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Discussion Starter · #1 ·
i was surfing around and found that dcsports.com now has a dyno for the header system for the tC. largest gains are 7.5hp @ 6200rpm and 11.5 tq @ 3300rpm. what do you guys think? good or bad? believe it or not? worth getting?
 

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Look here for the answer to this question.
 

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You know how people talk all the time about what will or won't void your car's warranty? The DC Headers will.
 

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Discussion Starter · #8 ·
anyone know what would happen if you removed the 2nd cat? would it throw a CEL? i saw somewhere that the 2nd one is there just to make sure the 1st one is working so its kinda useless. is this true? would there be any negative impact removing the 2nd one?
 

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Very bad info. The second one has a different wash and does things the first doesn't, primarily with oxides of nitrogen (NOx). Removing it will most assuredly set a CEL code unless you install an O2 simulator.
 

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Discussion Starter · #10 ·
oh ok. do you know if removing both cats is harmful to the engine? or does it just throw a CEL to tell you theres something wrong? i know it will not pass smog because the cat is not there to filter out the exhaust gas. but does it actually do any harm to the car? or does the ECU just sense theres no cat and the CEL goes on? cause i know some people that would get the header and drive around with the light on if it doesnt hurt the car.
 

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If it didn't use VVTi for EGR, I'd say there's no issue. Since it does, there could be problems that might cause damage. It's an outside chance, but something to consider. Inadequate EGR can cause detonation when the ECM is expecting EGR that doesn't happen. The real question is what code gets set by the header in operation. Since we're all just guessing here, it's kind of academic.
 

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Lance, how do you think the ECU will catch the fact that the second cat is missing? There is no O2 sensor behind it.
 

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im not saying i know because im just speculating at this point in time but is the o2 behind the 2nd cat or not? if not it wont set a code to remove the cat....and lo bux most modern cats have both oxidation and Redux beds in the same cat, i have seen them split up, but do u know for sure if thats the case on the tC?

either way like i said earlier, if the o2 sensor is upstream of the 2nd cat all ur gonna do is fail smog, inspection and u will burn in hell for intentionally killing the atmosphere!!!

lol jk about that last one
 

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I haven't dug that deep into the tC specifically, but the first cat is usually a two way and the second is a three way. The reason is to get the first one lit as soon as possible after start up. You'd be amazed what the OEMs do to meet cold cycle emissions, it's a huge effort.

Yeah, I should probably pull out the books and confirm the location of the second O2. Here's the other part though, the first one is usually smaller and the more restrictive of the two, at least it is that way with Supras.
 

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Discussion Starter · #15 ·
so much trouble with getting an aftermarket header and everything. why does the tC have 2 cats while most other cars only have 1? also, some other guy told me that the tC only has one cat. the 2 things under the car is the resonator and the one after that is something called a sub-muffler. i dont know what that is. i was wondering if you could switch the header and just put on 1 cat under the car that does both jobs. what do people think?
 

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the TC has 2 cats
one in the manifold and one in the center pipe
the person who told you otherwise is mistaken
 

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Not only that, but it is illegal to change the cat before the federally mandated 100k mile emissions warranty unless the cat fails. So, changing the cat on this car and showing up for a smog check could be very hit or miss. It would depend entirely on how strict your inspector is.
 
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