LT1-LT4 Modifications 1993-97 Gen II Small Block V8

MAC mid question

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Old Jun 26, 2009 | 11:50 AM
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Default MAC mid question

Have been searching all morning but i cant find anything to answer my question. I might be purchasing headers later in the summer and was wondering if MAC mids actually move the cat? because for emissions as long as cat remains in stock location ill pass, will I pass with MACs or have to go Shorty?
Thanks George
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Old Jun 26, 2009 | 01:24 PM
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Originally Posted by LT1 Z/28
Have been searching all morning but i cant find anything to answer my question. I might be purchasing headers later in the summer and was wondering if MAC mids actually move the cat? because for emissions as long as cat remains in stock location ill pass, will I pass with MACs or have to go Shorty?
Thanks George
Only shorties will keep the cats in the stock location.
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Old Jun 26, 2009 | 01:36 PM
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Originally Posted by LT1 Z/28
Have been searching all morning but i cant find anything to answer my question. I might be purchasing headers later in the summer and was wondering if MAC mids actually move the cat? because for emissions as long as cat remains in stock location ill pass, will I pass with MACs or have to go Shorty?
Thanks George
I ran the Mac mids and passed emissions/smog testing twice w/ no issues. The cat I upgraded to a high-flow magnaflow 3''. It was a nice set up and gained great low/mid range power. I would highly suggest doing an OTVC wire set because the Mac sits close to the block and I went through 2 sets of wires from burning them.
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Old Jun 26, 2009 | 01:38 PM
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For my own curiosity...why would the cat have to stay in the stock location to pass emissions??? What is the difference in stock loc and moving them down the pipe???
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Old Jun 26, 2009 | 01:51 PM
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Originally Posted by Z28Camaro30Ann
For my own curiosity...why would the cat have to stay in the stock location to pass emissions??? What is the difference in stock loc and moving them down the pipe???
Moving the casts will make you fail the smog inspection, not the sniffer test.
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Old Jun 26, 2009 | 01:52 PM
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how so? I dont have CATS so I havent had to deal with any of this yet...when I move back to Texas I will though. How does it matter on the smog inspection??
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Old Jun 26, 2009 | 01:56 PM
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Originally Posted by Z28Camaro30Ann
how so? I dont have CATS so I havent had to deal with any of this yet...when I move back to Texas I will though. How does it matter on the smog inspection??
Every state is different. Here in CA (and other smog **** states) they will actually look and see if you have all of your factory emmissions systems installed and in the correct location. If you have mid's and LT's and have cats but in the wrong location (they will be further down) they won't pass your car and won't even put in on the roller to sniff test it.
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Old Jun 26, 2009 | 01:58 PM
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Originally Posted by ss.slp.ls1
Every state is different. Here in CA (and other smog **** states) they will actually look and see if you have all of your factory emmissions systems installed and in the correct location. If you have mid's and LT's and have cats but in the wrong location (they will be further down) they won't pass your car and won't even put in on the roller to sniff test it.
Another reason why CA sucks.
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Old Jun 26, 2009 | 01:59 PM
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wow...that's freaking rediculous...if you HAVE the CATS, and it passes the sniff test, it shouldn't freaking matter if you have them in stock locations or not...its not like the stock location effects how well the cat works!!! I hope Texas doesn't do that!
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Old Jun 26, 2009 | 01:59 PM
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Originally Posted by whytryz28
Another reason why CA sucks.
This I know...
But there are ways around it...
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Old Jun 26, 2009 | 02:02 PM
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Technically according to the Dept. of Trans. If you move the location of the cat/cats you have altered their ability to do their job as the manufacturer intended, therefore making the vehicle illegal to operate on the roads. Technically if you replace a functioning cat, that too is illegal. The Federal DOT has made all these smog rules to "protect" the environment from fossil fuel burning engines.. Truthfully does it matter...imo no, but they seem to think so. Usually it won't hurt you unless your state does a visual inspection, and you get a guy/gal that knows exactly where your cat belonged.... Now if a part is sold with a CARB #, then you technically need to have the sticker from that part under the hood as well, so that the inspector can verify the parts on the car are legal, then it doesn't matter since it is carb approved....BTW CARB is the California Air Research Board...if you live in Cali, technically everything you do to your Street car needs to have only carb approved parts (so I'm told).
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Old Jun 26, 2009 | 02:05 PM
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Originally Posted by duh
Technically according to the Dept. of Trans. If you move the location of the cat/cats you have altered their ability to do their job as the manufacturer intended, therefore making the vehicle illegal to operate on the roads. Technically if you replace a functioning cat, that too is illegal. The Federal DOT has made all these smog rules to "protect" the environment from fossil fuel burning engines.. Truthfully does it matter...imo no, but they seem to think so. Usually it won't hurt you unless your state does a visual inspection, and you get a guy/gal that knows exactly where your cat belonged.... Now if a part is sold with a CARB #, then you technically need to have the sticker from that part under the hood as well, so that the inspector can verify the parts on the car are legal, then it doesn't matter since it is carb approved....BTW CARB is the California Air Research Board...if you live in Cali, technically everything you do to your Street car needs to have only carb approved parts (so I'm told).
You are correct. The guy at the smog shop didn't want to pass me once long ago after doing a TB bypass, lol.
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Old Jun 26, 2009 | 02:10 PM
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That's horsesh*t.......Cali is GAY! I'm gonna call the Texas Dept. of Trans. and see what their policy is.....that worries the hell out of me lol. Also just in case, can someone let me know these secret ways aroun......uh oh lol

Just thought of this. I deleted mt A.I.R system, and EGR system plus all the mods below....do I even need to be concerned with CATS? Or even if I DID have them, would I even pass???
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Old Jun 26, 2009 | 02:11 PM
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SH*T... I have TB bypass done too lmao....does the CARB only apply to Cali, or no?
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Old Jun 26, 2009 | 02:14 PM
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Some other states will follow it, but if your car is registered in a state it is only held to the laws of that state, so if you don't do emmissions in your state, you won't have to do them in another state.
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Old Jun 26, 2009 | 09:32 PM
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ss.slp.ls1 - thank you for your reply so unfortunately I'm stuck with shorty and the reason i ask is because Stafford is really **** about there emissions testing here and if the cat is moved then they fail you since i need shorty what do you recommend? Oh and ill be carlisle tomorrow so might be able to find some headers for cheap and duh thank you for the technical response so i can tell some of my other f-body buddies
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Old Jun 26, 2009 | 11:34 PM
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that's weird stafford does emissions testings...but I guess if you're closer to DC you have to deal with emissions. I live in Chesterfield - right outside of Richmond and no emissions here. I have Pacesetter LT's hi-flow cat and some other mods (check my sig). Maybe you could get your car inspected in another county?
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Old Jun 27, 2009 | 01:08 AM
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I heard that the cats need to be close to the enigne because they need to get hot to work.
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Old Jun 27, 2009 | 02:41 AM
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the entire exhaust gets hot......ever grabbed your tailpipe after running it for a few?? lol
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Old Jun 27, 2009 | 04:21 AM
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Originally Posted by rufrntn
I heard that the cats need to be close to the enigne because they need to get hot to work.
Yes, your catalytic converters will be more efficient being close to the end of the header, aka hotter. If you move them too far down the exhaust, you will lose efficiency.
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