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Practical Standalone Tuning: Step 8: Steady State Ignition Tuning

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Step 8: Steady State Ignition Tuning


00:00 - Alright the next step of our process is to essentially repeat what we've just completed with our fuel, only this time of course we're going to be optimising our ignition timing.
00:08 And in order to do this, we're going to be using the torque output graph on our dyno so let's just have a quick look at that on the dyno right now.
00:16 We've got two places where we can watch the torque.
00:19 First of all, we've got this gauge, that will give us a needle pointer, essentially showing us the torque.
00:25 It'll also give us a digital read out here at the bottom of the torque.
00:29 This is useful to a point but it will be moving around quite a lot so it's not really that useful I find when we are trying to achieve MBT timing.
00:39 On the other hand, we've also got this live graph which obviously at the moment, the engine isn't running on the dyno but that red line is going to auto scale and give us a torque reading so that is what we're going to be focusing on.
00:52 The idea here is we should be starting with our base ignition timing table which is nice and conservative, essentially should be well retarded from MBT and we're going to go into each cell, starting again just like we did with the fuel at our lowest load and lowest RPM we can achieve and we're going to optimise that cell using the torque graph and then we're going to increase the load and basically work our way through.
01:16 Unlike the fuelling, we're not going to be tuning ahead or guessing ahead unless we find a point where the engine is actually knock limited, in which case we're going to retard the timing at that cell and at higher load cells as well.
01:29 So we're always going to be starting from a place hopefully of being safely retarded with our timing.
01:35 What I'm going to do here is make incremental changes in 2° increments, should be enough that we can actually see the effect on our dyno graph.
01:45 If need be, we can start getting a little bit more granular with that as we get going.
01:50 So key points here of course will be to audibly listen for knock while we're going this.
01:55 I'm going to present two columns here showing the process and then I'll complete that process, we'll speed up the recording a little bit so that we can get through this quickly and I'll be using my audio knock detection as I'm doing that as well.
02:09 Again, just to reiterate from the fuel, we're going to be tuning out to around 40 kPa, even though we can go a little bit higher than this, and we're going to be copying our trends out to the area that we can't access so hopefully when we do start doing our wide open throttle ramp runs, we're already ahead of the game and probably should be at least there or there abouts in terms of our timing.
02:29 Alright so the first column I'm going to do here, just to try and get the engine running smoothly because the car was running a little bit rough on the dyno in terms of a little bit of oscillation at 1500, just to make our recording a little bit smoother, I will actually do this at 2000 RPM here.
02:47 So let's get our fans going and we'll get ourselves up and running and see what we can achieve.
02:53 Alright so at the moment we're at 2000 RPM and we are in the middle of the 60 kPa cell.
02:59 We can see that we're showing about 38 to 45, maybe 50 pound foot of torque, it is moving around a little bit.
03:08 If we look at the graph we can see that that's quite irregular.
03:11 The reason being here is that we're right on the absolute minimum reading that the load cell can provide so we're not going to get really good data here.
03:19 We should be able to achieve something but certainly if I reduce my throttle lower, you can see we're actually still running on the dyno but we're reading zero so there's obviously no way that we can really use this to get down into that 40 kPa cell.
03:34 Pretty much the same as what we saw with the fuelling here, we just couldn't get down that low.
03:38 So that's alright, let's come back up to the 60, this one's going to probably be a little hard to tune accurately because we're so low in the load but we will get cleaner readings as we increase our load and our throttle opening.
03:52 So let's see if we can make some sense of this.
03:55 What we're going to do is enter a value of 17, that won't take effect until I press the enter key.
03:59 What we want to do is make sure that we're as close to central in that cell as we can.
04:02 Looking at that graph, which as we can see is oscillating around a little bit, but we just want to sort of mentally average that and as I press enter, we can see that that red line has increased, it's minor but again we're in a position where we're right on that limit so it's going to be hard, let's try another two degrees though, we're going in the right direction.
04:23 Graph's a little bit smoother now, we'll press enter and again we see the torque graph increase, albeit only a minor amount.
04:31 Let's try another two degrees, we'll go to 21 and while it might be a little hard to notice on this recording, even those 4° of timing that I've put in here, I can tell that the car's actually running smoother and sounds cleaner as well.
04:44 Alright we'll just get in the centre of that cell.
04:47 Again looking at our graph before and after we press enter, enter key, we've had an increase but it's really really minor so we're probably getting pretty close to optimal, we'll try another 2°.
04:59 Just see if we can tell the difference here, again mentally smoothing that graph before and after we press the enter key, yeah I have still seen an improvement, does sort of cycle back down so I'm going to leave that cell at 23° for the moment.
