Tuning Questions

[SeddyBRZ]

I've been reading up on tuning over the last few days. I am a total noob when it comes to this stuff but I really want to get into it as I have an OFT. I have been reading several posts about little adjustments and also a thread by steve99 and several others.

I have a few questions that I haven't seen the answer to or perhaps I missed it (I apologize if I have).

• What throttle settings do I data log at?
• what should AFR be at cruising and WOT?
• How do I adjust AFR? Is it done through the closed loop fuel map and adjusting timing?
• What does adding more timing do vs retarding timing?
• If making minor adjustments, what are the typical values to follow (ex: 1.00, 0.50, 0.01)
• What is knock correction and MAF scaling and how do they work?
• Is AFR, timing, and overall everything done different if running e85?

I understand that some if not all of these questions have been talked about before but if I could be pointed in the right direction for the harder to answer questions that would be great. I just want to dial in my OFT tune to work with my UEL and Intake. Keep in mind I am editing the stg2 e85 v4 tune off their website.

[tomm.brz]

you literally won t be able to tune yourself if you can t answer by yourself to any of your questions, sorry

Better to ask help directly by let the tuner do the work

ots tunes are already a good start to understand what it is usually modified
the rest is mostly basic knowledge about engine management, if you have no clue what maf scaling is for or what fuel trims are, even after reading all steve' stuff that already explain most of the stuff.. i don t think it s a good idea to tune yourself for now

[SeddyBRZ]

Originally Posted by tomm.brz

you literally won t be able to tune yourself if you can t answer by yourself to any of your questions, sorry

Better to ask help directly by let the tuner do the work

ots tunes are already a good start to understand what it is usually modified
the rest is mostly basic knowledge about engine management, if you have no clue what maf scaling is for or what fuel trims are, even after reading all steve' stuff that already explain most of the stuff.. i don t think it s a good idea to tune yourself for now

its almost like I should make a form post asking the community to help steer me in the right direction to learn so I can get to that point or maybe ask a few questions with things I am struggling to understand.

I also never claimed to have read all of steves posts nor did I say I didn't know what fuel trims are. I was asking general questions that I have not seen on here and want to better understand the correlation between two different parameters and what changing one does to the other.

[tomm.brz]

Well by the specific questions you asked, it seems obvious you have no idea how modern engine management works, sorry.. So if you want a starting point, buy online courses. https://www.hpacademy.com/courses/

If you don t want to spend money to educate yourself on the topic, you either do some digging around to at least learn the very basics (which afr is desiderable, how maf sensor works to set the afr, how knock management works, etc) and then you come with more focused and less generic questions, or at this point is like asking for spoonfeeding but the topic is quite big so good luck in that

There are reasons tuners ask for >250 usd usually, one of that is they have spent monthes in learning and experience in modyifing tunes

Nasioc is a good source for how subaru ECM works, also the pdf about tuning our specific ecu available on ecutek website, also every post of steve99 in here

[shr133]

Originally Posted by SeddyBRZ

I've been reading up on tuning over the last few days. I am a total noob when it comes to this stuff but I really want to get into it as I have an OFT. I have been reading several posts about little adjustments and also a thread by steve99 and several others.

I have a few questions that I haven't seen the answer to or perhaps I missed it (I apologize if I have).

• What throttle settings do I data log at?
• what should AFR be at cruising and WOT?
• How do I adjust AFR? Is it done through the closed loop fuel map and adjusting timing?
• What does adding more timing do vs retarding timing?
• If making minor adjustments, what are the typical values to follow (ex: 1.00, 0.50, 0.01)
• What is knock correction and MAF scaling and how do they work?
• Is AFR, timing, and overall everything done different if running e85?

I understand that some if not all of these questions have been talked about before but if I could be pointed in the right direction for the harder to answer questions that would be great. I just want to dial in my OFT tune to work with my UEL and Intake. Keep in mind I am editing the stg2 e85 v4 tune off their website.

AFR should go from 14.5 for idle and cruising up to around 12 to 11.5 at wot. but that is something you tune for.. You would need to rescale the stock O2 sensor or have a wide band.
knock correction tells you that you have too much timing... run as much timing that doesn't produce knock correction or it makes less power , but has to be dialed in.

with fuel and timing adjust a few tenths .2 to .5 at a time, some things are limited by the ecu. maf 1% or 2 % at a time.

MAF is how you scale your intake sensor to make sure the computer knows how much air is going into the engine.. You have to do this before you can accurately adjust the fuel...

So a lot to learn, go slowly, make lots of notes, save and label all variation of the tune, save the base tune and keep learning, tons of information out there but don't change anything until you understand what you are changing.

[NoHaveMSG]

Originally Posted by SeddyBRZ

its almost like I should make a form post asking the community to help steer me in the right direction to learn so I can get to that point or maybe ask a few questions with things I am struggling to understand.

I also never claimed to have read all of steves posts nor did I say I didn't know what fuel trims are. I was asking general questions that I have not seen on here and want to better understand the correlation between two different parameters and what changing one does to the other.

If you want better answers, ask better questions.

If you haven't read Steve's threads in his sig, then do that first. Write down notes on what you don't understand, then try searching google. At that point I would imagine you should have an idea of what more detailed questions you will want to ask. What you are asking now are such broad subjects someone could write a dissertation on them and nobody here is going to do that if you haven't even bothered to read the basics which are laid out in Steve's sig.