Practical Standalone Tuning: Step 8: Steady State Ignition Tuning
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Step 8: Steady State Ignition Tuning
25.36
| 00:00 | - Now that we've got our fuelling dialled in under steady state conditions to 4500 RPM, we're going to repeat this process only this time we're going to be looking at our ignition timing. |
| 00:10 | To help us with our ignition tuning we're going to be using the torque feedback from our Mainline Pro Hub dyno. |
| 00:17 | And we'll head across to our dyno screen and have a quick look at the two inputs we can use here. |
| 00:22 | First of all I've set up this graph and this is a real time moving graph. |
| 00:26 | The yellow parameter we've got here, the bottom is our ignition timing and this will just show the ignition timing coming through from the ECU so we've got a guide there, obviously we'll also be able to see this on our laptop screen. |
| 00:38 | The red line here is our torque, obviously we're not operating on the dyno at the moment so our torque is reading zero. |
| 00:45 | Alternatively you can simply use the torque analog gauge up here, this will show the total torque being output as well as displaying this numerically. |
| 00:55 | It's personal preference on how you do this, I find using the graphical output makes it easier to pick up the subtle changes to the torque as we're advancing our timing. |
| 01:05 | The process we're going to go through here is exactly what we'd look at in the course, we're going to start with our conservative ignition timing, we're going to remain in steady state in a cell, we'll advance our timing at least initially in two degree steps and we're either trying to find the point where we achieve MBT or alternatively where we start suffering from the onset of detonation in which case we're going to retard the timing to provide a safety buffer of perhaps two or three degrees from that detonation onset. |
| 01:33 | Now for this, I recommend using audio knock detection. |
| 01:37 | I'm going to go through our first couple of RPM rows here without the benefit of that and then once we've demonstrated the procedure I'm actually going to also use my own audio knock detection, we'll speed up the process and continue through to 4500 RPM. |
| 01:53 | So let's get our engine up and running on the dyno, again we'll be starting with the same point that we did with our fuelling, 1500 RPM and as low in the load as we can achieve. |
| 02:07 | Alright so we're operating right in the middle of our 60 kPa cell and it can be a little bit tricky when we are very low in the load because we aren't producing a lot of torque so we can have problems with the resolution and sensitivity of the dyno down low but we'll see how we get on. |
| 02:22 | We can see at the moment, we are registering somewhere around about 50 pound feet of torque but we can see the red trace on our graph is moving up and down and it's just indicative of the problem I'm talking about. |
| 02:35 | That's not necessarily an issue though because as we increase our load, we'll start to see the numbers start making more sense in terms of our torque readout. |
| 02:43 | For the moment though, let's just see what we can achieve so we'll add 2° here, so we'll enter a value of 17° and we're looking for the before and after value on our torque graph, just looking at what happens immediately when we press enter which we've just done and we do see that our torque did pick up a little bit. |
| 02:59 | So we've gone the right way, let's add another 2°, we'll enter 19, again just looking for stable torque before we press enter, pressing enter and looking at what happens there, again we see our torque does increase so we're still moving towards MBT. |
| 03:16 | Let's enter a value of 21, again just stabilising our torque before we press the enter key and we can see that subtle oscillation, there is a bit of a talent here in just averaging out mentally the oscillations we do see in our torque before we start taking our readings. |
| 03:32 | So we'll just wait for that to stabilise, we'll press enter and we see our torque has moved around a little bit, we're not really seeing much of a change there. |
| 03:40 | We'll just get back into the centre of that cell as well. |
| 03:44 | And we'll try another two degrees just to really see if that last change made any difference. |
| 03:52 | Let's just get our torque stable again, we'll press enter. |
| 03:55 | See no difference there with our torque realistically with that additional 2° so we're going to come back to 21° and that's going to be close enough for the moment. |
| 04:05 | And as we build up in our load we may need to come back and revisit these sites. |
| 04:10 | For the moment let's just increase our throttle, we'll come up to 70 kPa and we'll have a look at the torque. |
| 04:18 | Now we should get a slightly more stable torque reading given that we are producing a little bit more torque, we've got a little bit more load on the engine. |
| 04:26 | We're sitting at 15° here, we've got about 118, 120 pound foot of torque. |
| 04:33 | Again we've got that gentle oscillation but let's just add 2° to that. |
