Axelback vs Catback

Harper55987 · 06-14-2013, 08:38 AM

Looking at some of the Berk exhausts and I'm torn between axelback vs. catback/full performance.

Performance wise, will an axelback give any real benefits to an N54 or do I need downpipes back to really get a good increase?

My thought is to go in on the Berk Group by for axelback and then replace my mids with N55 mids later on.

Does this make sense or am I missing a part of the exhaust in here?

c_ozanich · 06-14-2013, 09:14 AM

Exhaust is broken down into 3 sections, downpipe (DP)--mid pipe (mids)--and axle back.

DP give you the most horse power, typically are one of the first things done to our cars because it reduces temperature in the turbo housing and improves exhaust flow. They come with and without catalytic converters (catted and catless) and in various sizes and makes. Most are around 3.5"-4" but some go up to 5"

HP Gains: 12-20 depending on other mods
Brands considered good/popular by the forum: AR Design, Berk, VRSF, BMS

Mids are the section in between the DP and the axle back, stock the n54 has resonators that restrict flow. A popular upgrade is to buy n55 mids which do not have these resonators and give a more pure engine sound. Upgrading mids to aftermarkets of some kind are where the exotic, high power sounds come from. Typically resonators are slightly longer and are dyno tested for flow and power and utilize larger diameter piping when compared to stock (2.5" to 3")

HP Gains: 5-10 depending on other mods
Brands forum considers good: Berk, Maddad, N55 Upgrade

Axle Back is where the most sound comes from in terms of changing the exhaust note/pitch/tone. The power gains are negligible but the sounds typically cause more excitement driving so its a trade off.

HP Gains: 2-5 depending on other mods
Brands forum considers good: Just about any, its personal preference for sound.

I personally bought a 4" catless AR Design DP first, but that alone made the car too loud for my taste. Power increase was great but wasn't worth the noise in my opinion. I bought Berk mids next, they took care of all sound issues, eliminated any drone, and gave the car a crisp, smooth, exotic note. If I had to do it again, the mids would be first. I don't have an axle back yet, I currently am using a JB4 to eliminate flapper (golf tee mod) and I am quite pleased with the current sound.

if all else fails, listen to these and pick someone to copy their set-up
http://www.1addicts.com/forums/showthread.php?t=211676

Happy Modding!

Harper55987 · 06-14-2013, 12:09 PM

Definitely been through that thread to many times

I am torn on doing the downpipes for a few reasons:
1. Smell
2. Noise
3. Wastegate rattle/tightness issues seem to happen if not done perfectly
4. I am not very mechanically inclined I can add/swap out them for visits or warranty work

The exhaust systems I have been going between are:
Berk Axleback + N55 midpipe
Maddad Whisperback catback
Maddad street sport

I am not a big fan of the loud, smelly exhausts. I want it to be nice and refined, bubbling at 1-3k RPM, and grow from there.

EDIT: I should note, I have a JB4 installed right now

c_ozanich · 06-14-2013, 01:03 PM

Quote:

Originally Posted by Harper55987

Definitely been through that thread to many times

I am torn on doing the downpipes for a few reasons:
1. Smell
2. Noise
3. Wastegate rattle/tightness issues seem to happen if not done perfectly
4. I am not very mechanically inclined I can add/swap out them for visits or warranty work

The exhaust systems I have been going between are:
Berk Axleback + N55 midpipe
Maddad Whisperback catback
Maddad street sport

I am not a big fan of the loud, smelly exhausts. I want it to be nice and refined, bubbling at 1-3k RPM, and grow from there.

EDIT: I should note, I have a JB4 installed right now

In all honesty, midpipes are what you are looking for. my dealer said he didn't have a problem with me replacing any piping... he basically gave me the go ahead on basic bolt ons. I've had work done since the DP and all he said was "what'd you do?" I replied with catless downpipe, he said it sounded good and then offered to clear the code from it. Wasn't an issue at all. Gotta talk to them and see what's good with them. Asking first makes a big difference rather than just showing up and complaining if they deny you anything. Up front is best. JB4 will void way more than piping will.

DP was loud but smell wasn't bad.

Harper55987 · 06-14-2013, 01:14 PM

Is there a big difference between:
Berk Axelback + N55 Midpipes
vs
Full Berk Street exhaust from downpipes back

Other then the top one saves me about $300 total I think.

c_ozanich · 06-14-2013, 01:29 PM

Quote:

Originally Posted by Harper55987

Is there a big difference between:
Berk Axelback + N55 Midpipes
vs
Full Berk Street exhaust from downpipes back

Other then the top one saves me about $300 total I think.

i'm saying to just buy midpipes and see how you like it. don't have to do it all at once

Harper55987 · 06-14-2013, 09:46 PM

I think I will take a look. A much cheaper place to start...

