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Practical Standalone Tuning: Step 8: Steady State Ignition Tuning

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Step 8: Steady State Ignition Tuning

48.16

00:00 - Now that we've completed tuning the volumetric efficiency table and steady state out to 4500 rpm we're going to repeat the process, only this time we're going to be optimizing the ignition timing.
00:13 The process is the same; we're going to be starting with a minimum amount of load and rpm, we're going to hold the rpm consistent using the Dyno, and we're going to increase the load, gradually tuning each cell individually before moving onto the next rpm column.
00:33 While we're doing this, we always want to be listening for knock or detonation using audio knock detection equipment and, in fact, we'd be using this even while we're tuning the fuel or VE table just to ensure that while we are tuning, we've got no knock occurring.
00:51 It's very important and while I'm not going to be using this today, I'm obviously presenting while I'm tuning and I'm also very familiar with exactly how much ignition timing our Nissan VQ35 engine will take on pumped gas, so I'm not concerned about knock for our demonstration.
01:11 You certainly should be when you're tuning your own vehicle.
01:14 Now, what we're trying to do when we're optimizing the ignition timing, we want to start with our timing at a safe and retarded ignition advance angle and we're going to be using the torque feedback from the Dyno and we're going to be gradually advancing the timing up and watching how that affects the torque.
01:34 The aim is to set the ignition advance in each cell at MBT, which stands for minimum timing for best torque, also known as maximum brake torque timing.
01:45 So as we advance the timing up, we'll see the torque increase, it will plateau, and if we keep going, it will actually start decreasing.
01:53 We want to set the timing at the point where we first see peak torque being produced.
01:59 Now, we're going to be using the torque feedback from the Dyno and we can see that that is represented graphically.
02:08 Here we've got a little graph that says ignition tuning.
02:12 And we've got the engine running and let's just do that now.
02:14 We'll just get the engine into fourth gear.
02:16 What we'll actually see is that that graph will increase once we actually have the engine held against the Dyno load cell and the Dyno's applying some force to hold the engine consistent and you can see that's represented now by a little red line.
02:35 You can see that our torque is being displayed numerically at the bottom in our red number here, so we're seeing around about 15 newton-meters of torque from our engine at 2,000 rpm currently we're running at.
02:50 Okay, so before we begin our actual tuning, I'm going to do a quick demonstration using the torque optimization feature of our mainline Dyno and this is going to demonstrate graphically how the torque is affected by our ignition timing.
03:07 So what I'm going to do for the moment is we're going to have our engine running at 2,000 rpm and 50 kPa of manifold pressure and I'm going to keep that consistent using the throttle.
03:22 And then what I'm going to do, you can see I've highlighted this group of cells at the moment, these are the ignition timing cells across the range that the engine's operating in, and we're just going to gradually advance the ignition timing and see how that affects our engine torque.
03:39 So we've got our torque optimization screen showing here on our mainline Dyno.
03:44 And when I press begin, what I'm going to do is just simply advance the timing at about a degree a second and we're gonna do that now.
03:53 And while I do this, the Dyno is going to plot a red line, which you'll be able to see now, and that's just showing us how the torque is being affected by the ignition angle.
04:07 So we're just going to keep advancing the ignition timing up and we're gonna go all the way through to about 50 degrees so you'll be able to see how the timing actually affects the torque and you're also going to be able to see exactly where the engine makes peak torque.
04:25 This is a really clear way of understanding exactly what's going on inside the engine, makes it really, really obvious and this is going to be quite powerful when we look at how we would conventionally use the torque input from the Dyno to help us tune because we're not going to perform this exact test at every cell in the ignition table.
04:48 All right, so we've got our timing all the way through to 50 degrees and I'm just going to back off now.
04:56 So what you can see is our nice, smooth red line that shows us how the torque changes, how it increases as we advance the timing.
05:04 We have the ignition angle on the bottom axis here on our x-axis, and this is coming from the ECU via can and we have the torque being measured on the vertical axis from our Dyno.
05:14 So the crosshairs here show us where we actually made peak torque and it's also displayed up here at the top.
