prodigymb

I saw there were a few thread on this topic already but there was no real concensus on which or both to remove.

I am defiently getting rid of the stock resonator.

I also want to ditch the cats and put angle block spacers or spark plug antifoulers before the secondary o2 sensors. I am fairly sure my cats are clogged as (60k on the car) as after a nice pull there is a smell coming from the exhaust.

Has anyone removed cats? Which ones?
Primaries?
Secondaries?
Both?

jangy

VRP replaced my resonator with an X pipe and put in straight pipes for the secondary cats (which have no sensors). Maybe Vadim will chime in on any plans to sell the setup.

I thought a nice smell on richness was a sign that the cats were working? I dunno about this stuff......

prodigymb

doesnt smell like richness. smell like rotten eggs - which is a sign of clogged cats.

thanks for the input jangy. so no check engine light with removing secondaries

jangy

Nope, no problem with that. Just cut them out. There is not a sensor anywhere near them.

jrcart

No cats on my ride, just some small aftermarket resonators.

prodigymb

sounds good. thanks.

i will start with them and if that doesnt work i'll cut the primaries out as well and run an angle block before the o2 sensor and it should be fine. people used to do it on the mkv GTIs and those things threw check engine lights with 100 and 200 cell cats.......and the angle blocks went CEL free with test pipes

prodigymb

e55? get check engine light?

InTheBenz0

How much did that cost ya if you don't mind, also any CELs?

And more importantly, did you notice any gains?

prodigymb

quick pic of what i want to do for the 2nd O2 sensors to avoid the CEL

jangy

Haha!! Actually, not sure yet. It had leaks and stuff when i saw it. It should be clean and ready to dyno today. I am hoping for any top end gains. My dig is huge, so I really want a way to get to 150 pulling strong.

jangy

Also, I think my VRP/Powerchip tune has the O2 sensors turned off, so I get no CELs from that anyways. That is just what I think my datalogger was telling me. I dunno. Either way, no cels at all and you would not. There are no sensors near any of the work I've had. I left the primary cat and o2 sensors alone. All else is changed, except the mufflers.

MJ50

i too have 2nd cat removed...
no CEL no issues...

InTheBenz0

Just 2nd cat removed? Did they just prefab something to fit in it? Also did you notice any gains?

MJ50

yes. u won't pass smog if u remove both cats...
removing 2nd cat allows to exhale better than b4...

prodigymb

got the resonator and the secondary cats removed over the weekend. cost me 180$ for parts and labor. car sounds sweet,just a bit louder when cruising but when going wide open throttle it rumbles

definetly happy with the outcome and the cost, highly recommend this.
as far as power goes, its hard to tell small gains on a car thats almost 500hp. hehe. plus my stock heat exchanger pump is on its way out. johnson cm30 should be here today or tommorrow so i will go to englishtown to see how much better i can do than 12.7@109.

V12Godspeed

Who did the job for you? I am interested in removing my primaries....

Zod

does ur car only have one set of cats?
i heard the sl 65 only has one were as the sl55 has 2 is htis true?

prodigymb

my buddy owns a Meineke few minutes away from my house (i'm about an hour away from ETOWN), they do good work.

V12Godspeed

Yeah only one set of cats....I figured they would free up some ponnies, but of course will throw a cell light. Wonder if I could trick it with some simulators...Hmmm.

V12Godspeed

Ok, got you.

prodigymb

yeah you should be able to trick your sensors with the angle block things i posted pictures of or maybe the old spark plug anti fouler trick. they run about 70 a pair shipped for the angle blocks. guy has them machined for this purpose and i haven't heard of them not working. i believe my emission is due in February so after i pass, i will take my primaries out (just in case the angle block doesnt work i'll have a year to figure out what to do)

V12Godspeed

Could always get a tune and a pulley, they could program out the CEL code of the primary cats out.

The Law

Okay, you guys are definitely speaking a foreign language to me so I apologize. But, this forum is for asking questions, right? I've been reading most threads for a couple months now to learn as much as I can. Anyway, the one post I came across on this thread reference the smell of rotten eggs. After running hard and parking in my garage, I've noticed this smell. Does this indicate any problems I should be aware of?

Thanks.

Max.H

that simply means your cat(s) are clogged and probably robbing power. maybe its time to get rid of them or replace them with higher flowing ones if you dont want to increase the sound at all. hope this helps!

prodigymb

i had a similar smell and it got better after i removed the secondaries, it has only been a few days but i haven't noticed it be as bad as wehn i first got the car.

replacing cats with OEM units is outrageously expensive, so aftermarket or catless is theway to go