| 04:37 | And we'll see what the effect is, press enter there and we see that our torque does jump up a little bit, we're up to about 125, 123 pound foot of torque. |
| 04:48 | Again moving around a little bit, just mentally smoothing that, let's go a little bit further, we'll add another 2°, we'll go to 19°, pressing enter, looking for our change in torque. |
| 04:59 | Again we've seen our torque jump up so we're going the right way there. |
| 05:02 | Let's add another 2° here, press enter, our torque didn't really change that time so we've got no benefit from that additional torque and we'll come back to 19° and just see if we see our torque drop away. |
| 05:16 | And we haven't, we've seen really no benefit there so this is the process we're going to go through, just advancing the timing, seeing if we do see a benefit from the additional timing. |
| 05:26 | If we move up in timing, we add more torque, we're going to keep going. |
| 05:29 | If we see no benefit from the timing, we're going to remove that timing again. |
| 05:34 | Let's continue, we'll come up to 80 kPa and we're again at 15° with our base timing. |
| 05:40 | Looking at our torque, letting that stabilise, we're around about 175 to 185 pound foot, obviously that gentle oscillation there. |
| 05:50 | We'll just allow that to stabilise and we'll enter a value of 17° in there, just making sure that we are in the centre of that cell before we do press enter. |
| 05:58 | I've seen our torque jump up because it wasn't quite central in that cell. |
| 06:02 | And we'll press enter now, looking at what our torque does. |
| 06:06 | We see it jumps up but again it's a very small subtle change, we've almost settled back to where we were so we're seeing the sort of trend is pretty consistent, let's try another 2° just to see what effect that does, we'll press enter now, looking at our change in torque. |
| 06:23 | Again really not much if any change there. |
| 06:27 | Let's go back to 17 and just see what that gives us. |
| 06:31 | And we've seen no drop off in our torque so 17 or 18° and at the point we're at now we are splitting hairs as well, we're only talking about a few pound foot of torque difference so it's not really significant. |
| 06:43 | If we're at that situation, it's always easiest and safest to err on the side of a slightly more retarded timing as well. |
| 06:50 | Let's advance our, or increase our load up to 90 kPa and we'll have a look again at our torque. |
| 06:58 | At this point, making sure that we are central in that cell, we're seeing our torque stabilise at around about 250 to 255 pound foot, moving around again a little bit. |
| 07:09 | So let's try advancing our timing up again, we'll go from 15 to 17°. |
| 07:13 | Again we are moving around a little bit so I'll just increase my throttle opening, make sure we are central here. |
| 07:19 | Looking at our torque value now, we're actually closer to about 260, 270 pound foot, press enter and we'll see what happens. |
| 07:27 | Potentially picked up a little bit. |
| 07:29 | With the oscillations, really hard to pick a significant difference there. |
| 07:33 | Let's try another 2°, we'll go to 19, press enter. |
| 07:38 | And we can see that we really haven't seen any difference there so we'll go back to 17° and we'll leave that there. |
| 07:44 | Let's come up to 100 kPa now, we'll get into the centre of that cell. |
| 07:50 | See our torque's jumped up quite significantly now, we're up to about 340, 345 pound foot and again we'll try adding 2° and see what the effect of that is, again just making sure we are central before we do press enter. |
| 08:05 | Press enter there, haven't seen any change at all. |
| 08:09 | So we'll go back to 15° there. |
| 08:12 | Let's now increase our throttle opening, remembering we can't quite get into the centre of our 120 kPa cell at this point. |
| 08:20 | We're just tipping into it though so let's see what the effect of a change is. |
| 08:24 | We're at 15° now and we know looking at the trend here, we're probably going to expect that we're going to be maybe 15° maybe a little bit retarded from that and we're always looking at that trend and extrapolating that out. |
| 08:38 | At the moment we're sitting at about 465, 470 pound foot. |
| 08:42 | Let's first of all just try advancing the timing, given that I know we're not likely to have any problems with knock here, press enter and see what happens there. |
| 08:51 | We can see absolutely no improvement in our torque. |
| 08:54 | Let's try going to the other way, let's retard our timing back down to 13° and we'll see what happens there. |
| 08:59 | We actually have seen our torque drop there so regardless of the trend we are seeing for that particular cell, 15° does seem to be the ideal timing. |
| 09:08 | Alright so let's have a look now at what we've achieved so far. |
| 09:12 | So we have been able to tune the columns there from 60 kPa through to 120 kPa. |
| 09:19 | Now we've got the areas at higher load that we haven't obviously been able to tune and we have also got these areas at low load that we haven't been able to tune. |
| 09:29 | What we're going to do is extrapolate some of our trends out here. |
