Modding my SL exhaust system

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Pitts Pilot

Active Member
Joined
Mar 11, 2012
Messages
698
Location
Near Folkestone, Kent
Car
SL63 AMG 6.3, VW Tiguan 2.0
Having owned my R230 SL350 for a couple of years I have always enjoyed the sound the V6 makes, although it’s not particularly audible unless the top is down.

So I would like to increase the exhaust sound slightly. Not so much as to sound like an AC Cobra or a Harley Davidson, but enough to give a little extra thrill of satisfaction as I race along country roads.

I've shopped around for “Custom” exhausts and “sports” exhausts, and those available are simply too loud.

For example, I listened to a CSK ‘sports’ exhaust on YouTube and it sounded like a BTCC car at Silverstone. Fine if you are 24 years old and don’t care if you look like a boy racer, but I'm 54 not 24, so I can’t go round shaking peoples windows, I’d look like a sad git with a mid-life crisis!

So after some web research and looking at past posts, I can’t find anyone that will help me achieve the subtle change to the exhaust note I'm after, so I'm thinking of making the changes to my existing exhaust system myself:

1. Cut open and remove the innards of the rearward cats, weld up. Thus there will be a cat visible for MOT's, but actually empty. Apparently this will not have much effect on emissions and they don’t have O2 sensors to contend with either – apparently it’s the front cats you must leave well alone.

More YouTube on “Gutting cats” and the difference in sound is barely detectable, although the car is said to rev more easily and be smoother. Fine. If the exhausts are off the car and I have my angle grinder and arc welder to hand – do it.

2. Cut open the rear muffler and cut some slots in strategically chosen solid tubes to release a bit of gas and thus sound. Repack and weld up.

All work and cutting done to the top side of the boxes so its invisible when back on the car.

I remember seeing a post, with photos, of a guy who did cut open his mufflers and ‘de-restrict’ the internal pipes just a little. It seemed quite ‘do-able’, and the result was apparently very pleasing and didn't sound like a tractor.

So what do you think?

Have I taken leave of my senses?

Will the car throw up endless fault codes?

Should I act my age and leave the exhausts alone and live with the muted sound?

Has anyone got experience of doing either of the mods?

Do you know of a garage that would be prepared to do the work for me?

Go ahead, tell me I must be mad, it’s OK, really!

Cheers :)
Robert
 
Not advisable not even legal. There a lots of sports exhaust about surely one would be acceptable?
 
MBS at Southampton has gutted the secondary cats on one of the MBO members cars (an SL500). No problems and it sounded very nice.

At the MSL dyno day, I had my secondary cats and resonator removed and replaced with a stainless steel x pipe. Sounded so much better and no EML lights displayed.
As long as the car passes the emission tests there isn't a problem...............but that is fluid and could change.

Incidentally, MSL (Torqueflow) do this work and do MOT tests. Do they fail their own work?:dk: I doubt it:thumb:
 
MBS at Southampton has gutted the secondary cats on one of the MBO members cars (an SL500). No problems and it sounded very nice.

At the MSL dyno day, I had my secondary cats and resonator removed and replaced with a stainless steel x pipe. Sounded so much better and no EML lights displayed.
As long as the car passes the emission tests there isn't a problem...............but that is fluid and could change.

Incidentally, MSL (Torqueflow) do this work and do MOT tests. Do they fail their own work?:dk: I doubt it:thumb:

That sounds very interesting.

Can you give me an idea of what "secondary cats and resonator removed and replaced with a stainless steel x pipe" cost?

Many thanks :)
Robert
 
Had m secondary cats and resonators deleted, best thing I've done to the car...

With the car missing its 'standard factory installed' secondary cats, is there not an MOT "Fail" issue to contend with?

However, gutting the cats would seem a clever way round the MOT inspection?

Many thanks,
Robert
 
With the car missing its 'standard factory installed' secondary cats, is there not an MOT "Fail" issue to contend with?

However, gutting the cats would seem a clever way round the MOT inspection?

Many thanks,
Robert

I've never had a problem, it still passes emissions, most testers I've had have never even tested a CL before let alone know it's meant to have 4 cats...
 
The 350 engine in my experience does not sound too great when the secondary cats and resonator is deleted. They can be a bit boomy and fairly loud. It is personal taste though. Some people love it.

I think the best option is to gut the rear boxes. I think this will give you the sound that you are after.
 
Thanks Olly

Thanks sounds perfect.

I'll book it in with you shortly :)

Cheers,
Robert
 
Lots of discussion already regarding modded exhaust and MOT rule...

http://www.mbclub.co.uk/forums/general-discussion/122642-mot-test-changes-1st-jan-2012-a-2.html

I understand from 2012 the rule is :-
Exhaust
A catalytic convertor fitted as original equipment but missing will be a reason for failure.

I don't know anyone who has failed MOT due to a modded exhaust / CAT, the tester would need to understand system design, although I have seen people on the forums state the stations can view this...I really don't think they would have time, having had many cars through modded with no issues I would not worry too much...
 
Never act your age fella ! you just luv a good tune and are seeking to improve it ...similarly Im looking for an alternative...there are some great tunes played on an old fiddle but Im seeking to improve mine +++ Ive seen a black 350 on You tube which has a great sound ...but am not sure the neihgbours or their windows would stand start up and take off early in the morning ...Im looking at a company called Edenstahl I think it is ! Somebody somewhere must have the solution ....more respectable grunt please is not much to ask !
 

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