Is there such a thing as too big of an exhaust? - Ford Powerstroke Diesel Forum
Please Visit our Site Sponsors
Powerstroke.org is the premier Diesel Truck Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 08-27-2012, 01:22 PM
Compression Ignition Addict
 

Join Date: May 2011
Location: Alvarado, TX
Posts: 248
Feedback Score: 0 reviews
Is there such a thing as too big of an exhaust?

Looking at exhaust systems and trying to decide whether I should go 4" or 5".

In a turbo application back pressure /scavanging is not really a concern.

Does it really come down to a sound preference? 5" can lower EGT's a bit more correct?

Thanks,
Rascal
Reply With Quote
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-27-2012, 01:54 PM
Compression Ignition Addict
 

Join Date: Nov 2009
Posts: 185
Feedback Score: 0 reviews
Usually larger pipes will lower egts. You can go too big though, the velocity of the exhaust gasses are important too. What do you have done to your truck? Do you have future upgrade plans?
Reply With Quote
  #3 (permalink)  
Old 08-27-2012, 01:55 PM
Premium Member


 

Join Date: Dec 2011
Location: Spokane, WA
Posts: 11,944
Feedback Score: 5 reviews
I wish I would have gone with a 5"....

They sound Sick
Reply With Quote
  #4 (permalink)  
Old 08-28-2012, 04:47 AM
Banned
 

Join Date: Sep 2008
Location: Fort Bragg, NC/Buff, NY/Midlothian, VA
Posts: 5,630
Feedback Score: 0 reviews
No you cant go "too big" on an exhaust. The bigger the better. Deeper sound, louder turbo, more responsive turbo, lower egt's. This is exacerbated with more modifications, also.
Reply With Quote
  #5 (permalink)  
Old 08-28-2012, 04:51 AM
Premium Member

 

Join Date: Jun 2012
Location: Trinidad Colorado ,USA
Posts: 1,572
Feedback Score: 0 reviews
5" and LUVIT....and yes you can go to big but 5 is not too big
Reply With Quote
  #6 (permalink)  
Old 08-28-2012, 04:56 AM
Banned
 

Join Date: Sep 2008
Location: Fort Bragg, NC/Buff, NY/Midlothian, VA
Posts: 5,630
Feedback Score: 0 reviews
Quote:
Originally Posted by kinnisoj View Post
and yes you can go to big but 5 is not too big
Maybe in your opinion of the sound quality, but in terms of technicalities, there is no "too big".
Reply With Quote
  #7 (permalink)  
Old 08-28-2012, 05:50 AM
Compression Ignition Addict
 

Join Date: May 2011
Location: Alvarado, TX
Posts: 248
Feedback Score: 0 reviews
Quote:
Originally Posted by Jrz13 View Post
Usually larger pipes will lower egts. You can go too big though, the velocity of the exhaust gasses are important too. What do you have done to your truck? Do you have future upgrade plans?
Nothing really yet. When I got the truck it was bone stock minus someone cutting th muffler out and replacing with straight pipe.

I plan to do some intake/exhaust/intercooler mods to help her breathe better. Maybe one day I will upgrade turbo/injectors/valve train but for now I want to keep her as dependable as possible.

Thanks,
Rascal
Reply With Quote
  #8 (permalink)  
Old 08-28-2012, 07:10 AM
Compression Ignition Addict
 

Join Date: Oct 2011
Location: Dover
Posts: 1,576
Feedback Score: 0 reviews
Quote:
Originally Posted by 85_305 View Post
Maybe in your opinion of the sound quality, but in terms of technicalities, there is no "too big".
Yes you can go to big technically. You seem to spread a lot of info that is just hear say or bad.

If the pipe is too big, the air inside will get lazy (slow down) and actually create resistance. This is why "velocity" was mentioned.
Reply With Quote
  #9 (permalink)  
Old 08-28-2012, 07:20 AM
Banned
 

Join Date: Sep 2008
Location: Fort Bragg, NC/Buff, NY/Midlothian, VA
Posts: 5,630
Feedback Score: 0 reviews
Quote:
Originally Posted by Turbostang500 View Post
Yes you can go to big technically. You seem to spread a lot of info that is just hear say or bad.

If the pipe is too big, the air inside will get lazy (slow down) and actually create resistance. This is why "velocity" was mentioned.
Really? So what size is "too big" then, where the numbers begin to reflect upon your statement?

A turbo diesel doesn't need "velocity"... theres a fat ****ing garrett turbo pushing the exhaust out


A turbo wants the least amount of resistance and restriction in the path of the intake and exhaust. Why do you think sled pullers run a filter clamped to the turbo and the biggest exhaust they can fit with the shortest path routed?


Here's a nice little article written by a former Garrett development engineer, on how scavenging and velocity theory goes out the window with a turbo:
http://www.tercelreference.com/terce...st_theory.html






Next time think twice before you attempt to slander somebody

Last edited by 85_305; 08-28-2012 at 07:35 AM.
Reply With Quote
  #10 (permalink)  
Old 08-28-2012, 07:45 AM
Compression Ignition Addict
 

Join Date: Oct 2011
Location: Dover
Posts: 1,576
Feedback Score: 0 reviews
I can't give you an exact size because I don't know the math and it would depend on a lot of other factors.

Pulling trucks are a very different senerio! They are forcing a ton more air through the engine so they NEED larger exhaust to vent it all. Also, as you mentioned, these "pulling" exhaust are as short as possible. If you understood fluid dynamics you would also understand that the length of the pipe largely impacts flow velocity.

I didn't read your article so I don't know what was talked about. I am talking about velocity after the turbo.
Reply With Quote
Sponsored Links
Advertisement
 
Reply

Thread Tools
Display Modes

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
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -8. The time now is 10:08 AM.


Powered by vBulletin® Copyright ©2000 - 2013, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.5.2
Garage Plus, Vendor Tools vBulletin Plugins by Drive Thru Online, Inc.

vB.Sponsors