How short can a downpipe be? - SaabCentral Forums
* site search:  
Home Saab Pictures Saab Classifieds Saab Dealer Listings Saab Forum Saab Forum

Go Back   SaabCentral Forums > Saab Classic 900, 1979-1993 & '94 Convertible > Saab Classic 900 Performance, Mods & Tuning
Saab Classic 900 Performance, Mods & Tuning Covers Tuning & Performance modifications for the Classic Saab 900

SaabCentral.com is the premier Saab Forum on the internet. Registered Users do not see the above ads.
Reply
 
Thread Tools Display Modes
  #1  
Old 18-07-12
gustavm gustavm is offline
Saab Crazy
 
Join Date: Oct 2007                                                
Location: Newzealand
My Saabs: 1985 900spg Hillclimb car
Posts: 959
Question How short can a downpipe be?

Im getting a 3 inch dp done tommorow and Im wondering what the minimum length can be and still be effective . I was thinking only to the junction just behind the of the engine then back to standard exhaust which in my case is a resinator and 2 1/4 inch pipe through to a glasspack standard rear muffler with twin megaphone type tail pipes. Obviously later with funds availiable more 3 inch pipe could be added .BTW Battery is under the air intake pipe so a nice initial curve is not a problem

Last edited by gustavm; 18-07-12 at 05:59 AM.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 18-07-12
dmgb5's Avatar
dmgb5 dmgb5 is offline
dmgWarden
 
Join Date: May 2003                                                
Location: Portland, OR / Oxted, UK
My Saabs: '89 900 T16Spg, '97 9000 Aero
Posts: 2,144
Default

Umm...? Whats your objective here...i.e. what do you hope to gain from a 3" downpipe? What are your plans for the rest of the exhaust?
Reply With Quote Quick reply to this message
  #3  
Old 18-07-12
gustavm gustavm is offline
Saab Crazy
 
Join Date: Oct 2007                                                
Location: Newzealand
My Saabs: 1985 900spg Hillclimb car
Posts: 959
Default

To safely support about 12-14 lbs boost and increase spool up time . No big turbo or high horse power stuff . Id like to leave the rest fairly standard to keep that old fishing boat sound ! The guys are working on it at the moment and have decided to only go to the end of the engine block just after the hanger in 3 inch .Will give you all a report once Ive driven it.
Reply With Quote Quick reply to this message
  #4  
Old 19-07-12
dmgb5's Avatar
dmgb5 dmgb5 is offline
dmgWarden
 
Join Date: May 2003                                                
Location: Portland, OR / Oxted, UK
My Saabs: '89 900 T16Spg, '97 9000 Aero
Posts: 2,144
Default

Even just getting rid of the cast iron elbow would help with spool. So building it to the CAT/heat shield is plenty for what your after. Is the battery staying put or are you moving it for your downpipe?
Reply With Quote Quick reply to this message
  #5  
Old 19-07-12
gustavm gustavm is offline
Saab Crazy
 
Join Date: Oct 2007                                                
Location: Newzealand
My Saabs: 1985 900spg Hillclimb car
Posts: 959
Default

Battery is on the air intake side so no problem there.
Reply With Quote Quick reply to this message
  #6  
Old 20-07-12
gustavm gustavm is offline
Saab Crazy
 
Join Date: Oct 2007                                                
Location: Newzealand
My Saabs: 1985 900spg Hillclimb car
Posts: 959
Default

New DP . Seems to have done the trick . Pulls well from 1500 revs in 5th now.

Last edited by gustavm; 28-01-14 at 02:31 PM.
Reply With Quote Quick reply to this message
  #7  
Old 20-07-12
dmgb5's Avatar
dmgb5 dmgb5 is offline
dmgWarden
 
Join Date: May 2003                                                
Location: Portland, OR / Oxted, UK
My Saabs: '89 900 T16Spg, '97 9000 Aero
Posts: 2,144
Default

Thats shorter than I imagined but it should certainly do the trick. Is it stainless? Why is it painted black?
Reply With Quote Quick reply to this message
  #8  
Old 20-07-12
gustavm gustavm is offline
Saab Crazy
 
Join Date: Oct 2007                                                
Location: Newzealand
My Saabs: 1985 900spg Hillclimb car
Posts: 959
Default

Maybe to prevent corrosion ? Paul did the same thing on my 9000 3 inch DP I must check if its still black after a couple of years .Im sure its just ordinary steel . The engine revs more freely and the car seems lighter ! that has to be a good sign. I may continue the 3 inch pipe one day . Bilstein rear shocks next.

