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Thread: Open Loop, Closed Loop and MAF

  1. #1
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    Open Loop, Closed Loop and MAF

    (Hi, I posted this in the Gen 4 and was hoping for some answers. But no luck so far, so trying here too...... it is a bit of a long winded message, but hoping someone can help answer it.
    Thanks
    Red.

    Hey guys, Red here from New Zealand. Rather new here, so have a number of questions. I have spent quite a bit of time going through (mainly) the Gen 4 forum to try and research/answer my questions. But the knowledge and answers here can really fly over the top of my head at times. Kyle's YouTube from Goat Rope have been a great help, same with HP Academy, plus all the answers everyone else have here.

    My tuning experience is 95% Superbikes. I use a Dynapack dyno (with an adaptor I made), along with mainly Woolich Software and to be honest, the tuning of the bikes is so much easier when you look at all the different tables/maps that are here in HPT for cars. Although now the bikes are getting a lot more technical within their ECU's with fly by wire, many different power modes for each gear etc etc. Where the bikes are a long way ahead of the cars is their Traction control, Slide Control, Anti Wheelie.... bah blah.

    So please bare with me.

    Our car is a 2010 Chev Camaro SS with the LS3 and 6 speed manual. The only change is the air filter and intake, other than that, standard. I don't know if anyone has been inside the ECU before me. I downloaded the file that was in it and stored that away as the original bin file. I did have a 2001 Holden HSV GTS 300 in the 2000's which I tuned myself with the HPT. it was all pretty simple as that engine was MAFLESS. Did change the cam, airbox, headers etc and ended up with about 470 SAE at the wheels.

    Questions.....

    THROTTLE: Command..... so this is the foot throttle, with a fly by wire to the TP.... and 100% is 100% at the foot?
    Throttle Position (SAE) ..... at 83.9% (on my car) is 100% at the foot. And the 83%, is the blade actually open 100%?? And I am guessing the 83% is 83% of 5v as the TP ranges from 0-5 volts???
    Relative Throttle...... what is this related too??
    Accelerator Position..... what is this???
    Desired Throttle .... On a R1 superbike, with the fly by wire throttle, and in full power mode, I have the hand throttle same as the TP..... 80% is 80%, 35% is 35% etc, but when I tried to do this in the Desired Throttle Area Map A, after a reflash, once my rpm got above something like 2500, it would switch to a limp home tune. So I have left this map standard.... just wondering if this is possible to change (and yeap, saw the comment warning from HPT.....but was curious!!!)

    Area Rate Limits.....this is set to 100% from standard. But is this to do with the "speed" that the blade opens?? After our big earthquakes, quite a few of our roads are not the best; very bumpy, which can make a very jerky
    throttle, so was wondering if this would mellow it down??

    OPEN LOOP: So I have been trying to learn the HPT set up, and have been "tuning" with Speed Density using an AEM WD Sensor. So Trims are off, MAF off, O2's off........ Is switching from Closed Loop to Open (with every sensor switched back to normal) controlled by the P.E setting parameters?? So roughly my settings are (Enable) 30% TP, 15kpa, 300 rpm..... (Delay) 5000rpm. So it can switch to Open Loop with the Enable settings quite early, but, P.E won't happen until after 5000 rpm.....??? Yes??

    Open Loop Gains.... Anyone use "Air Flow Gains" table to cover a base area of their VVE table when in Open loop and then fine tune in the VVE??

    Equivalence Ratio Commanded.... Is this the Commanded EQ that is looking at the other compensation maps, like for example, Airflow Gain, IVT Gain Gas, Open Loop (gear), EQ Ratio Min.... and what ever the engine is demanding at the time, the ECU provides the EQ of the highest EQ??? So lets say if "IVT Gain Gas" is 168 degrees intake Valve and at MAP 75kpa and the EQ is say 1.1000 and in your VVE table at 75kpa 3000 rpm at exactly that zone the number are 2,167, the ECU figures out what the VVE fueling would equate too when converted to EQ, comparing to the IVT Gain GAs table, and picks which Zone in those tables that has the "strongest" EQ Command........ (not going into P.E mode though).... is this correct????

    CLOSED LOOP: When in Closed Loop, is the engine trying to always run at Stoich ARF.... so what ever you have tuned when tuning in Speed Density, the CL is then trying to change this to 14.68 even if you had it running say 14.25????
    And if you go into the FUEL... GENERAL.....Stoichiometry, and change the 0% to 14.32, then when in CL it will then try and keep things at 14.32???
    So if running the car with CATS removed, there is no reason why you can't run at 14.2 on light throttle/cruising??

