Practical Reflash Tuning: Step 5: Optimising the Tune
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Step 5: Optimising the Tune
41.19
| 00:00 | - We're now going to look at the process of optimising the tune on the dyno. |
| 00:04 | Now because we've now got our MAF scaling dialled in correctly and accurately, we know that in the closed loop portion of operation the air-fuel ratio control is very accurate and we don't really need to worry about any tuning in the closed loop region. |
| 00:20 | We can simply focus our energy now on the wide open throttle area where we're going to be operating in an open loop. |
| 00:28 | Now before we do that though, we need to go back and make some changes to our ROM file. |
| 00:34 | Now remember if we go back into our Fueling and we go back into our Fuel Map Mode I, you can see that we've still got our fuel map where we have our wide open throttle operating area set to a target of 11.0. |
| 00:51 | Let's go back to our Mode II map, which is one of the ones we set up earlier. |
| 00:56 | And I'm going to press ctrl + alt + C and ctrl + alt + V to copy that map back into our Mode I map. |
| 01:04 | Now again, just to reiterate the reason we have these four mode maps here is simply because we're using the Race ROM functionality. |
| 01:12 | And once I've completed my tuning, we're going to copy those, the fuel map and ignition maps, into those other modes so that they're all the same. |
| 01:22 | Now, this is our starting point. |
| 01:24 | However, remember we set this up before we'd actually scaled our MAF. |
| 01:28 | So you can see that particularly in the wide open throttle area of operation under high load and high rpm, we're now targeting a very rich air-fuel ratio, 10.5, 10.3 to 1. |
| 01:41 | And there's no way we need to be that rich. |
| 01:45 | Now that we've got some confidence that our MAF scaling is going to be accurate. |
| 01:49 | Hence the ECU should accurately track our air-fuel ratio targets. |
| 01:54 | So we can be a bit more realistic with these targets. |
| 01:58 | Before we start tuning this table though, it's handy to know where about we're going to be operating in this table. |
| 02:05 | And generally, if we do a full throttle ramp run on the dyno, we're going to start somewhere around about 1.2 to 1.25 grammes per revolution. |
| 02:15 | And as we come up in the rpm, we're going to move up towards about 1.7, 1.75. |
| 02:22 | And then at higher rpm, we may see that taper off a little bit. |
| 02:27 | So what I'm gonna do first of all is select the entire area that we're going to be operating in at wide open throttle and everything from 3600 rpm and above and I'm going to set that to an 11.8 AFR target. |
| 02:44 | This course isn't meant to teach you what particular air-fuel ratio to tune your engine to, but rather how we adjust our tune to achieve our target air-fuel ratio. |
| 02:55 | From experience with this particular supercharger combination, I know that for our fuel that we're running it on, this is gonna be a safe air-fuel ratio target. |
| 03:04 | Okay, we don't want to just leave our fuel map looking like this though. |
| 03:08 | You can see now, we've got a relatively erratic shape, particularly in this area here as our load drops. |
| 03:15 | And we don't want that, so what we're going to do now is make some changes to the other areas of this table and I'm going to start by looking at our higher load area so 2.3 grammes per revolution. |
| 03:28 | Now typically we're not going to expect to reach this with our supercharger. |
| 03:33 | It's a belt-driven positive displacement supercharger, so the boost is very much dependent on the pulley sizes and the engine rpm. |
| 03:44 | However, with a turbocharger, if we had a wastegate or boost control problem, it would be quite possible for us to end up moving out to the higher load areas or higher than we expect to be. |
| 03:55 | It's a good practise just to start targeting a richer air-fuel ratio at these higher load areas just in case we do end up in those areas for any particular reason. |
| 04:06 | Likewise, as we drop down in our load, we're not going to need as much fuel. |
| 04:11 | We don't need such a rich air-fuel ratio. |
| 04:14 | So I'm going to start targeting a slightly leaner air-fuel ratio as we move down to 1.3 grammes per revolution and then again in 1.5 grammes per revolution. |
| 04:26 | We'll target 12.6 to one. |
| 04:28 | And then finally I'm going to leave the target air-fuel ratios in the one gramme per revolution column as they are. |
| 04:37 | Now that's got something of a reasonable shape to our wide open throttle running area. |
| 04:42 | However, we've still go this erratic quite large step here and in order to fix that, what we can do is simply use the Interpolate function in the EcuTek tuning software. |
