Practical Standalone Tuning: Step 8: Steady State Ignition
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Step 8: Steady State Ignition
27.44
| 00:00 | - Now that we've got our fuelling tuned under steady state conditions, we're going to repeat this process but with our ignition timing. |
| 00:07 | We're going to essentially go through the same range of our ignition map that we've already looked at with our fuelling, 1500 through to 4000 RPM, essentially for all the same reasons. |
| 00:17 | Once we've tuned under steady state, we're also going to do a little bit of extrapolation, much like you saw me do with the fuel table out into those untuned areas so that we're going to be there or there abouts once we actually start doing our full power ramp run tuning and dial in our VTEC switchover point. |
| 00:34 | Now the process we're going to go through here is going to look the same, we're starting at low RPM and low load and we're going to be using this time the torque output from our dyno in order to help guide our tuning. |
| 00:47 | What we're looking for here, just as a refresher, we're trying to advance the timing until we either find MBT or alternatively we reach the knock threshold for the engine. |
| 00:57 | If we do at any point encounter detonation, what we're going to want to do is stop, back the engine out of the zone that we're tuning to safeguard it, we never want to hold the engine in a condition where it is suffering from knock, and then we'll retard the timing a few degrees and recheck that area, making sure that we don't have any knock. |
| 01:16 | I always like to leave at least a 2-3° window or buffer between the timing that I'm actually running and the point where knock is occurring. |
| 01:24 | Now the torque output on the dyno, we've got two options to look at that so let's head across to our dyno screen and see what we're going to be using. |
| 01:33 | Now we've got a gauge here on the dyno screen. |
| 01:36 | This will show us the immediate torque output, it's also got a numeric value which will display the torque as well. |
| 01:44 | This is difficult to use though, given that the torque output is always going to be moving around a little bit, it's never nice and stationary so watching this gauge is a little bit tricky. |
| 01:55 | Instead what we're going to do is use the graph, the time graph down below here, obviously the engine isn't running at the moment so we've got nothing to see but the red line there is going to move around and it's going to display our torque. |
| 02:07 | This does require a little bit of mental smoothing for the reason I've just mentioned, that torque is never constant, it's always moving around a little bit so what we're doing is essentially taking a mental snapshot of the torque as it is before we change the timing, we'll advance the timing in 2° increments and what we're going to do is watch what happens to our torque as soon as we press the entre key, that's when that timing change will be locked in and we're going to then have a look at our torque graph and see what's actually happened there. |
| 02:37 | If the torque jumps up, that's a good sign, we're moving towards MBT and provided we don't have any knock, we're going to go another 2° and just repeat that process. |
| 02:46 | Due to the way I'm going to be doing this, I generally find that the easiest approach is to physically enter the timing numbers into the table on our laptop rather than using the plus and minus key. |
| 03:01 | The reason for this is we can enter the number but it doesn't actually take effect until that enter key is pressed whereas if we are using the plus key and tapping that a couple of times, the torque is going to jump up, we're not going to see that immediate change that we get when we make that 2° change and press the enter key. |
| 03:17 | So let's get our engine up and running now and we'll let it get up to temperature and we'll start the process. |
| 03:22 | OK we've got ourselves up and running now and we can see that both our intake air temperature and our coolant temperature are essentially in the normal operating range, really important to make sure that we aren't starting in a heat soaked condition so we want really nice realistic results. |
| 03:39 | Now we can see at the moment we're operating in the middle of the 40 kPa cell so let's jump across to our dyno and see what's going on there. |
| 03:47 | So we can see we've got our numeric read out here showing we're sitting around about 140 pound foot of torque and you can see now what I was talking about or explaining, the numeric value is actually quite erratic, it's moving around quite a lot, even though my foot is pretty consistent and smooth on the throttle. |
| 04:05 | Makes it really hard to really sue this as an input. |
| 04:09 | If we come down to our time graph though, we can see that while yes our time graph is also moving around, it is a little bit easier to get a read on what's happening there and use that as our input. |
| 04:20 | Now what I'm going to do though is just reduce the throttle opening because we're currently in our 40 kPa cell and you'll remember we started our fuel tuning from 30 kPa, let's just drop our throttle down and get into the 30 kPa cell and we'll see why this isn't going to be possible to tune on our dyno here. |
