Jul

24th

Atikinson Cycle Tuning

Modifying Subaru's VVT system or Dual AVCS to optimize fuel economy and torque. read more.....

Jun

25th

First Open Source Tune

Hi guys, this weekend I have started logging and tuning my car. I will be providing details for people interested in this thread. Basically I will be using opensource tuning software such as Romraider and ECUFlash. I will use romraider for logging and ecuflash to read and write to the ECU. read more.....

First Open Source Tune

From TSC Journal, Jun 2013

Hi guys, this weekend I have started logging and tuning my car. I will be providing details for people interested in this thread. Basically I will be using opensource tuning software such as Romraider and ECUFlash. I will use romraider for logging and ecuflash to read and write to the ECU.

The equipment need to perform ECU reflash are as follows:
- Tactrix 2.0 adapter and USB cable
- A laptop with 32-bit JRE installed
- A subaru with CANSF bus (07+)

The process is to first read the ECU and to modify the downloaded map and then to write the modded map back on the car. Very simple.

So far my objectives are:

1. Fix the sensitive drive by wire throttle and make it more linear. Currently the throttle of the car is setup to us only the first 40% or so of the gas pedal's range. I want to use the whole 100% percent. Here is a map of how much throttle requests how much torque (input):

252 is just an arbitrary number and it doesn't mean anything. it's just used here to determine a range of values. however 252 doesn't mean 100% torque here because of another table:

so you see you have many factors here in order for ecu to determine throttle plate opening. i'm not going to go through the details for that, instead you can have a read here subaru drive by wire and how to improve it - nasioc but basically if we were to plot the stock throttle setup as such (black dots), we would want to be tuning for the red line. 50% throttle means actually 50% throttle plate opening and 100% means actually 100% etc etc...>

2. second part of this tune is to disable the closed loop /> open loop delay. This is the most annoying part of this car for me. Have you ever noticed (if you have a wideband sensor or have done dyno runs) that the car stays in closed loop with stoich ratios if you go wide open throttle up until 4500 rpm? Well this is because of this guy:

normally the values would be 1250 instead of zero but setting them to null allows the car to switch to open loop immediately.

3. The third part of this tune will be fueling and ignition advance to gain a bit of pep. I'm looking for mid range improvement mostly as this is how the transmission in this car has been geared for. From looking at the stock maps the car already seems pretty aggressive. However from the logging I have done the car is not as lean and ignition happy as the stock maps suggest. For example the car likes to run lean at the bottom and rich up top but stock maps suggest lean everywhere:

I will have to investigate this further. As for ignition timing i'm not sure on how to go about it as the ECU takes many factors into account to decide on final ignition advance (knock correction advance, feedback, IAM, AVLS, etc.).

But I will be keep you guys up to date and will be posting pics.