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Practical Standalone Tuning: Step 8: Steady State Ignition Tuning

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Step 8: Steady State Ignition Tuning

33.13

00:00 - Now that we've got our fuel delivery dailed in accurately in steady state, we're going to do exactly the same task, but this time we'll be optimising our ignition timing.
00:10 The idea behind this is, we're going to be looking at the torque being measured by the dyno and we're going to be advancing the timing slowly while watching what happens to that torque.
00:24 What we're looking to do is optimize the torque and when we reach the ignition timing where the dyno is showing us peak torque is being produced.
00:34 This point is known as MBT which stands for minimum timing for best torque.
00:39 It's also known as maximum brake torque timing.
00:44 We're going to perform the tuning in exactly the same way where we start at low RPM and load and move forward and this is going to give us a general trend for the ignition table much like we got for our fuel table.
01:00 However, I'm going to jump ahead a little bit and we're going to have a look at a quick demonstration now to graphically represent exactly what is going on in the dyno, because if you don't understand what is happening it can be a little bit difficult sometimes to actually see what the torque is doing on the dyno.
01:22 So, we're going to start by bringing the engine up to 2000 RPM and we're going to use the torque optimization function on our main line dyno, and this function will let us graph the engine torque and see how that varies with the ignition timing as the ignition timing is altered.
01:47 So, let's just bring our dyno control back down and we'll get us to 2000 RPM and we're going to go to minus 50 kPa so we're just about right there now.
02:04 OK, we're operating in the middle of our minus 50 kPa 2000 RPM site.
02:11 What I'm actually going to do for this purpose is I'm going to highlight all of cells around that minus 50 kPa site as well, so let's bring up our torque optimization test, and what you'll be able to see here, on the vertical axis we have the torque being registered by the dyno, and on the bottom axis we have our ignition advance which is coming from the ECU via CAN.
02:39 So what I'm going to do is I'm just going to hold the engine operating at the same point and I'm just going to advance the timing at a degree every second and you can see that as I do this the dyno plots the change in torque and we'll see exactly where the engine makes peak torque so we're getting up to 27 degrees now.
03:09 We're going to advance the timing all the way through to about 45 or 50 degrees and what we're expecting to see is that the torque will increase.
03:19 It will reach a peak and it'll plateau and then if we continue to advance the timing it will actually start to drop off and we're starting to see that now.
03:33 We're up to 43 degrees and we can see that our torque is actually starting to drop away, and so we'll keep going all the way through to 50 degrees of Ignition Advance.
03:47 Alright, I'll close the throttle now and we'll have a look at what we've got on our dyno screen.
03:52 So, you can see the red line representing our torque versus ignition timing, and at the same time, the dyno also shows us conveniently that, for this particular cell in the ignition table, MBT timing was 37.7 degrees and at that particular point the engine was producing 147 Newton metres of torque.
04:16 OK, so we can use that torque optimization test to do an ignition sweep like we've just done at each cell in the ignition table.
04:27 Of course, that'd be incredibly time consuming and it's not strictly necessary.
04:31 The test is simply there to show you exactly what's happening.
04:36 Now, what we're going to be doing is we're going to be relying on our ignition tuning graph which you can see down here.
04:42 Now, the little red line, which, at the moment, isn't doing anything, this shows us how much torque is being monitored by the dyno, and let's just get the engine up and running again, and we'll see that little graph start moving around.
05:00 So, the graph automatically scales and we can see numerically, our torque value is also represented at the bottom of that graph.
05:11 If we want, we can also see the torque is being represented by a needle gauge up here.
05:17 OK, so what we're trying to do is optimise the ignition timing until we reach our peak torque.
05:26 Of course, we jumped ahead there, moving to 2000 RPM.
05:30 What we're going to do is we're going to start our ignition tuning at 1500 RPM.
05:37 Remember that we started our fuel tuning at 1000 RPM.
05:44 It's a little more difficult to optimize our ignition timing at such low RPM.
05:50 We're not going to get a really good representation from the dyno at 1000 RPM, and, of course, we never drive our car at wide open throttle at 1000 RPM anyway.
06:01 So, it's not as critical that the engine torque is optimal there, so we're going to start with 1500 RPM and as low as we can get in the load, which, again, is our minus 60 kPa site.
06:14 So, we're sitting at 15 degrees now and we're looking at the torque graph on our dyno, and you can see that we're seeing around about 18 to 20 Newton metres, and we see that the torque graph does move around a little bit, and that's one of the skills we need to learn as a tuner, is to mentally average the torque reading so that we can see when we make a change to the ignition timing, whether we've seen an improvement or not.
06:41 So, what I'm going to do now is I'm going to advance the timing by two degrees.
