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Old Feb 25, 2019 | 08:58 PM
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Default Dyno tuning

I am having to put cats on my car in order to pass emissions.

Is it necessary to have the shop dyno it afterwards?
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Old Feb 25, 2019 | 09:28 PM
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I would think that would depend on whether you had it dyno tuned after removing the cats.
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Old Feb 25, 2019 | 09:31 PM
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Yeah probably should have given a little background.

I had had a dyno run after installing headers, catless x-pipe and exhaust.

Now that im having to go back to cats, is it necessary to retune?

Prefer not to since it’s not cheap. Hoping to understand the impacts of doing it or not doing it. Thanks in advance!
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Old Feb 25, 2019 | 11:47 PM
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I would think that it would be a good idea to have it retuned if you have to pass an emissions inspection or if putting the cats back on would trip a trouble light on the dash.
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Old Feb 26, 2019 | 12:06 PM
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Find a friend who has a good scan tool, drive your car about 100 miles after you put the cats back on and then scan the emission pids with the scanner. It will tell you if you have any emission problems
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Old Feb 26, 2019 | 01:22 PM
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Thanks everyone! I called the shop this morning. They said it is already tuned to send false signals to the O2. So it shouldn't throw any codes and should be fine but should get a tune when I have time. So I guess I will quit being lazy and throw on the ls6 intake that's in the garage and tune it all at once.
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Old Feb 26, 2019 | 01:40 PM
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why not just install dummy cats?... basically it's just a shell you put over your existing pipe and looks just like a converter housing... that would be cheaper/easier and no worries about your tune... inspectors are not going to remove those and verify that there is actually catalyst inside of them lol
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Old Feb 26, 2019 | 01:44 PM
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Yeah I almost went that route but I don't want to raise any eyebrows with that stench coming from the tail pipes. It's a noticeable difference in smells. These emissions ppl in GA are ridiculous. There's only 13 counties in the state that require this testing. It's been a nightmare. Ready for it to be over with.
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Old Feb 26, 2019 | 03:34 PM
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Just remember, cats are for 'the good of the people' Mao
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Old Feb 26, 2019 | 04:08 PM
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Are there still places that do the mail-in tunes?
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Old Feb 26, 2019 | 04:26 PM
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Originally Posted by grampi50
Are there still places that do the mail-in tunes?
Yep. More and more remote tuners these days.
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Old Feb 26, 2019 | 08:39 PM
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Originally Posted by anorman02
Yeah I almost went that route but I don't want to raise any eyebrows with that stench coming from the tail pipes. It's a noticeable difference in smells. These emissions ppl in GA are ridiculous. There's only 13 counties in the state that require this testing. It's been a nightmare. Ready for it to be over with.

Yeah Texas has cracked down on this too. You can't get it register until it passing state inspection. With the muffler bypass my car is a little loud. They also check to see if there is a muffler there. So no more SPL loud mouths.
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Old Feb 27, 2019 | 06:22 AM
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Originally Posted by anorman02
Yeah I almost went that route but I don't want to raise any eyebrows with that stench coming from the tail pipes. It's a noticeable difference in smells. These emissions ppl in GA are ridiculous. There's only 13 counties in the state that require this testing. It's been a nightmare. Ready for it to be over with.
I used to have this problem in Ohio in the early 2000's - I lived in a county that would actually stick a sensor in the tailpipe to read the emissions. I had a '98 Cobra with a procharger P1SC running 10 lbs of boost, and there was no way to run cats or put cats back on it temporarily.

So my solution was to register the car at my dad's house many counties away. Do you have a UPS store in the next county over that doesn't inspect you could use as an address? The addresses look normal and not like a PO Box? Could be one option if your not looking to go on the $1k adventure ahead of ya.
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