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Practical Standalone Tuning: Step 8: Steady State Ignition Tuning

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Step 8: Steady State Ignition Tuning

21.34

00:00 - In the next step of our process, we're going to move on with our steady state ignition tuning.
00:04 And really this is going to be very similar to the way we approached our fuel tuning.
00:09 We're going to be steady state tuning from low down in the RPM and load and probably start at 1250 or 1500 RPM and we're going to start from the lowest throttle we can use to hold steady state on the dyno and then progress up through the load cells until we've got our complete column tuned and then copy that out to the next row, column I should say and then we're going to repeat that process.
00:31 Here we're going to be relying on feedback from our Mainline dyno in terms of how much torque is being produced, that's going to be the main driver to help guide us with when we have reached MBT.
00:44 If we head across to the dyno, we'll look at the 2 options we're going to use for this purpose, we've got our torque gauge here for a start.
00:50 This shows us the amount of torque being measured by the dyno.
00:54 It'll show us a graphical representation of that torque as well as the numeric numbers down below.
01:00 However it's quite difficult to see subtle changes in that, for this reason we're going to be relying on our moving graph here down below.
01:08 The red line in particular here is going to show us the amount of torque.
01:12 Because this is tracking in real time when the engine is running we'll be able to see the change to the torque immediately before and after we press enter and lock in a change to our timing.
01:23 Now while we have started here with conservative timing and as I've already discussed a couple of times, the numbers here, we should be pretty confident aren't going to result in any knock occurring so we're going to be starting from a safe retarded timing, it's always a good idea to monitor and particularly when we are optimising the timing, we may run into an issue where we reach the knock threshold so we always want to be using audio knock detection while we are going through this process.
01:49 For our worked example here I'm going to start by showing the process for a couple of those columns and then as we build up to higher load and higher RPM I'll actually switch across to using knock detection as well.
02:01 For these purposes I've got an auxiliary knock sensor that's mounted on the side of the engine block and I'm monitoring this using a Link G4 + knock block.
02:10 Now that we've got a bit of an idea of what we're trying to do here, let's get ourselves up and running and we'll have a look at the process.
02:16 Alright we're up and running here, we're going to start with our 1500 RPM column and it is worth just mentioning here that particularly when we're operating at very light load, when we're really at the bottom of measurement range of the load cell in the dyno, we may get some inconsistencies so it's once we start getting up to higher throttle openings and we're pushing the engine a little bit harder, these results will start to become a little bit more consistent but what we're going to be extrapolating is well is the shape and trends we see.
02:43 So at the moment we can see that I'm sitting at around about 80 kPa and if I close the throttle down, probably find that I can't actually get much lower in the load.
02:53 Important to mention here that this particular table goes the opposite way to what we're seeing with our VE table.
02:59 As we open the throttle we're actually going to be moving down into the lower regions so that's just something that you need to take note of there.
03:09 So if we look over at the dyno at the moment we can see that we're sitting around about 60 to 70 pound foot of torque and pretty inconsistent.
03:17 What we're looking for though is the shape of the red line, we can see that red line's moving around a little bit.
03:24 Want to try and be as consistent on our throttle position as we can so that's as accurate as we can get it.
03:30 There will always be some movement and oscillation as we can see there.
03:33 So we're at 15° here, let's try adding 2° to that cell, so what we'll do is we'll start by pressing the space bar to get to our current cell.
03:41 We'll enter a value of 17 now that value, that change is not locked in until I press enter.
03:45 So again we'll just head back over looking at our red graph, we'll press enter and we'll see the effect of that change.
03:51 We actually see that our red graph did pick up quite considerably.
03:55 So that's a good thing.
03:56 It also means that when we see a large change like that, this generally indicates that we may be some way away from MBT so when we see that, provided we've got no knock occurring, we're just simply going to repeat that process.
04:07 When I'm starting here, I will make coarser changes of 2° at a time so let's repeat that process again, being steady on the throttle, looking at our graph, pressing enter and again we see our torque jump but this time not quite as dramatic so we are still heading towards MBT.
