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Practical Standalone Tuning: Step 3: Base Table Configuration

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Step 3: Base Table Configuration

25.28

00:00 - The next step of our 10 step process is to set up our base table so that we've got our table set up in a position where we can at least get the engine up and running.
00:09 It's important to understand here that we don't need the final numbers in our tables, this is just a rough approximation to get us in a position where we can start the engine and begin our tuning process.
00:20 This is going to involve setting up our fuel tables, our target air/fuel ratio or lambda tables, our ignition tables.
00:28 Because it's a rotary engine, our trailing split table which is a little unique, also going to look at setting up some limits around the likes of our RPM and our boost so that we are going to safeguard the engine while we are initially getting our tuning underway.
00:43 As part of this, there are also a few aspects of the tuning modes and the axes that we need to also consider so let's dive into our Adaptronic software and we'll take a look.
00:55 So we're going to start on our tuning/fuel tab and we're going to begin here on our tuning modes which is what I've got being displayed at the moment.
01:05 So this just allows us to set up how the ECU is actually going to function.
01:11 For a start we can see we've got a tick box here, do we want to have dual maps, in this case we're keeping things nice and simple, just a single map.
01:18 You've also got the ability to set individual correction maps and at the moment you can see I've selected that we will have no individual correction maps.
01:27 Looking at our drop down menu, we can have these based on iMAP or TPS if you want.
01:34 This will allow you to account for fluctuations in fuel delivery from one cylinder to another or one rotor to another.
01:40 Moving down, the next option is to select our temp correction mode or how this will be handled.
01:47 So you can see at the moment, this is set to manifold heat soak percentage.
01:52 If we look at our drop down menu, we can also set up a separate coolant or air temp correction.
01:57 This is really up to the individual tuner.
02:00 Essentially if we've got this set to manifold heat soak percentage then what this does is it looks at the engine coolant temperature and intake air temperature, makes an approximation on how that's going to affect the charge temperature which is really, that's the part we're most interested in, we want to know what the air/charge temperature is going to do as it goes in through the intake valves or in this case, our rotor housing in through our inlet ports and that's the important part because that affects the air density.
02:30 So if we select manifold heat soak percentage then this is all dealt with essentially automatically within the fuel model.
02:36 There is a little bit of work that we do need to do which I'll show you in a second.
02:39 Alternatively we can select the separate coolant and air temp correction tables and then it'll work much like conventional ECU, we've looked at how the air temperature in particular affects the air density through the body of the course and you'll remember our approximation there is somewhere in the region of 2.5 to 3% per 10°C change in temperature.
03:01 So at the moment we've got this on manifold heat soak so we do need to understand how that works and we'll go into this in a little bit of detail here.
03:08 We'll highlight this in a bit more detail inside of the member's webinar if you want to dive deep into the topics.
03:14 So if you come over here to our temperature correction options, and first of all we have our manifold heat soak percentage so we'll have a look at this here.
03:22 So what we can see is we've got a 3D table here, we've got RPM on our horizontal axis, we've got our manifold pressure or our load will be on the vertical axis.
03:31 And the numbers in this table define whether the ECU is going to be biasing more towards our engine coolant temperature or more towards our intake air temperature.
03:40 A value of 70 here, which we've got down in the idle areas, that means we're biasing more towards our engine coolant temperature.
03:49 A value of 100% would mean that the ECU solely uses engine coolant temperature for the charge temperature estimate, a value of 0% would mean that it biases completely towards the air temperature.
04:00 So we can see, in the low load, low RPM areas, we've got values of 70% and this means that we're going to be biasing more towards engine coolant temperature because air speed is low, giving a lot more time for the air charge to absorb temperature through the inlet manifold, the ports etc as it makes its way into the cylinder or in this case our rotors.
04:22 On the other hand at higher load and higher RPM you can see that we have a number of 50%, meaning it's biasing much more towards our inlet air temperature because air speed is higher.
04:32 So the combined function there will define the charge temperature and then that is used automatically in the ideal gas law calculation for air density so we don't really need to worry about that.
04:45 In most instances, provided you've got the manifold heat soak percentage table set up accurately or correctly for your particular application, you're going to find that the air/fuel ratio will track pretty consistently regardless of changes in air temperature or coolant temperature.
