N55 midpipe swap to N54

startover · 09-14-2011, 02:24 PM

I have a N54 135i with completely stock factory exhaust. If I only want to swap out the midpipe (part number 18307559994 , which has cats) for a N55 midpipe (part number 18307599743, which has no cats):

Will the car have any drone or unwanted raspy noise?
Will the car have any bad smell?
Do I still have "resonators" on the car?

I'm new at this and the search results got me confused.

thebigragu99 · 09-14-2011, 05:13 PM

Quote:

Originally Posted by startover

I have a N54 135i with completely stock factory exhaust. If I only want to swap out the midpipe (part number 18307559994 , which has cats) for a N55 midpipe (part number 18307599743, which has no cats):

Will the car have any drone or unwanted raspy noise?
Will the car have any bad smell?
Do I still have "resonators" on the car?

I'm new at this and the search results got me confused.

Funny you asked that,I just deleted my mid cats yesterday and left the rear resonator with stock muffler..I'm running 3 inch downpipes catless with the modded up mids,and it sounds awesome..It's not loud at all it's aggressive only wot,and spools faster plus the turbo screem threw the muffler..P.s no smell do it the stock rear cats are restrictive..

135roller · 09-14-2011, 05:32 PM

i wonder if this is an legal processes, if it is, im really down to do this

icabod7 · 09-14-2011, 05:57 PM

I would imagine its legal -- I mean, if you buy a brand new 2012 135i they don't have cats in their midpipes so...

thebigragu99 · 09-14-2011, 06:40 PM

It's legal !!

135roller · 09-14-2011, 07:10 PM

thats sick, but itll fit to my downpipe and axle back right?

startover · 09-14-2011, 11:20 PM

Thanks for the answers but you guys all have other mods (down pipes and cat/axle backs etc) while I'm 100% stock. I want to know if it will sound ok with my setup.

135roller · 09-14-2011, 11:47 PM

Quote:

Originally Posted by startover

Thanks for the answers but you guys all have other mods (down pipes and cat/axle backs etc) while I'm 100% stock. I want to know if it will sound ok with my setup.

im 100% stock so ill be doing this as well

xerox445 · 09-14-2011, 11:57 PM

Anyone know if you can buy this from BMW?

Elsabor67 · 09-15-2011, 01:10 AM

Quote:

Originally Posted by 135roller

thats sick, but itll fit to my downpipe and axle back right?

Yes it will fit your Dp and axleback. I have one in my car right now.

Quote:

Originally Posted by startover

Thanks for the answers but you guys all have other mods (down pipes and cat/axle backs etc) while I'm 100% stock. I want to know if it will sound ok with my setup.

It will. Before I installed my first set of DP's all I had was a Berk tech. Street Perf. exhaust and it had a good mellow sound.

Quote:

Originally Posted by xerox445

Anyone know if you can buy this from BMW?

Should be able to. I wouldn't see why not.

startover · 09-15-2011, 01:41 AM

You can buy the N55 mid pipe from getbmwparts.com. It's only $337. If it can really free up just a little bit of power (say 8hp with a tune?) and improve the sound a little (close to how a N55 sounds), then it's probably one of the cheapest exhaust mods one can do.

RimasRS · 09-15-2011, 02:09 AM

Will there be any rasp with N54 engine? I want to go same way

Imo135 · 09-15-2011, 02:54 AM

1. Is there any HP gain on a vitually std car, (drop in filter and bmw perf exh)?
2. Has anyone done a before and after dyno run?

3. Would the set up look the same if you look under the n54?

4. Will codes ever appear and must the car be taken to bmw for clearing of codes?

Thanks guys, this mod is very new to me and I wouldlike todoit as it seems to comply with warranty and is/looks oem...

htt760 · 09-15-2011, 11:16 AM

Its exactly the same. Just used a different exhaust setup on the N54 N55, check out realoem.com to make sure

Dackelone · 09-15-2011, 11:27 AM

Quote:

Originally Posted by htt760

Its exactly the same. Just used a different exhaust setup on the N54 N55, check out realoem.com to make sure

errr... NOOP!

N54 mid pipes have secondardy cats.
N55 mid pipes have NO secondary cats!

N55 mid pipe...

rear N55 resonator... not much in there!

The diagram in RealOEM is not correct. They show a N54 diagram for the N55 as well. But the part numbers ARE different! RealOEM does list (the correct) different part numbers.

OneThreeFive · 09-15-2011, 11:33 AM

Quote:

Originally Posted by thebigragu99

Funny you asked that,I just deleted my mid cats yesterday and left the rear resonator with stock muffler..I'm running 3 inch downpipes catless with the modded up mids,and it sounds awesome..It's not loud at all it's aggressive only wot,and spools faster plus the turbo screem threw the muffler..P.s no smell do it the stock rear cats are restrictive..

Tempting.

Anyone else with this setup (CL Downpipes + the N55 mids)? Any additional comments?

thebigragu99 · 09-15-2011, 12:38 PM

Quote:

Originally Posted by OneThreeFive

Tempting.

