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Smoking catalytic converter

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Old Nov 14, 2017 | 08:48 PM
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Smoking catalytic converter

So yesterday I hollowed out one of my cats and started my car up once the cat was back on. Today I noticed that there is smoke coming from the cat I didn't hollow out. Reason being I didn't hollow the other one out because the top stud was stuck and I couldn't get it so I was going to take it to a shop to break it loose. Could this be because of uneven air flow? I'm not driving the car now because I ordered new cats and don't want to mess anything up. Please help! Thank you!
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Old Nov 14, 2017 | 10:20 PM
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Lmao. Bro. Test pipes are like 80 bucks. Fml. You people are retarded.
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Old Nov 14, 2017 | 11:20 PM
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Originally Posted by PNW_IPL
Lmao. Bro. Test pipes are like 80 bucks. Fml. You people are retarded.
didnt want test pipes, I bought high flow cats. Test pipes smell too strong and I don't want those. If your not gonna help and just talk crap then don't comment please
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Old Nov 15, 2017 | 12:39 AM
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Why not just sell your cats for scrap and buy the high flow ones to begin with? After you've hollowed out the cats would they not basically be test pipes at that point? Man oh man.
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Old Nov 15, 2017 | 01:10 AM
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Once you hollow out cats they will smell since there is no catalyst to react w/ the exhaust.
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Old Nov 15, 2017 | 07:47 AM
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So no one can actually help? Just comment on what I should have done?
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Old Nov 15, 2017 | 10:17 AM
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What exactly are you expecting/wanting us to say? You destroyed one of your cats and the other is now "smoking-" whatever that means. Ok, fine. No going back from this point. You can't put the catalyst back in the old cat and you can't remove the catalyst from the other cat because of the demon bolt (been there/done that x2, first with Berks then with Fast Intentions).

Is the car safe to drive? For a short distance, probably. Would I drive the car in that half-assed modified state? Not at all. Air flow is the least of your potential problems until you get this resolved.

You are getting HFC's. My opinion, park the car until you get the new cats professionally installed and chalk it up lessons learned: a) do it right or don't do it all, and b) the right tools for the right job.

Last edited by ILM-NC G37S; Nov 15, 2017 at 10:40 AM. Reason: typo
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Old Nov 15, 2017 | 10:22 AM
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My diagnosis is that you broke something and now you need to replace it. I would give you the same diagnosis if you told me you removed the battery to save weight and now the car wont start. What sort of advice do you want?
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Old Nov 15, 2017 | 11:03 AM
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My question is to why my cats could be smoking. I get the fact that I messed up by hollowing one and not the other out. That's not the problem. But thank you for all the "advice"
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Old Nov 15, 2017 | 02:50 PM
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Originally Posted by Dillons VQ37
Today I noticed that there is smoke coming from the cat I didn't hollow out.
By chance, did you soak the bolts with some type of penetrating lubricant? If so, is it possible that some of the residue is just burning off? There should not be any "smoke" coming from the cat unless something is burning off. Otherwise any "smoke" would just flow through the y-pipe and out through the muffler. If the car is smoking, and it persists, than you might have a different problem altogether.

Slightly off topic, but if it is a exhaust leak, did you re-tighten the two bolts that you did manage to break loose? How about the two bolts at the y-pipe flange?

I doubt seriously that any differential in air flow between bank 1 and bank 2 would cause any "smoking" to occur on just one bank. Granted the ECU is probably going nuts trying to figure out what is going on and compensate, but being emissions-related, the most that will happen is that the ECU will remain in open-loop. Still, nothing to cause one cat to smoke and not the other.

Last edited by ILM-NC G37S; Nov 15, 2017 at 02:56 PM.
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Old Nov 15, 2017 | 03:50 PM
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Originally Posted by ILM-NC G37S
By chance, did you soak the bolts with some type of penetrating lubricant? If so, is it possible that some of the residue is just burning off? There should not be any "smoke" coming from the cat unless something is burning off. Otherwise any "smoke" would just flow through the y-pipe and out through the muffler. If the car is smoking, and it persists, than you might have a different problem altogether.

Slightly off topic, but if it is a exhaust leak, did you re-tighten the two bolts that you did manage to break loose? How about the two bolts at the y-pipe flange?

I doubt seriously that any differential in air flow between bank 1 and bank 2 would cause any "smoking" to occur on just one bank. Granted the ECU is probably going nuts trying to figure out what is going on and compensate, but being emissions-related, the most that will happen is that the ECU will remain in open-loop. Still, nothing to cause one cat to smoke and not the other.
thank you for the help, probably the pb blaster than. Yes I'm new to the car stuff so I just needed a little help. That's the response I was looking for again, thank you
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Old Nov 15, 2017 | 04:17 PM
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Not a problem. Once you get your HFC's installed you can start working on your next mod!
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Old Nov 15, 2017 | 04:48 PM
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Originally Posted by ILM-NC G37S
Not a problem. Once you get your HFC's installed you can start working on your next mod!
so I noticed something. When I put the nuts and everything back on I put some universal lube/ grease on them to help them slip on and found out that it might be the cause of the smoke. Is that bad, should I try to remove all of the grease?
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Old Nov 15, 2017 | 06:05 PM
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Unless you put it on extremely thick you should be okay but if you can wipe it clean I would. That is more than likely what was/is smoking more so than the PB Blaster. When I installed my Berks HFC's (and later the Fast Intentions RHFC's) I used a copper-based anti-seize compound. The bolts are still a bi*ch though...

About the only thing I would recommend highly is to add some high temperature silicone sealant to the gaskets during installation. It adds just a little extra insurance to avoid exhaust leaks.

Last edited by ILM-NC G37S; Nov 15, 2017 at 06:07 PM. Reason: typo
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Old Nov 17, 2017 | 05:23 AM
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So one time at band camp
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