05:22 And this particular cell at 50 kPa and 2,000 rpm, we saw a peak torque of 93 newton-meters being produced with an ignition advance angle of 34.4 degrees.
05:35 Now, of course, we don't necessary need to be as accurate at 0.1 of a degree, but this is a great way of demonstrating what's going on.
05:44 Okay, so now we've done that, what we're going to do is start how we would normally begin our tuning and this was just a demonstration to show you what's going on.
05:54 With our ignition table, unlike our VE or fuel tables, we're not strictly going to start our tuning at a thousand rpm and there's a couple of reasons for that.
06:05 First of all, we never really under load a thousand rpm, we never really driving the car down the end, we're only really transitioning out of the idle areas there.
06:16 It's also very difficult to get really solid feedback from our Dyno on the effect of changes in timing at such low rpm, there.
06:26 We're not really going to be able to get a good picture of what's going on.
06:29 So generally, what I like to do is focus on the areas we're actually driving the car in and then interpolate those results back into the idle areas, which is what we're going to look at.
06:39 So we're going to start by getting our engine running at 1,500 rpm in fourth gear and we'll have a look at doing some Steady State Tuning of the ignition timing and load zones.
06:51 So let's just get ourselves up to 1,500 rpm, first of all.
06:57 And you can see we're now sitting at 40 kPa, 1,500 rpm, and we wanna click into that particular cell.
07:05 And what we're looking at is the torque graph here and also you can see our torque is displayed numerically.
07:14 And what we want to do is look at the torque graph immediately before and after we make a change to our ignition timing.
07:24 It's very important to get the engine running as stably as we can and you can see that the torque is always moving around a little bit.
07:32 So part of the skill that we need to learn as a tuner is judging the average torque as that torque tends to oscillate up and down.
07:41 So you can see we're sitting around about 30 to 31 newton-meters at the moment.
07:45 So what I'm going to do is, just make sure we're back at 40 kPa before I make this change, I'm going to enter a value of 17, so I'm adding two degrees.
07:55 That change won't be locked in until I press Enter.
07:57 So we're looking at the torque immediately before and after we press Enter.
08:03 So we're sitting at about 30, 31 newton-meters.
08:07 I press Enter and you can see that we gained torque.
08:10 We went up to about 36 to 37 newton-meters, so that's a positive change.
08:15 We've moved towards MBT, so we know we're in the right direction.
08:19 That would suggest that we're going to go further.
08:22 So let's try another two degrees.
08:24 Again, we're looking at before and after, 35, 36.
08:27 And you can see we jumped up again.
08:29 Only a small change this time, but we've gone up to about 39 to 40 newton-meters.
08:34 So we've seen a small improvement.
08:36 That would suggest that we want to go further, though.
08:39 We're still moving towards MBT, so I'm going to add another two degrees.
08:43 21 degrees this time.
08:45 Again, the change is not locked in until I press Enter.
08:48 So we're looking at our torque.
08:50 We're sitting at about 38, 39 newton-meters.
08:53 Press Enter and we go up again, this time to about 42, 43 newton-meters.
09:00 Again, we're just averaging, mentally averaging, the oscillations we're seeing in that torque graph.
09:06 And sometimes viewing the numerical number can actually be misleading.
09:13 I find it's easier to watch the graphical representation of the torque and look at how that line on the graph changes.
09:21 Immediately, I press Enter and lock in that change.
09:24 So we've seen a positive change with our 21 degrees.
09:28 Let's try another two degrees.
09:31 You'll see I'm making two degree changes at this point.
09:34 And there's no real requirement to make a certain size or step change, but I find if we're making very small changes of perhaps a degree, it can be hard to see the effect of that change.
09:47 And you've seen, we're only seeing very small changes to our engine torque.
09:52 So I find, initially, two degree increments is enough to see if we're actually getting an effect from that change.
09:58 All right, so let's make our next change.
10:01 Just get us back down close to our 40 newton, our 40 kPa zone.
10:06 And we're sitting again at about 40, 49, 50.
10:12 I make a change.
10:13 And again, we have seen an increase, but this time we only saw an increase of about one or two newton-meters, so that tends to suggest we're getting quite close to MBT.
10:26 We're getting very, very small gains for our increases in ignition advance and when we start seeing that taper off, we know we're getting close to MBT.
