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Gringosteve

2nd cat removal

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Hi

I'm hoping someone has the same setup I am thinking of getting, either:

Standard exhaust with non-resonated 2nd cat replacement

Or

Standard exhaust with resonated 2nd cat replacement

I am wondering what both sound like so any videos would be great and opinions as to any performance differences noticed

Thanks!

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I've got a non-res Milltek with a Miltek overpipe and second cat delete. The second cat delete is worth doing to be fair, as I think that's where I got a power gain, albeit only 5% or so. But it does sound good. 

I don't really have any vids apart from some in car ones though. 

See: https://www.youtube.com/channel/UCrjqIA364geu73mZT-woweg

Scroll down for the Snetterton runs, not sure what it sounds like exhaust wise from these vids, I'm on slow hotel wifi so can't check! 

Edited by Lauren

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If you're not mapped already, bare in mind the second CAT removal will bring on an EML light too Steve.

Second CAT removal but keeping stock manifold and exhaust will give you a little more 'bark' but it should still be subtle when cruising.

 

Cheers

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If you're not mapped already, bare in mind the second CAT removal will bring on an EML light too Steve.

Second CAT removal but keeping stock manifold and exhaust will give you a little more 'bark' but it should still be subtle when cruising.

 

Cheers

Incorrect. the Lambda sensors are only in the manifold so you can completely remove the 2nd cat without a tune and not get any CEL/EML

Isn't a remap only required if you change the manifold cat? I changed the front pipe and didn't get an EML in the 2/3 weeks before I did the rest.

yep, remap only required if you decat the manifold

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2nd cat delete gives you a lovely rise in tone and because you will be running the stock cat back you won't have any drone. No CEL issues and you free up some flow! 

A catless manifold is what you want to do if power/noise is your sole aim though, as it frees up a lot of flow and obviously it will become very loud! I haven't run a stock cat back with a catless manifold, but you will have some drone at motorway/cruising speeds after you have it done. 

A map will be required to optimise the system though and clear all CEL lights due to the 02 sensors going mad! I ran mine unmapped with a catless setup for a few months though and the CEL does no harm to the engine. Just drives you mad if you suffer from OCD :P 

 

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No idea where that came from, must still be recovering from JAE 

Ztox, Tareim, completely correct, for some reason i've read that as primary CAT :mellow:

I've got second decat pipes in stock Steve, seeing as you're local to us!

Excellent mate! Where are you located and do you have any videos?

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So can you have a Hi-Flow Cat Fitted on a GT86 ?

Another wards I don't want to put the Cat back on every time the car is MOT'ed !!

 

Yes you can. And mine still passed the exhaust emission test, without front cats. However, this was a high-spec 200CEL version from Germany, dunno if a cheapo version will do the same . .

 

Spec K

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I've got a non-res Milltek with a Miltek overpipe and second cat delete. The second cat delete is worth doing to be fair, as I think that's where I got a power gain, albeit only 5% or so. But it does sound good. 

I don't really have any vids apart from some in car ones though. 

See: https://www.youtube.com/channel/UCrjqIA364geu73mZT-woweg

Scroll down for the Snetterton runs, not sure what it sounds like exhaust wise from these vids, I'm on slow hotel wifi so can't check! 

I can't get that video link to work Lauren

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I'm new here and have been reading up so I don't know for sure...

I think the standard manifold cat with 2nd cat delete pipe can pass emissions and get some gains.

An aftermarket manifold with no cat, and a sports cat in the secondary location may pass mot and get better gains, but best speak to the regular tuners as they would know what has worked before.

I am planning decat manifold and standard secondary cat, assume that will easily pass mot, not sure if it will hamper gains?

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It won't hamper the gains, what you gain from the removal of both cats is barely noticeable anyway. As for emissions, there have been some people who have failed with a sports cat but some have passed. I guess it's a case of you get what you pay for on that front? :S

 

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I can't get that video link to work Lauren

Sorry. It's not that interesting anyway! Just in car of me doing a sprint run.

Come to the Amber meet on the 3rd, plenty of exhausts there. Might be in the AE86, we'll see. 

Edited by Lauren

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