Clogged Secondary Cats?

BmwECY · 06-08-2013, 03:14 PM

I've heard where running Catless downpipes with the stock exhaust and secondary cats can cause issues in the long run with clogged secondary cats. Any truth to this, and has anyone experienced it?

Jeff@TopGearSolutions · 06-08-2013, 03:27 PM

Where did you hear that?

cstavaru · 06-08-2013, 03:41 PM

I remember either BMS or Vishnu (can't remember which) blaming "clogged secondary cats" for some hardware event that happened to a customer of theirs. I would say it's entirely possible, if your turbos are worn, to clog the secondary cats with soot from burnt oil.

OMRITIME · 06-08-2013, 03:54 PM

I don't know if it related
But my e92 2008 has 90k km
And recently I delete the secondary cats 20 km later
My turbo start to have this f***** wastgate rattle

Jeff@TopGearSolutions · 06-08-2013, 03:56 PM

Some people have always had wastegate rattle but it becomes more apparent when your open up the exhaust.

Typically people blame catless downpipes for wastegate rattle when it just so happens they always had it. They just hear the rattle more now that the exhaust is opened up and louder.

robc1976 · 06-08-2013, 04:33 PM

I just deleted mine and they where perfectly clear....I had OEM turbos with the worst seals Rob bech had ever seen....I will say that with higher power levels it seems you notice a good gain in power, my RB'S spool much faster and grab boost faster evident in a log I did last night. I am not saying you will gain 50 Hp our anything crazy. My buddy who has a lot less power than I do did not really feel much with his delete....I think this only applies to higher power levels. Only damage I could see to the secondaries was the Screen being pushed out on the seams wich makes be believe these are a restriction. I am glad I have the JB4 so I can adjust the exhaust note with the muffler delete...huge difference in rasp.

Wedge1967 · 06-08-2013, 04:34 PM

It's a myth, don't remove them if you don't need to... I was on the dyno @ some shop I won't name. Everyone said it smelled like my cats were burned out so they talked me into taking my car to a shop that agreed to cut the out... Worst mistake. Come to find out they looked like new and were burning off the smoke from the vast amount of oil my turbos were leaking. Car smoked so bad I was ashamed to drive it. After the fact I had a shop want to charge me $250 to put the back in.... If you want to go catless, buy a VRSF exhaust and keep your cats in your stock pipes. You just never know when you'll want to go back to stock. Especially if your turbos are smoking really bad.

enrita · 06-08-2013, 04:48 PM

Quote:

Originally Posted by Wedge1967

It's a myth, don't remove them if you don't need to... I was on the dyno @ some shop I won't name. Everyone said it smelled like my cats were burned out so they talked me into taking my car to a shop that agreed to cut the out... Worst mistake. Come to find out they looked like new and were burning off the smoke from the vast amount of oil my turbos were leaking. Car smoked so bad I was ashamed to drive it. After the fact I had a shop want to charge me $250 to put the back in.... If you want to go catless, buy a VRSF exhaust and keep your cats in your stock pipes. You just never know when you'll want to go back to stock. Especially if your turbos are smoking really bad.

this

robc1976 · 06-08-2013, 04:55 PM

Quote:

Originally Posted by Wedge1967

It's a myth, don't remove them if you don't need to... I was on the dyno @ some shop I won't name. Everyone said it smelled like my cats were burned out so they talked me into taking my car to a shop that agreed to cut the out... Worst mistake. Come to find out they looked like new and were burning off the smoke from the vast amount of oil my turbos were leaking. Car smoked so bad I was ashamed to drive it. After the fact I had a shop want to charge me $250 to put the back in.... If you want to go catless, buy a VRSF exhaust and keep your cats in your stock pipes. You just never know when you'll want to go back to stock. Especially if your turbos are smoking really bad.

Agreed...I did it because I have RB'S that do not smoke...if your seals are bad it will be bad smoking. Wedge, I thorny the VSRF exhaust was from dps back?

Wedge1967 · 06-08-2013, 07:03 PM

Quote:

Originally Posted by robc1976

Agreed...I did it because I have RB'S that do not smoke...if your seals are bad it will be bad smoking. Wedge, I thorny the VSRF exhaust was from dps back?

I wish I would have bought an exhaust rather than cutting. Live and learn. I think for the $ the VRSF exhaust is worth looking at.

robc1976 · 06-08-2013, 07:22 PM

Quote:

Originally Posted by Wedge1967

I wish I would have bought an exhaust rather than cutting. Live and learn. I think for the $ the VRSF exhaust is worth looking at.

