Welcome to the North American Subaru Impreza Owners Club Sunday July 13, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Engine Management & Tuning > Open Source Reflashes

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, 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 free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 05-20-2012, 09:38 PM   #1
scootarida1
Scooby Newbie
 
Member#: 154534
Join Date: Jul 2007
Chapter/Region: Tri-State
Location: Wilkes-Barre, PA
Vehicle:
2005 Forester XT
Borg Warner S261

Default IAT Compensation - Blow Through

Hello,
I recently have installed a custom blow through setup on my Forester with a Borg Warner S261. I notice that when I park the car after the engine is hot, and then start the car, the afrs will drop and run very rich. My question is can I just 0 out the IAT Maf Compensation table since the sensor will be reading actual temperature or should I decrease the table by some percentage. I'm not sure how I should approach this so some input would be appreciated.
* Registered users of the site do not see these ads.
scootarida1 is offline   Reply With Quote
Old 05-20-2012, 10:57 PM   #2
WhiteBgeye02
Scooby Specialist
 
Member#: 224785
Join Date: Sep 2009
Chapter/Region: MWSOC
Location: neenah
Vehicle:
2005 wrx-jdm207
i went black...

Default

well the pipe is heat soaked from the radiant heat off the engine so it will take a quick drive to get it to cool down. personally i wouldnt put them at zero. maybe decrease them a bit. then wrap your cold pipe and see if that helps with keeping the temps down. make sure its the silver/shiney wrap so it blocks the heat. std pipe wrap w/o the reflective outer part wont work.
WhiteBgeye02 is offline   Reply With Quote
Old 05-21-2012, 07:21 PM   #3
scootarida1
Scooby Newbie
 
Member#: 154534
Join Date: Jul 2007
Chapter/Region: Tri-State
Location: Wilkes-Barre, PA
Vehicle:
2005 Forester XT
Borg Warner S261

Default

Quote:
Originally Posted by WhiteBgeye02 View Post
well the pipe is heat soaked from the radiant heat off the engine so it will take a quick drive to get it to cool down. personally i wouldnt put them at zero. maybe decrease them a bit. then wrap your cold pipe and see if that helps with keeping the temps down. make sure its the silver/shiney wrap so it blocks the heat. std pipe wrap w/o the reflective outer part wont work.
Okay, I might try lowering them a tad and see if it helps.
scootarida1 is offline   Reply With Quote
Old 05-22-2012, 08:17 PM   #4
WhiteBgeye02
Scooby Specialist
 
Member#: 224785
Join Date: Sep 2009
Chapter/Region: MWSOC
Location: neenah
Vehicle:
2005 wrx-jdm207
i went black...

Default

yeah like i said though there is the compensation there for a reason but since you have post intercooler temp sensing you have more control compared to the draw through were intercooler heat soak has a huge affect but isnt taken into the calc until knock occurs. should be a good way to fine tune the car.
WhiteBgeye02 is offline   Reply With Quote
Old 05-31-2012, 06:08 PM   #5
scootarida1
Scooby Newbie
 
Member#: 154534
Join Date: Jul 2007
Chapter/Region: Tri-State
Location: Wilkes-Barre, PA
Vehicle:
2005 Forester XT
Borg Warner S261

Default

I did not end up changing the IAT Compensation yet but I ran into a scenario where only when it rains, the car goes into a very quick afr swing from 14.4-15.2ish on the wideband during idle. Almost sounds like its cammed. During normal weather, the idle is spot on. Im thinking the IAT Comp is effecting this. Any thoughts?
scootarida1 is offline   Reply With Quote
Old 06-11-2012, 03:34 PM   #6
Bamofo
Scooby Specialist
 
Member#: 159743
Join Date: Sep 2007
Location: Plymouth Ma
Vehicle:
07 STI Limited
TurboMike Tuned 2.35

Default

sounds like a bad coil pack... I normally make the IAT compensation less but still leave the higher/Lower values the way they are. if the IAT is actually reading 120F or 140F i want to take out some timing... at the same time if its 20 degrees out in MA i dont mind adding a bit more timing.
Bamofo is offline   Reply With Quote
Old 06-11-2012, 03:43 PM   #7
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

I had to make some massive changes to my IAT compensation when I went blow through, high temps would cause it to swing very rich. I'm still not sure why it did this in blow through and not draw through, but either way patching up the IAT table fixed it.
the suicidal eggroll is offline   Reply With Quote
Old 06-11-2012, 05:33 PM   #8
scootarida1
Scooby Newbie
 
Member#: 154534
Join Date: Jul 2007
Chapter/Region: Tri-State
Location: Wilkes-Barre, PA
Vehicle:
2005 Forester XT
Borg Warner S261

Default

Quote:
Originally Posted by the suicidal eggroll View Post
I had to make some massive changes to my IAT compensation when I went blow through, high temps would cause it to swing very rich. I'm still not sure why it did this in blow through and not draw through, but either way patching up the IAT table fixed it.
so basically making the adjustments less extensive then?
scootarida1 is offline   Reply With Quote
Old 06-11-2012, 05:52 PM   #9
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

Actually I had make the adjustments very large. This is how it ended up looking (stock vs modded):


the suicidal eggroll is offline   Reply With Quote
Old 06-20-2012, 10:36 PM   #10
wgr73
Scooby Specialist
 
Member#: 232458
Join Date: Dec 2009
Chapter/Region: SWIC
Location: Las Cruces, El Paso
Vehicle:
2008 STi (OBP)
CAMTuning.com