04:25 I'd say we're probably pretty close given that small change but let's try again.
04:29 We'll enter a value of 21, again looking at our red graph, pressing enter.
04:34 Actually again we have seen our torque jump up but from the initial jump up it does kind of settle back very similar to where we were so again we're probably there or there abouts.
04:45 Let's try 23° and see what that gives us, we'll press enter now.
04:51 See again a very marginal change but probably just about settled back to where we were, we'll just go back to 21 and just see if we do lose any torque there.
05:03 And we do actually lose a bit of torque so I'm going to leave that particular cell there set to 23°.
05:10 OK let's open our throttle, we'll come down to our 90 kPa site here and at 90 kPa again we've got 15° we're starting from our retarded timing value there.
05:20 We're looking at our red torque graph so let's again add 2°, we'll enter a value of 17 and we can just see our manifold pressure is oscillating very slightly so we'll just make sure that we're as accurate as we can be.
05:33 Press enter and we do see that the torque jumps up which is exactly what I'd expect, given how far we are away from the 23° we saw in our last cell.
05:42 So let's go again, we'll add another 2°, enter a value of 19 there.
05:48 An again we see our torque jump up not too much this time through so again we're getting close to MBT.
05:54 We'll try 21°, press enter there, 21°, really hard to decipher that so lets just go back to 19° so it's always easy if we don't really see a clear cut decision there we can always go back and see where we were.
06:09 This one a little bit harder because we are seeing that oscillation a little bit more pronounced compared to what we saw before.
06:15 Let's try 21° again, press enter.
06:19 And we do see a very slight increase but very hard to pick it.
06:24 Now what I'm going to do here, I've actually got an additional cell in this table that we really don't need 95 kPa so let's just get rid of that because we'll have overlooked that when we were setting up our tables but this is how easy it is to make changes on the fly here so we'll just get rid of that particular cell.
06:40 Don't need that tight a resolution.
06:43 Let's go down to our 100 kPa cell and as we get higher in the load we're going to find that this becomes easier because we are now making a little bit more load, everything starts to run a little bit more smoothly here.
06:55 So we're sitting at 15° and 100 kPa, don't have a lot of load on the engine at the moment, we're only running at around about 18% throttle just to give you some indication.
07:05 Let's try increasing our timing to 17° again looking at the before and after, we'll press enter now..
07:13 Straight away we do see our torque jump up, not a lot but it has jumped up.
07:16 Let's try again, we'll enter a value of 19°, waiting or our torque to be consistent, pressing enter and again we've seen our torque jump up.
07:24 So let's try 21°, the same value that we've got in our 90 kPa cell, again we'll wait for our torque to be stable, press enter.
07:34 Do see a small increase there but we've almost come back to where we were.
07:38 So I'm actually going to go back here to 19°, when we're really starting to split hairs about the gain in torque that we're seeing, always better to be a little bit conservative with our timing.
07:49 Alright let's increase our throttle opening now and we'll come down to 110 kPa and at such low load this is about as high as we can get or such low RPM I should say, this is about as high as we can get in the boost.
08:02 We're at 15° at the moment so let's enter a value of 17, I am now at 100% throttle and we'll just wait for our torque to stabilise, press enter, straight away we see that torque has jumped up so let's try 19° there.
08:17 Press enter.
08:20 Very marginal increase there, let's try 21° and just see what that gives us though.
08:26 21° makes no difference so we will come back to 19°, assuming of course that we aren't knock limited at that point then there's no reason not to be at MBT so what I'd probably do here, remembering that it was a little bit inconclusive here in our 100 kPa site, I'm just going to follow the trend here so we can basically split the difference here, we can use the interpolate function as well, we'll set that to 20°.
08:53 Now before we move ahead and we tune our 2000 RPM column, we do also want to have a bit of a look at the areas we couldn't access.