06:45 I'm going to enter a value of 17 degrees in that particular site, and before I press enter I want to make sure we're in the middle of our cell and we want to look at our torque before and after we press enter, so you can see, at the moment, we're sitting at 24 to 25 Newton metres.
07:04 I'm going to press enter.
07:07 You can see that the torque jumped up.
07:10 It's jumped up to 30 to 32 Newton metres, so there's been a positive change.
07:15 We've gone the right way.
07:16 We've moved towards MBT.
07:18 Now, when I see a change like that, when I see the torque increase, what I'm going to do, as long as we're not monitoring any knock, I would go further in the same direction, so, this time, we'll add another two degrees and we'll go to 19 degrees.
07:34 Again, we're looking at the torque value before and after I press enter, so we're sitting at 30.
07:42 Let's just get back into the center of this cell.
07:44 Sitting at 32, 33 Newton meters.
07:47 I press enter and we have seen, again, the torque jump up.
07:52 This time we're sitting, now, at 37 to 38 Newton meters.
07:55 So, again, a positive change.
07:57 We would simply continue in the same direction.
08:00 Let's try 21 degrees.
08:03 We've entered 21 degrees and as soon as I press enter you can see the graph actually jumps up a little bit.
08:10 So, I'm using a combination of the visual of the graph, what the graph line is doing, and in that case it was positive, as well as the numerical values.
08:18 So, now we're sitting at about 42, 43 Newton meters, so let's go a little further.
08:24 Let's enter 23 degrees in that site.
08:27 Again, I'll just get back into the center of the cell before I make that adjustment.
08:32 So, we're sitting at 39, 40 Newton meters.
08:35 I press enter and again we've seen a positive change.
08:39 We've gone up about two or three Newton meters.
08:42 However, you will also notice that now, the amount of torque change we're seeing per two degrees is starting to get a little smaller, so, that, again is indicative that we're getting close to MBT timing.
08:57 Let's continue though.
08:59 We'll try 25 degrees now.
09:01 So, again, we're just getting back into the center of our cell.
09:05 It's very important that we are central and constant in that cell before we make our change, so we're sitting at 47, 48 Newton meters.
09:13 I press enter and we've still seen a positive change.
09:17 We've jumped up to 51, 52 Newton meters.
09:20 Let's continue. Let's go to 27 degrees.
09:25 Get back into the center.
09:27 We're sitting at 46, 45, 47. Press enter.
09:34 Now, this time we've seen a change but it's very, very small.
09:38 We've seen maybe one Newton meter of change.
09:42 Let's try 29 degrees.
09:46 Now, with 29 degrees, this time we've seen no change at all.
09:50 So that suggests to me that 27 degrees was our MBT timing for that particular cell.
09:57 What we can do now, before we move on, you can see, just like the fuel table, we have these two cells here.
10:04 The minus 100 and minus 80 kPa zones that we can't access.
10:10 Now, I'm not just going to leave those at 15 degrees of ignition timing.
10:17 Again, with the trend that we'll see with our ignition timing, we'd expect, as we reduce our load, we would expect the timing to potentially increase, so I'd expect the timing in these cells to be at least 27 degrees, if not more.
10:31 So, what I'm going to do before I move on is I'll just copy the 27 degrees into these two cells.
10:38 Now, there's a very good chance that MBT timing in these cells would actually be slightly more advanced.
10:44 It gets to a position where we're not really that worried though because we're not going to be driving the car in these cells.
10:52 We're only likely to transition or lightly move through these cells, so if we're not quite optimized at 27 degrees we're going to be so close that we're only going to be talking a few percent, and it's really not a consideration.
11:08 So, we're just simply going to copy that value down.
11:12 Now we're going to move up and we're going to move into the minus 50 kPa site and we're going to start by repeating the same process and then I'll show you how we can speed up that process.
11:23 So, we're going to do the same.
11:24 We're going to add two degrees and we're going to move to 17, and we're looking at our torque before and after, so at the moment we're sitting at about 81, 83 Newton meters.
11:35 Press enter and that jumps up to 85 to 86.
11:40 So we've moved in the right direction.
11:42 We'll go another two degrees, and, again you can see that the torque jumps up, this time, to 88 to 89 Newton meters, so we'll continue to tune to MBT.
11:56 We'll enter 21 degrees, and you can see, again, an immediate spike in our torque graph.
12:01 We're up to 92, 93 Newton meters.
12:06 We'll go to 23 degrees, and, again, we've increased our torque up to 98, 99 Newton meters, and we'll try 25 degrees.
12:19 We're seeing a very small change that time.
12:21 We've gone up about one Newton meter.
12:24 Again, that's an indicator that we're getting close to MBT.
12:27 Let's try adding another two degrees.
