cygnusx1 Posted September 19, 2008 Share Posted September 19, 2008 Anyone here using autotune (closed loop mode) with MSII and an LC1 O2 Sensor. What are your settings for: EGO Control and Automatic Mixture Control I am about to try MSII in closed loop mode to fine tune the maps. I have done all my tuning up to now with Megalogviewer and its VEanalyzer. Thanks Quote Link to comment Share on other sites More sharing options...
Zmanco Posted September 19, 2008 Share Posted September 19, 2008 I'm running MS2/Extra and tried autotune early on while my maps were pretty coarse and it was of little value. Unfortunately automatic mixture control is not supported on Extra so I don't have much experience with it. But I did notice that with Autotune (which I believe is the same for MS2 and MS2/E) that it often was too far away from a datapoint to make changes. It seemed to be worse when I switched to the 16 x 16 tables. I know the parameters can be changed in the .ini file, but I just haven't spent the time to mess with it yet. I know that's not much help, but didn't see anyone else replying so thought I'd share what I knew so far. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted September 19, 2008 Author Share Posted September 19, 2008 The megamanual seems to talk about SOME of the parameters that I can tweak in MT but for some reason I can't find information about others. I'm trying to do some fine tuning. Most of the coarse tuning is done, so I want to set it very "light" and just let it do it's thing running in closed-loop. for example: WB Controller Settings section, in the second attachment. I can't find info on those settings.---nevermind I found the section. Now I need to study. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted September 19, 2008 Author Share Posted September 19, 2008 Well, I drove for an hour all over the place at different speeds and loads. When i came back from the ride and checked the old VE I had saved and the current VE which I saved before shutting off the car, and they were IDENTICAL! Hmm maybe I need to increase some O2 authority...or maybe my map is very close already. I did see a few EGO corrections in the 93% and 106% ranges during the drive but it didn't make any table changes. I suppose my parameters were too strict. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted September 20, 2008 Share Posted September 20, 2008 Closed Loop EGO != Autotuning. For closed loop EGO control, most cars I've ever tuned need about 10% authority for a bit of adjustment without getting crazy. I like to see about 20 ignition events per adjustment with a 1% step. If I could, I'd cut both numbers in half, but I don't think the step can be a fractional percentage. Over that 10% authority and you need to tune more. I don't ever recommend the "autotune" feature on any car. Ever. I've yet to see the strategy that can deal with samples that aren't dead on the load cell and not screw up and chop up the fuel table. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 20, 2009 Author Share Posted April 20, 2009 EGO Control, Automatic Mixture Control, Autotune....? What is the difference? If I enable AMC, does that mean I am Autotuning? Or is Autotuning a separate thing that needs to be turned on to automatically to tweak the VE Table? Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 20, 2009 Author Share Posted April 20, 2009 OK I went back to hit the books and read up the Megamanual. I went out for a drive and got the Autotune working. I still need to learn more about it, but it already made a few mild changes to my VE table and it feels better already. Placebo? Maybe. I will summarize the process when I learn it inside and out. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted April 20, 2009 Share Posted April 20, 2009 EGO Control, Automatic Mixture Control, Autotune....? What is the difference? If I enable AMC, does that mean I am Autotuning? Or is Autotuning a separate thing that needs to be turned on to automatically to tweak the VE Table? Closed Loop is the same as Automatic Mixture Control which is the same as EGO Control. It is the use of the Oxygen Sensor (or wideband) along with a target A/F ratio table (which you fill out) to temporarily and immediately alter the amount of fuel injected to hit the target A/F ratio. This is typically only done for low throttle cruise applications. Likewise, general rule of thumb is to give it about 10% authority. Anything over that, and you probably need to tune it more. Autotune is something else entirely. Many ECU's don't use it. I personally think they are crap, but YMMV. Autotune uses some level of datalogging to sample what your actual A/F ratio is versus a target A/F ratio table. After a pre-determined amount of samples, it will start to alter your actual fuel table in the particular fields where it has logged enough samples. These changes are permanent until you either go in and undo them or the Autotune makes changes again. IMHO, autotuning is a very lazy tool for someone who should not be tuning in the first place and should be taking it somewhere to get it corrected quickly. If the map is off badly (such as in boost), autotune isn't going to rapidly close the throttle and make coarse adjustments to avoid blowing your motor. I have seen spreadsheet/macro systems before that harvest data from a datalog and fill out an "average A/F ratio" for each load point and gives you a feel for what changes you need to make, but you have to be pretty close to do that and you have to monitor the engine while datalogging. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 21, 2009 Author Share Posted April 21, 2009 Great explanation. I have run many, many datalog and VE analyzer cycles against my AFR table with manual massaging, and the car runs great all the way up to 6000rpms and 15psi boost. Yes, I have gone through two head gaskets but hey, it's a learning curve Now I know the limits. Just when I get it running great, I like to start going for economy by taking the AFR's in the daily-drive range leaner. Making small changes to the AFR table and datalogging. I just figure since MSII has the autotune, and/or closed loop capability, I would utilize it; mostly for fun and educational purposes. Thanks for explaining the "pre-determined amount of samples". I didn't realize that those samples had to be from the same vertex before the change gets written. So I can raise the "sample required" number to get a better average read of a vertex. Incidentally, my map feels really close in most of the range. One day I will get on a load hold dyno with Z-YA up in NH. Last tank of mixed driving I got about 21mpg and I can still scare most people out of the passenger seat with monster acceleration in the 12.3AFR's . Gotta love it! Quote Link to comment Share on other sites More sharing options...