04:58 However there can be some areas where the charge temperature estimate essentially over or under compensates and this can bring in lean or rich areas.
05:07 In that instance, we do have the option to also use our charge temperature correction tables.
05:13 So we'll open that up.
05:14 Conventionally you should start with this set to zero.
05:17 The axes here, we've got our manifold pressure or our load on a vertical axis and then on the horizontal axis we've got our calculated charge temperature so this is the charge temperature the ECU is calculating based on our manifold heat soak percentage table and our engine coolant temperature and our intake air temperature.
05:35 So as I've mentioned, this should be set to zero and what we can do is use this to compensate if there's an area where it's too rich or too lean at a certain temperature so you can see in particular here, at lower calculated charge temperatures and lower load I've actually added a percentage into there for exactly this reason.
05:55 So I'm not going to dwell too much more on that, the default numbers from Adaptronic will be good enough to get you up and running and they should be pretty close.
06:03 Let's head back over to our tuning modes now.
06:07 The next selection we've got here is our load selection for our target lambda table.
06:12 So we've got this set to manifold absolute pressure, this would be our conventional option there under most circumstances, matching the same load axis we're using for our fuel table.
06:22 One area where we may have different axes would be if we're running an ITB setup where we've got a turbocharger and we'd want to use throttle position for our fuel table axis but manifold pressure for our lambda target.
06:35 Moving on, we'll come over to our master fuel trim.
06:40 So as its name implies, this does allow you to add in an overall master fuel trim.
06:45 Trimming more or less fuel in and out of the engine.
06:48 I strongly advise that at least once you've got the engine up and running you leave this at zero and this can end up having knock on effects if you've adjusted this and you haven't accounted for it.
06:59 Particularly with the accuracy of the volumetric efficiency numbers in our table.
07:03 Next we'll come down to our fuel map one setting.
07:07 So the first option we've got here is the operator, so how is the fuel system or map going to be set up.
07:15 So in most instances here we would use MAP which is our default setting which we've got selected.
07:21 If we look at our drop down menu though, we can choose TPS which would be ideal for engines that are naturally aspirated running individual throttle bodies.
07:29 On the other hand, we've also got two other options, MAP + TPS or MAP x TPS.
07:36 MAP x TPS, this would be useful for individual throttle body turbocharged engines.
07:40 This would bring about two maps that would be available, one our primary map would be RPM versus throttle position.
07:47 Our secondary map is our RPM vs manifold absolute pressure.
07:51 And the two maps, essentially the numbers are multiplied together.
07:56 Essentially the same thing happens with our MAP + TPS option except as it would suggest there, the numbers are added together so for most instances we're going to use MAP.
08:09 We've then got our stoich source or stoichiometric air/fuel ratio source.
08:13 Which in this case you can see that that's set to constant so this is what we'd be using for a non flex fuel vehicle.
08:19 We can also use flex fuel with a constant lambda target table or we can change our air/fuel ratio lambda targets based on ethanol content.
08:28 So again we're keeping things simple here, leaving that constant.
08:31 And of course you also need to actually enter the air/fuel ratio for the stoich air/fuel ratio for that particular fuel that you're using.
08:39 So in this case, pump gas, 14.7:1.
08:42 We've got the option to select a volumetric efficiency mode which we would use for most instances, there's no real benefit in not using the VE mode.
08:51 However there is the ability here to force the volumetric efficiency mode off during cranking which in this case we use a millisecond based fuel table.
09:00 Again not 100% sure any instances where that would be really strictly necessary.
09:06 We've got our pressure selection here, so we can choose between manifold absolute pressure, pressure ratio which is iMAP divided by exhaust map, TPS or manifold gauge pressure and again conventionally, most instances we will be using manifold absolute pressure.
09:20 So that's got our main fuel table set up, relatively straightforward.
09:24 Now that we've got our main settings dialled in, we can see we've got one fuel map available so we can head across and have a look at that.
09:31 This is already configured, reasonably close to what I'd want here, we can see we've got our 3D table being shown graphically up the top here and we've also got it shown numerically down the bottom.
09:43 Got our load axis on the vertical axis and RPM on the horizontal axis.
09:47 Now if you want to change the axis break points, what we can do there is simply click on the axis, double click on the axis and in this case I've clicked on the RPM axis.
