best exhaust for n54 135i? max gain and best noise

[aren]

I'm looking to get an axle-back or cat-back exhaust after installing my DP's today. Before I buy my axle-back or cat-back exhaust I wanted to know what are you favorite axle-back exhaust noise wise and performance wise.

And also sorry for the noob question but what is the difference between cat-back and axle-back?

[SV Concepts II]

It is hard to say which exhaust is "the best" because each person will have their own idea of what is best. A catback exhaust system is a full exhaust system that stretches from the cats down to the rear exhaust tips. An axleback exhaust system is just the rear section of the exhaust or muffler portion. Berk exhaust makes a nice full exhaust system. Active Autowerke also makes a really nice sounding axleback exhaust system. It all depends on what sounds the nicest to you. Here is a video of AKopp's 135i with the Berk exhaust and ar DP's.

[1speedbike]

The 135i exhaust is sectioned into three. The downpipes, the midpipes, and the muffler or axleback. The axleback is the section from right about where the rear axle is, all the way back to the tips.

"Cat-back" refers to the midpipes and the axleback, either as one unit or separate, because this section of the exhaust starts from the catalytic converters (the downpipes) and runs back to the tips of the exhaust.

"Turbo-back" is similar. It includes pretty much the whole exhaust. It starts at the turbos, which leads directly to the downpipes, and then to the midpipes and axleback.

An axleback by itself will run you in the neighborhood of 500 bucks, possibly a little more, if you get one of the popular ones. Berk, aFe, Maddad, and many others make reasonably priced axlebacks. Of course there are the more expensive brands, many of which offer quad-tips, etc. But all of these more reasonably priced axlebacks sound absolutely great, and I fell in love with the Berk exhaust sound, so that's what I bought. Berk and Maddad make midpipes (others do as well, but they're the most popular), so buying a set of midpipes and an axleback will get you a "catback" exhaust. You can either buy them matched (Maddad midpipes and axleback, or Berk midpipes and axleback) or mix and match to your liking.

Downpipes will net you the most gains. Replacing the midpipes will net you slight gains since you're getting rid of the resonator and the two secondary cats, and upgrading the axleback (really, removing or upgrading the muffler) will probably net you 5 horsepower at most and is really done mostly for sound. The bigger the downpipe(s), the greater your gains will be, because you will have much more room for the air leaving the turbos which allows them to breathe a lot better. By the time the air gets to the axleback, it won't be nearly as fast or turbulent, so freeing up that section of the exhaust has the least gains. And as I said, the midpipes will net you moderate gains, especially in a 2008 N54 car since there are secondary cats in the midpipes for those cars and removing those cats will get rid of some restriction. I see you have a 2008, so in my humble opinion, AR Design and Macht Schnell make the best 3" downpipes, while Raceland makes decent quality 2.5" downpipes for a much cheaper price.

Hope this helps!

[andnkuhn]

wonderful post ^

[Eyeman]

I definitely prefer the MadDad stuff. Get the Whisper if you want it more civilized, the Street if you want slightly better gains and want it noisier. Add MadDad midpipes if you don't mind being completely catless and want even more gains.

[eric@helix]

Originally Posted by 1speedbike

The 135i exhaust is sectioned into three. The downpipes, the midpipes, and the muffler or axleback. The axleback is the section from right about where the rear axle is, all the way back to the tips.

"Cat-back" refers to the midpipes and the axleback, either as one unit or separate, because this section of the exhaust starts from the catalytic converters (the downpipes) and runs back to the tips of the exhaust.

"Turbo-back" is similar. It includes pretty much the whole exhaust. It starts at the turbos, which leads directly to the downpipes, and then to the midpipes and axleback.

An axleback by itself will run you in the neighborhood of 500 bucks, possibly a little more, if you get one of the popular ones. Berk, aFe, Maddad, and many others make reasonably priced axlebacks. Of course there are the more expensive brands, many of which offer quad-tips, etc. But all of these more reasonably priced axlebacks sound absolutely great, and I fell in love with the Berk exhaust sound, so that's what I bought. Berk and Maddad make midpipes (others do as well, but they're the most popular), so buying a set of midpipes and an axleback will get you a "catback" exhaust. You can either buy them matched (Maddad midpipes and axleback, or Berk midpipes and axleback) or mix and match to your liking.

Downpipes will net you the most gains. Replacing the midpipes will net you slight gains since you're getting rid of the resonator and the two secondary cats, and upgrading the axleback (really, removing or upgrading the muffler) will probably net you 5 horsepower at most and is really done mostly for sound. The bigger the downpipe(s), the greater your gains will be, because you will have much more room for the air leaving the turbos which allows them to breathe a lot better. By the time the air gets to the axleback, it won't be nearly as fast or turbulent, so freeing up that section of the exhaust has the least gains. And as I said, the midpipes will net you moderate gains, especially in a 2008 N54 car since there are secondary cats in the midpipes for those cars and removing those cats will get rid of some restriction. I see you have a 2008, so in my humble opinion, AR Design and Macht Schnell make the best 3" downpipes, while Raceland makes decent quality 2.5" downpipes for a much cheaper price.