slown280z Posted April 21, 2009 Share Posted April 21, 2009 Did you mess with the INI files for the autotune? If not, you might have not been modifying too much. I think they have an RPM and a KPH cutoff, and if left to defaults, it's pretty low. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 21, 2009 Author Share Posted April 21, 2009 I set the RPM (>1200) and Kpa(<180) limits in Megatune. I'm using MS11 v2.687. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted April 21, 2009 Share Posted April 21, 2009 On a turbo car especially, you can play with about any A/F ratio you want at such low load conditions for lean burn. Just leave timing alone and play with A/F. I have tuned cars to 17.x:1. It's basically down to drivability. To some degree, if you go too far, the engine just builds more load (to get out of the lean condition) to make the power you need to putt around town. I found 16.5 is pretty good. Cars will be sensitive to surging and whatnot when getting that far so be sure to smoothe out the edges of the map where you taper into stoich or boost conditions. I usually put target A/F leaner from about 2000~4500 rpm and avoid changing the A/F target in the highest vacuum load row and the 0 psi relative load row. This gives you a box of "common cruising load" without tinkering with idle, high revs, boost transition or very very light throttle. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted April 22, 2009 Share Posted April 22, 2009 I'll put a plug in for MSII/Extra. The latest beta now has the ability to do the fuel calculations taking into account the target AFR table. In effect, this means that when you are tuning, you are tuning for the real VE of the engine separate from the AFR table. The value of this feature is that you can make a change to the AFR table and not need to go back out and datalog and tune again. Unfortunately the first time MS is changed to operate in this mode the entire VE table needs to be retuned. Quote Link to comment Share on other sites More sharing options...
slown280z Posted April 22, 2009 Share Posted April 22, 2009 I'll put a plug in for MSII/Extra. The latest beta now has the ability to do the fuel calculations taking into account the target AFR table. In effect, this means that when you are tuning, you are tuning for the real VE of the engine separate from the AFR table. The value of this feature is that you can make a change to the AFR table and not need to go back out and datalog and tune again. Unfortunately the first time MS is changed to operate in this mode the entire VE table needs to be retuned. Do you have a link to that? I can't find it anywhere and I'm REALLY interested in it! Quote Link to comment Share on other sites More sharing options...
Zmanco Posted April 22, 2009 Share Posted April 22, 2009 Here's the link to the thread on the latest beta: http://www.msextra.com/viewtopic.php?f=91&t=30944 If you're not a member on the msextra.com forum you may not be able to see it. The development threads can only be seen by members. BTW, this beta is very close to being released. For the features I'm using it's rock solid stable and I wouldn't hesitate to use it on a daily driver. Quote Link to comment Share on other sites More sharing options...
slown280z Posted April 22, 2009 Share Posted April 22, 2009 Didn't see it mentioned their either. As of now, I tune by myself with target AFRs only used for telling MegaLogViewer what I want the AFR to be. I haven't turned on the corrections yet, and if/when I do, they'd only be for cruise, not while in boost (where I even have accel/decel turned off). Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 23, 2009 Author Share Posted April 23, 2009 You can limit autotune or closed loop mode, by Kpa limit, so it only tweaks the areas you specify. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted April 23, 2009 Share Posted April 23, 2009 IMHO, Megasquirt doesn't have enough map resolution to attempt autotune. Too large of an rpm/load area that is claimed by a single load cell to let the ECU try to do it. I personally like 24x24 tables. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 23, 2009 Author Share Posted April 23, 2009 True, I was wondering what MS would try do do if it wasn't near a vertex and it adjusted incorrectly. What I did was keep the vertex tolerances pretty tight so that it wouldn't tune in the "black holes". This certainly decreases the speed that it will autotune, so it will take longer. MS will interpolate linearly between the vertices which should be pretty close...or at least close enough for a hobby car. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 23, 2009 Author Share Posted April 23, 2009 Let me ask this question. Last time I loaded the msq and disconnected the laptop, the AMC and O2 control were enabled, and autotune was enabled. With the laptop disconnected, is MSII auto tuning (VE map tweaking) or is it just O2 compensating (closed loop) based on the AFR map(without actually flashing the VE table)? I am a bit confused as to how and what happens when the laptop is disconnected. Quote Link to comment Share on other sites More sharing options...
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