Secondary cat delete

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fil28

Active Member
Joined
Nov 29, 2013
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109
Car
c63s
I am thinking of having the secondary cats and possibly the resonator box removed from my c63, would like to hear from members that have done it.
I am in South Yorkshire and wanting recommendations for where to take it?
 
If your going to do this it has to be done properly. Not just a cut and weld job. I've heard story's of people having this done cheap and actually losing bhp.
 
I am thinking of having the secondary cats and possibly the resonator box removed from my c63, would like to hear from members that have done it.
I am in South Yorkshire and wanting recommendations for where to take it?

I guess Birmingham would be too far from you, but if not give Acid a call at MSL as Torque Flow exhausts work alongside in the MSL workshops. It would also give you a chance to have a chat with Acid and see their set-up as I'm sure you will start considering other mods:devil:
 
I am thinking of having the secondary cats and possibly the resonator box removed from my c63, would like to hear from members that have done it.
I am in South Yorkshire and wanting recommendations for where to take it?

I'm in South Yorkshire and been in the Motorsport business for over 30 years, the only competent place in South Yorkshire is Exhausts UK Sheffield ( Ask for Matt, they did C240sports AMG CLS X pipe) or West Yorkshire Tony Banks Exhausts Leeds they did my last CLK exhaust manufactured to my spec in satin finish marine stainless and did a brilliant job.

Personally though for something like this I'd make the trip to Birmingham to MSL, sure they will look after you :thumb:
 
Thanks guys, I will contact Exhausts uk. Should I lose the resanator box or just the cat's?
 
Thanks guys, I will contact Exhausts uk. Should I lose the resanator box or just the cat's?

Ask Matt at Exhausts UK he wont give you bad advice, what you do depends on what you actually want by deleting the cats, more power, better sound etc. I've taken Aston's, Ferraris and SWMBO Audi S8 there always took Matts advice and he's never been wrong yet :thumb:
 
I've taken the trip down from Doncaster to MSL/Torque Flow for exhaust work on my CLS and highly recommend them.
 
Would be most interested to know how you get on with this as I'm also thinking of the same mod, and am based in west yorks
 
Going Cobra Exhausts (Exhausts UK) tomorrow to get the car on the ramp and sort out the secondary cat delete
 
You are aware of the new mot regulations I take it?
 
I'm going to do sec cat delete on mine 100%. But I'm either going for the miltek cat bypass kit they do around £350 or wait for Phil at rebelion to finish his set up that's in the pipeline.

I wouldn't just go into any old exhaust place and have em cut n shut a couple of bits of strait pipe in. I've heard from more than one person that cut n shut jobs can actually lose bhp. Unless they purge the pipe when they weld it you will end up with more weld sitting inside the pipe than outside hence reducing the inside diameter of the exhaust. Call me fussy but I'd wanna know it's done properly.
 
I have done quite a bit of searching and cant find any figures that say a secondary cat delete improves power......Would be good to see before and after Dyno sheets for this.

If your taking the cats and resonator off so its louder, why not just go for a full valved exhaust (Agency / IPE or Rebellion) then i would assume you may get a small BHP increase.
However add Long tube headers and you would be looking at a decent power gain.
 
This is why on my C55 I still have all four cats and the resonator. Sadly somebody has carefully opened up the secondary cats and resonator, stolen the guts, and closed them back up again. Dammm..
 
With the new laws coming in Garages would have been informed "I expect" not to pass if the Cats or DPF have been removed or indeed tampered with,
otherwise they risk having the MOT test station approval removed and fined.

There is meant to be a system either in place or going in place to show the original exhaust layout / design.

Furthermore as its a legal requirement, I doubt you will be covered from an insurance point, so its something I would check with your insurance company, unfortunately, ignorance is no defence in these circumstances.


You as the driver will ultimately face any fines the link below is about DPF's but should give you an idea why the law has been changed.

Its up to you as a driver what route to take, but my original plan for my system has been canned, and now will look at the rear boxes only, leaving the rest stock.


https://www.gov.uk/government/uploa...63018/diesel-particulate-filters-guidance.pdf
 
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As of March 2013, a catalytic convertor fitted as original equipment but missing will be a reason for failure.

I asked 3 different test centres about this last October when my mot was due including MB main dealer. All said the same thing to me, that as long as my car passed the emissions test then they had no problem if any cats had been removed!? My car duly passed with no issues and that was at the MB main dealer.

I'm sure some test centres could take a different (and correct) view, but no issues for me. My car currently has secondary cats and resonator removed so looks clearly non stock from the underside.

Sounds a lot better too:thumb:
 
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I asked 3 different test centres about this last October when my mot was due including MB main dealer. All said the same thing to me, that as long as my car passed the emissions test then they had no problem if any cats had been removed!? My car duly passed with no issues and that was at the MB main dealer.

I'm sure some test centres could take a different (and correct) view, but no issues for me. My car currently has secondary cats and resonator removed so looks clearly non stock from the underside.

Sounds a lot better too:thumb:

Thinks its Feb or March this year Simon they have to fully inspect, if the Cat including 2nd Cat is missing its a failure mate its pretty black and white, its nothing to do with emissions, you still have the appeal process with Vosa, if a garage turns a blind eye then that would be their risk. either way they have covered that by putting the onus on the driver.

I would advise anyone to check with VOSA and your insurance to see the implications if any, either before your MOT, or before any Decat
 
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I'd never mess around with a C63's exhaust system, it sounds perfect as stock.

Just be prepared to loose a few bhp when you de-cat it.
 

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