Anyone else with this setup (CL Downpipes + the N55 mids)? Any additional comments?

I told someone else on a different thread that the rear resonator was not restricted and was straight threw!!The main restrictor is the rear cats on the mid pipes,and the stock primary cats on the d.p's..Just me man,I hate loud cars,but normal driving it's ultra quiet untill wot after that it sounds mean and clean sounding..My car also sounds like a mini diesel truck with a really loud whistle.I think the gains are 13 whp with the rear delete plus the rear muffler on the 1 is actually a resonator not a muffler.

Elsabor67 · 09-15-2011, 01:24 PM

Quote:

Originally Posted by OneThreeFive

Tempting.

Anyone else with this setup (CL Downpipes + the N55 mids)? Any additional comments?

Here's my example when I had Raceland DP's, N55 Mids and BT Street perf Exhaust. I now have AR Design catless, N55 Mids, and Berk Technology Street performance exhaust. I fail at the camera angle and closeness. If you want to know how loud it is, Ask Dackelone. He was rolling behind me on the way back from the 1er meet at the 'Ring....

Dackelone · 09-15-2011, 01:30 PM

[quote=Elsabor67;10426788]Here's my example when I had Raceland DP's, N55 Mids and BT Street perf Exhaust. I now have AR Design catless, N55 Mids, and Berk Technology Street performance exhaust. I fail at the camera angle and closeness. If you want to know how loud it is, Ask Dackelone. He was rolling behind me on the way back from the 1er meet at the 'Ring....

It was sooo loud(!) that when we drove thru that tunnel on the A3 Autobahn in Aschaffenburg (just before Frankfurt direction)... I had my windows UP and Nick was like 15 car lengths behind me. AND DAMM was his car loud when he went WOT in that tunnel!!! lol THAT was sooo funny!

I gotta install my N55 mid pipe - bc I think it really is the best poor man's PE (mod) out there. Getting rid of those secondary cats has GOT help the turbos spool up faster and make more of a whistling sound. Quite at part throttle cruising yet louder at WOT. Not anywhere near as loud as Nick's car though. So I hope.

thebigragu99 · 09-15-2011, 02:29 PM

[QUOTE=Dackelone;10426828]

Quote:

Originally Posted by Elsabor67

Here's my example when I had Raceland DP's, N55 Mids and BT Street perf Exhaust. I now have AR Design catless, N55 Mids, and Berk Technology Street performance exhaust. I fail at the camera angle and closeness. If you want to know how loud it is, Ask Dackelone. He was rolling behind me on the way back from the 1er meet at the 'Ring....

It was sooo loud(!) that when we drove thru that tunnel on the A3 Autobahn in Aschaffenburg (just before Frankfurt direction)... I had my windows UP and Nick was like 15 car lengths behind me. AND DAMM was his car loud when he went WOT in that tunnel!!! lol THAT was sooo funny!

I gotta install my N55 mid pipe - bc I think it really is the best poor man's PE (mod) out there. Getting rid of those secondary cats has GOT help the turbos spool up faster and make more of a whistling sound. Quite at part throttle cruising yet louder at WOT. Not anywhere near as loud as Nick's car though. So I hope.

Don't know about yours ,but my cat with no rear cats and 3 inch downpipes mkaes the whistle stupid loud..Are you running 3 or 2.5 downpipes?????

thebigragu99 · 09-15-2011, 02:32 PM

From looking at the pic ,the n54 mid pipe has less bends then the n55..WHat I had the guy do is cut the cats out,and make the pipe as straight as possible without issues.Yes I think this is the best sleeper exhaust and best sounding for the money.

Elsabor67 · 09-15-2011, 03:40 PM

Barely whistles. I have 3" AR Design catless. I'm gonna try to do a vid tomorrow on the way home from work since I can't find the one I did a couple of months ago when I changed to the AR Design.

