E90Post
 


TNT Racewerks
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N55 Turbo Engine Tuning and Exhaust Modifications - 335i Tuning > Is it worth it? best bang for buck? exhaust idea



Reply
 
Thread Tools Search this Thread
      11-20-2010, 07:08 PM   #45
Bakeme521
Some say...
Bakeme521's Avatar
United_States
81
Rep
4,272
Posts

 
Drives: Fresh
Join Date: Mar 2010
Location: Baton Rouge n NOLA

iTrader: (12)

Garage List
2007 BMW 335i  [4.04]
When did I say something contradictory? When I agreed to what he said about drag cars? B/c what he said was a true statement. Stock cars need a bit of backpressure to run correctly, b/c that is how they are designed. I'm pretty sure we are on agreeing terms I just do not agree with how you went about saying it with no facts to prove what you are saying. We do not need comments like that and I am tired of seeing people bash others about a topic, its stupid and immature.
__________________

I have exhaust and an intake...
Appreciate 0
      11-20-2010, 07:09 PM   #46
BrianMN
Colonel
43
Rep
2,429
Posts

 
Drives: 4 Door Family Sedan
Join Date: Sep 2009
Location: Minneapolis

iTrader: (7)

Techno- whatever you say dude
Appreciate 0
      11-21-2010, 09:42 AM   #47
techlogik
Major
20
Rep
1,339
Posts

 
Drives: 07 335i Coupe
Join Date: Dec 2006
Location: FL

iTrader: (1)

Quote:
Originally Posted by Bakeme521 View Post
When did I say something contradictory? When I agreed to what he said about drag cars? B/c what he said was a true statement. Stock cars need a bit of backpressure to run correctly, b/c that is how they are designed. I'm pretty sure we are on agreeing terms I just do not agree with how you went about saying it with no facts to prove what you are saying. We do not need comments like that and I am tired of seeing people bash others about a topic, its stupid and immature.
That was meant for BrainMN, but I was taking care of both responses in the one response I made, didn't come across that way.
__________________
SOLD: 2007 E92 335i Space Gray. Loaded. 6AT | GIAC Stage 1 w/map switcher 330rwhp/332tq | CX Racing IC | Drop-in Filter | Eibach Pro/Koni Yellows | M6 Reps | Toyo Proxes IV Tires, 235/35/19F-265/30/19R
Appreciate 0
      11-21-2010, 09:45 AM   #48
techlogik
Major
20
Rep
1,339
Posts

 
Drives: 07 335i Coupe
Join Date: Dec 2006
Location: FL

iTrader: (1)

Quote:
Originally Posted by gbreeE90 View Post
You do need a little bit of back pressure. But the main thing is, his exhaust sounds awesome, and its fully reversible


Ok, now we have you jumping in this discussion.

So then, explain the physics theory and how back pressure is needed and what the purpose it serves related to exhaust design?

My last post before this explains more, but I'm not doing physics research for you guys anymore. I posted enough of basic pressure theory and the well documented fact of 1HG of back pressure will reduce HP by 1HP.
__________________
SOLD: 2007 E92 335i Space Gray. Loaded. 6AT | GIAC Stage 1 w/map switcher 330rwhp/332tq | CX Racing IC | Drop-in Filter | Eibach Pro/Koni Yellows | M6 Reps | Toyo Proxes IV Tires, 235/35/19F-265/30/19R
Appreciate 0
      11-21-2010, 09:56 AM   #49
techlogik
Major
20
Rep
1,339
Posts

 
Drives: 07 335i Coupe
Join Date: Dec 2006
Location: FL

iTrader: (1)

Quote:
Originally Posted by BrianMN View Post
Techno- whatever you say dude
Haha...you just don't understand physics. You don't even know what a wastegate does.

Don't want to hijack the thread, but let's go over some basic 4-cycle engine theory.

At the point after air/fuel mixture is burnt, the piston then comes back up while the exhaust valve is open...known as the exhaust cycle.

So as the piston is rising, and it is now pushing air out the open exhaust valve.....here's the question...explain exactly how in terms of physics we want back pressure to push/work against the piston as this happens and why it is necessary?!?!?!

Of course we don't want any "back pressure" going against the piston and air as it is moving upward. That takes away power.

I just gave you the formula that 1HG of pressure is equal to 1HP.

So if you increase pressure by 1HG, you will lose 1HP...that is physics...nothing you can do or say about it as much as you want to come ans say I have no proof. That is your proof...

Why don't we have a 6" pipe for exhaust? Why stop there?? Because, as air expands, it slows!! Here again...physics. You need to test and design the optimum size of the exhaust to: 1) Reduce backpressurer; and 2) Increase velocity. Accomplishing this across the entire RPM range is the challenge due to those changing as engine RPM increased.

I'm not doing your physics research for you...I know the facts on pressure, exhaust design and velocity.