| 04:54 | So if we highlight a range of cells and we press ctrl and I, that's going to interpolate between the high and low points. |
| 05:02 | So that's what I've just done here. |
| 05:04 | And I'm just going to continue and do that through our cells that we've just looked at. |
| 05:11 | And what that's going to do, you can see that's smoothing out the air-fuel ratio targets as I do this. |
| 05:18 | Now, again we can make changes to this particular table at a later point if we feel the need. |
| 05:25 | This is just getting us some nice safe starting points that should be relatively close to where we want to be. |
| 05:31 | Alright, so now you can see we've got a relatively smooth shape to our curve. |
| 05:37 | We're going to be starting again, remember, at beginning about around down here. |
| 05:41 | And we've got our target air-fuel ratio set to around about 13 to one at the low rpm areas, because we don't need as much fuel. |
| 05:50 | As we move up to higher rpm and higher load, we're setting with a target of 11.8. |
| 05:56 | Okay, so let's close that map down and we'll save it and we'll save our ROM file and we will flash that ROM into our ECU. |
| 06:07 | Now, before I do this, it's important to mention that at the moment, we're going to be focusing on the tuning, optimising our tune under wide open throttle in two different ways. |
| 06:18 | We're going to focus first of all on the fuel tuning. |
| 06:22 | So remember, we've already started with a conservative ignition map. |
| 06:26 | Now we're going to always be audibly listening for knock, even when we're tuning the fuel. |
| 06:32 | However, as long as we're not suffering from any knock, at the moment, we'll be just forgetting about the Ignition table and we'll concentrate solely on getting our air-fuel ratio dialled in. |
| 06:44 | Once you're a little bit more confident and a little bit more competent with the software and operating the dyno, you'll tend to optimise both the Fuel and Ignition Timing tables simultaneously. |
| 06:54 | But particularly when you're learning, it's always easiest to focus on one task at a time. |
| 06:59 | So let's program that ROM file into our ECU now and we can do our first test. |
| 07:05 | Now that we're going to be doing some optimization of our tune under wide open throttle conditions, I've added some parameters into our logger, so we've got a little bit more information to look at and some things that are going to be relevant to the tasks we're performing. |
| 07:20 | In particular, you can see that I've added here our VVT Exhaust and Intake Angle. |
| 07:26 | Now, the reason I've added this is simply so that we can see, after a start-up, after we've flashed the ECU and restarted it, when the valve timing does become active. |
| 07:36 | And again, this is just simply because if we start the car up and immediately do a run after we've done a reflash on it, the valve timing doesn't work immediately and this can result in us showing much less power than the engine's actually making. |
| 07:51 | So we always want to simply give the engine a little bit of a rev and make sure that our valve timing is actually moving when we rev the engine up. |
| 08:01 | I've also added some parameters in here with regard to our Ignition Timing. |
| 08:07 | You can see I've got some Ignition Correction factors as well as our actual Ignition Timing. |
| 08:12 | And further down, I've got our Knock Correction values. |
| 08:15 | Now, I'm going to explain exactly what those mean very shortly. |
| 08:19 | For now, again, because we're gonna be separating our tuning out into fuel followed by ignition, provided the engine isn't suffering from any knock, we can simply concentrate on getting our air-fuel ratio correct. |
| 08:33 | So let's do that now. |
| 08:34 | Let's perform our first run on the dyno. |
| 08:59 | So that's completed our first run and this time we're going to be looking at the air-fuel ratio data over on our Mainline Dyno and you can see the red line here represents our measured air-fuel ratio. |
| 09:11 | I've conveniently put in a target line here which is the grey dotted line at 11.8 to one. |
| 09:17 | And straight away, you can see, this is where the payoff in correctly calibrating or scaling our MAF sensor comes in, because straight away we are almost absolutely perfectly on our target air-fuel ratio line without making any further changes. |
| 09:35 | So if we've got any errors and you can see that we do have particularly this one spot here at 6500 rpm, we're siting at 11.9 to one, and if we wanted to be fussy, we're also around at about 11.7 to one here at 4600 rpm. |
