narrowband tuning

[eXo3901]

Yo-yo?ing is usually chasing various temp(and actual weather) changes and the computer doing things in the background as mentioned.

Pick a day, filter your data more strictly, drive smoother, get whatever error % you are using to +/- 3-5%(err on the side of being rich) and then leave it alone. Take some longs over a few different days and compare them. You?ll see closed loop doing what it?s supposed to do. Finer adjustments can be made then if you still are not happy. Instead of multiply by half, use smaller increments. Do not use data right after a re-flash. Drive around for 10 minutes and then start logging.

[smokeshow]

This is how I do it, it might be too advanced for novices, but its the fastest and cleanest method with the littlest amount of overshoot.
1. Make a chart like mine using wideband a/f ratios in open loop, only start logging once the engine is warmed up after 15 minutes so you don't log very cold values.

2. sit down at the kitchen table and review the log. Go back and forth from log to VE map and make small corrections, nothing larger than + or - 1.0. use compare file feature to make the changes in each cell to keep track ofwhat you changed.

3. your logged a/f ratios each session will then gradually drift towards correct values using VE map corrections

finally you can re-enable closed loop and forget about it, done

none of the tuning efforts in the VE table will work properly if the rest of the file isn't setup right. Things like injector size, short pulse adders, injector data/delay, ECT/IAT bias, injector phase EOIT, all of that needs to be set before you start tuning. Just like it needs new plugs and stuff.

For example if you have the ECT bias active still the a/f will wildly swing anytime the Engine coolant temp changes

It sounds like you are still trying to tune an engine in closed loop.

It's the most difficult thing to do in all of tuning land. The closed loop correction makes up for environmental factors.
For example when you first start the engine the injectors and fuel is cold, they respond faster to current/voltage supplied.
And hour later the fuel and injectors are hot, they have a completely different response to the current being supplied by the ECU driver.

That means closed loop will correct slightly when cold, and more later when warmed up. It will throw an inconsistent wrench into your tuning efforts- do you want to make them happy when cold or hot? You will have two completely different resulting correction factors "fuel trims" and two completely different resulting fuel map demands and resulting air fuel ratios. And its impossible to tell how much the temperature of the injector changed or what the influence was, or how future environment changes will impact that haven't happened yet.

The same goes for IAT. There is a behind the scenes global IAT adjustment which we cannot control and it moves the a/f ratio leaner as the IAT rises. At least in gen3 this is true. That again means the closed loop correction will bedifferent cold then more or less later when the global adjusts a/f ratio as temps rise. The fuel map can be tuned for cold, or hot situations, but not both. The closed loop will make up for both but it will show you completely different resulting memory trims as a result. There may also be bias to the coolant temp but I disable that because sometimes my coolant temp rises 10 or 20* and i dont want the ecu pulling a bunch of fuel for that either. The less over-correction the better and the ECU loves to over correct

If you put the engine in open loop, you will be able to accurately estimate the a/f changes as the engine warms up. For example my a/f will climb from 15.2:1 at idle to 16.5at idle gradually just sitting in a drive through line. Then once I Leave and start driving it cools off and back to low 15's. If I Had a narrowband closed loop the fuel trims would be off the chart leans while sitting in the line and much less lean while driving. It will confuse novices that aren't away of the difference in closed corrections due to environmental variables.

Always love the walls of text... This is all wrong though. Closed loop is fine as an onboard method for calibration. The temp discrepancy IS the ECT/IAT bias you brought up in the other post. And it's present both in open and closed loop. Good luck with the cancer research..

[kingtal0n]

Always love the walls of text... This is all wrong though. Closed loop is fine as an onboard method for calibration. The temp discrepancy IS the ECT/IAT bias you brought up in the other post. And it's present both in open and closed loop. Good luck with the cancer research..

Its easy to say something is wrong on the internet, too easy.
Too bad you can't produce proof that I am wrong because I'm not wrong. You simply lack experience and are full of salt, just say "its wrong" and walk away, great jealousy at work



Never said closed loop tuning isn't fine, its just hard for novices to understand why they are +2 then -4 then +7 then -3,
to get the same trims you have to tune the engine between 6pm to 8pm, only on sundays when the sun is going down and humidity is exactly 39% and holding your tongue in the correct position...