10:36 Let's try another two degrees.
10:37 We'll enter 25.
10:39 So we're looking at our torque again and we're sitting around about 50 to 52 newton-meters.
10:43 I lock in that change.
10:46 We have seen another very small change.
10:49 We've gone up about one, maybe two newton-meters, so again, we've seen a positive change.
10:55 Let's try 27 degrees and we'll press Enter.
11:00 This time, but the time everything's settled, we haven't actually seen any effect on our torque.
11:07 Now, if we do this, if we make a change of two degrees, we add timing, and we see no effect on the torque, that means we've gone too far, we haven't seen an improvement, so I would just simply take that two degrees back out.
11:20 And you'll see when I do that, we still see no difference in our torque, it stayed the same.
11:26 Now, of course, I'm making two degree changes.
11:29 When we start getting really fussy, we could drop that down to smaller changes of one degree increments.
11:35 Now, we've tuned our 40 kPa zone.
11:38 Before we move on, what we can see is we've got these zones down at 20, 30, and zero kPa that are still set at our initial target of 15 degrees.
11:51 Now, before we move on and tune above our 40 kPa zone, I'm going to simply select these zones and I'm going to set them to 25 degrees also.
12:02 Now again, while we can't tune these zones, it's exactly like what we did in our VE table.
12:09 There's a very good chance the the ignition timing, as we drop our load, will either be the same or more advanced than the cell that we've just tuned at 40 kPa, so it definitely isn't going to want to decrease back down to 15 kPa.
12:28 In fact, there's a very good chance it's probably going to want to be slightly more advanced, but we can't tune these cells because we can't get into them, so we're simply going to extrapolate the results we've got from 40 kPa and move down.
12:44 Now initially, you saw we set the axis up in 10 kPa increments.
12:50 Now, strictly speaking, we don't need to be that fussy with our ignition break points.
12:57 We're going to look at how we can tune in 10 kPa increments and then I'm also going to look at how we can start spreading our zoning a little bit more coarsely and using the interpolate function on the Infinity ECU to speed up our tuning because, much like the volumetric efficiency, we can expect a smooth trend to our ignition table.
13:20 Okay, so let's bring our load up now to 50 kPa by using the throttle and we'll just drop our engine rpm slightly again.
13:32 So we're back at 50 kPa now and we're going to do exactly the same process.
13:38 So we're at 15 degrees at the moment.
13:40 And you can see we're sitting at about 90, 92 newton-meters.
13:44 Let's add two degrees and see what happens.
13:49 And we saw an improvement there.
13:51 We've gone up to about 96, 98 newton-meters.
13:55 Now again, I'm also judging the likely ignition advance I'm going to want to see.
14:02 As we advance, as we increase the load, generally, we'll see the ignition timing taper off or retard slightly.
14:10 We're not expecting to see a massive jump between surrounding cells.
14:13 So if I'm at 25 degrees at 40 kPa, I'm going to expect I'll probably be somewhere between about 22 and 24 degrees in this 50 kPa zone and we'll see how we can use that to speed up our tuning as well.
14:28 Okay, so we say a positive change there.
14:30 Let's make a three degree jump this time and we're going to go to 20 degrees.
14:34 We're, again, looking at our, our torque.
14:38 We're sitting at 97 to 100 newton-meters.
14:42 I press Enter.
14:43 And we've seen a small increase there up to about 103 newton-meters.
14:49 It's a small increase, but it is still an increase.
14:51 So we're going to want to go further than that, so let's enter 22 degrees.
14:56 Okay, we're sitting stable at 101, 102 newton-meters.
15:00 Uh oh, just got a little bump there in our torque, so I'll just wait for it to stabilize again.
15:05 Yeah, we're stable, now, at 102, 103.
15:08 I'll press Enter.
15:10 And we have seen our torque increase again up to 104, 105.
15:14 So it's an increase, but it's a very small one.
15:17 Let's try 24 degrees.
15:20 Press Enter.
15:22 This time, yes, we actually have seen a one newton-meter increase, but we know that we are very close to the target.
15:30 We're very closer to MBT.
