How long have your secondary cats lasted w/ catless DP's

10-07-2015, 02:58 PM

Quote:

Originally Posted by Miller335

The few times Ive ran pump gas my exhaust tips get black/sooty in no time but running e85 the tips never even get dirty really.

On what maps? Custom map for each type of fuel? Any logs for both fuel types? etc.

I would imagine that OTS maps target richer values as opposed to custom, etc. Too many variables in this instance, but certainly an interesting observation, especially if both maps were custom in your case.

Miller335 · 10-07-2015, 04:16 PM

Quote:

Originally Posted by FCobra94

On what maps? Custom map for each type of fuel? Any logs for both fuel types? etc.

I would imagine that OTS maps target richer values as opposed to custom, etc. Too many variables in this instance, but certainly an interesting observation, especially if both maps were custom in your case.

Custom maps both pump and E85.

nitehawk · 10-07-2015, 09:42 PM

Quote:

Originally Posted by marcvtec

I just changed my secondaries today to magna flow 200 cell count.
Looked through the old ones and I could still see light through them, looked in decent condition I would say.
Performance wise I don,t feel any difference.
Car has 175,000KM on it and it been tuned since birth.

Yea kinda fell like I spent money today on this for nothing, but at least my mind is peaceful knowing there new, lol.

wow, well that's good to know. I take it all those miles were on straight pump gas?

Can you post some pics of the old cats?

marcvtec · 10-09-2015, 09:36 AM

Quote:

Originally Posted by nitehawk

wow, well that's good to know. I take it all those miles were on straight pump gas?

Can you post some pics of the old cats?

Yes pump gas
didn,t care to take photos of em

Stucks · 10-09-2015, 03:09 PM

Earlier this week, i cut my stock secondary cats out and welded in some 100 cell high flow metallic cats from MBS. Didnt take any pics of the stock cats, but when held up to light, you could not really see through them. the 100 cells.....light passes right through lol. also, there is a lot more "backspool" noise as you let off the gas and the rpms are floating back down to idle after a rev. just cruising around, the car remains just as quiet as it did with the stock secondaries in there, and up top there is maybe a little bit more power. a lot less torque down low due to the freed up exhaust and less backpressure it seems. my car has 102k miles on it, fwiw.

nitehawk · 10-10-2015, 11:00 PM

Quote:

Originally Posted by marcvtec

Yes pump gas
didn,t care to take photos of em

Got a part number or link of the magnaflow HFC's?
How much did it set you back?

nitehawk · 10-10-2015, 11:08 PM

Quote:

Originally Posted by Stucks

Earlier this week, i cut my stock secondary cats out and welded in some 100 cell high flow metallic cats from MBS. Didnt take any pics of the stock cats, but when held up to light, you could not really see through them. the 100 cells.....light passes right through lol. also, there is a lot more "backspool" noise as you let off the gas and the rpms are floating back down to idle after a rev. just cruising around, the car remains just as quiet as it did with the stock secondaries in there, and up top there is maybe a little bit more power. a lot less torque down low due to the freed up exhaust and less backpressure it seems. my car has 102k miles on it, fwiw.

Nice, is this the one?

http://mandrelbendingsolutions.com/m...ace-converter/

Is there any smell after making the switch?

Stucks · 10-11-2015, 02:10 AM

Quote:

Originally Posted by nitehawk

Nice, is this the one?

http://mandrelbendingsolutions.com/m...ace-converter/

Is there any smell after making the switch?

it seems mine are the 4 inch diameter version, which they dont make anymore. 5 inch should be ok though, if not flow slightly more.

marcvtec · 10-11-2015, 10:22 AM

Quote:

Originally Posted by nitehawk

Got a part number or link of the magnaflow HFC's?
How much did it set you back?

magnaflow 59959
$400 + tax

Amazon has em for around $130 bucks each.

nitehawk · 10-24-2015, 12:56 PM

Stucks marcvtec
Any increase in exhaust smell from running the HFC's?

marcvtec · 10-24-2015, 01:41 PM

Quote:

Originally Posted by nitehawk

Stucks marcvtec
Any increase in exhaust smell from running the HFC's?

