Does the 500e have both primary and secondary cats like the SL500?

[Benzy Boy]

The SL500 M119 has 2 big cats right under the engine and then another 2 smaller cats where the 500e has its cats as well.
Does the 500e have the a pair of big cats too or just 1 pair of smaller cats further down?

Furthermore if it doesn't, would you recommend removing the secondary cats from the R129?

 

[gsxr]

No primary / secondary on the 400E/500E. Only primary cats, big ones in the center of the floor.

DO NOT remove any factory cats on M119 engines, regardless of chassis. There won't be any power gain, plus it's illegal... and will severely hurt resale value.

 

[Benzy Boy]

No primary / secondary on the 400E/500E. Only primary cats, big ones in the center of the floor.

DO NOT remove any factory cats on M119 engines, regardless of chassis. There won't be any power gain, plus it's illegal... and will severely hurt resale value.

Why shouldn't I remove the secondary cats? A lot of M119 cars don't have them and apparently they are only there to help until the primary cats warm up. Apparently they can also cause blockages over time?

My main reason is for better sound. I have an extremely beautiful sounding muffler which is a corsa pro series that in my opinion sounds better than the AMG muffler and even custom exhaust jobs and absorbs ALL drone but I want the car just a tiny bit louder. I already removed the resonator. Secondary cats also don't have O2 sensor

 

[Benzy Boy]

Reviving this thread to get some more thoughts:

My currently muffler (+resonator delete) sounds amazing, sounds louder than an eisenmann when you step on it but has no drone whatsoever at cruising (corsa has a patent on anti-drone mufflers... and trust me it actually works).


But I want it louder. My only option is deleting the muffler which will create a horrible raspy sound and lots of drone, OR delete the secondary cats. I will still have the primary cats. Is this a bad idea? the 500e doesn't even have secondary cats so why should the R129?

The logic behind this is that the current muffler will still catch the drone, but the secondary cat removal will give me that extra sound I'm looking for when I step on it.

 

[szvook]

Can you put up an example of how your exhaust sounds now?

 

[Benzy Boy]

Can you put up an example of how your exhaust sounds now?

I don't have any right now. Let's revive this thread in March/April when it's out of storage. It just sounds really good is all I can say.

Sounds 99% exactly like this guy's:

He just has an aftermarket straight through muffler and res delete. Mine sounded the same with the previous AMG muffler + res delete too.

The only difference now, is that my corsa muffler has no drone compared to other muffler options I've tried so it sounds even better because it's more refined but just as loud. So when you're cruising you don't have any annoying drone frequencies and can hear the engine itself so clearly (I removed my hood insulation). The special thing about this muffler is that it is also straight through and has no internal insulation material. How it's able to accomplish the drone cancellation I have no clue.

But yeah besides the point I want it even louder than it is right now to have more presence on the road hence the secondary cat delete idea.

 

[szvook]

That sounded pretty good. Since you deleted the resonator, a lower cell count cats will open up the sound…but you need to know which lower cell cats can still pass the emissions tests in your nick of the woods.

Also, if you want a deeper and throatier sound, you might want to increase the piping diameter from the exhaust manifold to the muffler(s) (gradually, to maintain the gas flow velocity), get an X pipe (if running a dual exhaust) and have larger tips on the muffler(s). It‘s the combination of all of the components that will play into the final decibel increase and the exhaust note. I have a dual exhaust from the exhaust manifold down to dual mufflers and I tried an H pipe and X pipe for crossovers and I preferred the X pipe, as it gave more of an exotic note, which is what I wanted. I’m running straight through mufflers as well, with only a straight-through perforated stainless steel core, with no stainless mesh wrap and acoustical fiber fill. They look like the below example. I did have some drone with the new exhaust, but that was due to the mufflers tips pointing down to the ground. Once the tips were changed to go straight out, the drone was gone.


This is what I mean by getting an exotic sound and this is just at start up, and with 200 cell cats.

And at partial throttle, from about 50 feet away.

 

[gsxr]

... OR delete the secondary cats. I will still have the primary cats. Is this a bad idea? the 500e doesn't even have secondary cats so why should the R129?

If the oxygen sensors are UPSTREAM of the secondary cats, it won't upset the computers. However if there are O2 sensors downstream of the secondary cats, that may cause problems. Looks like the sensors are upstream of the secondary cats. If you do remove them, save them, so they can be re-installed if needed. If you have emission testing where you live, it may not pass with these removed - I'm not sure.

 

[Benzy Boy]

That sounded pretty good. Since you deleted the resonator, a lower cell count cats will open up the sound…but you need to know which lower cell cats can still pass the emissions tests in your nick of the woods.