15:33 We're not seeing very much influence on our torque as we advance that timing.
15:38 In this case, I would try going further.
15:41 We can try 26 degrees.
15:43 And we'll know that we're probably going to not see an improvement from that.
15:47 At least press Enter.
15:49 And, other than that little peak that we've just seen, once everything stabilizes, we're back at exactly the same torque.
15:56 So we've gone too far.
15:57 We'll come back to 24 degrees.
15:59 Okay, now let's look at how we can use the interpolate function.
16:05 So because I have quite tight zoning here, we don't necessarily need to tune every zone in this table.
16:12 We're probably going to get a perfectly good result if we interpolate between zones, so let's have a look at that.
16:20 And we'll jump up to 70 kPa now.
16:25 And we'll just bring the throttle up to get us to 70 kPa and at the same time I'll just bring our engine up here and back a touch on the Dyno.
16:35 All right, so we're at 70 kPa.
16:37 And we're back at our 15 degree starting point.
16:41 You can see now we're seeing 195, 197 newton-meters of torque on our Dyno.
16:49 Let's try adding two degrees to that cell.
16:54 We'll go to 17.
16:56 And we've seen a small increase there.
16:59 We've gone from about 199, 200, to about 205, 206.
17:04 So let's try adding another two degrees, now.
17:10 And again, we've seen an improvement.
17:12 We've gone from about 205, 206 to around about 207, 208.
17:19 Now, again, we're starting to see very small changes for our increased ignition advance, so we know that we're probably getting close to MBT.
17:28 Let's try 21 degrees, now, and see the effect of that.
17:33 We've picked up two newton-meters.
17:36 We went from about 206, 207 to about 209, maybe 210.
17:41 So we've seen, again, a small increase.
17:43 Let's try 23 degrees there.
17:47 And this time, we see no net effect for our additional two degrees, so we're gonna go back to 21 degrees.
17:57 Okay, so now we've tuned the 50 kPa zone and we've tuned the 70 kPa zone.
18:03 Now, you can see we've only got a small difference.
18:06 We've gone three degrees, we've retarded between 50 and 70 kpa.
18:11 So rather than tuning every zone, here, when I've got tight zoning like this, we can simply highlight the three cells, the two zones that we have tuned and the untuned zone, and if we press the V key on the keyboard, that will interpolate those cells and what that does is it just puts the correct value and, or the average of these two cells and adds 60 kPa.
18:39 Of course, this is just to illustrate the point that when we're tuning our zoning for our ignition tables and our fuel tables, we don't need to have incredibly tight zoning, so we could've just as easily chosen...
18:56 Load breakpoints every 20 kPa, instead of 10 like you've seen here.
19:01 Okay, so now what we're going to do is we're gonna move forward and we're gonna tune the 80 kPa zone.
19:07 And you can see that I've purposely retarded the timing slightly further here to 10 degrees.
19:13 But what we also can do is take some note of the trend in our curve and we can see that we started at 40 kPa, we've gone 25, 24, I've gone 21, so we're taking around about, let's say, two degrees per 10 kPa out of our timing.
19:34 So instead of starting with 10 degrees in this point here, we can look at this, we're jumping 10 kPa, two degrees per 10 kPa would bring us to 19.
19:45 Let's take two more out for safety 'cause we always would prefer to start with our timing more retarded and then build up, rather than being over advanced when we begin tuning a new cell.
19:57 So let's bring us up into our 80 kPa zone, now.
20:04 And we'll have a look at what we need to do to our timing.
20:09 Okay, so we're sitting there, now, 80 kPa and 17 degrees and we're registering 266 newton-meters.
20:19 Let's try entering 19 degrees in there.
20:25 And you can see that essentially we've seen no difference.
20:30 We might've picked up one or two newton-meters, but we strayed away when we went into that cell because we had made that guess, extrapolated the shape of our curve ahead.
20:39 We're already very, very close.
20:41 Let's try going a little further.
20:44 Let's try 21 degrees and we'll see if we see any improvement from that.
20:50 And again, there's been absolutely no change there.
20:53 So let's go back to 19.
20:56 We're still in our 266, 267 newton-meters, and I'll try our original value of 17 degrees in there.
21:06 We actually have dropped a little bit there between 19 and 17, so it looks like 19 degrees is where we want to be at 80 kPa.
21:16 Let's just increase our load, now, and we're going to go into the 90 kPa zone.
21:23 Now this time, again, we're using that same trend, two degrees per 10 kPa, so that will take us to 17.
21:29 Let's be a little bit conservative and start with 15 degrees.
21:35 Let's increase our throttle opening and I'll just get back down to our 1,500 rpm.
21:44 Right, so, we're sitting there now at 19 kPa and 1,500 rpm and we're sitting at 319, 320 newton-meters.
21:53 Let's just add two degrees and try 17.
22:00 We've gone up about one newton-meter.
22:03 So you can see we're starting to really split hairs on the effect of our timing, it's really not making much difference.
22:13 We'll try 19 just to demonstrate that.
22:17 And again, 19, we've seen absolutely no change there.
22:21 So we saw a very small improvement from 15 to 17 degrees, so we'll leave it at 17 based on the fact we don't have any knock occurring.
22:30 If we're starting to get to a point where the engine is a little bit sensitive to knock, we're only talking about the difference of about one or two newton-meters.
22:40 We'd always err on the side of caution and we're better to have a couple of degrees less timing.
22:45 No driver's going to be able to pick up the difference of two newton-meters anyway, it's just such a small difference.
22:52 So let's try our wide open throttle, 100 kPa zone or as close as we can get to 100 kPa.
23:00 And we're starting with 13 degrees.
23:04 We're seeing 356, 355 newton-meters.
23:09 Let's add two degrees and see what the effect of that is.
23:15 You can see that we have, again, picked up just a really tiny amount of torque there, just a couple of newton-meters.
23:22 Let's try 17 degrees.
23:25 Absolutely no difference from our 17 degrees, so we'll go back to 15.
23:31 All right, so that tunes our 1,500 rpm column.
23:36 So now that we've tuned that column, let's just bring the engine back to idle, now, and we're going to make some changes to the 15, the 2,000 rpm column.
23:48 So what we can do for exactly the same reason that when we were tuning our volumetric efficiency table we sped the process up by taking the slice of the rpm column that we've just tuned and copying it across, likewise, when we're tuning our ignition timing, we know that as a general rule, as we move from low rpm to higher rpm, we've got this trend where we need to advance the ignition timing.
24:18 So what I can do is simply use the Control + C to copy the 1,500 rpm column and move it across to our 2,000 rpm column.
24:29 Now, I'm typically going to expect the timing to advance up, but we always want to start with our timing safe and retarded and advance it towards to the MBT, rather than moving ahead and finding we're already over advanced.
24:45 Now, there's a point I should've mentioned as well, if we are tuning ahead, like you saw me doing there as we moved up in the load, and we get into a new untuned zone, we've taken a guess at the ignition advance, if we then add some timing to that cell that we've guessed and we see no improvement in torque, or worse still, we see the torque drop off, that may mean that we have actually guess an ignition timing that's too advanced.
25:14 So if I see that situation, I would try retarding the timing back below where we started and see if that results in the torque staying stable or increasing.
25:25 So we need to use the input from the Dyno, the torque input from the Dyno, to help guide us with our tuning.
25:32 So when we move from 1,500 to 2,000 rpm, despite the fact that we could reasonably expect the timing to be more advanced, we're going to start using the same values we had a 1,500 rpm for safety.
25:46 Okay, I'm now going to complete the tuning of the ignition timing out to 4,500 rpm and you can watch as I go through this process.
40:10 What we've just seen come on there is a really good example of what you do need to watch out for when you're performing a Steady State Tuning, both during the fuel delivery tuning in Steady State, as well as our ignition timing.
40:23 We're obviously putting a lot of sustained high load on the engine.
40:27 And what you've seen just come up there on the Dyno was a high water temperature warning.
40:31 Now, I've set the Dyno to warn me any time the water temperature goes above 100 degrees.
40:35 Particularly when you're just learning to tune, it's very easy to get so tied up in what you're doing that you actually lose track of the basic engine parameters such as water temperature and air temperature, perhaps oil pressure and oil temperature as well.
40:52 It's always a good idea to scan those.
40:54 And if we do get into a situation where the water temperature gets a little high, we just need to allow the engine a few minutes just to cool down before we can go back into our higher rpm operation.
41:07 We're back down to 89 degrees centigrade now, so let's go back and tune our last zone, our 4,500 rpm row.
42:54 Okay, so that's got our ignition table tuned there out to 4,500 rpm.
43:02 And you can see straightaway how powerful it is when we're using the column that we've already tuned and copying it across, particularly if we look graphically at our table, we've got a very consistent shape.
43:17 And down in this area between 3,500 and 4,500 rpm, I've essentially made no changes at all to the ignition numbers.
43:26 I've tried advancing them, saw no difference.
43:29 You'll also notice when I advance the timing, as I mentioned earlier, and I see no improvement, I will also try retarding the timing two degrees and see if it loses torque and if it does, it means that we were pretty close right from the start.
43:43 And this is reasonably consistent with what we might expect from most engines.
43:49 We'll get a smooth ignition curve, as you can see here, and once we get higher in the rpm, we see smaller changes.
43:58 Okay, so now what we're going to do is look at how we can copy that curve out into the areas we haven't been able to get to yet.
44:08 So what we're going to do is exactly the same as we did with our fuel or VE table, we're going to use the Control + C and Control + V to copy and paste the ignition numbers we have tuned out into the area of the table we haven't been able to get to.
44:29 Now at the same time, what we want to also do is address these areas down here.
44:35 Remember, I said we can't really adequately perform Steady State Ignition Tuning on most engines down as low as 1,000 rpm.
44:44 And realistically, the numbers we're going to get there aren't that critical since we don't really operate the engine in that area.
44:53 It's quite common for most modern four valve engines to idle quite happily, somewhere between about 15 and 20 degrees of ignition advance.
45:02 And you can see at the moment we've split the difference there and we've got 15 degrees.
45:07 What we do want to do though is prevent this quite large step that we've got at the moment of 10 degrees as we move from 1,250 rpm to 1,500 rpm, and we can do that just simply by copying it by highlighting those cells and we can use the keyboard shortcut.
45:28 If you always, if you forget the keyboard shortcuts, you can right-click.
45:31 And what we're trying to do here is interpolate horizontally.
45:35 So that's the H key and that will just interpolate those cells and give us a nice, smooth shape to that curve.
45:45 The same thing, we can do through our area here.
45:49 Now remember, we only guessed at our 10 degree, 10 degree ignition advance here at 100 kPa and 1,000 rpm.
45:59 The chances are we're never really going to be operating there.
46:02 So we've got two option here.
46:04 We can do the same, we can copy, highlight across like this and use the H key to copy our, to interpolate our numbers across like that and give us a nice, smooth shape.
46:14 Or alternatively, what we could've done is we could've copied our 1,500 rpm column here, which we have tuned, and we could then paste that into our 1,250 rpm column, and then we could split the difference there, so we can use the Down key there and I'm just simply going to end up with numbers in between.
46:40 It doesn't really matter, strictly speaking, because as I say, we're not going to be operating in that area.
46:46 What we want to do is just maintain a smooth shape to our curve.
46:51 Now, the other thing to consider as well is this 80, 90, 100 kPa area at 500 rpm, this is likely to be the area the engine's going to be operating in when it's cranking.
47:04 If we do happen to have our ignition timing in this area very over advanced, that can cause issues with some engines starting cleanly, so it's always a good idea to have the cranking areas of our ignition table somewhere around 10 degrees.
47:21 Now, that's given us a nice, smooth ignition table that we can now work on in our wide open throttle tuning where we're going to be looking at ramp tuning in our next module.
47:32 Before we do move on, one last point I'll make is if we've completed our tuning of our ignition table and we don't have a smooth shape to the table, perhaps we've got some really big peaks and dips in our table, that would be a sign that perhaps we want to go back and re-address those particular areas.
47:52 We should normally see a relatively smooth shape to our curve, as you can see here graphically, and if we haven't got that smooth shape, then I would tend to go back and reinvestigate any areas that are showing a really erratic nature.
48:09 All right, we're done with the Steady State Tuning.