| 09:51 | If we want to make any changes beyond this to correct our air-fuel ratio, rather than making them in the MAF scaling, it's usually easier and more accurate to now make these further changes to fine tune our air-fuel ratio target table in the AFR target table itself. |
| 10:11 | Now, this is where we need to already have our MAF scaling close and I'm not going to be using this technique if our MAF scaling is a long way out. |
| 10:20 | I'm only going to be using this to make small changes of perhaps one or two percent. |
| 10:24 | So let's have a look at how we could do that now. |
| 10:28 | So we're going to have a look at our data and you can see there on our dyno here, first of all at 6500 rpm, we have this area where our measured air-fuel ratio was sitting at 11.9. |
| 10:40 | So let's have a look at how we could correct that. |
| 10:43 | So what I'm going to do is we'll go back to our maps and we'll go back to our Fueling and our Fuel Map Mode I and we'll open that up. |
| 10:52 | Now what we're going to do is correct this error by adjusting our air-fuel ratio targets in those areas. |
| 11:00 | And we can work out how to do that, rather than guessing, by using our Calculator function and I'll just open that up now. |
| 11:08 | Using the correction factor that we talked about in the body of the course. |
| 11:12 | So here for example, we're at 6500 rpm and we have a measured air-fuel ratio of 11.9. |
| 11:20 | So let's enter that in. |
| 11:21 | Our measured air-fuel ratio is 11.9. |
| 11:23 | Our target is 11.8. |
| 11:26 | This means that we need to add, in this case, 1.008 or 1% fuel essentially if we round this. |
| 11:34 | We need to add 1% in order to correct our air-fuel ratio and get it on target. |
| 11:41 | Now of course, we're targeting, we're requesting air-fuel ratio targets directly. |
| 11:48 | We're not actually asking for a particular injected pulse worth. |
| 11:52 | So in order to get a richer mixture, we have to ask for a richer air-fuel ratio. |
| 11:57 | That's a smaller number. |
| 11:59 | So what we actually need to do is use the inverse function here, one over, which is the inverse function, and this gives us the correction factor we need to apply in our AFR target map. |
| 12:11 | So remember we're operating at 6500 rpm at this point. |
| 12:16 | And you can see we actually don't have a break point at 6500. |
| 12:20 | We have one at 6400 and 6800. |
| 12:23 | What I'm going to do is I'm just going to highlight those two areas there. |
| 12:28 | Actually, let's have a quick look. |
| 12:30 | I know where we're operating, but if we open our last log file here, we look in the Time Graphs and what I'm going to do is just bring up our engine rpm and our engine load for a start. |
| 12:41 | And if we look at the load, we wanna find the load that we're operating at at 6500 rpm. |
| 12:51 | So we're just gonna click through until we get to 6500 rpm and we can see that we have around about a 1.72 gramme per revolution load. |
| 13:01 | So this just tells us where we're going to be making these changes in our map. |
| 13:05 | I'm going to actually extend that down to the 1.5 gramme per revolution area as well. |
| 13:11 | And let's have a look at our Calculator again. |
| 13:13 | Remember we need to multiply this by 0.99, so if I use the percentage correction factor back over on our EcuTek software and I request a change of 99%. |
| 13:27 | That will remove 1% from that particular area on our table and request a slightly richer air-fuel ratio. |
| 13:35 | Let's have a look at the rest of our log here on our dyno and we can see here as well, between about 4200 and about 4800 rpm, we're sitting at around about 11.7 to one. |
| 13:49 | So we're about the same amount too rich this time. |
| 13:52 | So we can use our Calculator, but we already know, the change we're looking for, there is about 1%, so we're going to make a change from 4200 rpm and in this case, we again don't have a zone of 4200 rpm. |
| 14:07 | So I'm going to make the change at 4400 and 4600 and 4800 rpm. |
| 14:13 | Again, I'm going to extrapolate that change all the way through to 2.3 grammes per revolution and I'm going to, in this case, we want to target a leaner air-fuel ratio, so I'm going to add 1% there. |
| 14:28 | So we can simply go through our plot on our dyno and any areas where our air-fuel ratio wasn't exactly on target, we can make those corrections. |
| 14:38 | So the last change I'm going to make here, you can see between about 3000 rpm and about 3600 rpm, we're sitting about 11.9, so again we're about 1% leaner than our target. |
| 14:53 | So let's simply open our log file again. |
| 14:56 | Should've left that open, but let's just have a quick look, just to confirm what load we're operating in at that particular point. |
| 15:04 | And we're looking for, let's say, 3000 rpm and we're at 1.5 grammes per revolution. |