09:56 We can enter the maximum valve for that axis, the minimum value for the axis, in this case 0-8000 RPM and the number of break points you want in this table.
10:07 In this case you're limited to a maximum of By doing that and adjusting that and clicking update entry, that will then interpolate between your points with the number of break points you've selected.
10:18 Alternatively you can choose to manually enter a value and then on the right hand side here we can adjust these values to suit.
10:27 Now you can see I've already got this set up here, we've got essentially RPM break points every 500.
10:33 I've got a little bit of additional resolution down around the idle and transition areas, we've got a few break points there at 250 RPM increments which is pretty typical of how I would normally set this up.
10:44 We've also got our break points on our load axis there.
10:48 In vacuum we're looking at about every 20 kPa, again I've got a few more added in there, got one for example at 50 kPa, sort of where we're going to be in the idle and cruise transition area just for a little bit of more resolution and you can see actually out into positive boost I'm opening this up a little bit, we're looking at 25 kPa increments so again, as discussed in the body of the course, one of the common mistakes that tuners make is to add too many break points, thinking that they're going to get a better result.
11:16 Remember that the ECU will interpolate between the break points so there's no real need to go crazy with too many break points.
11:25 We're going to add break points in as required if we see we've got a large change in volumetric efficiency over a short range of the RPM or load and we can always come back and address this, add to them later.
11:35 What we're going to do while we're here, while we have got numbers in this table, we're of course starting from scratch here so I'm going to highlight the entire table here and we're just going to set the entire table to 50%.
11:45 This is one of the advantages with the volumetric efficiency based fuel model is that 50%, it's obviously not going to be right but it should be enough to get us up and running from where we will be able to perform our tuning.
11:56 Now that covers the main aspect of our fuel delivery however with a VE based fuel model we do also need to give some consideration to our target lambda or target air/fuel ratio table, we want to make sure that this is dialled in accurately as well.
12:09 So we can see we've got the same axes there, we've got our inlet manifold pressure versus our RPM.
12:15 We are working in units of lambda, if you prefer to work in air/fuel ratio units you can adjust this from the home screen where, we'll head back actually and have a quick look at that and if we go here we can see you can choose to display your air/fuel ratio in lambda, clicking on that will change it to petrol.
12:35 I prefer to work in lambda so for the rest of the lesson, the worked example, we will continue to do that.
12:41 We'll head back across to our target lambda table.
12:43 And this is a area where rotary engines are a little bit unique in that in comparison to a similar powered piston engine, we do tend to need to be a little bit richer on a rotary engine.
12:56 In particular, you can see that in the cruise, the idle areas I should say here, I'm actually tuning for around about 0.92 lambda which might sound a little bit rich.
13:04 It's a fine line here, you will find that if you try and target a stoichiometric air/fuel ratio at idle, generally the rotary engine won't be that happy idling at that, you'll get a much more solid and controllable idle if you do tune a little bit richer.
13:21 You can see that in the cruise areas in vacuum I am targeting lambda one because at the end of the day this will be a modified street car so we do still want to get some good fuel economy.
13:32 One of the things you will see with a rotary engine as we lean out the air/fuel ratio towards stoich is we do end up suffering from quite high exhaust gas temperatures so sometimes it can be beneficial to run a little bit richer, sacrifice a little bit of fuel economy for controlling those EGTs.
13:48 What we can see though is as we step up in this case to 100 kPa transition area, with a piston engine, I might be normally sort of in the region of 0.95 to 0.98 lambda.
14:00 We can see I'm tuning quite a bit richer there at 0.90.
14:03 In this case our target maximum boost, 200 kPa, again on a piston engine I might be more inclined to be in the region of about 0.80 lambda.
14:14 Again a little bit richer here, 0.76.
14:16 Now this does become a bit of personal preference as well.
14:20 I do know there are a lot of tuners that run much richer than even these targets on a rotary engine.
14:27 I've proven the numbers that I've got here for a modified street engine are absolutely reliable.
14:32 If I was tuning this to be a race engine I may be inclined to go slightly richer.
14:37 What we will find is that much richer than this, we will start to see the power on the dyno will start to fall off quite sharply so I tend to tune on the rich side of the area where we are still making good power before we start to fall off that cliff power wise.
