Secondary cat delete

[The _Don]

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.

+1

 

[Sp!ke]

Just to clear up any confusion.

 

[scottishblue]

Hiya, I understand re the cats, but does this apply to the resonator box as well? I thought the resonator box was something to do with noise?

 

[turboman]

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.

Perfect is very subjective....it sounds nice, sure, but is far too subdued inside the cabin..

I'm sure a bit more bass and volume would enhance the sound immeasurably

 

[Jc63]

Sorry to go a little off subject re cats, How much is a good set of headers and where from? i have heard good things on the US MB forums but all US dealers! is it a big job to fit a set?

Headers + Map = big sound and big gains?? but is it BIG £££!!

 

[turboman]

So has anyone her actually done a decat and if so what were your thoughts/experiences?

 

[kalvin928]

So has anyone her actually done a decat and if so what were your thoughts/experiences?

Bought my car with no cats.. Sounded mental but after seeing Andy at PCD and my own thoughts of potential MOT failure... Had primary cats put back as well as Lambda sensors.. Originally due to omission of these; the EML light had been blanked off.. Wasn't happy about this.. Anyway it had the x pipe mod done... And its fine.. Still has a subtle roar.. But this should be expanded when c63 boxes go on

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[Lee C63]

Sorry to go a little off subject re cats, How much is a good set of headers and where from? i have heard good things on the US MB forums but all US dealers! is it a big job to fit a set?

Headers + Map = big sound and big gains?? but is it BIG £££!!

If you mean Long Tube headers then speak with the forum sponsors. The American ones are for LHD cars.
I think Phils C63 (Rebellion) runs at 550 BHP with LTH and eurocharged map.

 

[W4E300]

So has anyone her actually done a decat and if so what were your thoughts/experiences?

I had the secondary cats removed from my CLK500 and had it lowered at the same time by the guys at EMP St Albans - and it looks & sounds great. No noticeable effects on fuel consumption or performance, but the thing was plenty quick enough for me anyway.......[although still considering the remap options...!]

I would say that longer motorway journeys can be a bit tiresome - the low-speed rumble becomes a constant 'drone' at 70.....

Insurance went up by £80.00 too.

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[H20 MRV]

My 507 is getting secondary cat delete late next week or early the week after,
I bought second hand std down pipes and am going to chop the secondary's and fit the Milltek delete,
I will put up before and after posts and a hopefully a vid.

Mercedes C63 AMG Milltek secondary cat bypass pipes | eBay

 

[Gt Two]

Beautiful work by Hayward and Scott

Sounds immense and also zero power loss, how can there be? If you look where the secondary cat is the diameter lowers to miss a torsion bar on the exit of the cat. The secondary cat delete provides a larger diameter all the way through.

I had mine decatted and remapped at the same time and the difference in noise and power is far more than I would have expected from a NA car.

 

[Lee C63]

Beautiful work by Hayward and Scott
I had mine decatted and remapped at the same time and the difference in noise and power is far more than I would have expected from a NA car.


So what increase in BHP did the de-cat give?

 

[Gt Two]

Beautiful work by Hayward and Scott
I had mine decatted and remapped at the same time and the difference in noise and power is far more than I would have expected from a NA car.


So what increase in BHP did the de-cat give?

Hard to quantify, I had a decat completed by a 'specialist'. It was a poor job and I felt the car was not as quick and low down torque was off. I had the car dyno'd and the drop showed in the figures.

I then had the work removed and re done by Haward and scott and the car felt instantly better. Perhaps it was only back to standard but it felt great to have it back and performing really well.

We measured the diameter of the first decat and it was less in a few mm, the welds inside the decat were poor also.

Now I have had Eurocharged tune the car and the difference is massive, especially from 5k revs. A friend of mine has a coupe and mine recently just slightly pulls on his on 8+ separate runs on different slip roads. Both manual and auto mode.

Im very happy, he is just about to order a Eurcharged box and tune.

 

[mars1960]

I had a secondary cat and centre silencer delete on my GF's CLK500, there is no more or no less power but it does sound awesome, in fact it sounds pretty much like a CLK55 now.
PS: it did pass it's MOT but i have been informed that a secondary cat delete on AMG models and it will not pass an MOT, unless of course you know a man .

 

[John]

I had a secondary cat and centre silencer delete on my GF's CLK500, there is no more or no less power but it does sound awesome, in fact it sounds pretty much like a CLK55 now.
PS: it did pass it's MOT but i have been informed that a secondary cat delete on AMG models and it will not pass an MOT, unless of course you know a man .

Mine passes at a 'regular' MOT station with no secondary CATs.

My guess is they see the primary CATs and tick the box.

 

[Sp!ke]

That does seem to be common at the moment. The concern however is that the MOT tester should be failing the car according to the MOT testers manual.

It's only a matter of time before VOSA force the issue and clamp down on testers that don't comply.

 

[Gt Two]

Will the tester know there is meant to be secondary cats? the primary cats are there to see at the bottom of the headers.

My MOT tester has always been good to me

 

[H20 MRV]

Well in that case you will get some switched on garage that specialises in mercs say in Birmingham who will have a stock of std exhaust's bought off ebay,

Then you get your mot with the std system, and then the original system is refitted,
thats what we used to do with the decat jap stuff we used to import,

Uk tyres and wheels, a uk exhaust and off for sva, pass then swap back.

 

[John]

Will the tester know there is meant to be secondary cats?

I think this is currently why my car passes to be honest. The tester hadn't even heard of the changes two years ago and still passes the car even now.

I have the missing parts so will either get them refitted or do what H20MRV suggests if push comes to shove.

 

[fil28]

hello again, I have just had the secondary cat delete done at Cobra exhausts (previously exhausts uk) in sheffield. they quite simply cut out the cats and replace with straight stainless pipe TIG welded in place. I saw the job complete on the ramp it was a very nice clean job! cost £175. The sound is increased by about 20% which i think is perfect, you also get more crackle and over run. I am very pleased!