C55 AMG True Dual Exhaust
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Joined: Sep 2012
Posts: 82
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W201 190E 3.0 M103
There has been a bit of confusion with armchair terminology and not a lot of qualified celebration of parts setups in this thread.
Resonators cannot restrict outputs, they're a straight-through type of muffler designed only to remove the upper wavelength, or high pitched sounds from the exhaust. It's a bit like sitting a speaker on a desk, or sitting it in a speaker box. A resonator is like putting it in a speaker box, taking away some of the annoying raspy and high pitched sounds produced by an engine.
They do not in any way restrict power. But they do help comfort levels especially on long drives and they do help lower total decibels a little by cutting some of the higher pitched exhaust noise.
Second, this "primary and secondary cats" terminology is a bit confused and topsy turvy. Up near the headers there are two pre-cats, sensor equipment is usually plugged into one of those. The primary cat, the main cat is under the car. It's called the underfloor cat. That's the one you need for emissions.
Mercedes cats suffer about 5-7hp drop which can be made up by simple race filters and plugs. If you were going to change any trying to squeeze every last little hp then you might swap the main (underfloor) one for a high flow aftermarket one.
If you were determined to delete some cats then you'd toss the pre-cats and relocate/tap sensor equipment.
It really isn't going to make much difference unless you were changing the headers to decent length/angled primaries with downpipes that lacked pre-cats as delivered, and in that case you're getting a lot more from the header design than you are the pre-cats being deleted.
Simply removing any pipe guage restrictions in the exhaust system, such as installing larger guage collection where two pipes go into one, and swapping the baffled mufflers for sports ones gets you best results. Keep your cats, keep your resonators, improve pipe guages and manifolding, that does the trick.
Trying to do what you do to a chevvy to a Mercedes often reduces overall performance and makes them whiny. They spend a lot of research dollars in engineering, you can trust them for terrific performance choices out of the box in most cases.
Resonators cannot restrict outputs, they're a straight-through type of muffler designed only to remove the upper wavelength, or high pitched sounds from the exhaust. It's a bit like sitting a speaker on a desk, or sitting it in a speaker box. A resonator is like putting it in a speaker box, taking away some of the annoying raspy and high pitched sounds produced by an engine.
They do not in any way restrict power. But they do help comfort levels especially on long drives and they do help lower total decibels a little by cutting some of the higher pitched exhaust noise.
Second, this "primary and secondary cats" terminology is a bit confused and topsy turvy. Up near the headers there are two pre-cats, sensor equipment is usually plugged into one of those. The primary cat, the main cat is under the car. It's called the underfloor cat. That's the one you need for emissions.
Mercedes cats suffer about 5-7hp drop which can be made up by simple race filters and plugs. If you were going to change any trying to squeeze every last little hp then you might swap the main (underfloor) one for a high flow aftermarket one.
If you were determined to delete some cats then you'd toss the pre-cats and relocate/tap sensor equipment.
It really isn't going to make much difference unless you were changing the headers to decent length/angled primaries with downpipes that lacked pre-cats as delivered, and in that case you're getting a lot more from the header design than you are the pre-cats being deleted.
Simply removing any pipe guage restrictions in the exhaust system, such as installing larger guage collection where two pipes go into one, and swapping the baffled mufflers for sports ones gets you best results. Keep your cats, keep your resonators, improve pipe guages and manifolding, that does the trick.
Trying to do what you do to a chevvy to a Mercedes often reduces overall performance and makes them whiny. They spend a lot of research dollars in engineering, you can trust them for terrific performance choices out of the box in most cases.