I also have a OEM laying here if I want to go to stock (don't ask lol! ). . I thought you had hpf exhaust? I am wanting the VRSF but trying decide if it is aggressive enough....don't want a stock sounding exhaust.

Marcadelic · 06-08-2013, 08:10 PM

Quote:

Originally Posted by robc1976

I just deleted mine and they where perfectly clear....I had OEM turbos with the worst seals Rob bech had ever seen....I will say that with higher power levels it seems you notice a good gain in power, my RB'S spool much faster and grab boost faster evident in a log I did last night. I am not saying you will gain 50 Hp our anything crazy. My buddy who has a lot less power than I do did not really feel much with his delete....I think this only applies to higher power levels. Only damage I could see to the secondaries was the Screen being pushed out on the seams wich makes be believe these are a restriction. I am glad I have the JB4 so I can adjust the exhaust note with the muffler delete...huge difference in rasp.

how'd you adjust the exhaust note with the jb4?

something to do with the wastegate rattle fix?

robc1976 · 06-08-2013, 08:21 PM

Quote:

Originally Posted by Marcadelic

how'd you adjust the exhaust note with the jb4?

something to do with the wastegate rattle fix?

trip...menu 10

Marcadelic · 06-08-2013, 08:49 PM

Quote:

Originally Posted by robc1976

trip...menu 10

what # did you put your tach on to get ride of the rasp?

robc1976 · 06-08-2013, 08:55 PM

Quote:

Originally Posted by Marcadelic

what # did you put your tach on to get ride of the rasp?

I have RB'S so it may be different (88-90) and 35 duty cycle (menu 12)

Marcadelic · 06-08-2013, 08:59 PM

Quote:

Originally Posted by robc1976

I have RB'S so it may be different (88-90) and 35 duty cycle (menu 12)

alright thanks, I'll play around with it. Did you remove your secondaries before or after you installed your rb's

robc1976 · 06-08-2013, 09:13 PM

Quote:

Originally Posted by Marcadelic

alright thanks, I'll play around with it. Did you remove your secondaries before or after you installed your rb's

After, just removed then yesterday.

Marcadelic · 06-08-2013, 09:16 PM

Quote:

Originally Posted by robc1976

After, just removed then yesterday.

oh alright I was thinking about removing mine but didn't know if it'd be worth it at all, i think the drone would get even worse and it might smell a bit

robc1976 · 06-08-2013, 09:29 PM

Quote:

Originally Posted by Marcadelic

oh alright I was thinking about removing mine but didn't know if it'd be worth it at all, i think the drone would get even worse and it might smell a bit

my drone went away and got a bit of rasp...I have no drone now...very slight smell only after going WOT and stopping.

Wedge1967 · 06-08-2013, 10:47 PM

Quote:

Originally Posted by robc1976

I also have a OEM laying here if I want to go to stock (don't ask lol! ). . I thought you had hpf exhaust? I am wanting the VRSF but trying decide if it is aggressive enough....don't want a stock sounding exhaust.

Only tested it... I think it has way too much drone. Stock with down pipes are raspy at higher RPM's, but after taking out the secondary cats I wasn't happy with the sound one bit. But now that I have new turbos, I'm really thinking the VRSF would be a nice add. I really want to hear it first. I hate buying exhausts because you never know what you're going to get unless you know someone with the same setup.

robc1976 · 06-08-2013, 11:02 PM

Quote:

Originally Posted by Wedge1967

Only tested it... I think it has way too much drone. Stock with down pipes are raspy at higher RPM's, but after taking out the secondary cats I wasn't happy with the sound one bit. But now that I have new turbos, I'm really thinking the VRSF would be a nice add. I really want to hear it first. I hate buying exhausts because you never know what you're going to get unless you know someone with the same setup.

I managed to get rid of the drone and rap I can get a lot of it out via the JB4 (menu 10) not all of it but a good improvement.....I will just wait for your to get the VRSF

Marcadelic · 06-08-2013, 11:20 PM

Quote:

Originally Posted by robc1976

my drone went away and got a bit of rasp...I have no drone now...very slight smell only after going WOT and stopping.

So removing your secondaries and messing the the jb4 got rid of your drone?

Are you auto or manual?

