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Discussion Starter · #1 · (Edited)
I come from the Subaru world, where I did my own tuning on my '04 WRX with V7 EJ207. A quick indicator that the engine was happy with the tune and fuel was the ECU parameter "IAM" (Ignition Advance Multiplier). Is there an analog to this parameter in the ST's ECU?

Although an AP w/ATR is in the future, I want to start logging via an OBD2 BT and Torque (Android) and would like to narrow it down to the most important PID's.

Thanks for any help on this.

Jeff
 

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I would compare IAM or DAM in a Subaru to OAR (Octane Adjustment Ratio) in a Ford ST. It will typically start around 0 if it hasn't stored a value. -1 is the best value and means the car is happy with the fuel and applying the most timing possible.

Ian
 

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Discussion Starter · #5 ·
Thanks for the input guys

I would compare IAM or DAM in a Subaru to OAR (Octane Adjustment Ratio) in a Ford ST. It will typically start around 0 if it hasn't stored a value. -1 is the best value and means the car is happy with the fuel and applying the most timing possible.

Ian
That's what I was looking for ...

Been doing some reading about OAR and Cobb's guide to tuning the ST, very similar in many ways to the WRX. Timing tables are crazy complicated though.

Jeff
 

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Discussion Starter · #6 ·
So doing some more digging, I found FORscan which shows a parameter called "Octane Adjust Ratio Learned", which shows as a percentage. On my car it is currently 87.6% on Shell 91, and was 73.x% on Husky 87. Seems this is the parameter I am looking for but it obviously is presented differently in FORscan than by Cobb.

The gents at FORscan were kind enough to send me the details on that PID:

PID 2203E8 (mode 22, PID 03E8)
2 bytes long,
signed.
Formula:
Y = (X/32767)*200 %

I plug this into Torque (Android App) and get a value of 1.17. Hmmmmm.

In the end I am hoping Braden (another Subaru convert from way back) could chime in with info on how Cobb derives their -1 to 1 values.

Jeff
 

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So doing some more digging, I found FORscan which shows a parameter called "Octane Adjust Ratio Learned", which shows as a percentage. On my car it is currently 87.6% on Shell 91, and was 73.x% on Husky 87. Seems this is the parameter I am looking for but it obviously is presented differently in FORscan than by Cobb.

The gents at FORscan were kind enough to send me the details on that PID:

PID 2203E8 (mode 22, PID 03E8)
2 bytes long,
signed.
Formula:
Y = (X/32767)*200 %

I plug this into Torque (Android App) and get a value of 1.17. Hmmmmm.

In the end I am hoping Braden (another Subaru convert from way back) could chime in with info on how Cobb derives their -1 to 1 values.

Jeff
Jeff,

That conversion is not accurate, divide by 16384 instead and you'll be all set. The value will be represented in percent form with your formula vs multiplier form with ours.

Cheers,
-Braden @ COBB
 

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Discussion Starter · #9 ·
Jeff,

That conversion is not accurate, divide by 16384 instead and you'll be all set. The value will be represented in percent form with your formula vs multiplier form with ours.

Cheers,
-Braden @ COBB
Thanks Braden. I used a few of your WRX tunes back in the day.

Can you tell me what the formula is to get the ratio that Cobb uses? I'd like to get in line with the AP output as I'll have one in the not-too-distant future and I might as well keep things the same.


Forscan kinda sounds like foreskin lol just thought that might help:p
Every time I go to fire it up that thought crosses my mind.
 
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