| 09:32 | So at the moment for every 10 kPa, give or take we're advancing the timing about 2° there or there abouts. |
| 09:38 | So what we're going to do is just extrapolate that trend out into the lower load areas. |
| 09:45 | Now we're getting to a point where we're not seeing much effect from the timing though so I'm not going to go too wild with my timing here. |
| 09:54 | What we'll do is for our 35 and 20 kPa sites we'll set the timing there to 25°. |
| 10:01 | Given that we don't want to be over advanced, we want nice smooth trends in our timing table. |
| 10:07 | That's more important than chasing every last pound foot of torque because we can get into problems if we've got an erratic shape to our timing table, can introduce drivability problems with the car. |
| 10:19 | We've also got this area out here which we can't actually get to so right now it's not that important but let's just extrapolate the sort of shape that we are seeing here and that's probably going to be good enough for the time being. |
| 10:34 | What we're going to do now is copy the 1500 RPM row, use control C there and we can paste that up to 2000 RPM. |
| 10:44 | Now as we increase our RPM, we're expecting to need to advance our timing in order to achieve MBT. |
| 10:51 | However it's always safest to start with our timing a little bit conservative a little bit retarded so we're going to leave that there. |
| 10:58 | Let's now get up to 2000 RPM and we'll repeat this process and we'll talk through another of our RPM rows. |
| 11:05 | So we'll just get our RPM set point on the dyno correct there, right on our 2000 RPM target and again we're going to come down as low as we can in our load, probably get us down to our 60 kPa, we know we can't really get too much lower than that. |
| 11:22 | And again we're going to be facing this same problem with the fact we're operating right on the bottom point of our dyno's load cell here and that's why we can see that slightly haphazard shape to our torque graph. |
| 11:34 | Let's start by just adding 2° here. |
| 11:37 | We'll just wait for our dyno to stabilise there and we'll press enter. |
| 11:43 | And we can actually see our torque has increased slightly so we know we've gone the right direction. |
| 11:49 | We are splitting hairs here again though and it is difficult with being right on the bottom of that load cell resolution to be accurate but let's just try 25°, we'll press enter and we can see that that really hasn't made a difference, other than that little spike we've got there, we've settled back to about the same point so we'll go back to 23°. |
| 12:09 | Now I've advanced the 60 kPa cell by 2°. |
| 12:13 | I want to extrapolate that change back lower in the load as well so what we're going to do is add 2° to these lower load sites. |
| 12:20 | Again the assumption here is if 60 kPa required an additional 2°, the sites below that will probably also benefit from that same timing. |
| 12:30 | Let's continue now, we'll come up to 70 kPa here and we'll have a look at our torque. |
| 12:37 | At 70 kPa once we've got everything stabilised we're sitting at around about 100 pound foot of torque, just making sure that we are stable in the centre of the cell. |
| 12:46 | Let's try adding 2° there, we'll press enter we see that our torque has increased very mildly so we know we're pretty close to our target. |
| 12:56 | Let's just try another 2° just to prove the point though, we'll enter 23°. |
| 13:01 | We've actually seen a bit of a jump there but I think that was simply be moving my foot on the throttle. |
| 13:08 | Let's go back to 21° at that same point and we can see this time our torque really hasn't changed. |
| 13:14 | We'll go back to 23°, just to be absolutely sure. |
| 13:17 | There is possibly actually a very small improvement there and this is sometimes an example of what we will need to do. |
| 13:25 | It can be very difficult to be precise, because that torque is always moving around and there is that mental smoothing that we need to do with these oscillations. |
| 13:34 | Sometimes a cell like we've just done there may take a few goes of just trying advancing or retarding the timing just to be absolutely certain. |
| 13:41 | Now I'm also looking at the trend here. |
| 13:43 | So we've now got 23°, two cells in a row. |
| 13:46 | That wouldn't necessarily be particularly common so let's just go one more time down to 21° there, looking at our oscillations and our torque graph, press 21° in there and we can see that we do in fact end up with our torque dropping very slightly so we'll go back to 23°, our torque does jump up so we'll leave it there. |
| 14:07 | Let's come up to our 80 kPa site, we've got 17° in there at the moment. |
| 14:12 | We'll just get stable in the centre, we'll enter a value of 19, just waiting for our torque to stabilise, we'll press enter now and we can see a very small increase in our torque, nothing particularly large but let's just try another 2°, we'll go up to 21, just again waiting for our torque to stabilise. |