Last edited by gustavm; 20-07-12 at 04:31 AM.
Reply With Quote Quick reply to this message
  #9  
Old 20-07-12
Squaab99t's Avatar
Squaab99t Squaab99t is online now
Saab Lunatic
 
Join Date: Jul 2005                                                
Location: Shoreline Wa USA
My Saabs: '89 900t 4dr'78 99t'76 99 16vt'11 9-3
Posts: 1,004
Default

Quote:
Originally Posted by gustavm View Post
Maybe to prevent corrosion ? Paul did the same thing on my 9000 3 inch DP I must check if its still black after a couple of years .Im sure its just ordinary steel . The engine revs more freely and the car seems lighter ! that has to be a good sign. I may continue the 3 inch pipe one day . Bilstein rear shocks next.

Looks good. Much improved over the stock, but Saab had other requirements and constraints. If you have not done already, put the turbine heat shield back in place. I ran with mine off, but with a turbine fiberglass cozy and would have hot soak start issues. Seems like the hall sensor failed to give signal when it got too hot.

When you say pulls at 1500 in fifth, what boost are you getting if any or is it boosting quicker?
Reply With Quote Quick reply to this message
  #10  
Old 20-07-12
gustavm gustavm is offline
Saab Crazy
 
Join Date: Oct 2007                                                
Location: Newzealand
My Saabs: 1985 900spg Hillclimb car
Posts: 959
Default

I will get one before summer . So are you saying get a heat sheild or a turbo cozy?. Mine never had the heat sheild . Dont think Im getting any boost at 1500 revs but there is a definate off boost torque improvement . Im predicting better mpgs.
Reply With Quote Quick reply to this message
  #11  
Old 21-07-12
Squaab99t's Avatar
Squaab99t Squaab99t is online now
Saab Lunatic
 
Join Date: Jul 2005                                                
Location: Shoreline Wa USA
My Saabs: '89 900t 4dr'78 99t'76 99 16vt'11 9-3
Posts: 1,004
Default

Quote:
Originally Posted by gustavm View Post
I will get one before summer . So are you saying get a heat sheild or a turbo cozy?. Mine never had the heat sheild . Dont think Im getting any boost at 1500 revs but there is a definate off boost torque improvement . Im predicting better mpgs.
I'd say both, in my mind they do separate functions. The heat shield protects the dist and ignition wires. The cozy keeps more of the energy (heat) in housing for better spool.
Reply With Quote Quick reply to this message
  #12  
Old 21-07-12
gustavm gustavm is offline
Saab Crazy
 
Join Date: Oct 2007                                                
Location: Newzealand
My Saabs: 1985 900spg Hillclimb car
Posts: 959
Default

Interesting, Im wondering though with the early oil cooled t3 that I have would that increase the chance of baking the oil at shut down ?
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the SaabCentral Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Do it yourself Short Ram Intake 2003saab93 Saab 9-3 SportSedan, Convertible ('04+)/Combi & 9-3X GENERAL Performance, Mods & Tuning 8 10-02-12 06:24 PM
a short vid Han Choi Saab Classic 900 Workshop 1 17-05-11 04:13 PM
Really bad short DustinS Saab Classic 900 Workshop 11 13-11-09 01:32 PM
Short shift kit MIKE AERO HOT Saab 9-5 Performance, Mods & Tuning 2 27-05-07 05:25 AM
short shifters Bladey Saab 9-3 SportSedan, Convertible ('04+)/Combi & 9-3X GENERAL Performance, Mods & Tuning 3 14-01-05 10:13 AM


All times are GMT -4. The time now is 02:36 AM.



Powered by vBulletin® Copyright ©2000 - 2014, vBulletin Solutions, Inc.

top of page | sitemap | email us



copyright © 2003 - 2011 saabcentral.com, All rights reserved http://www.whiter.co.uk - valid xhtml - valid css
SaabCentral is an independently run website and is not affiliated in any way to Saab Automobile AB.


Garage Plus vBulletin Plugins by Drive Thru Online, Inc.