06-08-2013, 03:14 PM	#1
BmwECY Banned 16 Rep 335 Posts Drives: Bmw Join Date: Sep 2012 Location: Earth iTrader: (0)	Clogged Secondary Cats? I've heard where running Catless downpipes with the stock exhaust and secondary cats can cause issues in the long run with clogged secondary cats. Any truth to this, and has anyone experienced it?
	Appreciate 0 Tweet Quote

06-08-2013, 03:27 PM	#2
Jeff@TopGearSolutions 3441 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	Where did you hear that?
	Appreciate 0 Quote

06-08-2013, 03:41 PM	#3
cstavaru Brigadier General 313 Rep 3,262 Posts Drives: 2009 335i M Sport Sedan 6MT Join Date: Aug 2008 Location: Bucharest, Romania iTrader: (0)	I remember either BMS or Vishnu (can't remember which) blaming "clogged secondary cats" for some hardware event that happened to a customer of theirs. I would say it's entirely possible, if your turbos are worn, to clog the secondary cats with soot from burnt oil. __________________ Mods(click): Cobb + RB Turbos \| Aquamist HFS-4 Meth \| Drexler LSD \| Bilstein B12 Pro-Kit \| Custom K&N Apollo Intake \| Wagner Intercooler \| Macht Schnell Downpipes \| BMW Performance Power Kit \| BMW Performance Exhaust \| BMW Performance Short Shifter \| M3 Subframe Bushings \|
	Appreciate 0 Quote

06-08-2013, 03:54 PM	#4
OMRITIME Lieutenant 106 Rep 589 Posts Drives: M4 Join Date: May 2010 Location: tel-aviv iTrader: (1)	I don't know if it related But my e92 2008 has 90k km And recently I delete the secondary cats 20 km later My turbo start to have this f***** wastgate rattle __________________ 2008 e92 335 FBO 2011 e92 M3 ZCP DCT 2015 f82 M4 DCT
	Appreciate 0 Quote

06-08-2013, 03:56 PM	#5
Jeff@TopGearSolutions 3441 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	Some people have always had wastegate rattle but it becomes more apparent when your open up the exhaust. Typically people blame catless downpipes for wastegate rattle when it just so happens they always had it. They just hear the rattle more now that the exhaust is opened up and louder.
	Appreciate 0 Quote

06-08-2013, 04:33 PM	#6
robc1976 DIYER 614 Rep 5,521 Posts Drives: E90 335i Join Date: Mar 2012 Location: Illinois iTrader: (14)	I just deleted mine and they where perfectly clear....I had OEM turbos with the worst seals Rob bech had ever seen....I will say that with higher power levels it seems you notice a good gain in power, my RB'S spool much faster and grab boost faster evident in a log I did last night. I am not saying you will gain 50 Hp our anything crazy. My buddy who has a lot less power than I do did not really feel much with his delete....I think this only applies to higher power levels. Only damage I could see to the secondaries was the Screen being pushed out on the seams wich makes be believe these are a restriction. I am glad I have the JB4 so I can adjust the exhaust note with the muffler delete...huge difference in rasp. __________________ JB4 G5, Stage 3 LPFP, Stage 2 MOTIV PI, VM 6466 ST, Custom OCC W/ SS lines, ER FMIC, ER CP W/HKS BOV, M3 control arms, M3 guide rods, M3 upper links, M3 front & rear sway-bars, HPA rear toe arms, Wavetrac LSD, HPF Gen 2, DEFIV kit, KW clubsport, Delrin solid SF bushings, stoptech rotors, Rogue Tranny Mounts, 1M bumper, M3 CF hood, M3 fenders, M3 OEM sideskirts, Mtech rear bumper, CSL trunk, MORR VS8.2 rims 245/295
	Appreciate 0 Quote

06-08-2013, 04:34 PM	#7
Wedge1967 Banned 125 Rep 2,172 Posts Drives: '07 e92 AT Sport Montego Blue Join Date: Sep 2011 Location: Portland, OR iTrader: (3)	It's a myth, don't remove them if you don't need to... I was on the dyno @ some shop I won't name. Everyone said it smelled like my cats were burned out so they talked me into taking my car to a shop that agreed to cut the out... Worst mistake. Come to find out they looked like new and were burning off the smoke from the vast amount of oil my turbos were leaking. Car smoked so bad I was ashamed to drive it. After the fact I had a shop want to charge me $250 to put the back in.... If you want to go catless, buy a VRSF exhaust and keep your cats in your stock pipes. You just never know when you'll want to go back to stock. Especially if your turbos are smoking really bad.
	Appreciate 0 Quote