Anyone in the South with secondary cat delete

[KillerHERTZ]

My CLS55 AMG (5.5 Kompressor) and also my current CLS63 AMG 5.5 BiTurbo have both had their resonator removed. each time it made the car sound more like an AMG should.

On each car it has sounded excellent. Start with this and if you still need more, explorer those options at your own risk.

Any garage can do this mod for around £100

 

[BlackC55]

My CLS55 AMG (5.5 Kompressor) and also my current CLS63 AMG 5.5 BiTurbo have both had their resonator removed. each time it made the car sound more like an AMG should.

On each car it has sounded excellent. Start with this and if you still need more, explorer those options at your own risk.

Any garage can do this mod for around £100

£100! Not for a decent job. Quality of steel, measuring and good welding is important. So many we have seen bodged up and we have to do them again.

My fabricator jigs the exhaust so the tips are in perfect alignment when it goes back on. We take the exhaust off to do it.

 

[AMGeed]

For the record, on my '63, once I removed the centre resonator, I started getting burbles the odd pop on overrun. Brilliant, simple mod.

My reply won't help the OP as I also have the biturbo which doesn't have secondary cats. But I had the resonator removed and it makes so much difference. The bark on a downshift from speed is hilarious.
Resonator removal for mine replaced with straight SS piping was £300 and took around 2 hrs.

 

[350cls]

So leave the secondary in place. Install straight pipes in place of the resonator. Its still apparent this can cause some drone. It's a conundrum to say the least lol.

Maybe I should leave as it is lol.

 

[KillerHERTZ]

No drone at all.

 

[AMGeed]

No drone on mine Tom, but its a different engine I know.
I had a very slight drone with secondary cats and resonator removed on the 55.
Again, different engine.

You need replies from 6.2n/a engine owners ideally.

 

[350cls]

I don't want to alter the tone to much away from the stock sound. Within the thread above, the US link, it is somewhat evident that the Res delete does make the exhaust note rasp somewhat over a secondary cat delete.

The secondary cat delete with straight pipes seems to keep the AMG bark with more amplified sound. This is on the 6.2 N/A lump. This set up seems the way most 6.2 owners go with

 

[350cls]

No drone on mine Tom, but its a different engine I know.
I had a very slight drone with secondary cats and resonator removed on the 55.
Again, different engine.

You need replies from 6.2n/a engine owners ideally.

Thanks Roger, I appreciate your advice and information. Thanks

 

[350cls]

No drone at all.

Thanks KH I appreciate the information.

 

[AMGeed]

I have heard the 6.2 with just the secondaries removed and they sounded great. You could go that route and straight pipe the gap.
If you are wary about removing the cats, open them up, gut them and reweld them. Just open them up at the top where the weld is unseen.

 

[Senator]

Does exhaust modding advice extend to all V8 engines (mine being the 4.3L M113), or does the sound vary depending on which variant it is?
I've heard sound clips of the Eisenmann rear exhaust on the CLK430 which is just what I'm after. Does the centre resonator delete give the same low end burble for less cost?

My fabricator jigs the exhaust so the tips are in perfect alignment when it goes back on. We take the exhaust off to do it.

Do you have a ballpark figure for this job?

 

[Neiltodd]

It sounds very good as stock, leave it as it is.

 

[flowrider]

Resonator delete is not illegal, removing secondary cats is a grey area. In theory its still legal (emissions wise) as the primary cats still allow the car to pass MOT emission laws, however if the MOT tester spots any modification it will fail.

Removing the Primary/all is illegal.


For the record, on my '63, once I removed the centre resonator, I started getting burbles the odd pop on overrun. Brilliant, simple mod.

I've asked before on the forum with no clear answer but when you say any exhaust modification is a MOT fail how do cars with aftermarket exhausts get pass the MOT? If it should be an automatic fail then why haven't the government shut down all the aftermarket supplies.

 

[KillerHERTZ]

I've asked before on the forum with no clear answer but when you say any exhaust modification is a MOT fail how do cars with aftermarket exhausts get pass the MOT? If it should be an automatic fail then why haven't the government shut down all the aftermarket supplies.

I didnt say an exhaust mod is a fail, I said removing the cats is. If a tester spots any modification to the cats, eg: indicating they have been removed then its almost certainly going to fail.

 

[Alex]

As been said before, the resonator in these cars is essentially an H-pipe that is there to equalise exhaust pressures between the two banks and kill sound waves responsible for droning vibrations. I suppose cats muffle the drone so those who have just deleted the resonator but kept the cats won't always hear it. It's also worth remembering that we all hear things differently so a drone or no drone is often a matter of perspective. Personally I would always try and use an X- or H-pipe to reduce the effects of back pressure on the engine unless you go with firing order specific headers and/or extremely short exhaust sticking through your wings.

PS: I thought M156 has the most glorious exhaust sound in the world. Evidently removing a resonator makes it sound even better. So you can perfect the perfection, hey.

 

[350cls]

As been said before, the resonator in these cars is essentially an H-pipe that is there to equalise exhaust pressures between the two banks and kill sound waves responsible for droning vibrations. I suppose cats muffle the drone so those who have just deleted the resonator but kept the cats won't always hear it. It's also worth remembering that we all hear things differently so a drone or no drone is often a matter of perspective. Personally I would always try and use an X- or H-pipe to reduce the effects of back pressure on the engine unless you go with firing order specific headers and/or extremely short exhaust sticking through your wings.

PS: I thought M156 has the most glorious exhaust sound in the world. Evidently removing a resonator makes it sound even better. So you can perfect the perfection, hey.

Moving them goal posts Alex, hey

 

[350cls]

With removing either resonator or secondary cats, change the exhaust note over stock?

What gives the more amplified tone, but keeping it more stock sounding with removing either of the above?

 

[flowrider]

I didnt say an exhaust mod is a fail, I said removing the cats is. If a tester spots any modification to the cats, eg: indicating they have been removed then its almost certainly going to fail.

What if I buy an aftermarket sports exhaust for my SL that only has 2 CATs, should that result in a failed MOT?

 

[Steve84N]

With removing either resonator or secondary cats, change the exhaust note over stock?

What gives the more amplified tone, but keeping it more stock sounding with removing either of the above?

Secondary decat.

If you join the C63 AMG UK group on Facebook there are loads of videos of different exhaust modifications. You can search just like on here.

 

[BlackC55]

What if I buy an aftermarket sports exhaust for my SL that only has 2 CATs, should that result in a failed MOT?

By VOSA rules, yes.