| 14:32 | Always coming back and checking we are actually still operating in the centre of the cell so we're not being affected by interpolation, press enter there. |
| 14:40 | And we see our torque really isn't affected so 19 looks like it is the ideal option for that particular cell, let's come up again now to 90 kPa, we're 17° again, we'll try advancing our timing here, go to 19°. |
| 14:58 | Absolutely no change in our torque, let's go to 15° on the opposite side, and we see our torque does drop away there so while we are looking at subtle changes, 17° is the optimal MBT timing for that particular cell. |
| 15:13 | Let's come up to our zone here at 100 kPa. |
| 15:17 | 15° in there of course to start with. |
| 15:20 | We'll look at our torque, nice and stable this time, sitting at around about 385 pound foot. |
| 15:26 | Let's enter a value of 17°. |
| 15:29 | We do actually see a small improvement in our torque there, let's try another 2° there, 19°. |
| 15:38 | And we've seen another small improvement in our torque there. |
| 15:42 | Let's try 21°. |
| 15:46 | 21° we really don't see any change there so 19° we'll go back to. |
| 15:50 | Now this gives us the situation now where we've got a value of 17° at 90 kPa, we've got 19° either side. |
| 15:59 | This would straight away be an indication that probably something isn't right there. |
| 16:03 | And this is quite likely to be a scenario we can get ourselves into. |
| 16:06 | You've seen that the sort of changes we're making result in relatively small subtle changes to our torque, we're also doing that mental smoothing with the oscillation of our torque graph. |
| 16:17 | So let's just come back down to our 90 kPa cell and let's just test and I'm really expecting here that probably the correct value here might in fact be 19°. |
| 16:28 | So we'll just again let our torque stabilise. |
| 16:32 | We'll enter a value of 19°. |
| 16:35 | And we do in fact see a subtle but noticeable improvement in our torque. |
| 16:40 | Obviously a bit of a dip there as we've moved the throttle but we do actually see an improvement. |
| 16:45 | We'll just try 21° just to prove the fact. |
| 16:47 | No difference really at 21° so 19°. |
| 16:50 | So this is just a case of we're not always going to get it right the very first time. |
| 16:54 | Be guided by the surrounding numbers and if you see a hole like that in your ignition table, just come back and review it, there's a chance it may be right, there's also a chance it might be telling you something that you haven't got it quite right there. |
| 17:08 | Let's continue now and we'll come up to 120 kPa here. |
| 17:14 | And 120 kPa we're in the centre of that cell there at wide open throttle so we've got 15° in there, see our torque sitting at about 550 pound foot, let's try advancing our timing up to 17°, we'll press enter and we see a very small increase in our torque but noticeable. |
| 17:38 | Let's try 19° here and we see with 19°, no real noticeable improvement so for the sake of safety here, we'll go back down to 17°. |
| 17:48 | So what we're going to do then is extrapolate that change that we've just seen here at 120 kPa out to the right so we'll take the two cells that we've tuned there or copied and we'll add two to those particular cells. |
| 18:03 | From here I'm going to now use my audio knock detection equipment because we're going to be moving higher in the RPM, higher in the boost and I want to be certain that as I'm tuning the timing table towards MBT, we aren't introducing any knock. |
| 18:16 | So we'll speed up the remainder of this process and of course we're just going to continue through here to 4500 RPM. |
| 18:24 | The process that I'll use is exactly the same as what you've seen me do already, so let's go through that now. |
| 19:14 | Alright we've got our ignition table dialled in there from 1500 up to 4500 RPM under steady state conditions. |
| 19:22 | And while we've spread up some of that process there are a couple of factors that I just want to touch on here that I had to go through. |
| 19:28 | First of all you'll remember from our fuel tuning that we added in a couple of additional sites, 3250 RPM and 3750 RPM. |
| 19:37 | As I mentioned, this was to deal with some of the idiosyncrasies around the Subaru fuel system. |
| 19:44 | Now in the Ecumaster ECU the load points or bins are the same between the fuel and ignition tables. |
| 19:50 | We don't strictly need the additional resultion in our ignition table so what I actually did there was I completely ignored the 3250 and 3750 RPM zones. |
| 20:01 | What I'll do now is show you how to deal with that. |
| 20:05 | So we tuned at 3500 and 4000 RPM. |
| 20:09 | We can now use the control L function which will do a vertical interpolation between those sites so we've already done that for 3250, I don't need to go and deal with it again. |
| 20:20 | Another factor that's pretty common, particularly with turbocharged engines is that once we got up in the higher load higher RPM zones, managing the engine coolant temperature was an issue. |
| 20:31 | Often this will also show up with our intake air temperature. |
| 20:34 | We can see that that is sitting a bit higher than what we've seen previously, up around 29-30°C. |
