Bmo Pete

Hi Guys,

One or both of my primary cats is dying (loud flutter/rattle), but I can't seem to find a direct fit high flow replacement (I previously had the secondaries removed).

I see the full OEM primary with secondary section from Benz and Davico available, but was hoping to find an affordable high flow option for only the primaries.

Btw, I have searched here and don't see anything about a direct fit (bolt-on) high flow option for the primaries.

Thanks!

Spooky55

I've seen original used cats on eBay and Craigslist. I don't believe wrecking yards are able to sell them by federal law. To my knowledge there are no aftermarket cats other than generic ones. Can't use those in California - I'm not sure what the laws are in MD.

Bmo Pete

Thanks!

Yep, the only full direct fit system I’m finding is by Davico. It’s somewhat reasonable at around $1,200 for both sides, though not sure about the quality. I wish the primaries were more accessible, so I could just have a couple hi-flow metallic cats welded-in. My muffler shop said there’s not enough room to cut-out and replace just the cats. The Magnaflow website shows one of their systems coming soon, but that may be an old listing that never got through development? Of course there are a lot more options for the W208.

Benzaddict32

I had a similar issue on my C55 where one catalytic converter was rattling. I ended up buying universal cats by magnaflow and found a reputable exhaust shop to cut out the old cats and install the higher flowing ones. They charged me $700 but I also had them convert the exhaust system to a true dual exhaust with an x-pipe and the sound is intoxicating. I’m not sure how hard it would be to cut out the primary cats, but it’s not impossible and I would imagine it would cost a lot less than $1200 with parts and labor. I would get a second or third opinion from another reputable exhaust shop that would be willing to do the work.

Bmo Pete

Yep, your setup was my preference. After checking two shops, both hesitant on cutting-out the primaries where they are, I just bought the direct replacement system ($1,000 at Rock Auto). Since this system has both the primaries and secondaries like OEM, I’m having the muffler deleted to gain some sound. It’s actually in the shop now, so we’ll see how it turns-out.

Thanks for the replying!

Bmo Pete

New basically OEM exhaust including all cats, but minus the muffler - sounds AWESOME!! The first few days I thought it was too loud, began looking for a good sounding sport muffler to attach, but now I feel I wouldn’t change a thing. Now I can hear it rumble cruising at low RPM (hell, now I can hear it at idle), but it’s the angrier volume when accelerating, and the pops at off throttle, that have become intoxicating. The feel of the sound at every increment of the throttle so enhances the experience with this car. Now it sounds like an AMG should!

Benzaddict32

I’m glad it worked out for you. Post a sound clip if you’re able to, I’d love to hear how it sounds.

Bmo Pete

Thanks will do soon! Btw, my elderly father is not a huge fan of the increased volume, presence - he's not a car enthusiast though. He'll probably ride in the Volvo from now on.