05:13 I may need to come back to this because I'm going to get a hint from this next cell so let's open our throttle a little bit further, and we'll come up to our 80 kPa cell.
05:23 Just make a small adjustment to our dyno set point to make sure that I am nicely central in that cell.
05:31 And hopefully now we should get a reasonably clean graph because we are a little bit, producing a little bit more torque so the dyno's not right on that minimal reading.
05:41 Alright so we're at 15°, let's enter a value of 17, again, looking at the graph before and after, we do see a very small improvement there.
05:49 We'll go again, 19°, pressing enter, see our graph increase but really really minor amount so we're sort of really not making significant headway into this.
06:05 I'll try another 2° though, knock at this point is very much unlikely so we're not going to do any damage.
06:13 Press enter, 21°, we do see it bump up but it's the smallest amount.
06:18 For the sake of safety here I'm going to leave that alone.
06:21 What that also looks like is we've gone from 60 kPa, 23°, we've increased our load, we've gone to 80 kPa, we've got 21° so we've dropped 2° for a 20 kPa increase.
06:33 That probably indicates we're in the ballpark and also probably indicates that the 60 kPa site is probably pretty close to optimal as well.
06:43 Not always going to be the case, sometimes when we tune a cell like we've just done there at 80 kPa, it's going to highlight that we were probably a little conservative or maybe a little over enthusiastic with the cell we've just tuned.
06:54 So I'll use the trends that we start to see developing to help guide those cells where it's very difficult to get really solid results.
07:03 Obviously with only two cells, difficult to say that is a trend but we'll see how this develops.
07:08 Let's increase our throttle opening now, we'll come up to 100 kPa.
07:12 Make sure that we're nice and central in that cell, just let our torque graph stabilise.
07:18 I'll enter a value of 17, waiting for that torque graph to stabilise, we'll press enter and we see our torque jump up.
07:26 Let's enter a value of 19.
07:30 Again waiting for our torque to stabilise, press enter, and we see our torque jump up but again, very very minor if any change.
07:39 So let's try again, go to 21, now my trend would suggest that 21 should be really no change, we're sort of seeing 2° so far per 20 kPa which if that trend's correct, 100 kPa we should expect to be about 19° but it's not always going to be right, let's just make sure we're central in that cell, press enter, and we do actually see a very very minor increase in torque but I'm going to actually just take that back, it was so minor, I'm not really concerned about it and I want a conservative tune in this as well so let's now increase our throttle opening, we'll come up to 120 kPa.
08:20 We can get central in that cell.
08:23 We're now producing some boost so we do need to be mindful of our temperatures.
08:27 And you can see we're sitting at 100°C, that in and of itself, not a concern but we obviously want to watch that.
08:32 Let's enter a value of 17 here.
08:36 And we see our torque does increase, again really really minor, let's try another 2° here, 19°.
08:43 The graph has just rescaled here so we did see an increase but let's go back down to 17.
08:51 So it does actually want to be 19 at that cell.
08:56 So now I can consider what I'm going to do with those other cells.
08:59 But before we look at those, let's just see if we can get up to the 140 kPa cell, no I'm now at full throttle and I can't so that's as far as we can go.
09:09 Let's come back to idle and discuss our results.
09:12 Alright so now we need to decide what we're going to do with what we've found here.
09:17 So we can see here, we've essentially got 19° at 100 kPa and 120.
09:22 We know that 120 kPa, 19°, was optimal.
09:27 I know that we're not knock limited here, again of course we would normally be audibly listening for knock but I know that's not happening.
09:34 So I could safely leave that at 19°.
09:37 Now how we can deal with this, two ways, we could leave that at 19° and we also saw a really small increase at 100 kPa with 21° which would suggest that these cells here, which we already talked about the fact that we were struggling to get a solid reading here, these could possibly be increased another 2° as well.
09:57 But we are starting to split hairs here, we're talking about a percent or so of torque.
10:02 So given that I know that this car is going to get a hard time and I want a conservative tune in it, my tendency here would actually be to purposefully be a little conservative at 120 kPa and make that 17°.
10:14 We've also got this trend here, remembering we couldn't get to 140 kPa but maybe if there's a little bit more heat in the turbo, maybe if we introduce boost control, maybe we will be able to but again we're following that same trend of -2° per 20 kPa so we're probably pretty good there.
10:32 We could go that a little bit further and copy that trend out into these untuned areas as well and what I'll do is just copy that out to 9° at this point.
10:43 Likewise we also need to consider what we're going to do at the lower load areas.