Nope, after now on the car for two weeks.
Exhaust note slightly louder, which I like and yes now the car does seem slightly quicker, mind u I am also pro tuning it at the same time, but maybe it needed a little break in period and adaption.
Overall glad I did it for peace of mind.

bradsm87 · 10-25-2015, 03:53 AM

Quote:

Originally Posted by Stucks

Earlier this week, i cut my stock secondary cats out and welded in some 100 cell high flow metallic cats from MBS. Didnt take any pics of the stock cats, but when held up to light, you could not really see through them. the 100 cells.....light passes right through lol. also, there is a lot more "backspool" noise as you let off the gas and the rpms are floating back down to idle after a rev. just cruising around, the car remains just as quiet as it did with the stock secondaries in there, and up top there is maybe a little bit more power. a lot less torque down low due to the freed up exhaust and less backpressure it seems. my car has 102k miles on it, fwiw.

You should not have less torque anywhere. The back pressure thing is an old wives tale. If you lost torque, you need tuning changes to take advantage of the changes.

Milan · 10-25-2015, 09:58 PM

LOL at losing TQ from less back pressure on a turbo car

Stucks · 10-26-2015, 07:51 AM

Quote:

Originally Posted by nitehawk

Stucks marcvtec
Any increase in exhaust smell from running the HFC's?

a little bit when you first start the car up, but once the cats are warmed up, no smell at all.

Quote:

Originally Posted by bradsm87

You should not have less torque anywhere. The back pressure thing is an old wives tale. If you lost torque, you need tuning changes to take advantage of the changes.

maybe its just the butt dyno, but it feels faster on the top end, and not so much down low. midrange feels faster as well.

STR8-6IX · 02-21-2017, 12:22 PM

best to just take those out before they shit themselves.. good engine sound, deeper exhaust tone and good gains+ throttle response above 4000RPM.

bradsm87 · 02-21-2017, 04:24 PM

Quote:

Originally Posted by 6IX-F10-N52

best to just take those out before they shit themselves.. good engine sound, deeper exhaust tone and good gains+ throttle response above 4000RPM.

Holy thread revival

What makes you think they'd shit themselves? They have a less dense cell count than the primary cats so less likely to get clogged. Our engines have perfect closed-loop fuelling so they're always running sensible AFR as long as your tune isn't crap so no clogging from overly rich mixtures. They're a sufficient distance from the engine that they won't be damaged from heat.

Do you have any evidence of the good gains and throttle response above 4000rpm from removing the secondary cats?

STR8-6IX · 02-21-2017, 05:08 PM

Quote:

Originally Posted by bradsm87

Holy thread revival

What makes you think they'd shit themselves? They have a less dense cell count than the primary cats so less likely to get clogged. Our engines have perfect closed-loop fuelling so they're always running sensible AFR as long as your tune isn't crap so no clogging from overly rich mixtures. They're a sufficient distance from the engine that they won't be damaged from heat.

Do you have any evidence of the good gains and throttle response above 4000rpm from removing the secondary cats?

someone talked about them clogging on this forum.

http://www.e90post.com/forums/showthread.php?t=1029980

I got this link from the first page of this thread.

Yes, I have evidence from deleting my own secondary cats... Maybe 4hp gain. more engine sound. better throttle response above 4000rpm and a noticeably stronger top end pull.

bradsm87 · 02-21-2017, 05:30 PM

Quote:

Originally Posted by 6IX-F10-N52

Yes, I have evidence from deleting my own secondary cats... Maybe 4hp gain. more engine sound. better throttle response above 4000rpm and a noticeably stronger top end pull.

Unless you have back-to-back dyno pulls, it's probably just placebo from the added sound.

STR8-6IX · 02-21-2017, 05:33 PM

Quote:

Originally Posted by bradsm87

Unless you have back-to-back dyno pulls, it's probably just placebo from the added sound.

you definitely feel a couple of HP in the high end, it pulls to redline more freely then before. the added sound and gains really isnt much to write home about, but the added performance is there (albeit fairly minor)

ian3924 · 02-21-2017, 05:46 PM

Quote:

Originally Posted by bradsm87

Holy thread revival

What makes you think they'd shit themselves? They have a less dense cell count than the primary cats so less likely to get clogged. Our engines have perfect closed-loop fuelling so they're always running sensible AFR as long as your tune isn't crap so no clogging from overly rich mixtures. They're a sufficient distance from the engine that they won't be damaged from heat.

Do you have any evidence of the good gains and throttle response above 4000rpm from removing the secondary cats?