Just keep responding with "whatever you say" and continue on in your world.
__________________
SOLD: 2007 E92 335i Space Gray. Loaded. 6AT | GIAC Stage 1 w/map switcher 330rwhp/332tq | CX Racing IC | Drop-in Filter | Eibach Pro/Koni Yellows | M6 Reps | Toyo Proxes IV Tires, 235/35/19F-265/30/19R
Appreciate 0
      11-21-2010, 09:58 AM   #50
Forcefed3
Banned
No_Country
64
Rep
4,742
Posts

 
Drives: 2008 335i
Join Date: May 2010
Location: South

iTrader: (2)

Garage List
2008 335i  [0.50]
Ok, everyone stop posting. Techlogik is the smartest man alive.
Appreciate 0
      11-21-2010, 10:56 AM   #51
BrianMN
Colonel
43
Rep
2,429
Posts

 
Drives: 4 Door Family Sedan
Join Date: Sep 2009
Location: Minneapolis

iTrader: (7)

Techlogik- read my post last page. Typical non-performance and non-sophisticated engines need backpressure to run PROPERLY - the reason is NOT for more power or torque. Why do they new backpressure to run Properly? Because they are TUNED to run with the specific exhaust system and the specific backpressure. Our BMWs are smart enough to adapt a/f to changes in backpressure. Many cars (even nowadays) cannot adapt themselves well enough to compensate. Go back to carbureted engines- if you wanted to run with no headers, that would require significant tuning to run properly again. So how Does It run poorly if not tuned differently? Lean. What happens when you run too lean? Burnt exhaust valves. Case and point: high school, Hyundai Elantra GT loaner car, a buddy thought it would be funny to take the header completely off. Although it was so obnoxious it was funny, it not run properly at all. Further, upon return my friend was charged $2400 to replace the head due to burnt exhaust valves.
So, you are right in the sense backpressure is not good for performance, but if it is tuned to be there, it, needs to be there.

Bottom Line- eliminating all backpressure is not beneficial for all engines unless you tune it to accommodate.

Last edited by BrianMN; 11-21-2010 at 11:54 AM.
Appreciate 0
      12-07-2010, 07:46 PM   #52
jmkworld
Captain
14
Rep
626
Posts

 
Drives: 2011 335i xdrive
Join Date: Sep 2010
Location: Philly

iTrader: (3)

just did the muffler delete today. one word amazing! will have a video up probably tomorrow
Appreciate 0
      12-07-2010, 08:13 PM   #53
shockin330i
Brigadier General
59
Rep
4,206
Posts

 
Drives: blue
Join Date: Jan 2007
Location: f y'all, I'm from Texas (RGV)

iTrader: (1)

Quote:
Originally Posted by jmkworld View Post
just did the muffler delete today. one word amazing! will have a video up probably tomorrow
At least you have res on the pipes, mine doesn't.
__________________
ERnie 2011 AW/e90/n55 12.9@107.53mph
*N55 Moderator*
I'm crawling similar to a ant cuz I'm low to the earth
Appreciate 0
      12-07-2010, 08:40 PM   #54
Bakeme521
Some say...
Bakeme521's Avatar
United_States
81
Rep
4,272
Posts

 
Drives: Fresh
Join Date: Mar 2010
Location: Baton Rouge n NOLA

iTrader: (12)

Garage List
2007 BMW 335i  [4.04]
Quote:
Originally Posted by jmkworld View Post
just did the muffler delete today. one word amazing! will have a video up probably tomorrow
Sweet I can't wait to hear it.
__________________

I have exhaust and an intake...
Appreciate 0
      12-07-2010, 09:16 PM   #55
kcalhoun27
loves his turbos
4
Rep
225
Posts

 
Drives: coupe
Join Date: Oct 2009
Location: DE

iTrader: (5)

i just did my exhaust as well to match the quad diffusor. first muffler delete, realized it was way too loud and drony (sp?) and then ultimately just had magnaflows put on. i have no desire to pay the BMW tax for a mod that isnt going to help as im more interested in looks anyways. that, and i think it sounds wonderful the way it is now
Appreciate 0
      12-08-2010, 01:47 AM   #56
hipnotic
Major General
hipnotic's Avatar
United_States
76
Rep
6,572
Posts

 
Drives: e92 335i
Join Date: Oct 2007
Location: So. Cal

iTrader: (6)

Garage List
2008 335i coupe  [3.50]
muffler delete easy to do and reversible
Appreciate 0
      12-08-2010, 02:06 AM   #57
Rylen
Colonel
Rylen's Avatar
59
Rep
2,775
Posts

 
Drives: White 335i Sedan
Join Date: Dec 2008
Location: Orange County CA

iTrader: (2)

lol
Appreciate 0
      01-09-2011, 09:21 AM   #58
thinbev
proud BMW 335 owner
thinbev's Avatar
United_States
1
Rep
117
Posts

 
Drives: 2007 BMW 335i
Join Date: Jul 2006
Location: Highland Beach, FL

iTrader: (1)

only one way in my book and on my car, dimisa tips

www.dimisatips.com and they have the straight angle ones back!!!
Appreciate 0
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
Forum Jump


All times are GMT -5. The time now is 03:47 AM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
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