14:54 Again we'll be able to see how this all pans out once we actually get up and running on the dyno.
14:59 While we are dealing with fuel I just will again mention the injector staging.
15:04 I've already covered this during the initial input and output setup so I'm not going to labour on with this.
15:10 Remembering again, with the Adaptronic we really don't need to do anything here with our two stage injection map.
15:17 We can leave that set to zero and the ECU will do that heavy lifting for us in the background.
15:24 That covers our fuel setup, we're going to now move across to our tuning/ignition.
15:29 An again we'll start with our tuning modes.
15:32 And a lot of this really follows through exactly the same options that are available under fuel.
15:38 We've got our dual map option, we've got that unticked, we've got the ability to add correction maps which again at this point I'm not.
15:45 We've got our load selection for our spark split, our rotary trailing split table.
15:51 So generally in most instance we're going to run this the same as our load axis for our spark table.
15:57 Likewise if you are using ethanol correction maps we can choose the load selection for that.
16:04 We've going to come across to our master ignition trim, again very similar to our master fuel trim and likewise with this I would urge you to leave this set to zero.
16:14 If you want to just do a run on the dyno and add 2° and see if that's been a benefit then yes you can do this here but it is important to keep track of those.
16:22 If you decide you like that change, I would advise you to carry that across into the actual ignition maps rather than leaving a permanent trim in your master ignition trim.
16:34 Then we'll move down to our ignition map one settings and here again just like our fuel we've got the operator for the ignition maps, we've got MAP, TPS basically much the same options that we've already looked at.
16:46 In most instances, the two that we're likely to use there are MAP, which is what we're going to be using, or TPS if you're running an ITB setup.
16:55 So that defines our base setup.
16:57 We can now come across to our ignition map one, I'll have a look at that and again looked very similar to our fuel map.
17:05 We've got exactly the same options here in terms of double clicking on one of the axis break points, we can adjust those break points to suit our requirements.
17:14 Again rule of thumb here, 20 kPa for load break points and 500 RPM for our RPM break points and that should be something that's going to be pretty good to go.
17:26 Now what we're going to do is again start with some base numbers that should be enough to get us up and running here.
17:33 So I've got a tuned table here, we can get this from one of the base tables for the rotary engine that Adaptronic provide.
17:41 But what I'm going to do here is just start by essentially setting our entire vacuum area, up to 100 kPa, we're going to set that to 15° to start with.
17:52 Now rotary engines actually run quite a lot more retarded than this at idle so again what I'm going to do is just come down here and I'm going to highlight up to 1250 RPM and we're going to set that to 5°.
18:04 So I've found for this particular engine, runs quite nicely at 5°.
18:08 What we're going to do, again for simplicity here is up to, from 100 kPa and above, start by just zeroing out all of those values there.
18:16 And again the rotary engine, given that is very fragile, we want to be a little bit more cautious with our timing on boost.
18:23 So what we're going to do is just trim our timing down to 10° up to 160 kPa and then from 160 kPa out to 220 kPa, we're going to add in 5° there.
18:37 It's a pretty basic map at the moment, this is just something that's going to be pretty conservative and it's going to be enough to get us up and running with no real risk of doing any damage to our engine.
18:47 From here, we're going to be able to optimise these numbers as we go through the tuning process.
18:53 Next we'll move along and we'll have a look at our correction map.
18:55 So we've got a coolant and an air temp correction map, we'll bring those up here.
19:00 At the moment you can see that I've got both of these set to zero, our coolant temp here and our air temp below.
19:10 This is a personal preference here, I know a lot of tuners will tend to trim timing out as the air temp and coolant temp comes hotter just for safety's sake.
19:19 So again that's up to the individual tuner.
19:22 Next we'll move across to our spark split table which we can find here out on the right hand side.
19:27 So this again, as I've mentioned already, one of the aspects that is a little bit unique to the rotary engine, they run two spark plug per rotor housing.
19:35 We've got the leading plug which will fire based on the ignition timing values in our main ignition table that we've just set up.
19:43 The trailing split will define how far after our leading plug the trailing plug will fire so this is not a timing map in itself, it just defines the split in terms of eccentric shaft rotation degrees, where the secondary plug will fire, the trailing plug will fire.