| 15:13 | And if we go out to 3800 rpm, we're at about 1.6. |
| 15:18 | so 1.5 to 1.6 grammes per revolution. |
| 15:21 | And just to confirm, we want to make that change between, yeah, 3000 rpm and 3600 rpm. |
| 15:29 | So let's have a look there. |
| 15:31 | We don't again, have a zone at 3000. |
| 15:33 | So I'm gonna make this change between 3200 and 3600 rpm. |
| 15:38 | We want to richen the mixture. |
| 15:40 | So again we're going to make that percentage change and target a richer mixture. |
| 15:45 | So now we've corrected those areas and we can now save this map, flash it back into the ECU, and see how close we are. |
| 15:55 | Now, again this is only going to be used if we're already very, very close to our target. |
| 16:01 | If we're within 2% or thereabouts then it's much more accurate to make these sorts of changes in order to actually correct any air-fuel ratio discrepancy that we're seeing. |
| 16:16 | If we're outside of those realms, much more than that sort of error, then we would probably be better off to revisit our MAF scaling and adjust that there to correct our error. |
| 16:29 | Let's program our ECU again and we'll see if we've corrected those differences. |
| 16:34 | Right, we've got our ECU reflashed. |
| 16:36 | It's back up and running, so let's perform another run on the dyno and see if our air-fuel ratio is now closer to our target. |
| 17:04 | Okay, so that's our next run complete there and you can see that this time how our air-fuel ratio was much closer to our target. |
| 17:12 | And basically through the whole of that run, we're within 1% of our target. |
| 17:16 | And when we're talking about air-fuel ratio, again, we've got a range that we are looking for and I'm generally going to be happier if my air-fuel ratio is within about 0.1 plus or minus of the target I've got. |
| 17:32 | So we could continue, if we've got any errors there, to go backwards and forwards and make further changes to our AFR target table in order to correct those. |
| 17:40 | I'm comfortable with the air-fuel ratios we've got there. |
| 17:43 | So now we can move on to the second part of optimising the tune, which is optimising the Ignition Timing. |
| 17:50 | Now, in order to optimise the Ignition Timing, we need to understand the parameters that the ECU is logging. |
| 17:56 | We need to understand how those affect the final ignition advance that's being delivered to the engine. |
| 18:02 | And we also need to understand how the Knock Correction functionality in the ECU works. |
| 18:08 | If we know all of this, then we're going to be able to very quickly and easily optimise our Ignition Timing. |
| 18:15 | So let's have a look now at a log file and I'll explain exactly what we've got to look at. |
| 18:20 | Alright, so here we've got a log file open and we're looking at our now custom 2D graph here and so this is an easy way of representing all of the parameters we're interested in together. |
| 18:29 | Now, the first thing we're actually going to talk about here is our Advance Multiplier and we've already discussed this earlier. |
| 18:37 | The Advance Multiplier is a number between zero and one, which defines how much of our ignition advance map is being added in or is available to be added in over and above our Ignition Base table. |
| 18:51 | So in a well tuned engine, we really want to see that Ignition Advance Multiplier or IAM number sitting constantly at 1.0. |
| 19:01 | That means that the ECU hasn't been creating a lot of knock retard and isn't doing anything to reduce that Ignition Advance Multiplier number. |
| 19:11 | You could think of the Advance Multiplier as a coarse correction that the ECU can use. |
| 19:17 | So if for example you put in a tank of poor octane fuel and the engine's suffering from a lot of detonation or knock then the ECU will reduce the Ignition Advance Multiplier in order to reduce the amount of advance that the engine's receiving. |
| 19:35 | Likewise though, the Advance Multiplier is constantly moving and if we then fill up with good quality fuel again, and the engine is operating without knock, then the ECU will start advancing the timing and increasing the IAM number again. |
| 19:50 | Okay, so all we really want to look at at this point, the Advance Multiplier value is shown in purple and we can see that this purple line in our plot here is sitting at 1.0 the entire way through our run. |
| 20:06 | So that's what we really need to know at the moment. |
| 20:08 | We need to know that the Advance Multiplier is in fact at one. |
| 20:12 | What I'm going to do now is just change that parameter and we'll add in our Knock Correction Learn value. |
| 20:19 | Okay, so the parameters we have available to view right now. |
