Welcome to the world of Saab ! Register
Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1
    Saab Fan
    Join Date
    07 Dec 2015
    Location
    WA
    Posts
    7
    Saab(s)
    2001 9-5 Aero
    Thumbs Up:   0

    Performance exhaust sizes

    Does anyone know what's Saab's reasoning behind sticking to using 2 1/4" exhaust even in 260hp Aero?

    Sent from my HTC_0PJA10 using Tapatalk

    0 Not allowed!

  2. #2
    Saab Fan
    Join Date
    22 Feb 2013
    Location
    England
    Posts
    47
    Saab(s)
    99T 2 door, 9.5 Hirsch Aero
    Thumbs Up:   6
    I understand that it is the downpipe that makes the difference. The size of the remainder of the exhaust has no effect on performance. A friend of mine (SAAB garage owner and well known track driver) has a SAAB 9.3 track car with large downpipe, which has the standard exhaust fitted. Pushing out well over 400bhp it goes rather well, as many a Evo and Subaru owners will testify.

    0 Not allowed!

  3. #3
    neil dale
    viggen02
    Join Date
    25 Feb 2017
    Location
    US tucson Arizona
    Posts
    8
    Saab(s)
    2002 saab viggen cv
    Thumbs Up:   1
    Quite possibly correct it is a turbocharged engine consequently exhaust tuning is less important

    in a. Non turbocharged engine exhaust tuning is very important because the pulses leaving engine having gone down the pipe can help pull out those that follow

    Sent from my Coolpad 3622A using Tapatalk

    0 Not allowed!

  4. #4
    Saab Nut Digger's Avatar
    Join Date
    28 Oct 2016
    Location
    Minneapolis Minnesota
    Posts
    294
    Saab(s)
    2006 9-3 Wagon
    Thumbs Up:   66
    When it comes to free flowing exhaust a mandrel bent 2 1/4 in will give you better flow than a standard bent 2 1/2 in. A standard bent 2 1/2 in pipe will give you better flow than a standard bent 3 in pipe.

    When it comes to street legal the catalytic converter sets the flow.

    1 Not allowed!

  5. #5
    Saab Fan chalpkin's Avatar
    Join Date
    01 Oct 2016
    Location
    Mitcham, United Kingdom.
    Posts
    37
    Saab(s)
    2004 saab 93 Aero Saloon auto
    Thumbs Up:   1
    Quote Originally Posted by Digger View Post
    When it comes to free flowing exhaust a mandrel bent 2 1/4 in will give you better flow than a standard bent 2 1/2 in. A standard bent 2 1/2 in pipe will give you better flow than a standard bent 3 in pipe.

    When it comes to street legal the catalytic converter sets the flow.
    Are you sure a 2 1/2 inch exhaust will flow better than a 3 inch?

    Sent from my SM-G800F using Tapatalk

    0 Not allowed!

  6. #6
    Saab Nut Digger's Avatar
    Join Date
    28 Oct 2016
    Location
    Minneapolis Minnesota
    Posts
    294
    Saab(s)
    2006 9-3 Wagon
    Thumbs Up:   66
    Quote Originally Posted by chalpkin View Post
    Are you sure a 2 1/2 inch exhaust will flow better than a 3 inch?

    Sent from my SM-G800F using Tapatalk
    Absolutely certain.
    Only a mandrel bend will maintain inner diameter. The standard pipe bending machine as found at most custom exhaust shops makes a radios bend without inner wall support and when you make a right angle radios die bend in a 3 inch pipe, you end up with less flow than you would if you had used a 2 1/2. To have better flow with a 3 inch than a 2 1/2, every angle needs to be mandrel bent.

    1 Not allowed!

  7. #7
    Saab Fan chalpkin's Avatar
    Join Date
    01 Oct 2016
    Location
    Mitcham, United Kingdom.
    Posts
    37
    Saab(s)
    2004 saab 93 Aero Saloon auto
    Thumbs Up:   1
    Quote Originally Posted by Digger View Post
    Absolutely certain.
    Only a mandrel bend will maintain inner diameter. The standard pipe bending machine as found at most custom exhaust shops makes a radios bend without inner wall support and when you make a right angle radios die bend in a 3 inch pipe, you end up with less flow than you would if you had used a 2 1/2. To have better flow with a 3 inch than a 2 1/2, every angle needs to be mandrel bent.
    In your post, you say that a standard bent 2 1/2 inch exhaust will flow more than a standard bent 3 inch, Sorry, I beg to differ, the 3 inch will always move more gases in a comparable standard bent system!