| 04:38 | Alright so let's get into the middle of that cell, sitting at 30 kPa now, we'll head across to our dyno, what we can see here is that we're only sitting at about 39 to 40 pound foot of torque, essentially we're very close to the minimum value that the dyno can read from the load cell and the resolution down here is not that great so we're not going to get useful data here, it's very difficult at this point to actually tune using the dyno to achieve MBT when we're making so little torque so what I'm going to do is step back up to our 40 kPa cell, we'll start there and we'll be extrapolating our results as you'll see anyway. |
| 05:17 | So not a big problem, we'll get ourselves nice and stable there in the centre of that cell, again making sure we are central so we're not being affected by interpolation and what I'm going to do, we know the value at the moment is 15°, we're going to enter a value of 17, I've entered that on the keyboard but again this doesn't take effect until I press enter. |
| 05:37 | We'll make sure we're stable, we're looking at our red time graph, just getting a mental image of what's happening there, I'll press the enter key and we see that our time graph steps up. |
| 05:47 | These are small changes, it's very subtle, you can always go back and forth if you didn't quite see whether we actually ended up with a change, it's easy to step back down to 15° and go again so we can actually see the effect of that change but we are looking for small changes, particularly down here where we're only at 1500 RPM as well. |
| 06:08 | So again I'll make sure before I make this next change, we've gone the right way, we've seen an increase in torque, albeit a small one so let's try again, we'll add another 2° and we'll go from 17 to 19, again just before I press enter, I'm making sure that I'm as central in that cell as I can be, we'll look at our time graph, get a metal image of that, press the enter key. |
| 06:29 | We saw again a small but noticeable increase in our torque there so this means that we are going the right way. |
| 06:37 | We also get a sense, and this will become a little more apparent as we get higher in the RPM, we get a sense from the magnitude of change when we're getting close to MBT. |
| 06:45 | When we're seeing little to no change, that means we're getting close to MBT and we're not going to probably need too much more timing. |
| 06:53 | Let's go again though, 19° was a step forward so we'll go to 21, again making sure that we're central in that cell, looking at our time graph, allowing that to stabilise, pressing enter. |
| 07:03 | And again a very small increase, let's go again, we'll enter 23, get stable in the centre of the cell. |
| 07:13 | Press enter. |
| 07:15 | This time no change at all so when we see that sort of effect, when we've advanced the timing and we don't see a change in the engine torque, what we're going to do is simply remove that change, come back to 21°. |
| 07:27 | Now I am being a little coarse here, making change in 2° increments. |
| 07:31 | Of course you can fine tune this and you may see a change with just 1° but for our example here, we'll just leave it nice and coarse so we can actually see the effect of these changes. |
| 07:41 | Alright so we know that we've got our timing value of 21° here at 40 kPa. |
| 07:46 | Now let's go up in the load, so we're going to go up to 50 kPa, we can see that the value there is 15°, we've gone from our 21° that we've currently got, up to 15°, or down to 15° I should say. |
| 08:00 | Probably enough of a step backwards that I'm not concerned that we're going to be over advanced, we always want to start from a safe retarded ignition timing here so let's again get ourselves operating in the centre of that cell, getting as accurate as we can there. |
| 08:17 | And again we're going to be looking at our time graph, wait for that to be stable, I'll enter a value of 17° here. |
| 08:25 | Looking at our time graph, pressing enter and we can see a noticeable jump up in our torque that time, that was quite clear. |
| 08:33 | OK so we've gone from 15 to 17, let's go again, we'll go to 19° here. |
| 08:38 | Waiting for our torque to stabilise, pressing enter. |
| 08:41 | OK we see small increase so we're going the right way but that increase was much less significant than the one when we went from 15 to 17 so again this means that we're getting close to MBT. |
| 08:54 | Let's go again though, we'll enter a value of 21° and I'll get back in the centre of that cell, waiting for our torque graph to stabilise. |
| 09:04 | And we'll press enter. |
| 09:08 | Absolutely no change so we'll go back to 19°. |
| 09:11 | And given the trend, although at the moment of course we have only completed the tuning of two cells, this is about what I'd expect. |
| 09:19 | 21° in our 40 kPa cell, as we increase the load we'd expect the timing to retard in order to achieve MBT, that's exactly what we've got. |
| 09:28 | Now we step into this area where we've retarded the timing to be a little bit safer so we're down to 12°, let's step up into that cell there, 60 kPa. |
| 09:37 | Again we'll make sure that we're nice and central, give everything a little bit of time to stabilise. |
| 09:44 | And let's enter a value of 14° here. |