| 20:23 | First of all, we have our Ignition Timing. |
| 20:27 | Now, this is the final amount of Ignition Advance being delivered to the engine. |
| 20:32 | So if we fitted a timing light to the engine and physically watched the timing the engine was receiving at the crank pulley, this is the Ignition Advance we would see. |
| 20:42 | The next aspect, the next parameter that we're going to talk about here is our Ignition Correction Coarse. |
| 20:49 | So the Ignition Correction Coarse value is the Ignition Advance table value multiplied by our Advance Multiplier. |
| 21:00 | So this is how much Ignition Advance is available to add in over and above our base map. |
| 21:06 | And it's going to depend on our Advance Multiplier value as well as what we have in our advance maps. |
| 21:14 | Next, I'm going to jump out of order a little bit here. |
| 21:16 | I'm going to talk about our Knock Correction value, which is shown here in red. |
| 21:21 | Now, this is somewhat misunderstood I find. |
| 21:24 | And the Knock Correction value isn't actually what we can rely on specifically for the ECU retarding the timing in response to knock. |
| 21:35 | The Knock Correction value is used for retarding the timing in response to knock, but it is only used for a momentary knock event and generally the ECU seems to use the knock retard here for transient functions. |
| 21:51 | So if we have a sharp throttle position change or we change gears and move the throttle sharply, and we see a very large change in load and the engine suffers from one or two knock events as a result of that, the ECU will use the Knock Correction value here to retard the timing in response to that. |
| 22:11 | So this particular type of knock retard is a one-off event. |
| 22:15 | It isn't stored in any map to be used in the future. |
| 22:20 | So this is when the ECU deems that the knock that it's just experienced is a one-off event and it doesn't need to worry about that knock event happening in the future. |
| 22:30 | So particularly when we're looking at wide open throttle ramp runs, which is what we're doing here on our dyno, we're unlikely to see any activity from our Knock Correction in our log files. |
| 22:43 | The parameter we do what to monitor however is our Ignition Correction Find value, which in this case is shown in yellow. |
| 22:51 | So this is the ECU's response to knock throughout the ramp run. |
| 22:58 | Typically what we really want to see from this particular parameter is a value of zero. |
| 23:04 | That means that there is no knock occurring. |
| 23:06 | The ECU isn't retarding the timing in response to knock. |
| 23:11 | So what we can see here, if I actually remove our Knock Correction parameter, you can see our yellow line here is in fact sitting at zero through the better part of our ramp run. |
| 23:24 | However you can see here at higher rpm, at about 66 to 6800 rpm, the value there does drop, and you can see it goes to minus one. |
| 23:36 | So this is the ECU retarding the timing in response to a knock event. |
| 23:43 | Now, the ECU is actually quite smart in the Toyota 86 and when the Ignition Correction Find value is negative like this, we'll actually update that value or a part of that value into a map, so that the next time we go through that particular load and rpm range, the ECU will already retard the timing somewhat to preempt knock occurring again. |
| 24:09 | So the way this works is that half of the instantaneous retard value is added into that map for the next time we go through it. |
| 24:18 | What I mean by this is, if the ECU retards the timing by two degrees in order to prevent knock during a ramp run, what it will do is update that map so that the next time we go through the same load and rpm range, it will already retard the timing by one degree. |
| 24:34 | Now the ECU's parameters all work in conjunction, so if we're seeing a lot of activity from our Ignition Correction Find and it's retarding the timing significantly, if the timing is retarded by more than half of the value in our Ignition Advance map. |
| 24:54 | So in this case, let's say we have an Ignition Advance value of six degrees, and the ECU's retarded the timing by three degrees or more, in that case the ECU will then actually reduce the Advance Multiplier value. |
| 25:08 | So it'll make an overall coarse adjustment to our Ignition Timing. |
| 25:11 | It'll then zero out the Ignition Correction Find table and the whole process will begin again. |
| 25:18 | Anytime the Advance Multiplier is less than one, then our Ignition Correction Find value can actually become positive. |
| 25:28 | And what happen is, if the ECU detects that no knock is occurring and our Advance Multiplier is less than one. |