    Sent from my SM-G800F using Tapatalk

    0 Not allowed!

  8. #8
    Saab Nut Digger's Avatar
    Join Date
    28 Oct 2016
    Location
    Minneapolis Minnesota
    Posts
    294
    Saab(s)
    2006 9-3 Wagon
    Thumbs Up:   66
    Quote Originally Posted by chalpkin View Post
    In your post, you say that a standard bent 2 1/2 inch exhaust will flow more than a standard bent 3 inch, Sorry, I beg to differ, the 3 inch will always move more gases in a comparable standard bent system!

    Sent from my SM-G800F using Tapatalk

    Mathematically you are absolutely correct, but we aren't talking about performance exhaust for a Mack Truck or a motor home where you have room for a four foot radios on a 90 degree bend.

    This is a link http://www.trick-tools.com/Huth_2008_Bender_HB2008_2282 to the type of bender found in most custom exhaust shops, this is the industry standard, top of the line, for custom automotive exhaust work and this does not do mandrel bends. Make a 90 degree bend in a piece of 3 inch, bend a piece of 2 1/2 to the same radios, turn on the fan and start making measurements.

    1 Not allowed!

  9. #9
    Saab Fan
    Join Date
    07 Dec 2015
    Location
    WA
    Posts
    7
    Saab(s)
    2001 9-5 Aero
    Thumbs Up:   0
    Quote Originally Posted by Digger View Post
    When it comes to free flowing exhaust a mandrel bent 2 1/4 in will give you better flow than a standard bent 2 1/2 in. A standard bent 2 1/2 in pipe will give you better flow than a standard bent 3 in pipe.

    When it comes to street legal the catalytic converter sets the flow.

    So, would it be safe (not the efficient, safe) to run a ~290hp tune on stock exhaust? The key hardware requirement for that amount of power is considered as the 3" downpipe but if the stock exhaust is going to flow better it should be fine?

    0 Not allowed!

  10. #10
    Saab Nut Digger's Avatar
    Join Date
    28 Oct 2016
    Location
    Minneapolis Minnesota
    Posts
    294
    Saab(s)
    2006 9-3 Wagon
    Thumbs Up:   66
    Quote Originally Posted by AeroV View Post
    So, would it be safe (not the efficient, safe) to run a ~290hp tune on stock exhaust? The key hardware requirement for that amount of power is considered as the 3" downpipe but if the stock exhaust is going to flow better it should be fine?
    That really depends on what you plan to do with the extra horsepower. Everybody has their own idea of normal driving, so if you plan to continue your normal driving with the occasional tromp on the foot feed for passing your exhaust should "safe" from frying your valves. If you're asking about red line racing, legal or street, that's a whole different dog.

    0 Not allowed!

 

 

Similar Threads

  1. sport combi performance exhaust
    By docman in forum Saab 9-5 (1998-2009)
    Replies: 12
    Last Post: 17 February 2016, 01:06
  2. Lets Talk Exhaust upgrade - Why Pay for a CAT BACK exhaust?????
    By Kenneth Pain in forum Saab 9-5 (1998-2009)
    Replies: 0
    Last Post: 03 September 2014, 20:26
  3. 2002 Saab 9-5 Aero (wagon) performance muffler/exhaust
    By cmrchrisrice in forum Saab 9-5 (1998-2009)
    Replies: 1
    Last Post: 20 June 2014, 15:56
  4. Need your help finding performance exhaust
    By Wats_SAAB in forum Saab 9-3 (2003-2014)
    Replies: 9
    Last Post: 03 March 2012, 18:37
  5. Why The Different Tire Sizes on Aero XWD?
    By CarbonFlash in forum Saab 9-3 (2003-2014)
    Replies: 4
    Last Post: 18 December 2010, 21:39

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
All times are GMT. The time now is 02:34.
Powered by vBulletin® Version 4.2.5
Copyright © 2017 vBulletin Solutions Inc. All rights reserved.