| 09:49 | Again I'll just get into the centre of that cell as well as I can, press enter and we see our torque graph jumps up. |
| 09:58 | Now we could take a bit of a guess here, we're probably going to be somewhere around about 16 to 18° if the trend follows so that was to be expected, so we've gone from 12 to 14, let's enter a value of 16 here, again just waiting for everything to stabilise, pressing enter and again we see our torque jump up. |
| 10:16 | Although not a significant jump up that time. |
| 10:19 | Let's try a value of 18° here. |
| 10:22 | And again waiting for our torque graph to stabilise, pressing enter. |
| 10:27 | Little bit of a jump up but not really too much there and again that would probably be to be expected, I probably wouldn't expect this cell to be wanting to be 18°, let's just go back and we can always do this again as I mentioned if we're not too sure, did we really see a change, that's easy, let's just jump back to 16° and see what happens when we press enter, really see no change there so to be a little conservative here when we're really splitting hairs, I'm just going to actually leave that at 16°, alright let's jump up to our 80 kPa cell. |
| 10:58 | Again 12° to start with, let's enter a value of 14, looking at our time graph here, pressing enter and straight away we see our torque jump up. |
| 11:10 | Not a massive jump but we're probably pretty close to where I'd expect MBT to be, given the trend we've got in our graph here, let's try 16° here, we'll press enter. |
| 11:21 | Absolutely no change so we probably are there or there abouts at 14°, we'll go back there. |
| 11:28 | So now we're getting into our 80 and our, sorry our 90 and our 100 kPa cells. |
| 11:35 | So if we want to follow this trend, I'm probably going to actually start by retarding the timing here at 100 kPa just to be safe. |
| 11:43 | Let's come up to, and actually let's start by being a little bit more conservative at 90 kPa. |
| 11:49 | So let's come up to 90 kPa, get in the centre of that cell and we'll go from 10 to 12°, looking for that torque change and it did jump up there so go from 12 to 14°, again making sure we're in the centre of the cell, pressing enter, no change. |
| 12:08 | Let's go back to 12°. |
| 12:11 | We can't tune that 100 kPa site but we are interpolating into it, we're foot flat on the throttle here, let's go from 10 to 12°, we'll press enter. |
| 12:23 | No change in our torque, let's go down to eight though, let's see what happens there. |
| 12:27 | OK with 8° we actually see quite a significant drop off, let's come back to 10 and we see our torque increase back up, let's back off and we'll talk about our results. |
| 12:39 | Alright so we've got a reasonably consistent trend and we can see this if we look at our graph here, we've got our 3D graph, got a reasonably smooth shape to that graph which is about what we'd expect. |
| 12:55 | We do have a little bit of an outlier here where we have got this drop off from 16 to, 19 I should say to 16° but all things being equal, we've got a pretty consistent shape to that graph which is what we'd expect. |
| 13:11 | We do however have this area that we couldn't tune down in this lower load area and again what I want to do is essentially follow a little bit of a trend, add a little bit of shape to this, we know we were essentially looking at around about a 2° per 10 kPa drop off so I'm going to follow that trend here, so at 30 kPa I'm going to guess that 23° should be probably in the ballpark and we're going to be reasonably close to MBT, might not quite be right but we'll be there or there abouts. |
| 13:40 | Now 20 kPa and below, we're unlikely to really be spending a lot of time in that area and given that we are 1500 RPM, this is really a transition area off idle as we start the car moving so it's not really a super significant area, what I'm going to do is I'm going to actually make all of these cells the same and we'll take that same step, we'll go 25° here. |
| 14:04 | So again we might find that down at 10 and 0kPa, maybe it might want to be 27 or 29° but we're not going to really be operating there so a little bit of conservatism here with our timing is going to be the order of the day. |
| 14:19 | So now we've got our first column, our 1500 RPM column tuned, let's now highlight that column and what we'll do is paste that out to 2000 RPM. |
| 14:29 | Much like with our fuelling, as we increase the engine RPM, we would expect the engine to want a little bit more timing to achieve MBT. |
| 14:39 | Unlike our fuelling though, I am not going to take that guess ahead of time. |
| 14:44 | We always want to start with conservative timing so we can advance it in order to achieve MBT so we're simply going to start with the same timing that we've got right now. |
| 14:54 | So let's get ourselves up and running and we'll repeat our 2000 RPM column. |
| 15:00 | Alright so we're starting here, I'm in the 30 kPa cell at the moment and as we already discussed, at 1500 RPM we weren't really making a lot of torque, quite close to the bottom end of the measurement scale. |
| 15:13 | I just wanted to revisit this because as our RPM increases and our torque increases, often we can drop down and tune the cells we couldn't previously get to. |
| 15:21 | We can see on our dyno at the moment we're sitting at around about 53 pound foot. |