20:01 So we've got the numbers set for this table here, let's just bring this up so we can see it in a little bit more detail.
20:07 We have a simple 3D table here, RPM versus our inlet manifold pressure.
20:13 Now a lot of tuners will chase these numbers around, trying to find additional power.
20:19 In my own experience, there is a relatively minimal effect from our trailing split on our engine power.
20:27 And the theory here is that a lot of the trailing split effect is actually around emissions but yes there is some benefit in terms of power.
20:37 What we do need to be mindful of is the numbers we actually use, we need to understand that as we advance the trailing split, to advance it that would be adding smaller numbers, has the overall effect of actually advancing our timing so we can be prone to detonation if we go too far with that.
20:55 The numbers that I'm using here, these are my go to map for at least the start of my trailing split tuning and what we can see is down in the idle areas we're using a trailing split of 15° which is not too different to what Mazda use so 15° in idle.
21:12 Under the cruise conditions, I've advanced that up a little bit to around 10° and we can see that as we move down this map into the positive boost areas, we are advancing it up a little bit further to about 8° so this map has essentially been developed from reverse engineering some of the factory Mazda maps and again just some experience in what numbers in this map will work with reliability without potentially causing you damage.
21:38 So I'd suggest this as a good starting point.
21:39 Feel free of course to then test and find what yourparticular engine likes but I don't suggest you're going to find significant improvements by making wholesale changes to this table.
21:51 At this point we've covered the setup of most of our base tables.
21:54 What we also want to do is make sure that we've got some safety protection strategies in place as well before we start tuning.
22:01 So we can find these if we go across to our functions option and what we're going to do is go across to our engine protection/rev limiter option.
22:11 An there are a variety of different engine protection strategies available here.
22:16 The two I'm going to focus on primarily will look for a start at our rev limiter which is what we're showing now.
22:23 So you can choose to use fuel cut, ignition cut or both.
22:27 I prefer, particularly with a stock rotary engine, to use a fuel cut.
22:31 This is a little less aggressive on the engine and particularly with stock seals, the rotary engine is not overly fond of popping and banging on a limiter, which can occur if you're using an ignition cut.
22:44 So fuel cut's the safest strategy to use here.
22:48 Then we have our RPM limit versus coolant temperature so we can click on view and edit table to see that and we can see we've got our RPM limit here is set up to 7800 RPM until we go above 103°C where we'll interpolate down to 5000 RPM at 120.
23:08 Head back to our rev limiter options here.
23:10 We can also see we've got an additional RPM for 100% cut.
23:16 So this allows you to program a soft cut or a hard cut, in this case we've got a hard cut occurring with full power cut at zero RPM above our target.
23:26 So again this comes down to a personal preference.
23:28 It can be a little bit softer if you have maybe 100, 150 RPM range on this however you do need to understand that that will allow your engine potentially to pull past the numbers that you are setting in that table slightly.
23:42 And then if you're using engine protection strategies we can set the RPM that will be used for that.
23:48 There is a note here that you can see, it says that this does not apply to oil pressure so that's its own separate entity there.
23:56 We'll come down to our overboost because obviously that's another consideration and we need with turbocharged engines, we need to start by actually enabling the overboost cut.
24:06 Our overboost selection here, we can choose either an outright map value or if you are using boost targets you can set a value above your boost target where the cut will occur.
24:18 We've got two options for our cut, we have an overboost allowed with a delay.
24:24 So basically this will be a brief period where a slight overboost is allowed.
24:28 In this case, 220 kPa.
24:31 We've also got an overboost allowed which will be instant so basically if we hit, in this case 240 kPa, instantaneously we will end up with a cut.
24:40 When you're setting up the boost cut, I suggest that you start a little bit cautious while you're finding out exactly where the boost is going to sit.
24:48 You can always come back and address these at a later point and adjust them accordingly.
24:53 It's always easiest to have a conservative boost cut limit there and then find that you need to raise that later on, rather than finding out that you've shot past your boost target dramatically and your protection strategy hasn't come in to protect your engine.
25:07 So at this point we've got our base tables all set up, our fuel and our ignition, we've got base values in there that should be sufficient to get our engine up and running and we've got some safety precautions set up as well just in case anything goes wrong while we are getting started with our tuning.