Has anybody gutted the main cats

5.0 V10 50v biturbo - 571 bhp
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Shaneyboi88
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Has anybody gutted the main cats

Post by Shaneyboi88 » Thu Aug 10, 2017 6:00 pm

Has anybody done this and dose it make a differance. ? Thanks

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Farravi
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Re: Has anybody gutted the main cats

Post by Farravi » Thu Aug 10, 2017 8:12 pm

I think most here have custom exhaust, that would mean getting rid of the primary and/ or secondary cats.


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SteveG
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Re: Has anybody gutted the main cats

Post by SteveG » Thu Aug 10, 2017 10:25 pm

I was under the impression that my car had a pre cat delete, but the primary ones are still there when I checked last week. The secondary cats can be removed as part of the "Cat back " sports exhaust system that a lot have. They simply add a straight pipe to replace where the secondary cats are located. I am not sure if the car would pass an MOT emissions test with both pairs of Cats removed TBH, so think carefully before removing all of them. Emissions on my car are spot on thankfully !
Last edited by SteveG on Fri Aug 11, 2017 10:56 am, edited 1 time in total.

Shaneyboi88
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Re: Has anybody gutted the main cats

Post by Shaneyboi88 » Thu Aug 10, 2017 10:45 pm

I have a stainless exhaust with seconary cats removed but thinking instead of replacing the downpipes just hollow them out to help with flow

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IanH755
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Re: Has anybody gutted the main cats

Post by IanH755 » Thu Aug 10, 2017 11:58 pm

MRC used to knock out the insides of the primary cats all the time, pumping the power from 740-ish to near 790+hp.

Also, just for clarity, the primary cats are at the top of the downpipes directly off the turbo exhaust housing deep in the engine bay and the secondary cats are the much bigger ones visible underneath the car and where "cat back" exhausts attach to.
***OLD*** Daytona C5 RS6 Avant - MRC'd - 500HP & 820NM (PistonHeads Link).

***NEW*** Daytona C6 RS6 Avant - MRC'd - 925HP & 1150NM (PistonHeads Link)

Shaneyboi88
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Re: Has anybody gutted the main cats

Post by Shaneyboi88 » Fri Aug 11, 2017 6:54 am

Yes the ones you can see under the car ive had removed with new exhaust but theres a possibility my engine might have to come back out again so i was thinking about asking the garage to hollow out the main cats while its out.

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IanH755
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Re: Has anybody gutted the main cats

Post by IanH755 » Fri Aug 11, 2017 1:17 pm

If the engines coming out it's easy to do with an air chisel etc but you will need a maptweak to stop the ECU light coming on when you have No Cats.
***OLD*** Daytona C5 RS6 Avant - MRC'd - 500HP & 820NM (PistonHeads Link).

***NEW*** Daytona C6 RS6 Avant - MRC'd - 925HP & 1150NM (PistonHeads Link)

Shaneyboi88
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Re: Has anybody gutted the main cats

Post by Shaneyboi88 » Mon Aug 14, 2017 10:18 pm

Ahh so i wouldnt be able to drive it once they have been removed. I was hoing that it would of been ok untill i had time and money to take it back to mrc

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