I was closed loop tuning in 2001. I wrote a piece of software to do it for me. I would do it again today if it was necessary.
https://www.thirdgen.org/forums/dfi-...der-950-a.html

I would never try to tune a closed loop manually without some aid from such a software that I developed for myself. I could easily make one for HPT but its completely un-needed using a wideband which is far more powerful than a narrowband.

get good

In my experience even with IAT and CTS disabled and flat lined there is still a lot of discrepancy going on, due to humidity, temperature of the injectors and wiring which plays with voltage even the voltage itself due to various alternators. and a hundred other things

[pannetron]

Try driving where your altitude varies over 7,000' on a single drive and you'll appreciate closed loop.

[smokeshow]

Its easy to say something is wrong on the internet, too easy.
Too bad you can't produce proof that I am wrong because I'm not wrong. You simply lack experience and are full of salt, just say "its wrong" and walk away, great jealousy at work



Never said closed loop tuning isn't fine, its just hard for novices to understand why they are +2 then -4 then +7 then -3,
to get the same trims you have to tune the engine between 6pm to 8pm, only on sundays when the sun is going down and humidity is exactly 39% and holding your tongue in the correct position...

I was closed loop tuning in 2001. I wrote a piece of software to do it for me. I would do it again today if it was necessary.
https://www.thirdgen.org/forums/dfi-...der-950-a.html

I would never try to tune a closed loop manually without some aid from such a software that I developed for myself. I could easily make one for HPT but its completely un-needed using a wideband which is far more powerful than a narrowband.

get good

In my experience even with IAT and CTS disabled and flat lined there is still a lot of discrepancy going on, due to humidity, temperature of the injectors and wiring which plays with voltage even the voltage itself due to various alternators. and a hundred other things

Its physics...that's the proof. There's no boogeyman hiding in the closed loop/narrowbands algorithm that skews your fueling based on IAT. That effect is constantly present when the airflow is a modeled value; the effect has been calibratable via HP Tuners on almost every platform for almost two decades. PV=nRT...notice fuel isn't a part of that equation. The temperature dance that happens can be easily represented by a first order linear differential equation. I've modeled it in simulink just for the fun of watching the effects...

kingtalon is an idiot.PNG

To be honest I think you like the attention as a small crowd gathers after you cover the screen in text and they don't know enough to call you on it. But anyone that has high school level physics education can reason through this with ease. Next time you want to mansplain something, ask yourself if you really understand the concept or if you're actually just overzealous and excited to impress people on the internet...

[sgod1100]

Its physics...that's the proof. There's no boogeyman hiding in the closed loop/narrowbands algorithm that skews your fueling based on IAT. That effect is constantly present when the airflow is a modeled value; the effect has been calibratable via HP Tuners on almost every platform for almost two decades. PV=nRT...notice fuel isn't a part of that equation. The temperature dance that happens can be easily represented by a first order linear differential equation. I've modeled it in simulink just for the fun of watching the effects...

kingtalon is an idiot.PNG

To be honest I think you like the attention as a small crowd gathers after you cover the screen in text and they don't know enough to call you on it. But anyone that has high school level physics education can reason through this with ease. Next time you want to mansplain something, ask yourself if you really understand the concept or if you're actually just overzealous and excited to impress people on the internet...

agreed. Some people LOVE to hear themselves talk that's for sure..lol.

[hannacorona]

I know this is an old thread but Man I guess some people are so good at open loop tuning, they never leave their neighborhood as in to a higher or lower elevation or get a bad tank of gas these days so they don?t need closed loop, afr stays spot on lol. Myself I got a bad tank of e85 the other day and it pegged fuel trims fuel rich, wouldn?t even run in open loop when I tried to switched it. I better keep my closed loop lol and that guy better keep his laptop handy in case he goes somewhere. It?s pretty clear to me that he hasn?t tuned a closed loop system since 2001 where he learned he didn?t know how obviously. 🤷*♂️

[sgod1100]

I know this is an old thread but Man I guess some people are so good at open loop tuning, they never leave their neighborhood as in to a higher or lower elevation or get a bad tank of gas these days so they don?t need closed loop, afr stays spot on lol. Myself I got a bad tank of e85 the other day and it pegged fuel trims fuel rich, wouldn?t even run in open loop when I tried to switched it. I better keep my closed loop lol and that guy better keep his laptop handy in case he goes somewhere. It?s pretty clear to me that he hasn?t tuned a closed loop system since 2001 where he learned he didn?t know how obviously. ��*♂️

uh oh..be prepared for a 100 page novel on how awesome and knowledgeable he is....now ya did it....lmao