| 15:27 | You can see in the time graph these drop outs where we are dropping down to the minimum value, I'm going to say at this point we're probably still unable to really adequately tune that cell, always worth having a look but we're going to step back up to our 40 kPa cell and have a look at that because we know we can do an adequate job in that 40 kPa cell so let's get ourselves central here and we're sitting around 135 pound foot of torque, got 21° in there at the moment, let's add 2°, we'll go from 21 to 23, again just getting central, looking at our time graph, pressing enter, and we can see that our torque does in fact jump up which is what I'd expect. |
| 16:08 | Let's try another 2° here, we'll go from 23 to 25, again allowing that torque graph to stabilise, 23 to 25, again we've got a jump up in our torque there, not super significant that time, let's try 27 an we'll just see what that does, 27°, absolutely no change there so we'll come back to 25, we could also go back to 23 and just see again that that change that we saw was real. |
| 16:36 | However in this case 4° seems about right. |
| 16:40 | Before we move forward, what I'm going to do is apply that same trend that we just saw there to the cells below and this is really the same as the basis for our fuel tuning, essentially if the 40 kPa cell wanted an additional 4° in order to reach MBT, I'm going to expect that we're probably going to need a similar change to the cells below so let's just make that change now. |
| 17:08 | OK so let's continue with our process, we'll jump up to our 50 kPa cell here. |
| 17:13 | Got 19° in there at the moment, just make sure that we are central in that call before we take notice of what's going on here. |
| 17:22 | I'll enter a value of 21 and we'll wait for our graph to stabilise before I hit the enter key. |
| 17:27 | We are stable now, press enter and we'll see our torque does jump up so exactly as we'd expect, let's enter 23°, press the enter key and we've actually had a little drop out there. |
| 17:40 | That's OK though, let's just go back to 23°, so to 21°, our last change that we made that did have an effect, again we'll make our graph or allow our graph to stabilise, we'll enter the value 23 and we'll just wait for our graph to stabilise here, I'll press the enter key and we see that our torque does increase, only very slightly. |
| 18:09 | We can go another 2° but essentially seeing what I've got there, I'm pretty confident we're going to want that 23° in that cell and that sort of follows that trend that we just saw at 40 kPa. |
| 18:21 | Let's jump up to 60 kPa here, starting with 16°. |
| 18:26 | Let's enter the value 18, again waiting for our graph to stabilise, I'll press the enter key. |
| 18:33 | And we see our torque jump up, not a significant jump though so I'm guessing again we're probably pretty close at 18° to where we want to be, we'll enter a value of 20 though, let's again press the enter key, see what happens there with 20. |
| 18:50 | Very very small change, almost insignificant, I'm going to split the difference here for the purposes of being a little bit more conservative, we'll enter a value there of 19°. |
| 19:00 | So we're just splitting the difference because we did see a very small increase, let's come up to 80 kPa, got 14° in there at the moment, we'll enter the value 16, again waiting for our graph to stabilise. |
| 19:16 | We'll press the enter key. |
| 19:20 | And we see a very very small increase in our torque, almost insignificant, let's try 18° here. |
| 19:28 | Press enter. |
| 19:30 | No change at all so again just for the purposes of being a little more conservative now that we're up a little bit further in the load, I'll actually go back to that 16°. |
| 19:41 | If we were only splitting hairs over maybe one or two pound foot of torque, I'd always err on the side of being a little bit more conservative. |
| 19:49 | Let's come up to 90 kPa. |
| 19:52 | 12° in there at the moment. |
| 19:55 | At a guess on our trend probably we're going to want to be at 14°, let's let our graph stabilise, we'll press enter and we do see a very very small increase in torque. |
| 20:06 | Let's try 16°, press enter. |
| 20:12 | Our graph's essentially flat there, I'll come back to 14°. |
| 20:16 | Now again we obviously can't get into the 100 kPa cell, go to full throttle here, just going to enter the value 12 because we are interpolating into it, we'll see if we notice any increase in our torque, very very small increase and because that follows our trend, I'll leave that there so let's come back to idle and talk about our results. |
| 20:38 | Alright so, we've essentially got the same trend there that we saw in our 1500 RPM column and the benefit of using the 3D graph as well is we can start seeing this shape come to life here and again we're seeing reasonably consistent trends and if I saw a real obvious outlier here, that was not following the trend of the rest of the column, I'd come back and revisit that cell and often as you start building this up as well, as you increase the load, you might be splitting hairs over whether the correct timing for a cell is 20 or 22° if you're not seeing a significant change in the torque and some of these can be quite subtle changes. |
