BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i)
 





 

Post Reply
 
Thread Tools Search this Thread
      02-27-2015, 07:28 PM   #1
neverdone
Major
Canada
182
Rep
1,232
Posts

Drives: X1 35i
Join Date: Jun 2014
Location: calgary

iTrader: (0)

building my own exhaust 128i

I'm a welder by trade but I've never made an exhaust and the 1er will be my first project. I'm just going to do a cat back just to get a bit of noise. My question is, what size pipe should I use and what muffler should I look at for a DIY?

I haven't even looked under the car yet to see what I'm getting into, it might just be mostly bending and clamps for all I know. Anything else I should know before I go ahead with this?
Appreciate 0
      02-27-2015, 08:20 PM   #2
SayHack
Private First Class
SayHack's Avatar
United_States
31
Rep
127
Posts

Drives: 2008 BMW 128i
Join Date: Feb 2013
Location: Los Angeles, CA

iTrader: (0)

Garage List
2008 BMW  [0.00]
I once had a 95 M3, and took it to an exhaust shop (keep in mind I was 18 back then) and the guy suggested he make me a custom catback, with a single 2.75 inch pipe, attached to an adopter to connect to factory cats. And the tip was "DTM" stile, with dual titanium tips. I know it sounds horrible, but a lot of people (including people with e36 M3 that were in their mid to late 30s) asking me what exhaust I had on that because it sounded so "bad a$$). My dad used to tell me that he can hear me downshifting from a block away. I am not sure how loud you want it to be, but N51/N52 engines are very similar to the s50 in the e36 M3. Just throwing it out there.

Last edited by SayHack; 03-01-2015 at 03:15 PM..
Appreciate 0
      03-02-2015, 05:41 PM   #3
Taskmaster
Banned
Japan
2306
Rep
9,158
Posts

Drives: M235i 6MT / E92 328 Msport 6MT
Join Date: Nov 2013
Location: Florida

iTrader: (6)

Single 3" With muffler and resonator in line.
Appreciate 0
      03-02-2015, 07:51 PM   #4
neverdone
Major
Canada
182
Rep
1,232
Posts

Drives: X1 35i
Join Date: Jun 2014
Location: calgary

iTrader: (0)

What muffler should I use?
Appreciate 0
      03-02-2015, 09:00 PM   #5
Tchao
Boost Addict
Tchao's Avatar
United_States
224
Rep
329
Posts

Drives: E30, E82, F30
Join Date: Feb 2015
Location: Charleston

iTrader: (0)

All modern (24v) BMW inline 6's needs resonator(s) if you want it to sound good.
If you're staying naturally aspirated, 2.50" is plenty plenty big.

Keep emissions in mind if you're doing a full exhaust.
Even if you aren't restrained by emissions, you want a high flow cat (100-200cell) if you don't want your car to smell like an old lawn mover.

After some headers...
I plan to to keep my OEM secondaries then Y pipe them to a single 2.50" with

Option A:
Two inline magnaflow universal muffs as resonators.

Option B:
A single dynomax turbo muffler as resonator.

Then a Vibrant stainless as the final muffler.

Just tossing some ideas around.
Appreciate 0
      03-02-2015, 09:03 PM   #6
631twentyeighteye
Colonel
631twentyeighteye's Avatar
United_States
168
Rep
2,265
Posts

Drives: 08 335i
Join Date: Aug 2012
Location: Long island

iTrader: (7)

If i ever get around to do the full exhaust(headers back), i want to try a big ol resonator like a cherrybomb to take out most of the rasp. And then just straight pipe to the tips. If that's too loud i'll add in a muffler before the exhaust tips.
__________________
08 e93 335i MT
Appreciate 0
      03-04-2015, 11:15 AM   #7
mike@x-ph.com
Joint Chiefs of Staff
mike@x-ph.com's Avatar
United_States
9930
Rep
110,069
Posts

Drives: 2007 e92 335i / 2013 F30 328
Join Date: Sep 2013
Location: Las Vegas

iTrader: (19)

Good luck and let us know how it goes
Appreciate 0
      03-04-2015, 02:50 PM   #8
andrey_gta
Brigadier General
andrey_gta's Avatar
Canada
255
Rep
4,053
Posts

Drives: 130i coupé ;)
Join Date: Nov 2011
Location: Bimmerpost

iTrader: (1)

Garage List
2008 BMW 128i  [5.00]
There was a thread here that referenced a Nissan 350z NA build exhaust.
The best result used stepped headers into a stepped exhaust was described as the following ms paint attempt:
Name:  NA exhaust.png
Views: 268
Size:  1.4 KB
The Muffler section was a 5 inch long trumpet section that was a curve, unlike the linear diagram. The article argued that the curved design had some gain over a linear, but for production a linear is easier.

Also there is a formula to capture drone and calculate placement of a resonator to capture the sound wave
__________________
128i Sport 6MT converted to Euro 130i spec, 3.73 diff, tuned by evolve ~220 whp 207 wtq(ft-lb) SAE
In-progress: //M front arm, M3 rack, e36M lip Wishlist: Coils, n55 mnts, headers, LSD, e60 finn diff


"The 1-series is the last car that BMW engineered before the Germans, as a car-making culture, fell out of love with driving." - R&T 2013 135is
Appreciate 0
      03-04-2015, 03:55 PM   #9
Taskmaster
Banned
Japan
2306
Rep
9,158
Posts

Drives: M235i 6MT / E92 328 Msport 6MT
Join Date: Nov 2013
Location: Florida

iTrader: (6)

Quote:
Originally Posted by andrey_gta View Post
There was a thread here that referenced a Nissan 350z NA build exhaust.
The best result used stepped headers into a stepped exhaust was described as the following ms paint attempt:
Attachment 1167580
The Muffler section was a 5 inch long trumpet section that was a curve, unlike the linear diagram. The article argued that the curved design had some gain over a linear, but for production a linear is easier.

Also there is a formula to capture drone and calculate placement of a resonator to capture the sound wave
I posted that:

http://www.e90post.com/forums/showthread.php?t=964717
The trumpet changes the way the exhaust diffuses energy causing a slight power gain.


And if it where me, a Magnaflow or Borla muffler. If you aren't keeping the stock headers, consider adding in a inline high flow cat. Go with 3" piping for maximum gains (even though the piping after the Y pipe doesn't matter in terms of peak) too small a pipe can reduce peak.
Appreciate 0
      03-05-2015, 08:05 AM   #10
andrey_gta
Brigadier General
andrey_gta's Avatar
Canada
255
Rep
4,053
Posts

Drives: 130i coupé ;)
Join Date: Nov 2011
Location: Bimmerpost

iTrader: (1)

Garage List
2008 BMW 128i  [5.00]
Quote:
Originally Posted by TheAxiom View Post
I posted that:

http://www.e90post.com/forums/showthread.php?t=964717
The trumpet changes the way the exhaust diffuses energy causing a slight power gain.
Excellent, Thanks for linking
__________________
128i Sport 6MT converted to Euro 130i spec, 3.73 diff, tuned by evolve ~220 whp 207 wtq(ft-lb) SAE
In-progress: //M front arm, M3 rack, e36M lip Wishlist: Coils, n55 mnts, headers, LSD, e60 finn diff


"The 1-series is the last car that BMW engineered before the Germans, as a car-making culture, fell out of love with driving." - R&T 2013 135is
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 04:35 PM.




1addicts
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST