Practical Standalone Tuning: Step 8: Steady State Ignition Tuning
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Step 8: Steady State Ignition Tuning
26.14
| 00:01 | - Now that we've got our fuelling dialled in under steady state conditions up to 4500 RPM, we're essentially going to repeat the same process, this time optimising our ignition timing up to that same point, 4500 RPM. |
| 00:12 | In order to do this, we're going to be using the torque reading on our dyno to help us optimise our ignition timing. |
| 00:19 | As you'd know from the body of the course, what we're looking to do here is advance our ignition timing up slowly, watching the torque and we're trying to find the point where we reach peak torque. |
| 00:31 | Now this can be a little bit tricky with our dyno, we're going to always see a little bit of a variation or oscillation in the torque so this does require a little bit of practice and a little bit of mental averaging or smoothing to the torque numbers that we're going to be seeing. |
| 00:45 | So let's jump across to our Mainline dyno for a moment and we'll look at the two aspects we're dealing with here. |
| 00:51 | First of all we have our total torque dial here and this will show both a dial indication of our torque level as well as numerically here directly below the torque. |
| 01:01 | This is useful to a point but personally I prefer to use the torque graph that we've got set up below, this red line here, once we are running, will indicate the torque reading from the dyno and this gives us a nice graphical representation when we make a change to our ignition timing of how that's affected that graph instantaneously. |
| 01:21 | We'll jump into our TunerStudio software and at the moment I am using another tuning page that we've set up, I've labelled here as ignition. |
| 01:31 | This has the relevant information that we want to look at here. |
| 01:35 | Of course we have our ignition table as we'd expect. |
| 01:39 | We've also got some other parameters that may be useful as we go through this. |
| 01:42 | We've got our air/fuel ratio or lambda as well as our target and our error. |
| 01:48 | So we can just keep an eye on these, making sure that they are within the realms of what we expect while we are tuning. |
| 01:54 | We've also got our engine speed being displayed, we've got our manifold pressure and we've of course got another little target showing us here how close we are to the centre of our current cell. |
| 02:07 | Again this is important to make sure that we are central in this cell while we are making our tuning changes so that we're not going to end up suffering from interpolation. |
| 02:16 | One other consideration before we start tuning here is that in some instances we may find that before we reach MBT, while we're advancing the timing in our table, that we do reach the onset of detonation or knock so it is really important as we've discussed already, to be monitoring for detonation while we are tuning the ignition timing. |
| 02:36 | So we're going to be tuning to either MBT or if we find the knock threshold then it's sensible to retard the timing two or three degrees and just leave a margin of safety between that onset of detonation and the timing that we leave in the table. |
| 02:50 | Alright let's get our engine up and running now, we're going to start with our engine running at 40 kPa and 1500 RPM. |
| 02:58 | Alright with our engine up and running now we can see that we are in the centre of our cell, we can see that on our dyno, we're just doing around about 22 to 23 pound foot of torque. |
| 03:09 | We've got a little bit of variance here and one of the reasons for this is that we are operating right on the very minimum reading that our load cell's capable of. |
| 03:16 | So we're basically only just using the dyno to hold the car at the moment. |
| 03:22 | For this reason we can find that our results in this particular cell can be a little bit tricky. |
| 03:26 | Now in usual circumstances I'm going to advance the timing in two degree increments. |
| 03:31 | Because we are right on the load cell's minimum reading. |
| 03:35 | I'm actually going to advance the timing initially to 20 degrees so we're going to add 5 degrees here. |
| 03:41 | So we'll press the equals key and we'll enter 20 and what we want to do is just take note of our torque reading before and after we press enter. |
| 03:49 | Now I will mention before I press enter here, we have seen some jumps there in our torque between 22, 23 and up to about 45. |
| 03:56 | Now those aren't real here, we need to apply a little bit of common sense there and we can see for the most part that we are sitting around that 22 to 23 pound foot region. |
| 04:06 | So let's press enter now and we'll see what the effect of that change is. |
| 04:10 | So we see a jump up there to, at the moment we seem pretty stable around about 45, 46 pound foot of torque, so a positive improvement there, we've definitely gone the right way. |
| 04:22 | What we'll do now is we'll start making smaller incremental changes so let's add another two degrees, we'll go to 22 degrees. |
| 04:27 | Again looking at our before and after, we'll add two degrees and we again see it jump up to 48 to maybe 50 pound foot again, just mentally averaging the numbers. |
| 04:38 | So we're going to still the right way, let's enter 24 degrees and see what that gives us. |
| 04:44 | Now 24 degrees we again see a small change, we've jumped up to 50 to 51 pound foot of torque so again small but it's an improvement so we'll enter a value of 26 degrees here and see what we get. |
| 04:56 | 26 degrees, really we've seen a potential small change there but we're only really seeing a change now of perhaps one, maybe two pound foot so we're right on the brink there. |
| 05:10 | Just to really reinforce that though, let's just add another two degrees and see if that gives us any improvement. |
| 05:16 | We'll go up to 28 degrees, with 28 degrees we can see that we've really seen no change at all. |
| 05:22 | So 26 degrees is about the area where we really saw the peak torque, or we've seen no change beyond that. |
| 05:32 | Alright so what we're going to do now, instead of tuning in 5 kPa increments, you see our next break point here is 45 kPa, not really strictly necessary to have such tight break points with our ignition timing. |
| 05:45 | How you deal with this is really up to your own personal preference and how much time you're prepared to put into your tune. |
| 05:52 | In this instance we're going to actually jump ahead and we're going to use the interpolate function. |
| 05:57 | So instead what I'm going to do is I'm going to come up to our 50 kPa break point here. |
| 06:01 | I'm going to increase our throttle position to get up to that cell. |
| 06:04 | Just again making sure that we are absolutely in the middle of that cell before we start making any changes. |
| 06:10 | And now because we are applying a little bit more torque to the dyno, we should start seeing a more obvious result from our dyno torque reading so it should be a little bit easier as we increase the torque being produced. |
| 06:24 | So again looking at what we've got there, we're sitting at about maybe 88 to 90 pound foot of torque. |
| 06:31 | So let's advance our timing. |
| 06:33 | Now we know that here at 40 kPa we've got 26 degrees. |
| 06:37 | So just to speed up the process here, I'm not expecting that we're going to be less than 20 degrees, generally as a rule of thumb I'd probably guess that we're going to be around about two to maybe four degrees retarded from what we found was optimal at 40 kPa. |
| 06:54 | So just to save time, let's jump ahead and we'll start by entering a value of 20 degrees. |
| 06:59 | Again, looking at our torque before and after we press the enter key and we see straight away a really noticeable increase, particularly in our red torque graph at the bottom so we've gone up to 95 to 97 pound foot just again doing some mental smoothing or averaging there. |
| 07:15 | So we're going in the right direction, let's continue here, we'll add another two degrees this time, again looking at the difference before and after we press the enter key there. |
| 07:24 | And again with the enter key pressed, we have seen a small but noticeable improvement in our torque, we're sitting more up around the 96 to 100 pound foot of torque mark there. |
| 07:36 | So let's go another two degrees, we'll enter 24 degrees and see what that gives us, pressing enter. |
| 07:41 | Again we see a small improvement on our torque on our red graph there. |
| 07:46 | We're seeing minimal improvement though so we know we're probably getting to the point of diminishing returns there. |
| 07:51 | Let's try 26 degrees and just see what that gives us though, we'll press enter and see what our 26 degree change does, absolutely nothing there. |
| 08:00 | So what we're going to do is go back to the last point where we saw an improvement and enter 24 degrees. |
| 08:06 | Now this gives us a situation where we've tuned our 40 kPa cell, we've also tuned our 50 kPa cell but of course we've got this site here at 45 kPa that we haven't tuned. |
| 08:17 | So what we can do is highlight the cells that we have tuned and the one between using the shift key and the arrow keys. |
| 08:23 | And then we have our interpolate function right here. |
| 08:26 | We can either click on that button or if you hover over it, you will see the key that we need to use in order to use the interpolate function. |
| 08:34 | That's done that, we can see that it's brought that cell up to 25 degrees. |
| 08:38 | Alright let's carry on here, we'll come up to 60 kPa. |
| 08:44 | Again we're going to be moving in 10 kPa increments here. |
| 08:49 | Come up to 60 kPa, get ourselves centered in that site. |
| 08:53 | And see what our dyno's showing us in terms of torque. |
| 08:57 | Alright so at the moment we can see once we've got stable we're at about 140 pound foot of torque. |
| 09:03 | Again just mentally smoothing those oscillations that we see there. |
| 09:06 | So again just using a little bit of common sense, we know we've gone from 26 to 24 degrees over a 10 kPa increment. |
| 09:13 | I can expect something pretty similar so right away I'm already expecting us to be somewhere in the region of perhaps 20 to 22 degrees. |
| 09:21 | So again I'll jump ahead and we'll make our first change, setting the ignition advance to 20 degrees. |
| 09:27 | Looking at our torque before and after we'll press enter and again we see quite a sizeable jump in our red torque graph so we know we've gone in the right direction there. |
| 09:35 | We're up to about 146 to 150 pound foot there, mentally smoothing those averages, those peaks I should say. |
| 09:43 | So let's add another two degrees, we'll go from 20 to 22 degrees. |
| 09:46 | Again looking for the before and after where we press enter. |
| 09:50 | And we press enter, we've seen a small improvement but really minimal, perhaps only one to two pound foot of torque so we're probably pretty close to MBT there. |
| 10:01 | Let's just try another two degrees though, we'll go to 24 degrees and see if that gives us any improvement. |
| 10:07 | Absolutely no change there so again, we're going to go back to our last result there, 22 degrees. |
| 10:13 | So again we can start to see that trend. |
| 10:15 | We're seeing essentially about a two degree drop per 10 kPa. |
| 10:19 | Let's come up to 70 kPa and we're going to repeat that process. |
| 10:22 | And again following that trend, we know we're probably going to be somewhere around about 18 to 20 degrees. |
| 10:29 | So for our first change there, let's go from 15 to 18 degrees, before we press enter let's look at our torque graph. |
| 10:36 | You can see there we're sitting around about 199, maybe 200 pound foot of torque, let's press enter, with our three degree change there and we've seen a nice improvement in our torque. |
| 10:48 | We've gone up to 203, 204 pound foot so we've gone the right way there. |
| 10:52 | Let's try another two degrees this time, we'll go from 18 to 20 degrees. |
| 10:57 | So again looking at our torque before and after, sitting around 202, 203 pound foot, we'll press enter. |
| 11:05 | We see another small improvement there, we've gone up to about 204, 205 pound foot of torque. |
| 11:13 | Again we're seeing that improvement decrease there. |
| 11:15 | Again really following our trend, we know that we're probably pretty close to our optimal timing. |
| 11:20 | Again though, just to prove that let's go to 22 degrees and see what that gives us. |
| 11:24 | 22 degrees, really no change at all. |
| 11:27 | So let's go back to our previous at 20 degrees. |
| 11:30 | Repeating this process, let's come up to 80 kPa in our site there, just increasing our throttle smoothly so we can get into the centre of that particular site. |
| 11:40 | We're there now, again taking note of our torque, we're seeing sitting around about 250 pound foot. |
| 11:49 | Again following our trend, we're expecting this is probably going to end up with somewhere in the region of maybe 18 degrees of timing as our optimal value, if the trend continues. |
| 11:59 | So let's start by setting that value though to 17, we'll add two degrees. |
| 12:03 | Looking at our before and after we're sitting at 250, we'll add our timing, we see an improvement up to about 253, 254. |
| 12:12 | Small but worthwhile improvement. |
| 12:14 | Let's add another two degrees here, we'll go to 19 degrees, we'll see what we get from that. |
| 12:20 | Again a very small but noticeable improvement, we're up to 254, 255 pound foot. |
| 12:27 | So let's try another two degrees. |
| 12:29 | And we're expecting probably this isn't going to net any effect here so let's try that. |
| 12:35 | And exactly as we expect, we really haven't seen anything, although I've got a wild oscillation there in our torque. |
| 12:42 | So we'll come back to 19 degrees here. |
| 12:44 | Now at this point, 19 degrees may be our optimal, we are making reasonably coarse changes there of two degrees at a time. |
| 12:51 | So it's possible that we can fine tune this a little bit. |
| 12:55 | Again just to test our theory here of two degrees per 10 kPa, let's just take out one degree here, we'll take it down to 18 which is what our trend suggests this cell should be. |
| 13:06 | That's not necessarily going to be the case. |
| 13:08 | So again we'll just make sure we're stable in our cell before we make any changes. |
| 13:11 | Looking at our torque we're sitting at the moment about 254, 255 pound foot. |
| 13:19 | That's moving around a little bit but that's about where we're at. |
| 13:21 | We'll go down one degree and we'll see if we end up with any change. |
| 13:25 | Haven't really seen any change there. |
| 13:28 | Maybe a little bit, we can just go back to 19 degrees and see if that picks up torque. |
| 13:34 | And it actually does look like it does so maybe that cell does actually want to be 19 degrees. |
| 13:38 | So this is where you can build up a bit of a trend but don't take that trend as gospel, you still need to test and find out what the engine actually wants. |
| 13:45 | Let's move up to 90 kPa now and again we've got 15 degrees in there at the moment. |
| 13:52 | Again following our trend there, in that last cell we dropped one degree for 10 kPa so we might be somewhere in the region here of 17 to 18 degrees, that's what we're expecting. |
| 14:03 | Looking at our torque, 296 to 300 pound foot, again oscillating lightly there. |
| 14:08 | Let's try adding two degrees, so we'll go from 15 to 17 degrees, we'll press enter, looking at our torque graph. |
| 14:16 | So we can see a very small improvement but it's really quite minimal. |
| 14:20 | Instead of oscillating down to 297 or so which we were seeing as our minimum, we're now seeing about 299, maybe 300, so we've seen an improvement but it really is quite miniscule. |
| 14:31 | Let's try another two degrees there, we'll go from 17 to 19 and see what that nets us. |
| 14:35 | I'll press enter there and essentially really no change there, we're still seeing our minimum sitting at around 299. |
| 14:44 | So what I'm going to do is take us back down to 17 degrees there. |
| 14:48 | And again particularly if we aren't seeing a change, we're always better, particularly on a pump gas engine, which may be knock sensitive, we're always better to err on the side of less timing rather than more. |
| 14:59 | Alright so what we're going to do now is go through to full throttle and this gives us a situation which is a little bit tricky because we now have two cells, we've got 95 kPa and 100 kPa. |
| 15:09 | Now here at our current altitude, the maximum manifold pressure we're likely to see is around about 97 kPa depending on our atmospheric conditions. |
| 15:19 | So what we're going to actually do is tune the 95 kPa and 100 kPa cells to be the same. |
| 15:24 | And we're going to go through to our full throttle now and we can see that we're sort of interpolating awkwardly between them, so what we'll do is highlight both of those cells. |
| 15:33 | Now looking at our torque currently we can see that we're sitting at around about 341, 342 pound foot. |
| 15:38 | Again just moving around lightly. |
| 15:40 | So let's just try for a start advancing our timing up by two degrees, we'll go to 17 and we'll see what that gives us. |
| 15:47 | We can see we've picked up maybe one or two pound foot there but essentially we've come back and settled almost at the same point. |
| 15:56 | So really at this point we're very very close to MBT. |
| 15:59 | In this instance, because the difference we saw potentially at the most was about one pound foot of torque, maybe two, less than 1% difference, I'm actually going to go back to 15 degrees here and just give us a little bit more of a conservative number, again just safeguarding against the potential for knock. |
| 16:19 | To see how we're lining up there with that 15 degrees though, before we finish off and move to our next column, let's actually retard the timing. |
| 16:26 | So we'll take the timing back by two degrees, this is always a good idea just to see where abouts you are on that timing curve, how close you are to MBT. |
| 16:34 | So again we are sitting at about 340, 342, let's take it back to 13 degrees. |
| 16:40 | And we see this time we do drop a little bit, we're done to about 335 to 337. |
| 16:45 | So definitely does want 15 degrees in there however 17 really didn't give us much of an improvement. |
| 16:53 | Alright let's come back down to idle and we'll talk about our results here. |
| 16:56 | So what we've done here for our 1500 RPM column is we have calibrated those cells between 40 kPa, that minimum that we could get to and we've gone all the way up to our 95, 100 kPa wide open throttle zones. |
| 17:11 | We've used interpolation there to do those sites that we had a 5 kPa increment. |
| 17:16 | Now there's a couple of problems here, first of all, we've got these areas down below 40 kPa which we weren't able to get to. |
| 17:23 | Now that doesn't mean that we can leave those so what I'm going to do here is just essentially extrapolate the sort of results we were seeing. |
| 17:31 | So again we're not seeing a massive change to our torque for additional timing so we can be a little bit conservative here. |
| 17:40 | What I'm going to do is just enter 27 degrees at our 35 kPa value, 28 degrees at our 30 kPa value and we're unlikely to get much further than that down in our torque so I'm actually going to continue and extrapolate that 28 degrees down. |
| 17:56 | The reason that I'm going to do this as well is it's important to make sure that we don't have massive steps in our timing, particularly as we come off idle. |
| 18:04 | Now on that note as well, at the moment we've still got our timing set to 15 degrees at idle, what I'm going to do is come down here and I'm going to set those zones in our idle area below to 18 degrees. |
| 18:16 | Now what we're going to do as well is extrapolate the results that we've seen here back down into our 1250 RPM column. |
| 18:26 | We can't really get great results at 1250 RPM. |
| 18:30 | That's not essential as well, we're not loading the car up at that RPM but we are transitioning through that particular column. |
| 18:37 | Now what we're going to do in our higher load areas, the areas we're not going to get to, you can either choose to extrapolate into those areas for the sake of completeness or in this instance, I'm just going to leave them, it doesn't matter, we're not turbocharged or supercharged, we're not going to be there. |
| 18:54 | So what we're going to do here is just copy the column that we've tuned at 1500 RPM, we're going to highlight that, control C, move to the left there, control V and that will paste that particular column. |
| 19:06 | Now what I'm going to do is essentially split the difference here beween our 1000 RPM idle area, 18 degrees and our 28 degrees that we've got here at 1500 RPM at the same sort of point, don't have to be particularly accurate here but what we're going to do is just use the control and comma key to reduce those numbers. |
| 19:24 | And what I'm going to do is just bring those down to somewhere around about 23 degrees. |
| 19:29 | So we're just getting a split of the difference there. |
| 19:32 | So what we can do now is also just highlight the areas above our idle area there, control C again and we're going to paste those into those lower load, lower RPM areas and again just for the sake of completeness we're going to just extrapolate the sort of shape that we've got here. |
| 19:52 | So we're just trying to get a nice consistent shape to our ignition table. |
| 19:56 | Remembering that when we are starting the car, this is the area that we're going to end up in, we've got our cranking timing anyway and as the car starts we're going to transition through this area down to our normal idle area. |
| 20:09 | So we've got our lower RPM ranges now complete, what we're going to do is again copy our 1500 RPM column, control C and we're going to paste that across to our 2000 RPM column. |
| 20:23 | And then we're going to go through and repeat this process. |
| 20:26 | Now we can expect that as we advance the timing like this, sorry as we increase the RPM like this, we can expect that our timing or optimal timing, MBT timing will increase. |
| 20:38 | For the sake of safety though, I'm not going to advance the timing before we increase our engine RPM. |
| 20:43 | Instead we're just going to go ahead and continue tuning that column. |
| 20:47 | So let's go through that process now. |
| 20:51 | Alright so the first cell that we can get to there is our 26 degree cell that we've got at 40 kPa, 2000 RPM. |
| 20:57 | And what I'm going to do here, again just like our fuelling, we can't really get below 40 kPa reliably. |
| 21:03 | So I'm going to make the same magnitude change here to our 40 kPa cell as I'm going to make to the cells directly below. |
| 21:12 | This is just extrapolating the sort of trends that we see, essentially I'm expecting that. |
| 21:16 | If we want more timing to reach MBT at 40 kPa, we'll also need about the same magnitude of change below that. |
| 21:23 | So we're just going to take note of the change we make. |
| 21:25 | So let's look at our dyno, at the moment we're sitting at about 45 to 48 pound foot of torque so what we'll do is we'll make a change here of two degrees, so let's enter 28 degrees. |
| 21:38 | Looking at our dyno and we see that straight away we pick up to around about 48 to 50 pound foot. |
| 21:45 | So two degrees has given us an improvement. |
| 21:48 | Let's go another two degrees, let's enter a value of 30 in there. |
| 21:51 | Again looking at our before and after as we press enter. |
| 21:55 | And we've seen another small improvement, we're now sitting between 50 and maybe 51 pound foot of torque. |
| 22:03 | So another two degrees has helped us there. |
| 22:05 | Let's try 32 degrees and see what that gives us. |
| 22:08 | We'll press enter and we've really seen no change there, we're still sitting around about that 50 to 51 pound foot. |
| 22:16 | So let's retard our timing back to our 30 degrees. |
| 22:19 | So at the moment we've added four degrees to that cell. |
| 22:21 | Again as I mentioned, we're going to add four degrees to the cells below so we can use the plus function here and we're going to enter an additional four degrees, press enter, so that's just followed that trend down. |
| 22:33 | Now we're going to complete the process now, exactly the same as what we've just seen, up to wide open throttle, we'll go through that now. |
| 23:03 | Alright, we've completed our 2000 RPM column so from here out to 4500 RPM, it's going to be a rinse and repeat of the process that we've just looked at, so let's go through that now. |
| 24:21 | Alright at this point we've got our ignition table tuned out to 4500 RPM in steady state. |
| 24:26 | And as I've been doing that, I've been using the variety of techniques that I've already discussed. |
| 24:31 | In particular, paying special attention to the sort of trends that we're seeing in the table and extrapolating those out. |
| 24:36 | So we've already got a pretty good idea of what the timing is likely to want to be before we get into a cell but of course we're still using the torque feedback from the dyno to let us know what the engine actually wants. |
| 24:47 | In this case I'm also using a little bit of caution here. |
| 24:51 | We're getting to a point, particularly under high load where we're advancing the timing but only seeing a minute change of 1% or less, then I'll err on the side of caution there and leave a slightly more conservative ignition timing in the table. |
| 25:05 | From this point, what we can do here is just copy out the numbers from the 4500 RPM column, so we'll control C and we'll just extrapolate those, copy those out into the higher RPM ranges. |
| 25:18 | Now we're likely to expect, with the normal trends we see in an ignition table, for the ignition timing to want to continue to advance at higher RPM. |
| 25:26 | However for our starting as we move into our ramp runs in our next step, we're going to start with nice, safe, conservative numbers there and see what the engine actually wants once we start doing those ramp runs. |
| 25:38 | It's also a good idea, before we move on, just to click on our little 3D view button here and we can view the numbers graphically. |
| 25:45 | So this just gives us an idea of what the shape of the ignition table looks like. |
| 25:49 | So we can see in particular the area we have tuned under steady state conditions, we've got a relatively smooth shape to the graph which is exactly what we'd expect. |
| 25:58 | Of course we've got this big flat area out here into the positive boost areas. |
| 26:00 | Obviously an area we're never going to be using, as we've discussed. |
| 26:04 | So at this point we've got our steady state ignition tuning complete, we can move on with the next step of our process. |