09-14-2011, 02:24 PM	#1
startover Enlisted Member 11 Rep 33 Posts Drives: Join Date: Aug 2008 iTrader: (0)	N55 midpipe swap to N54 - will it drone? I have a N54 135i with completely stock factory exhaust. If I only want to swap out the midpipe (part number 18307559994 , which has cats) for a N55 midpipe (part number 18307599743, which has no cats): Will the car have any drone or unwanted raspy noise? Will the car have any bad smell? Do I still have "resonators" on the car? I'm new at this and the search results got me confused. Last edited by startover; 09-14-2011 at 02:31 PM..
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09-14-2011, 05:32 PM	#3
135roller Banned 37 Rep 1,169 Posts Drives: 135i black...stock ;) Join Date: Nov 2010 Location: Glendale, Ca iTrader: (3)	i wonder if this is an legal processes, if it is, im really down to do this
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09-14-2011, 05:57 PM	#4
icabod7 Second Lieutenant 18 Rep 254 Posts Drives: 2008 135i Coupe Join Date: Jun 2011 Location: Dallas iTrader: (0)	I would imagine its legal -- I mean, if you buy a brand new 2012 135i they don't have cats in their midpipes so... __________________ cdv delete \| clutch stop \| bmw performance ssk \| meisterschaft gt \| berk mids \| dinan cai \| helix fmic \| m3 subframe bushings, swaybar, front and back suspension bits \| dinan stage 1 suspension \| dinan cf strut brace \|gc camber plates \| dinan oil cooler \| apex ec-7s w/PSSs \| cobb stage 1 + fmic
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09-14-2011, 06:40 PM	#5
thebigragu99 Banned 45 Rep 828 Posts Drives: 135 tuorbbo Join Date: Aug 2011 Location: nyc iTrader: (1)	It's legal !!
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09-14-2011, 07:10 PM	#6
135roller Banned 37 Rep 1,169 Posts Drives: 135i black...stock ;) Join Date: Nov 2010 Location: Glendale, Ca iTrader: (3)	thats sick, but itll fit to my downpipe and axle back right?
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09-14-2011, 11:20 PM	#7
startover Enlisted Member 11 Rep 33 Posts Drives: Join Date: Aug 2008 iTrader: (0)	Thanks for the answers but you guys all have other mods (down pipes and cat/axle backs etc) while I'm 100% stock. I want to know if it will sound ok with my setup.
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09-14-2011, 11:57 PM	#9
xerox445 Damenslip-Tropfer 23 Rep 543 Posts Drives: 2008 SGM 135i Join Date: May 2011 Location: LBI, NJ iTrader: (1)	Anyone know if you can buy this from BMW?
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09-15-2011, 01:41 AM	#11
startover Enlisted Member 11 Rep 33 Posts Drives: Join Date: Aug 2008 iTrader: (0)	You can buy the N55 mid pipe from getbmwparts.com. It's only $337. If it can really free up just a little bit of power (say 8hp with a tune?) and improve the sound a little (close to how a N55 sounds), then it's probably one of the cheapest exhaust mods one can do.
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09-15-2011, 02:09 AM	#12
RimasRS Colonel 85 Rep 2,438 Posts Drives: BMW X3 SD Join Date: Sep 2010 Location: Europe iTrader: (0)	Will there be any rasp with N54 engine? I want to go same way
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09-15-2011, 02:54 AM	#13
Imo135 I dont drive fast,I just fly low.... 15 Rep 49 Posts Drives: Bmw 135is Join Date: Jan 2010 Location: South Africa iTrader: (0)	1. Is there any HP gain on a vitually std car, (drop in filter and bmw perf exh)? 2. Has anyone done a before and after dyno run? 3. Would the set up look the same if you look under the n54? 4. Will codes ever appear and must the car be taken to bmw for clearing of codes? Thanks guys, this mod is very new to me and I wouldlike todoit as it seems to comply with warranty and is/looks oem...
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09-15-2011, 11:16 AM	#14
htt760 PROcede it and Call it a DAY 17 Rep 167 Posts Drives: 2011 135i DCT, 2011 335i Join Date: Nov 2010 Location: California iTrader: (0)	Its exactly the same. Just used a different exhaust setup on the N54 N55, check out realoem.com to make sure
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09-15-2011, 01:30 PM	#19
Dackelone European Editor 10596 Rep 22,992 Posts Drives: N54 e82 Join Date: Feb 2010 Location: Bayern, Germany iTrader: (1)	[quote=Elsabor67;10426788]Here's my example when I had Raceland DP's, N55 Mids and BT Street perf Exhaust. I now have AR Design catless, N55 Mids, and Berk Technology Street performance exhaust. I fail at the camera angle and closeness. If you want to know how loud it is, Ask Dackelone. He was rolling behind me on the way back from the 1er meet at the 'Ring.... It was sooo loud(!) that when we drove thru that tunnel on the A3 Autobahn in Aschaffenburg (just before Frankfurt direction)... I had my windows UP and Nick was like 15 car lengths behind me. AND DAMM was his car loud when he went WOT in that tunnel!!! lol THAT was sooo funny! I gotta install my N55 mid pipe - bc I think it really is the best poor man's PE (mod) out there. Getting rid of those secondary cats has GOT help the turbos spool up faster and make more of a whistling sound. Quite at part throttle cruising yet louder at WOT. Not anywhere near as loud as Nick's car though. So I hope.
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09-15-2011, 02:32 PM	#21
thebigragu99 Banned 45 Rep 828 Posts Drives: 135 tuorbbo Join Date: Aug 2011 Location: nyc iTrader: (1)	From looking at the pic ,the n54 mid pipe has less bends then the n55..WHat I had the guy do is cut the cats out,and make the pipe as straight as possible without issues.Yes I think this is the best sleeper exhaust and best sounding for the money.
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09-15-2011, 03:40 PM	#22
Elsabor67 aiming for 450..... 304 Rep 2,910 Posts Drives: Totaled :-( Join Date: Feb 2009 Location: Louisiana iTrader: (28) Garage List 2009 135i [10.00]	Barely whistles. I have 3" AR Design catless. I'm gonna try to do a vid tomorrow on the way home from work since I can't find the one I did a couple of months ago when I changed to the AR Design. __________________ Quote from Ezeedee regarding car mods: "you're only done when you sell the car "
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