Default

Quote:
Originally Posted by the suicidal eggroll View Post
I had to make some massive changes to my IAT compensation when I went blow through, high temps would cause it to swing very rich. I'm still not sure why it did this in blow through and not draw through, but either way patching up the IAT table fixed it.
Quote:
Originally Posted by the suicidal eggroll View Post
Actually I had make the adjustments very large. This is how it ended up looking (stock vs modded):


Very interesting suicide! I'm having this issue but mine swings lean when temps go up which in turn causes my fuel trims to be erratic! How did you narrow it down to specific cells? Did you log iat, corrections (a,b,c,d), and afr? Seems like you'd have to log quite a bit to pick your compensations for each cell like you did!
wgr73 is offline   Reply With Quote
Old 06-21-2012, 12:43 AM   #11
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

I ran straight open loop fueling, then logged AFR error vs MAF and IAT for different atmospheric temps. It took a while to nail down, but I started seeing improvements almost immediately. It probably took longer than it should have because I greatly underestimated the magnitude of the changes I ended up needing to make.
the suicidal eggroll is offline   Reply With Quote
Old 06-21-2012, 09:18 AM   #12
wgr73
Scooby Specialist
 
Member#: 232458
Join Date: Dec 2009
Chapter/Region: SWIC
Location: Las Cruces, El Paso
Vehicle:
2008 STi (OBP)
CAMTuning.com

Default

Cool. It would seem like it'd take a while. Crazy how huge the compensations are! I'm working on mine right now....the furthest two columns are set at 10% and 12% respectively. I'll probably have to change this later.

How are your fuel trims now?
wgr73 is offline   Reply With Quote
Old 06-21-2012, 10:07 AM   #13
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

Quote:
Originally Posted by wgr73 View Post
How are your fuel trims now?
I don't use AF Learning, but my AFR was good apart from the throttle dependent MAF readings that never went away. So a couple weeks ago I switched to speed density and am now working on dialing that in.
the suicidal eggroll is offline   Reply With Quote
Old 06-21-2012, 11:08 AM   #14
wgr73
Scooby Specialist
 
Member#: 232458
Join Date: Dec 2009
Chapter/Region: SWIC
Location: Las Cruces, El Paso
Vehicle:
2008 STi (OBP)
CAMTuning.com

Default

Never?...You always run OL? Interesting. I'm on speed density/maf blend as well, and this issue is apparent. The car runs awesome and is very fluid, it just kills me looking at the learned fueling.
wgr73 is offline   Reply With Quote
Old 06-21-2012, 12:44 PM   #15
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

I was running straight OL for a while, but a while back I switched to CL, just with no learning (forced min/max AF Learning to 0).
the suicidal eggroll is offline   Reply With Quote
Old 06-27-2012, 10:24 AM   #16
wgr73
Scooby Specialist
 
Member#: 232458
Join Date: Dec 2009
Chapter/Region: SWIC
Location: Las Cruces, El Paso
Vehicle:
2008 STi (OBP)
CAMTuning.com

Default

Gotcha. That's not a bad idea. I should try that for a while and see how it works. My eyes are glued to the wideband so the transition to it should be ok. I do like the fact that AF learning can help if there's a small change in fuel/air (leak)
wgr73 is offline   Reply With Quote
Old 07-05-2012, 05:51 PM   #17
scootarida1
Scooby Newbie
 
Member#: 154534
Join Date: Jul 2007
Chapter/Region: Tri-State
Location: Wilkes-Barre, PA
Vehicle:
2005 Forester XT
Borg Warner S261

Default

Quote:
Originally Posted by the suicidal eggroll View Post
I was running straight OL for a while, but a while back I switched to CL, just with no learning (forced min/max AF Learning to 0).
so basically you just fine tune it based on the wideband rather than let the car do af learning and compensation?
scootarida1 is offline   Reply With Quote
Old 07-05-2012, 06:41 PM   #18
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

Quote:
Originally Posted by scootarida1 View Post
so basically you just fine tune it based on the wideband rather than let the car do af learning and compensation?
Yes, because the AF Learning can do some nasty things. Most people disable the D range learning, I just disabled the whole thing.
the suicidal eggroll is offline   Reply With Quote
Old 07-06-2012, 03:41 PM   #19
scootarida1
Scooby Newbie
 
Member#: 154534
Join Date: Jul 2007
Chapter/Region: Tri-State
Location: Wilkes-Barre, PA
Vehicle:
2005 Forester XT
Borg Warner S261

Default

Quote:
Originally Posted by the suicidal eggroll View Post
Yes, because the AF Learning can do some nasty things. Most people disable the D range learning, I just disabled the whole thing.
ill have to give that a try and see what I can come up with.
scootarida1 is offline   Reply With Quote
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
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Blow through MAF - after turbo but before intercooler MY99 2.5GT Normally Aspirated with bolt-on Forced Induction Powertrain 10 04-04-2007 09:46 PM
FS: Ultimate Racing Blow Through MAF Housing - $150 InfamousDX Private 'For Sale' Classifieds 31 06-25-2006 05:59 PM
FS: Intakes and blow through maf - Perrin short ram, BIG maf, K&N.... 2theMAX Private 'For Sale' Classifieds 12 02-15-2006 12:19 AM
Blow through maf set up majnthr33 Mid West Subaru Owners Club Forum -- MWSOC 9 09-19-2005 10:01 AM
Blow Through MAF users! Javier Factory 2.5L Turbo Powertrain 6 07-29-2005 10:15 AM


All times are GMT -4. The time now is 01:30 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.