12:30 We'll go to 27 degrees, and, this time, we've seen no net effect from the addition of two degrees.
12:39 Any time I make a change and advance the timing and I don't see any improvement, I'll take that torque, that timing back out.
12:49 We've just dropped that timing back down and, again, you can see our torque is staying stable at about 100 Newton meters.
12:57 Now, the important point here is to remember, as we increase our load, or increase our airflow, we expect the MBT timing to become more retarded.
13:10 We don't need as much ignition advance.
13:12 So, the trend I'm expecting to see as we move to the right down the 1500 RPM row, I'm expecting that the timing will gradually retard.
13:28 So, we can work on that basis and you can see, we've just moved from minus 60 to minus 50 kPa and we've ended up removing two degrees.
13:36 Rather than starting with 15 degrees we move to the minus 40 kPa zone, we could quite likely take a guess that the correct value at minus 40 kPa might be somewhere around about 23 degrees just following that same trend where we've retarded the timing by two degrees, per 10kPa.
13:58 Because I'd like to start with the timing safely retarded and then advance it, I'd probably begin by retarding the timing a little further, so if our trend says it should be 23 degrees, you'd start by entering a value of 21 degrees in there.
14:14 Now, let's move up into our minus 40 kpa zone, and we'll see how the engine responds.
14:23 Let's get us in the middle of that zone.
14:25 So, we're sitting there, at the moment, with 145 Newton meters of torque.
14:29 Let's try 23 degrees, and you can see we did gain, but only margainally.
14:39 We've gone up about three Newton meters.
14:41 Let's try 25 degrees and we'll see if we pick up any torque.
14:45 With 25 degrees we've seen absolutely no change, so we're going to go back to 23 degrees.
14:52 So, that, straight away shows you how that trend can be used to kind of tune ahead and make an educated guess at what the ignition timing values are going to be.
15:03 Now, of course, if you've got a very knock sensitive engine we're always going to be more conservative when we're taking a guess at the values ahead of ourselves.
15:13 In this case, the engine is very safe and not sensitive to knock, so I can be a little bit more aggressive with the timing guesses that I'm making.
15:27 So, this is a good time to actually point out that when we're tuning an engine for real on the dyno as opposed to presenting a course like I am now, we would always be listening for knock or detonation with an audio knock detection device so that we can immediately back off if the engine does begin to knock.
15:47 OK, so now I'm going to also show you another way we can speed up our process.
15:52 Now, remember that we started with a relatively tight load input table for our ignition timing here and we have some break points every 10 kPa which aren't strictly necessary on our ignition timing.
16:09 That's because we see that general safe trend or general consistent trend in our ignition timing versus load.
16:17 So, what I'm going to do now is we're going to jump ahead and instead of tuning this minus 30 kPa zone we're going to jump all the way through to our minus 20 kPa zone, and remember, we're seeing a trend here at the moment at 1500 RPM.
16:32 We're retarding the timing at around about two degrees per 10 kPa, so we're moving up 20 kPa, so we could expect the timing, realistically, to be somewhere in the region of 19 degrees here.
16:44 We're going to start by being a little bit more conservative than that and we'll say let's start with 17 degrees.
16:53 Let's open the throttle through and we will just get ourselves running in the middle of that particular site there, and we'll have a look at what our torque's doing.
17:07 At the moment we have 240 Newton meters so let's try advancing the timing to 19 degrees, and 19 degrees is giving us a small increase to about 244, 245.
17:22 Let's try 21 degrees.
17:27 21 degrees actually has given us a modest increase.
17:31 We're seeing about a one Newton meter increase.
17:35 We can try going a little further.
17:37 Let's try 23 degrees, and, this time, we've seen the torque is sitting at exactly the same point.
17:45 So, our correct timing for that point would look to be 21 degrees, so, this time, instead of tuning the minus 30 kPa zone, what we're going to do is we're just going to use the linearize function which we can access by using the alt key on the keyboard.
18:06 That simply interpolates between the two surrounding cells so in this case we have highlighted the minus 40 kPa cell and we've highlighted the minus 20 kPa cell and the value that the ECU will put in the middle is simply the average of the surrounding cells.
18:25 So we can use this to interpolate between two surrounding cells or multiple surrounding cells.
18:32 OK, so now we're going to move forward and we're going to tune the zero kPa cell, so, again we're going to start by retarding the timing two degrees which is what we'd expect.
18:43 We want to be a little bit more conservative and try 17.
18:47 Go to wide open throttle and we can see what our torque is doing.
18:55 In this case, we're just doing about 325 Newton meters.
19:01 Let's try advancing the timing to 19 degrees.
19:08 We've really seen no change from that additional timing there, so we'll pull it back out.
19:17 Actually, we do see a very small change there.