    MAF SENSOR.... so when ever I have tried to go back to the standard sensor settings (using the MAF), the logged Lambda from the AEM is like flipped 180 degrees when compared to the Logged Data in Speed Density, So light throttle/cruise is rich while big throttle/MAP is lean. I have now read some where in here that even if you have the MAF settings standard (Dynamic Airflow RPM Disable 4000, Disable 3,900.... Mass Airflow Sensor Freq High/Low standard), and think you are using Speed Density, the ECU is still using a % of the MAF Sensor as well, and when it reaches your settings in the Dynamic Map settings, and switches to fully MAF, this needs to be tuned like you do with Speed Density, if wanting to run all the sensors in their standard settings... Is what I am trying to describe making sense???.
    So this then throws off my VVE map, when trying to switch sensors back to standard. So you need to also tune with the MAF as well, unless I am guessing, leaving the MAF off all the time...!!!!

    Have any tuners here ever done a test, of running a Wide band sensor before a Cat and also straight after a Cat????

    With my current set up my AEM is set up after the Cats, just because it is so tight trying to install the AEM in the Narrow Band Sensor position before the Cat (standard Exhaust). So i am curious to know at what rpm the exhaust gases do not get effected by the cats, and when they are in effect, how much of a difference the WB's are reading between each other???

    I am just using the current set up to learn the HPT system again. Because learning this on the dyno would take a lot of time and money ( i lease the Dynapack ..... i don't own it). So learning as much as I can on the light/meduim throttle and MAP loads, will hopefully save me time. Tuning WOT is easy, as I am sure everyone agrees, but doing all the small positions takes time.

    FINAL QUESTION..... I will attach (hopefully) a couple of logs and my current tune, for someone to have a look at please. I have a problem with the car dyeing completely for a split second. This seems to happen around the 1000-1400+ rpm
    Map say around 50-60kpa. If you can have a look at Log File "Map 14 ignition Maps Mystery Cut" at the 11:26min mark, you will see the ignition drop rapidly to 5 degrees (should be 41 degrees), then again at 14:14.....6.0 degrees (should be about 11).... I have both Octane tables the same and there are no Knocks or retards happening when it happens. So any ideas on what to look for??

    Just so you know, the fuel i use here is a 100 Octane measure in RON, which I think in the USA is about the same as 95 AKI (Anti Knock Index). map 14 Ignition Maps Same Mystrey Cut.hplMap BASE MAP PE CL and TRIMS off Map 14 Low Octane same as High.hpt

    I very much appreciate any advice/help that is around. Hope I have not wasted any ones time.

  2. #2
    Senior Tuner
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    Wow. That was a long read. LOL

    I'll give you a real quick response for now.

    84% throttle opening in HP Tuners is full throttle. We only have access to 6 of the 8 segments in the E38 PCM. The ones that we can't fully access are the throttle segments. You won't be able to make much of a change to the throttle opening without pissing off the PCM.

    You're right about the affect of the MAF sensor at lower rpms. The standard strategy is a hybrid MAP/MAF until 4000rpm, then it's MAF referenced. In your application, with a stock engine, there shouldn't be a reason to alter the VVE tables. However, the air filter and intake change will likely require the MAF curve to be changed. Simply drop the Dyn Airflow Disable and reenable values to something less than idle speed to force it to MAF mode.

    For part throttle tuning, You can then force it to open loop in order to tune with your wideband, or simply keep it closed loop and tune based on the fuel trim values.

    For WOT tuning, you'll need the wideband for sure. Typical values for best performance are 12.8-13.0 AFR at WOT and 25-26 degrees timing at peak HP with your fuel.

    There are timing modifiers based air temp/coolant temp and even burst knock tables that will alter the timing. You'll simply have to datalog each of these modifiers to see which are in play.

  3. #3
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    Thanks for the reply Kevin. Much appreciated.

    Am away on a little holiday at the moment. But will get back into it and ready your answer again when home.
    Cheers
    Red.

