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Old 01-05-2013, 09:11 PM   #1
maverick83
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Default Tune leaner than 14.7

Hi, is there any chance to tune the open loop maps,on a 2011 STI, leaner than 14.7?
Of course just in low loads,where from the factory it comes with 14.7.
I would like to set for example 15 or 15.5 just to save fuel during daily driving at low speed.
With Ecuflash I have seen that with the EVO is possible.
Some of you guys has got a solution for this?
Thanks
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Old 01-05-2013, 10:17 PM   #2
Jeffman44
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Open loop only happens under high load. You def wouldn't want to do that. closed loop it would be possible but the mpg gains would be pretty negligible and probably cause unwanted heat.
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Old 01-06-2013, 08:46 AM   #3
maverick83
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I've mapped in a way that it goes in open loop even in low loads under certain conditions.
Anyway do you know how to modify the closed loop maps in order to go leaner than 14.7 ?
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Old 01-06-2013, 10:09 AM   #4
quazimoto
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Change the Closed loop AFR target.
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Old 01-06-2013, 11:38 AM   #5
cowboy_Rob
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If your goal is fuel mileage why would you set it up to go open loop sooner? Closed loop will always be more efficient then open since its being constantly monitored and adjusted on the fly by the ecu
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Old 01-06-2013, 01:27 PM   #6
maverick83
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Quote:
Originally Posted by quazimoto View Post
Change the Closed loop AFR target.
Do you know which is the name of the table to change closed loop AFR target?
Is it CL Fueling Target compensation?
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Old 01-06-2013, 01:31 PM   #7
maverick83
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Originally Posted by cowboy_Rob View Post
If your goal is fuel mileage why would you set it up to go open loop sooner? Closed loop will always be more efficient then open since its being constantly monitored and adjusted on the fly by the ecu
Believe it or not,is more precise now in maintaining 14.7 than before...
And now it gives less problems with fine learning knock corrections.
Anyway basically in cruise it goes to closed loop quickly than with the oem map.
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Old 01-06-2013, 01:37 PM   #8
BlazeRex
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Quote:
Originally Posted by maverick83 View Post
Do you know which is the name of the table to change closed loop AFR target?
Is it CL Fueling Target compensation?
Quote:
Originally Posted by maverick83 View Post
Believe it or not,is more precise now in maintaining 14.7 than before...
And now it gives less problems with fine learning knock corrections.
Anyway basically in cruise it goes to closed loop quickly than with the oem map.
I never saw a measurable mileage increase from going leaner than 14.7

Of course its going to be smoother in maintaining AFR in OL, the factory system is designed to jump around a little, plus its always corecting itself up/down.
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Old 01-08-2013, 09:48 AM   #9
Jeffman44
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So I did a little digging around. The stock way of oscillating the afr actually is because it facilitates a chemical reaction in the cat. Putting it in open loop under low load is going to be fine just raise emmissions. Doesn't solve the original question though.... But I view it from the physics standpoint of conservation of energy. If you are running 14.7:1 you'll be using the full potential of your fuel, same with 15:1 or 16:1 anywhere above 14.7 and you will be maximizing fuel efficiency. Butttt that doesn't account for uncertainty in things like tip in enrichment... Might be worth it.

But yes to change closed loop afr its the 'closed loop fueling target.' Mine was in at 14.47 maybe that is the stock value. I changed it to 14.7 and the car seems to hang around 15.0 mostly. Still doing the oscillating down to 14.6 or so.

Last edited by Jeffman44; 01-08-2013 at 09:56 AM.
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Old 01-08-2013, 06:28 PM   #10
ProfessWRX
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Quote:
Originally Posted by maverick83 View Post

Do you know which is the name of the table to change closed loop AFR target?
Is it CL Fueling Target compensation?
Yes and ECT compensation.
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Old 01-08-2013, 06:33 PM   #11
maverick83
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Quote:
Originally Posted by Jeffman44 View Post
So I did a little digging around. The stock way of oscillating the afr actually is because it facilitates a chemical reaction in the cat. Putting it in open loop under low load is going to be fine just raise emmissions. Doesn't solve the original question though.... But I view it from the physics standpoint of conservation of energy. If you are running 14.7:1 you'll be using the full potential of your fuel, same with 15:1 or 16:1 anywhere above 14.7 and you will be maximizing fuel efficiency. Butttt that doesn't account for uncertainty in things like tip in enrichment... Might be worth it.

But yes to change closed loop afr its the 'closed loop fueling target.' Mine was in at 14.47 maybe that is the stock value. I changed it to 14.7 and the car seems to hang around 15.0 mostly. Still doing the oscillating down to 14.6 or so.
Do you have a "closed loop fueling target" table in your ECU?
I just have 2 tables that looks similar to that one and they are compensation tables. But oem they have already many negative values...so I guess I just have to decrease more this values in order to get what I was searching for.
Am I right? ...2011 Sti with 32bit ECU
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Old 01-08-2013, 06:47 PM   #12
ProfessWRX
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Quote:
Originally Posted by maverick83 View Post

Do you have a "closed loop fueling target" table in your ECU?
I just have 2 tables that looks similar to that one and they are compensation tables. But oem they have already many negative values...so I guess I just have to decrease more this values in order to get what I was searching for.
Am I right? ...2011 Sti with 32bit ECU
Those tables are additive. Meaning negative numbers are below 14.7. You want positive numbers.
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Old 01-08-2013, 07:27 PM   #13
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Yea I have that exact table. 16 bit 05 wrx though...
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Old 01-11-2013, 09:19 AM   #14
maverick83
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Thank you
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Old 01-11-2013, 12:46 PM   #15
endrswrd
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To be clear. Clearing out the CL compensation (load and ECT) will make the car target 14.7 full time instead of the 14.2-.4 correct?
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Old 01-19-2013, 04:56 PM   #16
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Correct
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Old 01-19-2013, 11:03 PM   #17
alexmartynyuk
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I don't think a 2012 sti rom has a cl target afr table, but it should have four "cl fueling target compensation" tables and you have to tweak those to get leaner afr than 14.7:1
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