19:20 We do see a small increase with our 19 degrees so as long as we weren't seeing any knock I'll put that 19 degrees back in there.
19:29 We're picking up around about two or three Newton meters.
19:32 OK, so that completes the tuning of our 1500 RPM row.
19:39 Now what we are going to do is increase the RPM on the dyno so we can tune the 2000 RPM row, but before we do that we're going to start by copying the numbers that we just tuned in our 1500 RPM row.
19:54 We're going to copy those using control C, and then using control V we're going to paste them into the 2000 RPM row.
20:04 Now, this is going to help get us close to MBT much quicker because, again, as we increase the RPM we know there's a general trend where we need to advance the ignition timing, so it's likely that we're going to need at least as much ignition time as we had at 1500 RPM in the 2000 RPM row, if not more.
20:29 OK, so now you can sit back and watch.
20:32 I'm going to do the same process.
20:34 I'm going to continue tuning the rest of the ignition table out to 4500 RPM in steady state.
27:37 Alright, so we've tuned in steady state out to 4500 RPM and you can see that once we get a little bit higher in the rev range, you tend to see very little change in that ignition table, and, in fact through quite a large portion there, the table is actually quite flat.
27:57 You also can see we've got this general smooth trend and shape to that ignition table.
28:05 Now, we're not quite finished yet.
28:06 There's a couple more jobs we need to do.
28:08 Now, the reason we're tuning out to 4500 RPM in steady state like this is to ensure that the timing is as close to optimal as possible across the areas that we're most likely to be using the engine.
28:22 That's going to give us the most torque and power from the engine.
28:25 It's going to give us the best results from the engine.
28:28 In the higher rev range we're much less likely to be operating at part throttle, so there's no need to strictly spend our time doing steady state tuning at the higher RPM range, and at that area we're more likely to be operating at wide open throttle, and we'll look at tuning that area in the next section where we're looking at ramp run tuning.
28:52 However, we're obviously not going to want to be seeing ignition timing at 15 degrees in this area so what we're going to do is we're going to extrapolate the numbers that we've got at four and a half thousand RPM and we're simply going to copy and paste those into this untuned area.
29:14 Now, remembering our trend with ignition time versus RPM as we tend to see the ignition timing advance as we increase the RPM.
29:23 So we know that we're probably going to need to see at least as much timing as we had at 4500 RPM, if not more, so while we might not be absolutely perfectly optimized to MBT.
29:36 We're likely to be very close.
29:39 OK, so that gives us one more area that we want to address, and that's this transition down between a thousand RPM and 1500 RPM.
29:49 Now, we don't generally want to see large changes between cells and our ignition table.
29:57 This is what can lead to erratic drivability.
30:01 So, we're sitting at 15 degrees now at idle and that's a relatively sensible run of the mill place for our engine to idle, typically anywhere from about 12 through to about 20 degrees, and we've kind of split that in the middle and gone with about 15 degrees for our idle ignition timing.
30:20 What we can do there is also add in another row if we like at 1250 RPM just to help with our transition off idle, so let's do that now, and we will add in another RPM site and we can do that just by clicking on the insert row and we'll add one row there at 1250 RPM.
30:45 Now, what that's done is it's just interpolated between 15 degrees at 1000 RPM and 27 degrees at 1500 RPM.
30:56 Now, what we might want to do is give that a slightly smoother transition into our operating area of the table from 1500 RPM and up.
31:12 That's just going to help smooth out our transition from idle at 1000 RPM or 800 RPM into where the engine's actually operating.
31:21 Now you can see we've also got this area down here which we've previously set at 10 degrees.
31:26 Now, we're never going to be able to operate the engine down there under normal conditions.
31:31 However, this will be the area that the engine will be accessing during cranking our initial startup.
31:38 So, if we have the ignition timing in this area over advance, it can cause poor starting, so having something in the region of about 10 degrees in this area of the map that the engine's going to be accessing during cranking and immediately after startup before it moves across and drops down into the normal idle area, its going to give us good smooth startup for our engine.
32:04 So now we've got a table which, as you can see, across here on the right hand side, has a nice smooth shape to it.
32:11 We don't have any really dramatic bumps or valleys and that's going to lead to an engine that's going to provide good drivability.
32:22 Now, one thing I haven't mentioned is with the Haltech Elite ECU, it does offer the ability to run closed loop control of the fueling based off the wide band controller.
32:37 So, while we don't strictly expect to see a change in our volumetric efficiency or our fuel requirements as we adjust our ignition timing, once I've tuned the fuel table I've just turned that closed loop functionality on to help make sure that my air fuel ratio is absolutely on target while I'm tuning the ignition table.
33:01 Alright, we've got our ignition table tuned in steady state.