| 21:18 | So what we'll find is that if we're splitting hairs and we're not quite sure if we should be let's say 20 or 22°, if we increase our load and fill in the next cell, this can actually help guide us with what the correct value for the cell before was, just following the same smooth trend that we've got. |
| 21:35 | So what I'm going to do now is I'm going to jump ahead, we're going to speed this up and we'll follow the same process that we've been using and you can watch me tune the rest of these cells out to 4000 RPM. |
| 21:45 | We're going to speed this up and I'll also be using audio knock detection equipment for this as I always recommend you do when you're tuning any engine. |
| 21:53 | Given the nature of this engine being stock compression and the fact that we are using a really good quality 100+ octane pump gas, I'm not expecting knock to be an issue but we never want to take the risk so let's go ahead and we'll complete our steady state ignition tuning now. |
| 23:26 | Alright we've got our steady state ignition tuning completed out to 4000 RPM so let's have a look at our table and see how that's come out. |
| 23:34 | And for the most part, what we've got, as we can see from our 3D table view, pretty consistent and smooth trend to that table, there are a few areas that we could possibly look at refining, we've got an area in here where we've got a bit of a spike in our timing and we've also got an area in through here where we look like we've got a little bit of a hollow. |
| 23:53 | Bear in mind here for the purposes of our worked example, I was making reasonably coarse 2° changes. |
| 24:00 | As I mentioned, you can go in and fine tune this, be a little bit fussier and what you'll find is that you may pick up a very small amount of additional torque, you may end up with a slightly smoother shape to your ignition table, the process is just going to take a little bit longer if you want to be a bit fussier. |
| 24:16 | Also worth mentioning here that we want a reasonably consistent and smooth trend to our table but we don't want to artificially smooth the table, we do want to give the engine the timing that it wants. |
| 24:30 | Now on this note though, if we've got any weird outliers, just like with the fuelling, this would be a bit of a red flag and I would tend to come back and revisit those sites. |
| 24:40 | Before we move on, we've got a couple of areas that we do need to deal with. |
| 24:44 | Obviously our higher load, higher RPM area that we haven't dealt with and we also haven't done anything with our low RPM area here. |
| 24:51 | So let's deal with our high RPM operation first and all I'm going to do here is highlight our 4000 RPM column, control C and we're just going to paste that out into the higher RPM operating areas. |
| 25:04 | This is almost certainly going to be reasonably conservative but I'm going to be more than happy with that, we can deal with this and fine tune it as we move on so let's get that done now. |
| 25:16 | Alright now we also need to deal with our idle cruise area, well our idle and transition area I should say, not idle and cruise, as well as our wide open throttle area. |
| 25:26 | Now this low RPM wide open throttle or high load area, we're never really going to be running in, we'll transition through this just like with our fuelling during our cranking and start but we will definitely be idling, as we already know, down in this region and we will be transitioning from that region up to our 1500 RPM column that we've already tuned. |
| 25:46 | Now generally we don't need to be too fussy here, we know that we're also using idle ignition control in the idle areas but what I'm going to do is highlight the areas down here and 16 to 18° is generally a pretty good run of the mill area in terms of timing to have in this region. |
| 26:04 | What I'm going to do, because we haven't tuned our 1250 RPM column, I'm just going to highlight out through that area and what we can do here is if we right click, we can then interpolate horizontal, vertical or area. |
| 26:18 | In this case what we want to do is interpolate horizontally and that is just going to basically interpolate and fill out the 1250 RPM region. |
| 26:27 | Looking at the rest of our table up above here, what we can do is just simply follow that same trend that we're starting to see. |
| 26:36 | So in this case if I copy the 50 kPa column up here, let's just do exactly that, we'll go that out to 1250, control C and then control V, we'll paste that and we can see that at 1500 RPM, we actually ended up pulling 3° out there so I'm just going to do exactly the same, we'll take out our 3° and our job's done there, control C and control V will paste that up, we want to take out an additional 2° there, so we'll do exactly that, control C, control V, again we've taken out 2°, and control C and control V one more time and we'll take out an additional 2°. |
| 27:21 | So all we're doing is keeping a consistent shape to this area of the table, even though it's an area that we're unlikely to be able to access, it's always good practice to just keep extrapolating the results that we have tuned out into those areas we can't get to. |
| 27:35 | So at this point we've completed our steady state ignition tuning and we're ready to move on with the next step of our process. |
