Clk55 exhaust mod or remap? Not sure boths an option

[Pittnathan]

A very quick one guys. I've got a single sided exhaust at the moment with secondary cat delete. I like the sound it makes now as its not to intrusive but it could do with having a little more rumble. Would changing to a aftermarket box make it really loud? And is it true that aftermarket mufflers can loose back pressure and cost bhp?

It's either that or spend the same amount on a remap?

I can only afford one so which would you guys go with?

 

[m2287]

Exhaust... When you hear the noise, you will know you made the right decision

 

[Cerbera]

Have you also has the large centre resonator box removed along with the secondary CATs? I've removed these two items and the sound is spot on, subtle on idle and in traffic but a deep rumble when you put you push the accelerator. You can definatly hear the V8 now. I looked down inside the standard rear box and it doesnt appear very restrictive so there seemed little point replacing it plus it retains the cars standard looks until you put your foot down and give the game away.

 

[DRBC43AMG]

Secondary cats and resonator delete is the way to go IMO

 

[whitenemesis]

Be aware of the possibility of failing the MoT by removing CATs ...

 

[flango]

Removing the secondary cats will be a definite MOT fail, there's a new directive to MOT testers from VOSA regarding the visual inspection of cats, if any are missing then it's a fail.

Best way is just to gut them so it looks as though they are there.

There's also a challenge to the ambiguity though from the MOT users group. For example what happens on an older car where the manufacturer no longer supplies the OEM exhaust and you can't get an aftermarket one from KwikFit, National etc. If an exhaust is fabricated for the car and uses one primary cat instead of 2 to achieve the same emissions then why should this be a fail?

Most MOT testers I know always pass stainless custom exhaust if the emissions are correct but fail standard exhausts that have clearly had sections or cats removed.

 

[whitenemesis]

Pragmatically, if the car emmisions are ok, what difference should it make?

 

[redbaron]

How do you afford to run a 5.5 V8 if you cant afford both a remap and some bits of steel pipe to sleeve the cats? Do both and MTFU

 

[Auto-mobile]

Pragmatically, if the car emmisions are ok, what difference should it make?

New rules state that the catalysts on the car should be as they are from the factory and not tampered with or removed, it is not just emission based.

 

[flango]

New rules state that the catalysts on the car should be as they are from the factory and not tampered with or removed, it is not just emission based.

What if you can't comply with that because the factory or aftermarket exhaust is not supported/made anymore?

If you gut the cats the MOT tester would never know and is not allowed to check internals. Suspicion of tampering is not a reason for failure

 

[DSB SL AMG]

Mine passed no issues...unless the tester knows the design of each system it will be hard to enforce the rule...

I agree if you fail emissions then he will explore further....

Removing the secondary cats will be a definite MOT fail, there's a new directive to MOT testers from VOSA regarding the visual inspection of cats, if any are missing then it's a fail.

Best way is just to gut them so it looks as though they are there.

There's also a challenge to the ambiguity though from the MOT users group. For example what happens on an older car where the manufacturer no longer supplies the OEM exhaust and you can't get an aftermarket one from KwikFit, National etc. If an exhaust is fabricated for the car and uses one primary cat instead of 2 to achieve the same emissions then why should this be a fail?

Most MOT testers I know always pass stainless custom exhaust if the emissions are correct but fail standard exhausts that have clearly had sections or cats removed.

 

[flango]

Mine passed no issues...unless the tester knows the design of each system it will be hard to enforce the rule...

I agree if you fail emissions then he will explore further....

The tester will soon know the design of each system, when he logs the car into the VOSA terminal it will give him a printout of what should be on there to compare to. The MOT is set for a lot of radical changes like a camera on MOT test lane linked to VOSA terminal so they can actually see what car is on test

 

[DSB SL AMG]

They can roll out any process they wish... its the understanding and execution of defined process at the MOT stations, do you really think DTI have teams of auditors monitoring this...back on planet earth I think NOT!

The tester will soon know the design of each system, when he logs the car into the VOSA terminal it will give him a printout of what should be on there to compare to. The MOT is set for a lot of radical changes like a camera on MOT test lane linked to VOSA terminal so they can actually see what car is on test

 

[flango]

They can roll out any process they wish... its the understanding and execution of defined process at the MOT stations, do you really think DTI have teams of auditors monitoring this...back on planet earth I think NOT!

You are joking right I'm an MOT Manager and there have been at least 3 occasions on our test lane when VOSA were sat outside on the side road in the car logged on to our terminal watching everything we did how long the car had been on the lane how we had logged on what faults and advisories we had logged. When it was logged off they would then come in and try and catch the customer before they left to seek there views on one occasion they insisted on an inspection and put the car back on the ramp. If you think MOT stations are not policed you are very much mistaken and its nothing to do with the DTI VOSA are the licensing authority. Big Brother is watching make no mistake

 

[Abdul]

Vosa do keep tabs on things for sure.

The day I fail an mot because of a secondary car delete ill simply stick some gutted cats in.

Job done.

It won't happen anyway as my mot tester also happens to be my exhaust fabricator lol!

 

[Auto-mobile]

Find a friendly tester, problems solved.

 

[flango]

Find a friendly tester, problems solved.

Agreed

 

[Cerbera]

Mine never has any problems with emissions with the secondary CATs and resonator delete. With just the primary CATs in place the emiisons are well within the limits.
Its a good bit of advice to find a friendly MOT garage and get to know them as it certainally makes life easier come MOT time.