IN an exhaust system, can you help me understand resonators and mufflers and cat's.

My understanding is:
Resonator and muffler's are for noise really
Cat's are more for emission

Both of them can "technically" hurt performance, however, a cat is usually the most stubborn of those 3 and can reduce the most performance.

06-14-2013, 08:38 AM	#1
Harper55987 Private 17 Rep 63 Posts Drives: BMW 135i Join Date: Apr 2013 Location: Southeast Minnesota iTrader: (0)	Axelback vs Catback Looking at some of the Berk exhausts and I'm torn between axelback vs. catback/full performance. Performance wise, will an axelback give any real benefits to an N54 or do I need downpipes back to really get a good increase? My thought is to go in on the Berk Group by for axelback and then replace my mids with N55 mids later on. Does this make sense or am I missing a part of the exhaust in here?
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06-14-2013, 09:14 AM	#2
c_ozanich Mech Engr 81 Rep 565 Posts Drives: 2011 135i 6MT Join Date: Sep 2012 Location: Aiken SC iTrader: (0)	Exhaust is broken down into 3 sections, downpipe (DP)--mid pipe (mids)--and axle back. DP give you the most horse power, typically are one of the first things done to our cars because it reduces temperature in the turbo housing and improves exhaust flow. They come with and without catalytic converters (catted and catless) and in various sizes and makes. Most are around 3.5"-4" but some go up to 5" HP Gains: 12-20 depending on other mods Brands considered good/popular by the forum: AR Design, Berk, VRSF, BMS Mids are the section in between the DP and the axle back, stock the n54 has resonators that restrict flow. A popular upgrade is to buy n55 mids which do not have these resonators and give a more pure engine sound. Upgrading mids to aftermarkets of some kind are where the exotic, high power sounds come from. Typically resonators are slightly longer and are dyno tested for flow and power and utilize larger diameter piping when compared to stock (2.5" to 3") HP Gains: 5-10 depending on other mods Brands forum considers good: Berk, Maddad, N55 Upgrade Axle Back is where the most sound comes from in terms of changing the exhaust note/pitch/tone. The power gains are negligible but the sounds typically cause more excitement driving so its a trade off. HP Gains: 2-5 depending on other mods Brands forum considers good: Just about any, its personal preference for sound. I personally bought a 4" catless AR Design DP first, but that alone made the car too loud for my taste. Power increase was great but wasn't worth the noise in my opinion. I bought Berk mids next, they took care of all sound issues, eliminated any drone, and gave the car a crisp, smooth, exotic note. If I had to do it again, the mids would be first. I don't have an axle back yet, I currently am using a JB4 to eliminate flapper (golf tee mod) and I am quite pleased with the current sound. if all else fails, listen to these and pick someone to copy their set-up http://www.1addicts.com/forums/showthread.php?t=211676 Happy Modding!
	Appreciate 0 Quote

06-14-2013, 12:09 PM	#3
Harper55987 Private 17 Rep 63 Posts Drives: BMW 135i Join Date: Apr 2013 Location: Southeast Minnesota iTrader: (0)	Definitely been through that thread to many times I am torn on doing the downpipes for a few reasons: 1. Smell 2. Noise 3. Wastegate rattle/tightness issues seem to happen if not done perfectly 4. I am not very mechanically inclined I can add/swap out them for visits or warranty work The exhaust systems I have been going between are: Berk Axleback + N55 midpipe Maddad Whisperback catback Maddad street sport I am not a big fan of the loud, smelly exhausts. I want it to be nice and refined, bubbling at 1-3k RPM, and grow from there. EDIT: I should note, I have a JB4 installed right now
	Appreciate 0 Quote

06-14-2013, 01:14 PM	#5
Harper55987 Private 17 Rep 63 Posts Drives: BMW 135i Join Date: Apr 2013 Location: Southeast Minnesota iTrader: (0)	Is there a big difference between: Berk Axelback + N55 Midpipes vs Full Berk Street exhaust from downpipes back Other then the top one saves me about $300 total I think.
	Appreciate 0 Quote

06-14-2013, 09:46 PM	#7
Harper55987 Private 17 Rep 63 Posts Drives: BMW 135i Join Date: Apr 2013 Location: Southeast Minnesota iTrader: (0)	I think I will take a look. A much cheaper place to start... IN an exhaust system, can you help me understand resonators and mufflers and cat's. My understanding is: Resonator and muffler's are for noise really Cat's are more for emission Both of them can "technically" hurt performance, however, a cat is usually the most stubborn of those 3 and can reduce the most performance.
	Appreciate 0 Quote