to pass without one? GTP just helps...

[CaptainHenreh]

Lol thats why I said serious shitter, I assume if you want to pass emissions you have a catalytic converter? Why would you attempt to try to pass without one? GTP just helps...

He *did* have a Catalytic Converter, the same one honda put on in 198whatever and it wasn't working no more. When he put on a *new* one, lo and behold it passed emissions just fine. That was my point. Maybe our dear friend's BMW's own cats have shat themselves and are in need of a replacement? And maybe replacing two non-functioning converters with one new one might enable him to pass a sniffer test, instead of putting some snake oil in his fuel tank?

Just a thought.

[xvxax]

I think I am going to run 2.5" from the header back with a very quiet muffler and a good resonator. I don't want to lose any torque and I am dropping my rev limiter soon too so I would rather have the torque. Right now it is somewhere around 7400 which makes me very nervous, but I digress.
The catalytic converters do not make the "rotten egg" smell yet, but I did buy them used and I am running an oxygen sensor off the rear 3 cylinders only. (the ones furthest down the fuel rail) Yes, I realize my car is ghetto rigged, but BMWs switched to a four oxygen sensor system in 1996, and I have obd2 cats because they are full dual, where as the 1995 catalytic converter merged into 1 pipe pre cat to heat it up further.Like this:

Mine look like this:


Thank you for the suggestion on the guaranteed to pass, but I don't feel comfortable sticking anything in my oil.
I found my test from two years ago:

High flow cats are pretty cheap, and I can resell it once I am done. Would running two cats help? Do you know what my emissions report means? It appears as though I almost failed on hydrocarbon ppm and CO%. Any tips?
Also, if I do purchase a catalytic converter I have noticed that OEM cats are really expensive, but cheap replacements can be found for less, i mean like 10 times less on ebay. Why is that? Do you get what you pay for?

[.RJ]

It appears as though I almost failed on hydrocarbon ppm and CO%. Any tips?

Running slightly rich, and perhaps the cats were on their way out then. Make sure all the emissions equipment is functioning (No OBD to tell you it isnt), check the plugs, filters and timing and make sure the car is fully warm (20-30 min driving) before having it tested. It cant hurt to go over the car and have it tested again *if* you find something off (busted EGR, timing off, etc).

[xvxax]

PASSED BAHAHAHAHAHAHskF;ASDFLKJSD;FK