SeeKlasse

does anyone know where to purchase some high performance cats for the c43's?

NitrogenBalance

Do an online search for "metal cats". They are 200cel stainless construction and super small which is important for our setup. The construction is quality and they have a very good reputation. I've had mine heating up under the car for over a year and they are still shiny actually

I assume this is for the secondary cats? What are your exhaust plans? Personally I replaced the secondary's because I plan on eventually installing headers without the primary cats. The primary cats really suck on our chasis and they are so hot and close to the motor. If you are going to retain the primarys and depending on emissions in your area I would consider removing the secondarys all together.

SeeKlasse

im just trying to tally up a comprehensive list of items which i need to make my exhaust system nice. nice as in performance oriented, but the sound needs to be respectable aka not too loud...

decent headers, highflow cats, y pipe with 3 inch all the way to muffler... is there an option for the primary cats?

Dr. C36

these are the new gen2 Vibrant cats, much less ghetto than their gen1s, their price is very affordable too, only $109 compared to $180 a pop for "Metal Cats". They are 200 cell and they come in 2.25" / 2.5" / 3.0" respectively (look at links below).

http://cgi.ebay.com/ebaymotors/2-25-...QQcmdZViewItem

http://cgi.ebay.com/ebaymotors/2-5-S...QQcmdZViewItem

http://cgi.ebay.com/ebaymotors/3-Sta...QQcmdZViewItem

Hope that helps

suicidal4life

I'm running 200 cel Metal'cats like Nitro. I've also heard a lot of good things about Random Technologies cats also VRP has hiflow cats for the W211 E55 boys that may work for your car. You might want to give them a call.

RBYCC

Random Technology is the premier spun metal cat...but consider the Magnaflow equal for half the price.

Dr. C36

magnaflows are always a safe bet. just make sure they are true metal 200 cell race cats and not the conventional ceramic grid core cads. sometimes on ebay they label one as the other.

SeeKlasse

oh i see, and these are the pre cats or what? can i use 4 of these total or something?

NitrogenBalance

The work involved to replace the primary cats would probably make it not worth it. The secondary cats are easy access but the primarys would require removing the down pipes from the manifolds. Also, you would need to modify the ends of each cat to the angles that match the stock cats. Take a look at the primary cats and you'll see what I mean. This is why I like the kleemann headers as they delete these.

RBYCC

I use two # 59954 in the true dual exhaust on my twin turbo.
I rattled the bricks out of OEM SL500 cats on the dyno.
The Magnaflows or the Random Technology are only about 8" long and 4" diameter, so no precats used.
High flow and take higher heat then the older ceramic brick technology.

http://www.planetmagnaflow.com/shop/...59954-686.html

e34m20

Your Fulton county GA emissions check for a 1998 only involves a code scan and visual inspection for cats. There is no exhaust gas sampling

ABSOLUTELY get headers that extend past the primary cats and eliminate them !!

THEN after you have completed that substantial upgrade, swap the standard (secondary) cat's with some high-flows.

THEN, if you're even still in need of any additional exhaust work, slap a Remus cat-back on there.

SeeKlasse

remus doesnt make cat back exhaust for the c43. a remus rep told me that they made a couple lots of amg mufflers for mercedes so they dont manufacture aftermarket versions... wether thats true or not they dont offer a cat-back with 3 inch piping thats for sure...

RBYCC

3" piping.....why

SeeKlasse

isnt that the stock pipe size going to the muffler? either 3 or 2.75 it looks really fat... was stating that remus doesnt make mufflers with a 2.75 or 3 inch pipe

RBYCC

I would be surprised if the stock pipe is 3"......would guess more like 2" to max 2.5"...

ProjectC55

It's 2.75 inches to be exact on the C43 from the resonator back. My custom system starts at 2.5" to 3" high flow cats back.SEARCH dude! The info is here. There are plenty of custom exh threads in this C36/C43 section.

Here's a gift just from ME doing an online search:

http://www.prostreetonline.com/s/exh...er-muffler.asp

you can go black stainless or silver stainless


http://www.vibrantperformance.com/pr...05/pg20-21.pdf


This muffler is also lighter than the stck muffler.

RBYCC

Thanks for the clarification...

The down pipes are the smaller diameter...

SeeKlasse

C55,

are you using the stock downpipes to 3" cats leading into a custom catback or are you using aftermarket headers which eliminated the precats?

is there an application for a X or Y pipe in these cars?

myc43amg

When the upper/primary cats get deleted on our c43's what happens with the O2 sensors? Do they care the cats where removed? In other words will the computer throw an eror code?

Also, will there be any gain in HP or MPG when they are removed?

RBYCC

You retain the O2 sensor as it is upstream of the cat.
Changing cats will not cause an error code.

Make sure you get a spun metal cat that meets federal requirements.
You should have no problem passing emissions with a performance cat

NitrogenBalance

I don't know of anyone who removed just the primarys..its usually a combination of headers and downpipes without the primarys. Kleemann feels its important. If you were able to remove just the primarys I'm certain it would help performance. For one, the cats are restrictive. Also, next time you go for a spirited drive pop the hood and look at the primary cats location(AMG had little room to work here) and feel the heat they throw off.

In terms of the O2's you will need to weld in some threaded bungs for the secondarys. The C43 picks up from the primarys, which is why people can simply delete tthe secondarys without issue. Just move em' down stream to read the secondarys.

ProjectC55

I endorse this 100%

myc43amg

Thanks guys!
So I CAN delete the primary cats with no issues and MAYBE some extra ponies,correct? BUT, to pass emissions and not get any codes I will need to hook up the secondarys O2 wires to the primary wires??? This part I am VERY confused, sorry. Can anyone explain this as basic as possible?

I read the part about making new threaded bungs but dont get it wy I would need this if there are bungs already. Cant I just use the wiring from the primarys to hook up to the O2 sencondary bungs?

Sorry very confused.

suicidal4life

The stock sequence goes something like this. The exhaust exits the engine into the exhaust manifolds. Then there is the first set of o2's (one on each side of the engine) that read the AF mixture of the engine and tell the computer how to tune the car. Then there is the set of primary cats. After the primary cats there is another set of o2's that check to make sure the cats are functioning properly. After these o2's are the secondary cats. There are no o2's after the secondary cats so the cars computer really doesn't know if you remove them. If you decide to remove the primary cats (while retaining the secondaries) the car will know something is up with your primaries. The solution is to keep the first set of o2's in place but move the second set of o2's (which used to be behind the primaries) behind the secondaries. This way the computer will see cats that are functioning and not know the difference.

SeeKlasse

i see.... one thing thats bothering me is i had my mechanic change my o2 sensor (pre-cat driver side) recently and i was watching him do it from under the car, fot he primary cats start after the downpipe clears the motor area?