| 25:36 | What it will do is it will start adding timing back in and as it adds timing back in, and no knock occurs, it will gradually increase the Advance Multiplier again to get back to one. |
| 25:48 | So all of the parameters are constantly working together and it's really important to understand that interaction so we can actually do a good job of decoding what's going on in our log files and deciding where the ECU is knocking or where the engine is knocking or if it isn't. |
| 26:04 | This'll guide us in what we're going to do when we're optimising our timing. |
| 26:09 | The final parameter I want to talk about is our Knock Correction Learn value, which you can see in this case being shown in purple. |
| 26:16 | Now, the Knock Correction Learn value is the final value that's going to be added on top of our Ignition Base table value. |
| 26:26 | So our Knock Correction Learn value is the sum of our Ignition Correction Coarse and our Ignition Correction Find values. |
| 26:38 | So in this particular case, you can see if we click here, we have our Ignition Correction Coarse value is six degrees and we also have zero as our Ignition Correction Find value, in which case, the Knock Correction Learn Value becomes six degrees. |
| 26:58 | So that will be added onto our Base Ignition table value. |
| 27:03 | If we look at the area where we had a little bit of knock activity though, in this particular point you can see that now our Ignition Correction Find value has dropped to minus one. |
| 27:13 | And in this case, our final Knock Correction Learn value becomes 4.4. |
| 27:19 | So that's what's being added and over on top of our base value. |
| 27:24 | Alright, now that we understand how these parameters work, let's look at making some changes to our Ignition table and we're going to see how we can go about using the dyno to optimise our Ignition Advance. |
| 27:37 | First of all, I'm going to go back into our maps and I'm going to go into our Ignition Timing and remember, we want to be making these changes to our Ignition Base Map VVT On Mode I, just like our fuel, we have four modes here and we would generally copy and paste the Mode I into our other modes if we don't want to be swapping between them for some reason. |
| 27:59 | Now, what I'm going to do is simply start by making an across-the-board adjustment. |
| 28:04 | Now, you can see particularly through here, we have quite a sharp drop as we move up in our load. |
| 28:12 | We've got quite a sharp drop in our Ignition Timing. |
| 28:16 | And what I'm going to do is simply highlight the entire table from one gramme per revolution and above and I'm going to press ctrl + A for the Addition function and I'm going to add two degrees to that entire map. |
| 28:30 | Now, we're going to store this map, we'll save our ROM file and we'll flash that into our ECU and perform another run. |
| 28:39 | Right, we've got our engine running again on the dyno. |
| 28:42 | We're in fourth gear. |
| 28:43 | We're ready to do another run and see what our results are. |
| 29:15 | Okay, so we've got our run complete there with an additional two degrees and if we look at the runs overlaid, first of all we can see that we've pick up power, everywhere, right through that entire run. |
| 29:26 | So that's positive. |
| 29:27 | That means that the additional two degrees has moved us towards MBT. |
| 29:33 | So that's great, that's exactly what we want. |
| 29:35 | We can check our air-fuel ratio and again we can see that that's absolutely perfectly on our target. |
| 29:41 | So what we're going to do now is open up a log file. |
| 29:43 | We'll have a look at the activity from our knock control system and make sure we weren't suffering from any knock. |
| 29:49 | Okay, so we've got our log set up so we can see everything we want. |
| 29:53 | And first of all, we're looking for our Ignition Correction Find or our Knock Correction values. |
| 30:00 | And you can see that throughout the entire run, both of those parameters are sitting at zero. |
| 30:06 | So what this means is that we weren't suffering from any knock. |
| 30:10 | Now any time we see this and we've had a positive result from the change we've made. |
| 30:16 | In this case we have, we've picked up power right through our entire run. |
| 30:21 | In that case what we'll do is go and make another change in the same direction. |
| 30:25 | We go further in that same direction and that's exactly what we're going to do now. |
| 30:29 | Now, I know from experience with this sort of combination on this fuel, I'm expecting to see the Ignition Timing at high rpm somewhere around about 22 degrees and you can see at the moment, we're sitting at about 20.5, so we probably are still a little bit below MBT timing or below the peak timing that the engine will handle. |
| 30:50 | So let's stop our logger. |
