RhysGoodwin Posted January 20, 2018 Share Posted January 20, 2018 Hi Guys, First post. I've been a Subaru owner for 10 years but previously with a 2000 Outback (JDM Lancaster) 2.5 NA. I enjoyed it for what it was, a great car but being an NA 4AT I never really got interested in performance or measuring anything out of the ECU. About a week ago I picked up our 'new' 2011 Legacy GT Wagon. Wow this machine is incredible. It's an imported JDM (as most cars are down here in NZ) with ~33,000 Kilometres on the clock. A few pics here if you're interested: https://drive.google.com/drive/folders/1KMD5XmVSZL7clXMTSuPAsLbZkYWAAqCf?usp=sharing I quickly got up and running with BtSsm (after some great support btw). I'm not exactly what you'd call a 'car nut' and not very knowledgeable but just learning as I go. I have one question to start with - when I read the learned values from the ECU it always shows IAM 0.7 just after I start the car but climbs to 1.0 within a few minutes of driving. I was under the impression that LVs were persisted in the ECU and required an ECU reset to clear? Cheer, Rhys Link to comment Share on other sites More sharing options...
Shadow_419 Posted January 20, 2018 Share Posted January 20, 2018 Really nice looking wagon. A little jarring to see the hood scoop without the 18 wheels the USDM gt's have as well as the auto trans. I'm not positive, but I think a good number of the factory roms did this. Does it take much time to rise to 1.0? Link to comment Share on other sites More sharing options...
mcg_ Posted January 20, 2018 Share Posted January 20, 2018 I have one question to start with - when I read the learned values from the ECU it always shows IAM 0.7 just after I start the car but climbs to 1.0 within a few minutes of driving. I was under the impression that LVs were persisted in the ECU and required an ECU reset to clear? FWIW, I'm not expert but it is my understanding that all stock tunes on the 5th Gens reset the IAM every time the car turns off. You can turn this off with a tune either using Cobb AccessPort or Opensource (of course, if there is a ECU def for your car). When I wanted an open source definition, the guys on Romraider created one for me, which included the switch turn on/off the IAM reset. See, e.g., http://www.romraider.com/forum/viewtopic.php?f=8&t=11262 Lastly, awesome car, man. Super jealous. Link to comment Share on other sites More sharing options...
RhysGoodwin Posted January 21, 2018 Author Share Posted January 21, 2018 Cheers Guys! I'm reading my way through some of the Cobb FAQs on knock monitoring etc. Learning a lot. Link to comment Share on other sites More sharing options...
Perscitus Posted January 21, 2018 Share Posted January 21, 2018 Cheers to a Kiwi! Please also read here: http://legacygt.com/forums/showthread.php/everything-you-wanted-know-subarus-knock-prevention-strategy-254139.html As far as I know, IAM (or DAM as CoBB calls it) shouldn't reset on these older Denso ECU based Subarus. On the newer 2015+ Hitachi ones it does and its far more Dynamic than even before. Having said that perhaps JDM cars or 5th gen LGTs do reset the IAM with each ignition cycle. I have no first hand experience tuning or monitoring these. It would be unique and rather odd though vs what the other boosted models or NA 5th gen engine flavors from this era do. Given how the stock KCA table is configured and what resultant max total timing you end up with when IAM is 1 vs 0.5 vs say 0.1, youre not really leaving much power on the table... maybe a bit up top but not really at cruise and mild acceleration loads and RPMs or Boost levels. Once tuned, all bets as to how a high or low IAM impacts total timing are off since you can just as easily disable RC, give KCA enough potential to add or remove very little or very much timing. Link to comment Share on other sites More sharing options...
RhysGoodwin Posted January 21, 2018 Author Share Posted January 21, 2018 Thanks *Perscitus, excellent info. It probably takes about 2 or 3 kms before it comes up to 1.0 so it's pretty quick. I haven't experimented with the SI Drive modes yet to see if that changes anything. I guess the advantage of retaining the learned values across cycles is that it can start out right away at 1.0 (including any adjustments). But dose engine temperature change the picture? I.e. Are the LVs for a fully warmed engine still relevant when you start cold the next day? Link to comment Share on other sites More sharing options...
Perscitus Posted January 21, 2018 Share Posted January 21, 2018 Yes, the ECU has many compensations based on various temps: coolant temp, intake temp, intake manifold (aircharge) temps. Unless you reset the ECU (via software, a reflash or brute force - battery pull), LVs are retained and updated as the ECU sees fit and kicks into the various routines that can change learned Fuel and Timing adjustments. IAM changes and potential resets on ignition cycle would be 100% independent of Fuel learn across all MAF ranges BUT YES, they would also reset Timing learn with each IAM change. A bit unsafe on a boosted Subaru if there is any knock up top and in boost. Otherwise just BAU, nothing to worry about. Still, this is the reason I think IAM resets on ignition cycle seem odd, unless timing is conservative... which it typically isnt on stock Subarus. Factory tunes tend to run lean down low, rich up top. Aggresive mid range timing. Somewhat aggresive timing throughout. Link to comment Share on other sites More sharing options...
RhysGoodwin Posted January 23, 2018 Author Share Posted January 23, 2018 Interesting, perhaps I should try and do some logging and see if that sheds any light. Link to comment Share on other sites More sharing options...
Perscitus Posted January 23, 2018 Share Posted January 23, 2018 Would be great, BtSsm log away and then analyze using Excel or Vipertuned great log analyzer http://blog.vittuned.com/viperdata/ Plot data vs time, vs Load, vs RPM. Calc your AF Error, Boost Error, see how/if IAM changes, when you get FKC/FLKC, how your total timing and fuel learn looks like how your VVTi angles look (if theyre in sync). Link to comment Share on other sites More sharing options...
dgoodhue Posted January 23, 2018 Share Posted January 23, 2018 The DAM on a stock 5th GT tune resets to 0.75 when restarting the car. Link to comment Share on other sites More sharing options...
Perscitus Posted February 3, 2018 Share Posted February 3, 2018 Some additional tables useful for tuning and likely not exposed in COBB definitions for the 5th gen LGTs... see last post from td_d. Note the ECU limits torque output based on IAT too, per gear. and based on IAM, per gear. Maximum_Torque_Per_gear_IAM Requested_Torque_per_gear_A Requested_Torque_per_gear_B Maximum_Torque_Per_gear_IAT http://www.romraider.com/forum/viewtopic.php?f=34&t=8706 Link to comment Share on other sites More sharing options...
Shadow_419 Posted February 3, 2018 Share Posted February 3, 2018 Some additional tables useful for tuning and likely not exposed in COBB definitions for the 5th gen LGTs... see last post from td_d. Note the ECU limits torque output based on IAT too, per gear. and based on IAM, per gear. Maximum_Torque_Per_gear_IAM Requested_Torque_per_gear_A Requested_Torque_per_gear_B Maximum_Torque_Per_gear_IAT http://www.romraider.com/forum/viewtopic.php?f=34&t=8706 These tables have been holding my tune up. Sucks having such an early car and rom Link to comment Share on other sites More sharing options...
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