| 20:40 | And we were getting our coolant temperature up around 98 to 99, even 100°C at one point. |
| 20:45 | Very important to be mindful of this and it's simple enough, just when you're getting to the point when the coolant temperature is a little higher than you'd like, just come back to idle for a minute or so, allow everything to cool back down and stabilise and then you can go back into the load zones. |
| 21:01 | Another aspect here is that you may choose not to tune every single cell and I did that just in that last zone there at 4500 RPM. |
| 21:09 | So we may, for example, choose to tune our 140 kPa site. |
| 21:13 | And then in the interest of not putting undue stress and strain on the engine, we could jump ahead and tune our 180 kPa site and then we can use the horizontal interpolation function to fill in the site that we haven't tuned there. |
| 21:28 | And this is something we can do both in vacuum as well as in boost. |
| 21:32 | In general, what we're expecting to see is a relatively consistent trend to that table. |
| 21:37 | What I've also done is I've extended that trend out into the higher load zones that we can't get to, 220, 240 and 260 kPa. |
| 21:45 | You can see for the moment I'm just removing around about 2° of timing per 20 kPa. |
| 21:52 | Now that may not prove to be sufficient and may prove to be too much, we can test that as we start moving into our ramp runs. |
| 21:59 | But just trying to keep that consistent shape. |
| 22:01 | This is a good point to now have a quick look at the graphical representation of our ignition table and see what we've got. |
| 22:08 | And we can see that the sites that we have tuned, we've got a pretty consistent shape which is what we'd expect. |
| 22:13 | As with our fuelling, if we've got any areas where there's massive idiosyncrasies then this could be something we may want to come back and review. |
| 22:21 | And also for example here, we can see a little bit of a step and that's an area of the table where we were at relatively low load and we weren't able to get a really accurate read on our torque graph. |
| 22:36 | So we may choose to come in here and actually smooth this manually. |
| 22:40 | We're in an area of the table where we weren't limited by knock so that's not an issue for us. |
| 22:47 | And again if can be a situation where smoothing these numbers, even if they're not necessarily resulting in a significant change in the torque on the dyno, can give us better drivability. |
| 22:56 | So just for an example here, what we may choose to do there is remove just a little bit of timing from the cells that we've got here and likewise if we jump up a little bit, we could choose to add a little bit of timing in here, so again just giving a little bit of manual smoothing, not significant changes there. |
| 23:15 | Moving on though, let's now copy our 4500 RPM row, we'll copy that, actually make sure we've copied that, and then we can simply paste this through the additional RPM rows. |
| 23:29 | Now again wth our ignition timing while we're expecting that the timing will increase with RPM, for the moment we want nice conservative timing as we switch into our wide open throttle ramp runs so we're going to leave that with a flat curve to our table. |
| 23:42 | This leaves the low load areas which we haven't been able to get to at low RPM. |
| 23:48 | So what we're going to do is of course extrapolate our shape out there. |
| 23:52 | So we'll take our 1500 RPM row. |
| 23:55 | Actually before we do that, let's just look at what we've got going on up in here. |
| 23:58 | Now obviously at 1500 RPM, even at 2000, 2500 RPM, we can't necessarily get to 240, 260 kPa. |
| 24:06 | But we do want to generally follow the trend that we've got in here so let's just go in and we'll make a few changes here, get this a little bit more realistic and we can then copy and extrapolate these particular sites down here. |
| 24:22 | Again we may want to remove a little bit of timing from them as well just to give us a consistent shape. |
| 24:28 | Now let's copy our 1500 RPM row and we can paste that down into our lower sites. |
| 24:35 | Now in our lower sites here, particularly we want to make sure that our timing around idle, we generally want this somewhere so we can advance it and retard it using our idle ignition control. |
| 24:46 | So generally somewhere around 16-18° is a pretty reasonable place to be. |
| 24:51 | So in order to do this, let's just remove some timing from those particular sites. |
| 24:56 | We've got our timing at high load here in the negatives, doesn't really matter, we're never going to be there and you can see that that's just showing a consistent shape to our table. |
| 25:06 | And again here, just so we've got a smooth step at 1250 RPM what we can choose to do is highlight the cells either side, the rows either side and use our control L function to just smooth that out and give us a nice shape. |
| 25:21 | So at this point we've got a ignition table that's developed, it's relatively smooth, it's showing the sort of trends that we would expect to see, we can now move on with the next step of our process. |