Also, if you want a deeper and throatier sound, you might want to increase the piping diameter from the exhaust manifold to the muffler(s) (gradually, to maintain the gas flow velocity), get an X pipe (if running a dual exhaust) and have larger tips on the muffler(s). It‘s the combination of all of the components that will play into the final decibel increase and the exhaust note. I have a dual exhaust from the exhaust manifold down to dual mufflers and I tried an H pipe and X pipe for crossovers and I preferred the X pipe, as it gave more of an exotic note, which is what I wanted. I’m running straight through mufflers as well, with only a straight-through perforated stainless steel core, with no stainless mesh wrap and acoustical fiber fill. They look like the below example. I did have some drone with the new exhaust, but that was due to the mufflers tips pointing down to the ground. Once the tips were changed to go straight out, the drone was gone.

View attachment 183271
This is what I mean by getting an exotic sound and this is just at start up, and with 200 cell cats.

And at partial throttle, from about 50 feet away.

Mine goes from dual 2.25" to 2.5" Y-pipe then straight into the muffler which 2.5" It's actually down from the 2.75" pipe and muffler the stock car came with (I picked 2.5 instead of 3 since there's no 2.75 SS piping) and my exhaust tips are Lorinser with 3.5" opening.

My province in Canada stopped doing emission tests altogether so we're good

 

[szvook]

My province in Canada stopped doing emission tests altogether so we're good

Then if you are willing, get lower cell cats and you should get the increase in decibels you are after.

 

[Benzy Boy]

Then if you are willing, get lower cell cats and you should get the increase in decibels you are after.

What do you recommend? You mean replace the primary cats too?

 

[2phast]

My cats were in need of replacement and I chose a Magnaflow high flow car, designed for 5.0l Mustangs. It was a large, 2 into 1 cat. Everything after the cat was replaced and I ran a single Magnaflow muffler. The sound was throaty, not loud at startup or at idle and would really scream if you got on the accelerator. No drone and no issues with emissions.

No HP gain from changing out the cat to the Magnaflow

 

[szvook]

@Benzy Boy Since you do not need any emission tests, might as well replace both cats, unless you want to do a 2-into-1 cat like 2phast did and his exhaust sounded good.

As far as which cats you should choose, it depends on how much you want to spend, just make sure the cats have a metallic substrate vs. a ceramic substrate and the cats have a good track record. I ended up using 200 HD (High Durability) cell cats from HJS in Germany. They make very high quality cats that can withstand any type of abuse and the ones I got are made to handle 640 whp (320 whp each cat) with no problems. It’s an all steel cat (shell and substrate) with the substrate being triple wound for additional strength and the substrate is brazed inside to the shell. It’s brazed at the both ends and center of the cats shell is slightly cringed, where the substrates is also brazed inside to the center of the shell. This keeps the substrate from telescoping under heavy usage. Basically, these cats are made for supercars level of spirited driving on the Autobahn. These cats are directional, so when installing them, the arrow on the cats outside shell needs to point towards the rear of the car.



I got the HJS cats from Fabspeed Motorsport in Pennsylvania, U.S., where they welded on the end caps, as the HJS HD cats are no longer sold in the U.S. as full cats and I’m not sure about their availability in Canada. Fabspeed Motorsport buys the cores directly from HJS and will weld on the end caps. These cats are not cheap, but they are made to last. I ran my whip at many autocross events, as well as over 200 drag races without any issues whatsoever. Bellow is what paid for the cats, but that was a while ago.


Btw, Kooks green cats looked promising, until I read more than a few reports of them failing prematurely.

 

[Benzy Boy]

@Benzy Boy Since you do not need any emission tests, might as well replace both cats, unless you want to do a 2-into-1 cat like 2phast did and his exhaust sounded good.

As far as which cats you should choose, it depends on how much you want to spend, just make sure the cats have a metallic substrate vs. a ceramic substrate and the cats have a good track record. I ended up using 200 HD (High Durability) cell cats from HJS in Germany. They make very high quality cats that can withstand any type of abuse and the ones I got are made to handle 640 whp (320 whp each cat) with no problems. It’s an all steel cat (shell and substrate) with the substrate being triple wound for additional strength and the substrate is brazed inside to the shell. It’s brazed at the both ends and center of the cats shell is slightly cringed, where the substrates is also brazed inside to the center of the shell. This keeps the substrate from telescoping under heavy usage. Basically, these cats are made for supercars level of spirited driving on the Autobahn. These cats are directional, so when installing them, the arrow on the cats outside shell needs to point towards the rear of the car.
View attachment 183433


I got the HJS cats from Fabspeed Motorsport in Pennsylvania, U.S., where they welded on the end caps, as the HJS HD cats are no longer sold in the U.S. as full cats and I’m not sure about their availability in Canada. Fabspeed Motorsport buys the cores directly from HJS and will weld on the end caps. These cats are not cheap, but they are made to last. I ran my whip at many autocross events, as well as over 200 drag races without any issues whatsoever. Bellow is what paid for the cats, but that was a while ago.
View attachment 183432

Btw, Kooks green cats looked promising, until I read more than a few reports of them failing prematurely.

Thanks. In the the spring first I'll remove the secondary cats and see how it sounds. Then potentially replace the primary cats with HJS as well.