  4. #4
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    Hi Red,
    I used to work for Woolich racing a few years ago. I helped Sloan out a few times in the early development of the 2017 GSXR-1000 at PI.
    Bikes are way more simple than cars but it?s also the Woolich software that makes if more user friendly.
    Bikes Tc maps are complex because they can be 6 axis measuring pitch, yaw and roll. Cars don?t generally wheelie in 6th gear lol.
    Get a decent Ecu like a Motec and you will see what you can do with a good launch control system on a car. At the end of the day a bike will usually get an exhaust and filter and it?s done. A simple open loop tune, adjustment to STP or ETV and your good to go.
    A car tune is very different as it gives you the possibility to adjustment everything.
    There are a heap of multipliers to tables with EQ ratios etc which is actually pretty amazing.
    If you give me your email address I?ll send you some info and links mate. It will get you more than started!
    Cheers
    Joel

  5. #5
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    Hey Joel.

    Thanks for the reply. Sorry, I have not looked back here for a while. I have managed to dig a little deeper into the Camaro's ECU and have learnt a bit more. Lately I have been having a go with tuning it with the Dynamic Airflow. And wow..... talk about sooooo much easier compared to Speed Density.
    Just actually spoke to the guys at Woolich last week with regards to the 2021 Yamaha R1M ecu. Prepping the bikes now and need Justin to sort out our ECU's as they have not got the bin file for them, so sending one 2 him this week. Yeap, I understand what your saying regards to the bikes TC/Slide control etc compared to cars. and yeap, cars have so many other compensation maps compared to the bikes eh.

    If you were able to send me any info about the Gen4 ECU etc, that would be great. I have spent a lot of time looking/reading on the net, but you can waste so much time trying to find it all, that I don't really have the time.
    Anyway, [email protected]
    Thanks Joel.

  6. #6
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    Hello redsuperbike, I will answer some of this ok.

    Move the WB o2 to the front position period it needs the heated airflow, since you are wanting to tune in open loop anyway use the special functions tab in Scanner to enable OL instead of changing all the tables! It is a temporary situation not permanent and easily returned to CL operation. You don't have cats anyway right? the COT is OFF and will destroy the cats if present? Short runs for tuning turn off ok but put COT back in if you got cats ASAP afterward. With my current set up my AEM is set up after the Cats, just because it is so tight trying to install the AEM in the Narrow Band Sensor position before the Cat (standard Exhaust).

    Next the IVT Gain (Gas) normally is a start up fuel enrichment multiplier and contributes if under load before CL begins too. Basically the IVT should be lower if the ECT is still cool and the table follows ECT roughly. This is a gain multiplier to the OL gas Gear and P/N tables. Set the open loop GAINS airflow back to 1.00 and adjust the IVT gain gas for fuel/air EQ ratio if needed not the airflow but make sure your VVE and MAF is correct.
    The bare minimum bolt ons you have should not need much adjustment, just use the normal CL fuel trims to make the minor adjustments to VVE and MAF and use a tail pipe clamp for WOT on the dyno. You can set it to run in VVE or install the 2 bar Operating system, either mode can still use the MAF sensor in blended mode just fine after you tune VVE table.
    continuing ... Again: Set the open loop airflow back to 1.00Open Loop Gains.... Anyone use "Air Flow Gains" table to cover a base area of their VVE table when in Open loop and then fine tune in the VVE??
    Yes you got it. So it can switch to Open Loop with the Enable settings quite early, but, P.E won't happen until after 5000 rpm.....??? Yes??

    If by this you mean you tuned SD mode at a lower AFR using a WB then yes the CL is trying to achieve Stoich. Change the stoich to the value you wanted 14.25%?. In CL the ECU is doing a great job of trying to keep the AFR stoich that's the purpose of CL. CLOSED LOOP: When in Closed Loop, the engine is trying to always run at Stoich ARF.... so what ever you have tuned when tuning in Speed Density, the CL is then trying to change this to 14.68 even if you had it running say 14.25????

    In Fuel-Open Loop Gains-Inj Temp Gain must make 1.00 whole table. if not you will have to drive around >20 minutes to get past that tables influence so just neutralize it or your AFR IS going to be wacky and not know why.
    Spark- Advance- Minimum spark- Torque management the ECU can reduce the spark TO THIS table not taking from main table, so set it to the minimum you want it to be. Log Trq Mgt Advance and see if that is the source of advance drop you spoke of.
    Hope that helps.
    Added 2 stock 2010 files I had.
    Attached Files Attached Files
    Last edited by Hondaeater; 10-04-2021 at 11:37 AM. Reason: clarify whn WB is needed

  7. #7
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    Hey im tuning a GEN 2 car and i don't see a 02 Readniess voltage to disable closed loop and force open loop so i dont know what to do to disable closed loop