| 30:52 | We'll go back into our maps and we'll pull open our Ignition map again. |
| 30:57 | And what I'm going to do is just make another two degree change right across that wide open throttle area all the way from one gramme per revolution and above. |
| 31:06 | We're going to add in another two degrees, close that map down, save our ROM, and flash it in again. |
| 31:13 | Now, the amount of change that we're making there, two degrees. |
| 31:17 | What I generally try to do, initially at least, is make a change of around two degrees, that's going to be big enough that we're actually going to be able to see the effect of that change. |
| 31:27 | If we make a very small change of half a degree or one degree, often it might not really show up as a change, so I'm making a change that's big enough to see. |
| 31:37 | Once we get closer to MBT, we can start making smaller changes and really fine tune our ignition curve. |
| 31:45 | Alright, we're ready to perform our next run. |
| 32:12 | Okay, so we've completed our next run there and we've seen quite a big improvement in power from that additional 2 degrees. |
| 32:19 | Particularly you can see, in the lower rpm area we've picked up quite a lot of power. |
| 32:24 | Through the mid-range, not quite such a dramatic change, but again in the top end, we've seen quite a large improvement. |
| 32:32 | Again, our air-fuel ratio is still absolutely on target. |
| 32:36 | So we're happy with that. |
| 32:37 | Let's have a look at our log file now and we'll see what the activity from the knock control system was. |
| 32:45 | Okay, so we've got our log file open here. |
| 32:47 | And for a start, I've got our Advance Multiplier parameter up and we can see that's in purple. |
| 32:53 | And again, all I'm doing is just checking that during that run we did have an Advance Multiplier of 1.0. |
| 33:00 | And this is one of the parameters you'll remember, we altered in our base ROM configuration. |
| 33:04 | We set the initial starting point for our Advance Multiplier to 1.0. |
| 33:10 | That just means we're starting with our maximum advance. |
| 33:13 | Particularly if this is dropped away, it's going to result in less ignition advance being fed into the engine and that's going to result in a difference in your power. |
| 33:22 | So we always want to start by making sure that our Advance Multiplier is in fact sitting at 1.0. |
| 33:29 | Now what I'll do is add in our Knock Correction Learn value. |
| 33:33 | Now, we can see, if I remove for the moment, or Knock Correction because that's again, not doing anything. |
| 33:40 | We can now we do have some activity from our Ignition Correction Find value here at higher rpm. |
| 33:49 | So that indicates that there was some knock and the ECU was responding but retarding timing and it's done that from about 5600 rpm through to about 6500 rpm. |
| 34:00 | So I'm going to address that by retarding the timing one degree in that area. |
| 34:06 | And you can see that our Ignition Advance at high rpm now is sitting at 22 degrees and that's about what I expect, as I just mentioned. |
| 34:14 | So I know that we're pretty close. |
| 34:16 | The other aspect that lets us know that we're probably getting close to our peak timing or MBT timing, is through that mid-range, we haven't really seen much of any improvement in our power. |
| 34:28 | So what I'm going to do now for the sake of completeness is we're going to remove some timing from our map between 5600 and 6500 rpm. |
| 34:38 | And we're also going to add some more timing at both above and below that and we'll make one more run and see what the results of that are. |
| 34:47 | So let's open our maps again. |
| 34:48 | We'll go to our Ignition Mode I map and again we're looking at everything below, in this case, 5600 rpm. |
| 34:59 | So I'm going to add in one degree up to 5200 and then I'm going to add in a further degree from 4800 rpm and below. |
| 35:10 | And the reason I'm doing this is because we know that the engine had suffered from a knock event around 5600 rpm. |
| 35:20 | So that means that we're probably getting pretty close in our timing around that area as well. |
| 35:24 | So if I advance the timing at 5200 rpm too far, we're almost certainly going to result in some more knock occurring. |
| 35:33 | So I don't want to do that. |
| 35:34 | The other aspect to consider when we're making changes to our Ignition table, is we always want to make sure we have a smooth shape to this table. |
| 35:43 | We don't want to see large changes across a small range of rpm or load that's going to result in erratic drivability. |
| 35:53 | Now what I'm going to do is correct our retard there that occurred between about 5600 rpm and 6400 rpm. |