Hope this helps!

This.

[JefryHorizon]

Originally Posted by 1speedbike

The 135i exhaust is sectioned into three. The downpipes, the midpipes, and the muffler or axleback. The axleback is the section from right about where the rear axle is, all the way back to the tips.

"Cat-back" refers to the midpipes and the axleback, either as one unit or separate, because this section of the exhaust starts from the catalytic converters (the downpipes) and runs back to the tips of the exhaust.

"Turbo-back" is similar. It includes pretty much the whole exhaust. It starts at the turbos, which leads directly to the downpipes, and then to the midpipes and axleback.

An axleback by itself will run you in the neighborhood of 500 bucks, possibly a little more, if you get one of the popular ones. Berk, aFe, Maddad, and many others make reasonably priced axlebacks. Of course there are the more expensive brands, many of which offer quad-tips, etc. But all of these more reasonably priced axlebacks sound absolutely great, and I fell in love with the Berk exhaust sound, so that's what I bought. Berk and Maddad make midpipes (others do as well, but they're the most popular), so buying a set of midpipes and an axleback will get you a "catback" exhaust. You can either buy them matched (Maddad midpipes and axleback, or Berk midpipes and axleback) or mix and match to your liking.

Downpipes will net you the most gains. Replacing the midpipes will net you slight gains since you're getting rid of the resonator and the two secondary cats, and upgrading the axleback (really, removing or upgrading the muffler) will probably net you 5 horsepower at most and is really done mostly for sound. The bigger the downpipe(s), the greater your gains will be, because you will have much more room for the air leaving the turbos which allows them to breathe a lot better. By the time the air gets to the axleback, it won't be nearly as fast or turbulent, so freeing up that section of the exhaust has the least gains. And as I said, the midpipes will net you moderate gains, especially in a 2008 N54 car since there are secondary cats in the midpipes for those cars and removing those cats will get rid of some restriction. I see you have a 2008, so in my humble opinion, AR Design and Macht Schnell make the best 3" downpipes, while Raceland makes decent quality 2.5" downpipes for a much cheaper price.

Hope this helps!

Truly detailed write up. I went the Raceland hit or miss route and have to say I should have went with VSRF(well priced) ARs, or MS.

[dwilli]

I would also like to know what the Active Autowerke down pipes are like...?

I just went back into an 08 135i. I did the whole car with Stage 3 Dinan throughout, I just now need to figure out 3 things:

1) down-pipes
2) mid-pipe
3) best limited-slip

PS. I came back after owning an 08 M3...

[uberschnell]

I've been running Berk midpipes with stock DP and axle back. Results are a very exotic sound on throttle with no increase in interior noise and no drone. Also slight bump in power since the it eliminates the mid cats.

[dwilli]

I would like some interior sound. I am coming from the S65 with high-flow cats and racing exhaust.

[dfv2]

I'm running catless VRSF downpipes, OEM mids and a Berk race axleback. It's pretty aggressive / quite loud. The OEM mids cut down on the rasp pretty effectively and it has a great tone. I decided not to touch the mids now as I can't really imagine it "better", which is quite subjective.

[Colt]

IMO, I think Berk Street Full Exhaust has the best rumble while still having a civilized tone for a DD. Most likely the route I'm taking.

[ken1137]

IMO...AR DPs, Berk resonated mid pipes, and Berk Street Performance Exhaust is the best combo for DD. That said, the HPF catback is the best sound imo, but too loud for me on a DD.

[Harlequin]

I've got the Berk Race Axle back on my N55 (No mid-pipe cats). it definitely gets looks

[RimasRS]

Meistershaft unbeatable sound

[Flash237]

Best midpipes?

[DPL8]

Originally Posted by dfv2

I'm running catless VRSF downpipes, OEM mids and a Berk race axleback. It's pretty aggressive / quite loud. The OEM mids cut down on the rasp pretty effectively and it has a great tone. I decided not to touch the mids now as I can't really imagine it "better", which is quite subjective.

How Loud is your exhaust at full throttle ? any Drone? do you backfire at all ?

[trickcruiser]

Berk was actually my first choice and had one ordered. Then a friend was parting out his car I he gave me a great deal on the RPI.

I am very partial to my RPI/AR combo.

Best thing that I have that demo's the sound inside the car.

[DFWsCars]

I'll weight in 5 years late, with saying the AFE is great. Haven't done exhaust specific video yet, but assuming the BMW did make say 300, 305 at crank, I really did get the 10 HP they promised.

In case anyone was curious enjoy the sweet sounds (and learning how much power a 10 year old BMW makes):

[Cmoney135i]

nvm can't read

[mike@x-ph.com]

My favorites are Active Autowerke and Cors

[Jeff@TopGearSolutions]

+1 on Corsa