Not saying it doesnt but don't waste your time trying to argue this guy's theories, he's been bumping old threads all day cause he took a video of his N52 making some noise

LMB335IS · 02-22-2017, 08:48 AM

Quote:

Originally Posted by ian3924

Not saying it doesnt but don't waste your time trying to argue this guy's theories, he's been bumping old threads all day cause he took a video of his N52 making some noise

Calling them theories is giving way too much credit. #alternativefacts

studio54 · 03-05-2020, 05:19 PM

Thread revival for people running catless dp with OEM midcats.

I know that we are numerous still running OEM midcats with tune (MHD Stage 2/2+ or custom) for multiple years and many miles now.

Any concern? (my concern is that it could be partially plugged, if it's totally plugged, i guess you can not reach boost target and it became obvious)

I would like to check mine without disassembling/cutting them, i don't know what is the best way.

I thought about the vacuum gauge test, but it's turbo, so it's probably better to disable turbo operation first by unplugging vacuum canister, so wastegates open, and measure vacuum at the intake manifold at idle and at 2500rpm steady for 30sec on warm engine.

If anyone want to make the test with me, so we can compare our value it could be helpful.
(even people fully catless, it could be a good way to see exhaust restriction difference between cat and no cat)

Any better idea to check them is appreciated too.

There is also probably some way to check them with reading logs, like AFRs ? but i am not expert with those values.

10-09-2015, 03:09 PM	#27
Stucks Lieutenant Colonel 172 Rep 1,910 Posts Drives: 2017 F30 340i Xdrive Join Date: Oct 2010 Location: Montgomery County, MD iTrader: (12)	Earlier this week, i cut my stock secondary cats out and welded in some 100 cell high flow metallic cats from MBS. Didnt take any pics of the stock cats, but when held up to light, you could not really see through them. the 100 cells.....light passes right through lol. also, there is a lot more "backspool" noise as you let off the gas and the rpms are floating back down to idle after a rev. just cruising around, the car remains just as quiet as it did with the stock secondaries in there, and up top there is maybe a little bit more power. a lot less torque down low due to the freed up exhaust and less backpressure it seems. my car has 102k miles on it, fwiw. __________________ Current: 2017 F30 340i xdrive Previous: 2008 e92 335i coupe: RB turbos, mach 116 race fuel, methanol, alot of boost. Previous: 2003 Honda Accord V6 coupe: AEM V2, zex 75 wet shot (sold)
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10-24-2015, 12:56 PM	#32
nitehawk Lieutenant Colonel 102 Rep 1,903 Posts Drives: e92 335i 6MT Join Date: May 2011 Location: Toronto iTrader: (15) Garage List E92 BMW 335i [9.00] E92 BMW 335i \| Retired [10.00]	Stucks marcvtec Any increase in exhaust smell from running the HFC's?
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10-25-2015, 09:58 PM	#35
Milan Captain 202 Rep 649 Posts Drives: F80 M3 Join Date: May 2014 Location: Boise, ID iTrader: (7)	LOL at losing TQ from less back pressure on a turbo car
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02-21-2017, 12:22 PM	#37
STR8-6IX Banned 537 Rep 2,825 Posts Drives: RWD 528i N52 Join Date: Nov 2016 Location: Toronto iTrader: (0)	best to just take those out before they shit themselves.. good engine sound, deeper exhaust tone and good gains+ throttle response above 4000RPM.
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03-05-2020, 05:19 PM	#44
studio54 Captain 202 Rep 713 Posts Drives: n54 Join Date: Feb 2017 Location: belgium iTrader: (0)	Thread revival for people running catless dp with OEM midcats. I know that we are numerous still running OEM midcats with tune (MHD Stage 2/2+ or custom) for multiple years and many miles now. Any concern? (my concern is that it could be partially plugged, if it's totally plugged, i guess you can not reach boost target and it became obvious) I would like to check mine without disassembling/cutting them, i don't know what is the best way. I thought about the vacuum gauge test, but it's turbo, so it's probably better to disable turbo operation first by unplugging vacuum canister, so wastegates open, and measure vacuum at the intake manifold at idle and at 2500rpm steady for 30sec on warm engine. If anyone want to make the test with me, so we can compare our value it could be helpful. (even people fully catless, it could be a good way to see exhaust restriction difference between cat and no cat) Any better idea to check them is appreciated too. There is also probably some way to check them with reading logs, like AFRs ? but i am not expert with those values.
	Appreciate 0 Quote