E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > Tuning & Tech > Driveline, Engine & DME Tuning

Driveline, Engine & DME Tuning
Talk about driveline improvements, NA tuning and DME tuning your E46 BMW here. This includes diffs, intakes, exhausts, chips, software and OBD tuning.

Reply
 
Thread Tools Search this Thread Rating: Thread Rating: 1 votes, 5.00 average. Display Modes
Old 02-22-2013, 04:15 PM   #1
Bino5150
Registered User
 
Join Date: Feb 2013
Location: Houston, TX
Posts: 175
My Ride: 99 323i
Question Anybody running single 2.5" exhaust?

From my experience with engines in this size and power range (Mazda KLZE; Nissan VG30), it just seems to me that 3" is a bit too big, and while it may net some peak hp way up top for the dyno queens, you will suffer mid to low torque. Usually on these size engines (2.5L, 6 cyl, 165-225 hp range) a single 2.5" is optimal, and we have actually suffered with too large of an exhaust. I know all engines are different, and I see a lot of people running these single 3" "race" exhausts, but I was curious to hear if anyone is running single 2.5"? Hell, I even see dual 2.5" exhausts, which should technically be way too big; that's what I ran on my twin turbo 300zx and my small block Chevy's.

I did the math on it, and a single 2.5" pipe will outflow (CFM) dual 1.75" pipes (stock, right?), and support ~275hp or so, plenty for my 323i, and I shouldn't lose my low-midrange torque.
Bino5150 is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 02-23-2013, 09:39 AM   #2
lcoleman
Registered User
 
Join Date: Mar 2007
Location: the barnyard
Posts: 2,458
My Ride: '79 Massey Ferguson
I am on the e30...I think with good extractors/headers, you'll be fine.
__________________
lcoleman is offline   Reply With Quote
Old 02-24-2013, 01:15 AM   #3
HakenTT
OEM ///Member
 
Join Date: Aug 2009
Location: gross deutsches reich USA
Posts: 526
My Ride: 323i with S54
Quote:
Originally Posted by Bino5150 View Post
From my experience with engines in this size and power range (Mazda KLZE; Nissan VG30), it just seems to me that 3" is a bit too big, and while it may net some peak hp way up top for the dyno queens, you will suffer mid to low torque. Usually on these size engines (2.5L, 6 cyl, 165-225 hp range) a single 2.5" is optimal, and we have actually suffered with too large of an exhaust. I know all engines are different, and I see a lot of people running these single 3" "race" exhausts, but I was curious to hear if anyone is running single 2.5"? Hell, I even see dual 2.5" exhausts, which should technically be way too big; that's what I ran on my twin turbo 300zx and my small block Chevy's.

I did the math on it, and a single 2.5" pipe will outflow (CFM) dual 1.75" pipes (stock, right?), and support ~275hp or so, plenty for my 323i, and I shouldn't lose my low-midrange torque.
Your 1999 323i already has 2.5 inch single exhaust
__________________
---------------------
Siemens tuning junkie
HakenTT is offline   Reply With Quote
Old 02-24-2013, 03:28 PM   #4
Bino5150
Registered User
 
Join Date: Feb 2013
Location: Houston, TX
Posts: 175
My Ride: 99 323i
Quote:
Originally Posted by HakenTT View Post
Your 1999 323i already has 2.5 inch single exhaust
Ah really, I guess I should go check... I just got the car and haven't crawled under it, but I thought all the E46's had the dual exhaust with a single muffler? If I do have the 2.5" single, then cool, I'll just change the muffler and resonator.
Bino5150 is offline   Reply With Quote
Old 02-24-2013, 03:36 PM   #5
325CiMaN
Registered User
 
Join Date: Aug 2012
Location: Napa, California
Posts: 380
My Ride: 01 BMW 325ci 3.0L
Quote:
Originally Posted by Bino5150 View Post
Ah really, I guess I should go check... I just got the car and haven't crawled under it, but I thought all the E46's had the dual exhaust with a single muffler? If I do have the 2.5" single, then cool, I'll just change the muffler and resonator.
I ran it on my 325Ci for a while and it was a big difference over stock, well according to butt dyno at least. I am now running headers with the full uuc tse3 exhaust, with a catco dual in dual out in place of the first set of resonators and boy it sounds mean as hell. But is also a 330 swap now so it's a little deeper tone

Sent from my DROID RAZR using Bimmer App

Last edited by 325CiMaN; 02-24-2013 at 03:37 PM.
325CiMaN is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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
Censor is OFF





All times are GMT -5. The time now is 04:33 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use