10:47 So again can't get to them, just like our fuelling, the timing, a little less critical than the fuelling.
10:53 We could run this engine at 40 kPa at 12° and probably 30° and the engine will run OK.
11:01 Yes it'll have a minor impact on our torque but my point here is we're dealing with an area that we're very seldom going to be driving in and we're also starting to split hairs over our torque so let's just take that same trend, I'm going to highlight the entire column above this cell and we're going to set that to 25°.
11:21 So again following that trend of 2° per 20 kPa there, I could have of course followed that up and increased the timing again at 20 and zero but again just being a little bit conservative, no I'm not going to do that.
11:34 So that's our 2000 RPM column tuned.
11:36 What we're going to do now is copy that out to the right to 2500 RPM.
11:44 And we're now going to repeat that process.
11:46 Unlike the fuel, I'm not going to add any timing even though I expect that probably as I go from 2000 to 2500 RPM, probably the engine will want a little bit more timing but again always best to start from a position of safety so let's get ourselves up and running, hopefully we can get ourselves back down to around about that 60 kPa cell.
12:06 And we'll see how we're looking.
12:09 Alright so what we can see this time is in the centre of that 60 kPa cell, we're making more like about 90 odd pound foot of torque so a little bit more than we were making before, we're basically off the floor of the load cell so we should be able to get reasonable results here so for a start, let's just try adding 2° so we'll enter a value of 25, again looking at our graph before we press enter, pressing enter, see a very very minor increase suggesting that we are at or very close to MBT but let's go again, we'll enter a value of 27, again just before I do this, making sure that we are central in that cell.
12:49 Letting our graph stabilise which it's now done.
12:53 Pressing enter, absolutely no change there so yeah we were very very close so we'll go back and add that 2° back in.
13:01 Now what I'm going to do is copy that change that I've had, just made, into the lower load area, so 0-40 kPa so again just exactly what we did there, we're going to add 2° to those cells.
13:15 Let's increase our throttle opening, we'll get to our 80 kPa cell.
13:21 Again just letting everything stabilise in the centre of that cell, I'll enter a value of 23, of course as usual, that doesn't take effect until I press enter.
13:29 Looking at our graph and waiting for that to stabilise, pressing enter.
13:34 And while we've got a little bit of a glitch in the graph there, it has actually shown an increase in torque.
13:41 Now if you aren't 100% sure, maybe the dyno's not being very clear, easy enough just to go back to where we were, let's go back to 21°, we actually see the torque reduce which is a good sign, and try that again so let's again enter 23, making sure that we're central.
13:58 23°, yep we saw a small increase in our torque which if the trend is correct is exactly what we expect, let's enter a value of 25 just to test.
14:07 I'm expecting that this should be beyond MBT.
14:10 Should see no change, press enter, another little glitch in the dyno torque graph so let's just go back to 23 and repeat that process.
14:20 We'll again wait for the torque to stabilise, pressing enter, yeah no change at all, so 23° is correct for that.
14:30 Coming up to 100kPa, so got 19° in there at the moment, I'm expecting with that trend, seems like we're adding 2° to each cell, so probably we should see an increase at 21°.
14:42 Just let our graph stabilise, we'll press enter, yep we did see the torque increase because the graph has rescaled, let's try 23° anyway, press enter.
14:53 I see the torque increase but straight away drop so I'm just going to go back to 21 again.
14:59 Not splitting hairs here for maybe a handful of pound foot of torque.
15:05 I want that conservative tune so we've got most of the torque that is available.
15:10 Let's come up to 120 kPa now.
15:15 And again the trend would suggest that probably we should be at 19°, we'll enter 19, let our torque graph stabilise, press enter.
15:24 So we've seen an increase but again really it's such a small increase.
15:29 We'll try 21° and see what happens here.
15:36 So again I'm going to go back to 19° there and we'll see if we can get up to 140 kPa.
15:43 I need to be mindful of the temperature here, we are sitting at 100°C.
15:48 Get in the centre of that cell, so again we probably should expect it to respond to another 2°, I'll press enter here.
15:58 Yep our torque has increased.
16:00 Try 19° here.
16:03 OK so we do see a small increase there but again just to be a little conservative, I'm going to come back to our 17° value.
16:11 Now couple of things I just want to talk about before we move on here.
16:15 Looking at our engine coolant temperature.
16:18 This is important obviously to monitor, I've already mentioned it a couple of times but particularly under sustained higher load and higher RPM, the temperature can climb.
16:27 Always want to monitor it, no problem just coming back to idle or backing out of the throttle, cruising at low load for a moment to let that temperature stabilise.