| 36:03 | I'm going to do that just simply by removing one degree and we're going to then add in another degree of timing from 6800 rpm and above. |
| 36:14 | Right, we'll save that map. |
| 36:17 | We will save our ROM and we'll flash that in and test the results of that change. |
| 36:24 | Alright, we're ready to perform our next run. |
| 36:51 | And that's our next run complete there and you can see that our peak power is almost identical. |
| 36:56 | And more to the point, you can also see through our mid-range here, we also haven't really picked up any additional power from that extra two degrees of timing. |
| 37:08 | And so particularly any time when we add Ignition Advance into the map, but we don't see a result of any improvement in performance or any extra power, that means we're already at MBT timing and we can simply remove that timing back out of the map. |
| 37:24 | It wasn't giving us any advantage, so there's not point having it in there. |
| 37:28 | So particularly at this point here we can see we've actually lost a little bit of power over our last run. |
| 37:35 | And that would make me suspicious that we were seeing some activity from our knock system so let's have a look at our log file now and see exactly what was going on during that run. |
| 37:45 | Alright, we've got our log file open here and again, we can see that our Advance Multiplier, which I've got in red here is 1.0 the whole way through our log file, so that's great. |
| 37:57 | We can see that right at the very top of our run here and remember we did add some Ignition Advance above 6800 rpm. |
| 38:05 | You can see that we are pulling one degree right at the very top of our run there. |
| 38:10 | We also didn't see any improvement in our power from that additional timing. |
| 38:15 | So I'd simply remove it back out. |
| 38:18 | Now the interesting area that we talked about here at 6300 rpm, where we actually lost a little bit of power, that is a result of this particular area in here. |
| 38:30 | And you can see that our Ignition Advance is actually dropped a little bit there. |
| 38:34 | And remember, that was the degree of timing we pulled out to prevent that knock retard that we did have. |
| 38:41 | We had a degree of Ignition Correction Find being removed from there. |
| 38:47 | So that's why we've seen that drop in power there. |
| 38:51 | However, it doesn't matter how much power the engine is making. |
| 38:54 | If we are seeing knock occur then we need to remove the timing and prevent that knock. |
| 39:00 | It doesn't matter how much power the engine's making because it's not safe or sustainable. |
| 39:04 | So at this point, this basically brings us to the completion of of tune. |
| 39:08 | From here, all I would do is remove the timing that we added back in here above 6800 or 7000 rpm to remove that high rpm ignition correction that we've just seen creep in. |
| 39:21 | And what we're really looking for is our final runs on the dyno to show absolutely no activity from that knock sensor. |
| 39:28 | Now, I just wanna talk about what's acceptable from our knock control system as well. |
| 39:34 | In the perfect world, we would like to see absolutely no knock retard at all in any of our log files. |
| 39:40 | However, often that's not practical and we need to understand what is acceptable and what is indicative of a problem in our mapping. |
| 39:50 | So even if we look at a log file from a completely stock standard car, we're going to see quite a lot of Ignition Correction Find where retard is being pulled out in response to knock events. |
| 40:02 | And that's not necessarily a problem in a stock car. |
| 40:05 | Obviously as we add a supercharger and we make more power from the engine, we are going to be less tolerant of knock occurring and as I said, in the perfect world we'd have no knock occurring. |
| 40:18 | In a log file, I'm prepared to accept the occasional instance of some fine ignition correction being pulled, maybe one or two degrees occasionally. |
| 40:30 | What I'm looking for that's indicative of a problem is where we're consistently seeing ignition corrections being pulled, some timing being pulled at the same load and rpm areas. |
| 40:41 | If that's the case, then we really need to address that and remove timing from our map. |
| 40:47 | So it isn't uncommon to see an occasional knock event and that isn't necessarily indicative of a problem in your tune. |
| 40:55 | So at this point, we've completed our tune on the dyno. |
| 40:58 | We've got great control over our air-fuel ratio. |
| 41:01 | We know that our MAF scaling is correct. |
| 41:04 | And we've got our ignition timing dialled in to provide optimal power without any knock activity occurring. |
| 41:11 | The next step is to take the car off the dyno and confirm this tune out on the road. |
