Welcome to the North American Subaru Impreza Owners Club Friday August 29, 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

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 09-01-2011, 02:05 AM   #1
NSFW
Scooby Guru
 
Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default Re-mapped ECU learning trick - 10-20hp in ZERO seconds

Just a little trick that will let you completely skip one of the ECU's learning processes...

The ECU maintains a number called the "Ignition Advance Multiplier" (IAM) to increase or decrease ignition advance over very wide RPM and load ranges. When IAM is zero, the ECU uses only the amount of ignition advance specified in the tune's base timing table. When IAM is at its maximum value, the ECU adds all of the timing advance specified in the "knock correction advance" table to the timing advance from the base table. When IAM is at 50%, the ECU only adds half of the "knock correction advance" to the base timing advance. (For 2.0L Subarus, the actual IAM value ranges from 0-16; for 2.5L Subarus, the IAM value ranges from 0.0 to 1.0.)

Normally, the IAM value is at 50% after you reset the ECU. It will then increase to 100% if you have a good tune, a healthy motor, and good fuel. The additional timing might be good for 10-20whp or so, depending on your tune. Alternately, if your tune sucks, or someone filled your tank with 87 octane, or your motor is broken, IAM might drop to zero as the ECU tries to avoid detonation.

When you're tuning and data-logging, you should have IAM at 100%, so that you can evaluate how the motor will behave with 100% of the ignition advance that the tune will allow. Otherwise you or your tuner might think the tune is great since you never saw it knock, only to have the ECU add a few more degrees of timing later on, and then start knocking as a result.

In the past, the folks at Vishu Tuning figured a way to force IAM to climb rapidly from its initial 50% value up to 100%. Their approach was to use simultaneous brake and throttle to force the engine to run a high load for a little while. The ECU would then notice that it's running at high load, and not knocking, and thus it would increase IAM.

However, there's an easier way. Just open the tune with RomRaider or EcuFlash, and look for the "Advance Multiplier (Initial)" table, in the "Ignition Timing - Knock Control" section. Set the to whatever the maximum IAM value is for your ECU.

Subarus with 2.0L motors use 16-bit ECUs, which have a maximum IAM value of 16 (so 50% IAM would be 8, and 75% would be 12, and so on).

Subarus with 2.5L motors use 32-bit ECUs, which have a maximum IAM value of 1.0 (so 50% IAM would be 0.5, etc).

So, you'll want the table to look like one of these, depending on which type of ECU your car uses:



After your next flash, you don't need to do anything to get the IAM to 100%. It will already be there. Just start logging your pulls. While you're tuning, you should be logging most of your pulls and reviewing the logs, and you (or your tuner) should be learning, not the ECU.

After your tune is finished, or if you're going to take a break from logging for a while, I suggest setting this table back to its original value. The ECU will consult this value during its regular knock control thought processes, and it's probably best to let it use the stock setting for that.
* Registered users of the site do not see these ads.
NSFW is offline   Reply With Quote
Old 09-01-2011, 05:57 PM   #2
Bill in Mtl
Scooby Newbie
 
Member#: 188357
Join Date: Sep 2008
Chapter/Region: E. Canada
Location: Quebec
Vehicle:
2007 WRX
Black

Default

Thanks for the tip - will have to give this a try

Regards,
Bill in Mtl is offline   Reply With Quote
Old 01-25-2012, 03:11 PM   #3
NSFW
Scooby Guru
 
Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default

Hey mods, how about we sticky this thread instead of the outdated and misleading one that's currently stickified?

If you don't see why, read the last page of the current sticky thread.

Thanks!

Last edited by NSFW; 01-25-2012 at 03:18 PM.
NSFW is offline   Reply With Quote
Old 03-23-2012, 01:29 PM   #4
Onejamasubaru
Scooby Newbie
 
Member#: 312346
Join Date: Mar 2012
Chapter/Region: South East
Location: Florida
Vehicle:
2012 WRX
Satin White Pearl Sedan

Default

Nice! If you could post a vid, that would be great
Onejamasubaru is offline   Reply With Quote
Old 03-23-2012, 04:10 PM   #5
quazimoto
Scooby Guru
 
Member#: 70395
Join Date: Sep 2004
Chapter/Region: MAIC
Location: Da-boonies,Va
Default

Quote:
Originally Posted by Onejamasubaru
Nice! If you could post a vid, that would be great
Why do you need a video?
quazimoto is offline   Reply With Quote
Old 06-30-2012, 04:21 AM   #6
JLHK
Scooby Newbie
 
Member#: 322967
Join Date: Jun 2012
Default

May i know when flashing the ecu with ecuflash, will it automatically reset the ecu (CLEAR the ecu learned values) as well? Or do i have to reset the ecu everytime i am flashing it?
JLHK is offline   Reply With Quote
Old 06-30-2012, 05:38 AM   #7
NSFW
Scooby Guru
 
Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default

Most Subarus will reset during a reflash, but not all.
To find out, use Learning View before and after reflashing.
NSFW is offline   Reply With Quote
Old 07-02-2014, 04:27 AM   #8
komietim
Scooby Newbie
 
Member#: 395181
Join Date: Jul 2014
Default

thx fffff
komietim 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
Re-Mapped ECU Learning Trick 10-20hp in 5 seconds :) Vishnu Performance Engine Management & Tuning 313 07-02-2014 04:26 AM
SCCA National Rallycross Championship - 10/09 - 10/11 in CO ryolse Motorsports 9 10-11-2009 09:44 AM
5,000 lbs. vehicle gets 60 miles to the gallon and does zero to 60 in five seconds! WRXdonkey Off-Topic 98 11-02-2007 03:29 AM
New Learning tool - My cheaspskate in car video joe-6STi Texas Impreza Club Forum -- TXIC 10 10-17-2007 07:14 PM
New Learning Tool - my cheapskate in car video set up... joe-6STi Motorsports 2 10-17-2007 12:46 PM


All times are GMT -4. The time now is 11:23 AM.


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.