16:36 Just as importantly though is our intake air temperature.
16:39 We want to make sure that the air temperature is somewhat realistic and it can be difficult to kind of replicate the air temperatures that we will see under open road conditions on a dyno.
16:50 Particularly with a Subaru WRX/STi with a top mount intercooler.
16:55 We're actually using an auxiliary carpet fan to blow straight into the hood scoop as well for that.
17:00 We've got our main dyno fan cooling the radiator so essentially the point is just to monitor these parameters and make sure that they aren't getting out of hand.
17:09 Typically I would expect with a good intercooler system, the air temperature to be within about 15°C of ambient so if it's getting really really high and heat soaked, that's going to affect the accuracy of your tuning, even if your air temperature correction table is really well dialled in.
17:26 Alright so let's have a look back into our table now.
17:28 So essentially, we've got this 2° increase that we've sort of seen pretty much through the whole of that 2500 RPM column so I'm just going to extrapolate that into the areas we couldn't get to.
17:40 And really just like the fuelling, this is the benefit of this process is that once we've got one column dialled in, the trends that we see will be pretty consistent for the most part as we move into those untuned areas so it's a case of taking that whole column and then just increasing or in some instances, maybe decreasing, but less likely, the overall ignition timing.
18:01 So what we're going to do now is speed this process up, we will copy our 2500 RPM column out to the right and I'm now going to do this process again just like we did with the fuelling, out to 4500 RPM.
18:14 It'll be sped up but it's just a rinse and repeat of what you've just watched so let's get that done now, I'll also be now using audio knock detection just so I can be confident that we haven't got a situation that's causing knock.
26:42 Alright so we've completed our ignition tuning there out to 4500 RPM as discussed and for the most part it's followed the patterns that we would expect so no big surprises there.
26:52 Still got a little bit of work left to do just like we did with our fuelling, we can see we obviously haven't touched anything out above 4500 RPM so let's deal with that first.
27:02 So this is going to be simply a case of copying the 4500 RPM column outwards and to the right.
27:08 Chances are that this will probably be a little bit conservative, particularly as we get higher in the RPM but again we're really trying to start here from a case of being safe with our timing, a little bit conservative so I'm happy with that, we'll be able to optimse that as we get into our wide open throttle ramp run tuning.
27:27 Now we have, again as discussed, only tuned up to 140 kPa there.
27:33 Didn't really have any issues with knock occurring and what we're going to do, we know that the base boost pressure is going to be somewhere around about 160, 165, maybe 170 kPa so again just for the time being, I would be happy enough to copy the trend that we're seeing of 2° per 20 kPa, pretty consistent, outwards and downwards so that's what we've got here.
27:59 So we can see that as we move to 160 kPa and 180 kPa, each step we're taking 2° out.
28:06 I have flatlined this for the time being up above 200 kPa but we're going to be addressing that we slowly but surely increase the boost.
28:16 Alright so that deals with our higher RPM range.
28:20 Now you'll note that I didn't start with our 1500 RPM column simply as explained, I normally would do this, just that the car's moving around a little bit on the dyno, making it a little bit harder for me to present this.
28:33 So I'm not really too worried at 1500 RPM though, this is a transition anyway.
28:39 So what I'm going to do is simply take our 2000 RPM column here, copy that back down and then we're going to also copy that across into our 1000 RPM and below area.
28:50 So what I'm going to do, you'll recall that we are already using idle ignition control for our idle speed control but 25° which is what we've ended up with there probably a little bit optimistic so 16-18° in the idle region, I'm just going to pull that down until we're there or there abouts.
29:09 So 16° that's going to be fine.
29:11 And you see what that does is it copies that trend so now, not that we could get there but 240 kPa at 1000 RPM obviously completely unrealistic but we've got 0° in there.
29:21 What I'm going to do now is again just like we did with the fuelling, copy between, or highlight I should say between 1000 and 2000 RPM, the entire column, shift and H, that's going to interpolate that so that's going to fill in our 1500 RPM column.
29:38 Now you could argue that maybe it's not quite right but again we're sort of going to be in the ballpark, within a few percent probably of MBT with a simple change like that.
29:48 Let's have a quick look at everything graphically and essentially we've got a ignition timing table that probably looks somewhat sensible, it's got a normal shape to it which we'd expect and currently we're in the idle area, as we sort of increase our RPM at low load, we've got our timing increasing, coming back to a table value, we can see we're sort of in the 39° region in the overrun area which again would be pretty realistic so at this point I'm happy with everything we've done, we'll press F4 and store that and let's move onto the next step of our process.

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