09:01 So obviously we've really tuned quite a narrow section of this table at this point.
09:06 Now we know that we've got our trends that we're going to see continue.
09:10 As we move lower in the load or higher in this table, we're going to expect the values, the timing values will end up increasing.
09:20 We can't get to those points at the moment but we can extrapolate that.
09:23 Not going to get too fussy there because if we can't get to them on the dyno we're not going to be spending a lot of our time in them anyway so looking at the sort of trends that we're getting, we're seeing about a 2° change per 10 kPa.
09:38 We're actually going now from 80 to 60 kPa.
09:40 To be a little bit conservative there even though it is 20 kPa, I'm just going to simply set those cells there to 25° and if we want to be a little bit more fussy, we could probably increase our timing just a little bit more down at 20 kPa and 0 kPa.
09:56 Now we could also extrapolate those trends as we move higher in our boost.
10:01 Obviously we can't get there but always a good best practice to just follow the trends that we're seeing there.
10:08 So again we're dropping around about 2° or 1° actually per 10 kPa.
10:13 Again just erring on the side of being a little bit safer there, we'll pull 2° out as we get to 120, we've naturally already got 2° coming out at 140 and we can just follow that trend through.
10:26 Even though we can't get to these areas it's going to be helpful 'cause we will be copying that in so I'll just go ahead now and extrapolate those numbers out.
10:40 Alright so now we've got our first column complete there at 1500 RPM, we'll copy and paste that up to 2000 RPM.
10:48 Now while we would rightly expect that the timing at 2000 RPM for MBT should be a little bit higher than 1500 RPM, we want to always start from a place where we are conservative, we're safe with our timing so I'm going to leave that there.
11:03 We'll bring our dyno set point up now to 2000 RPM and we'll repeat that process.
11:09 Alright so again the lowest we can get in our load there is around about 80 kPa.
11:12 We can see we do have our torque moving around so same problem we've already highlighted.
11:18 Does take a little bit to just average mentally the oscillations that we're seeing on our graph there but we're at 23° so let's start by adding a couple of degrees, let's enter 25, looking at our before and after and again we do see our torque increase so let's go again, another 2°, we'll go to 27°, again waiting for our graph to stabilise we'll press enter and we do see another increase there albeit a little bit smaller this time by the time we actually get back in the centre of the cell, let's try 29° though and we'll make sure we're in the centre of the cell, we'll press enter and we'll look at that oscillation there.
11:55 Absolutely no difference there so let's come back to 27°.
11:58 So what I've done there is we've added 4° over where we were at 1500 RPM.
12:04 Now I'm just going to simply add 4° to the lower load areas at 2000 RPM, the ones that we can't get to as well.
12:12 Working on the principle there that if we needed to advance our timing 4°, at 80 kPa, it's fair that we're probably going to be there or thereabouts at lower load as well.
12:21 Let's increase our throttle opening, we'll come up to 90 kPa now.
12:25 Got 21° in there at that moment we'll wait for our graph to stabilise, we'll enter a value of 23, looking at our graph, press enter and we see that our torque does increase, not quite as much of a dramatic increase but let's try entering a value of 25, we'll see what another 2° gives us.
12:44 2° yeah again we do see an increase.
12:47 We'll try 27, I'm not expecting given the trend in the table we should see much difference here, and we really don't, by the time everything stabilises there.
12:58 So let's bring that back to 25°.
13:00 OK so now what I'm going to do is continue this process through until we've completed our 2000 RPM column.
13:19 Right so you can see there we were able to get up to 120 kPa.
13:22 It's always a lot easier when we can actually achieve wide open throttle because it makes it very easy to make sure we are stationary in one particular cell.
13:32 So we've seen there that at higher load we've essentially ended up adding around about 2° compared to what we had for example at 110 kPa, we've gone from 19 to 21.
13:44 So what we're going to do is extrapolate that change down as well so we're going to add another 2° to the cells below.
13:51 Alright so at this point the rest of the process will be a rinse and repeat of what we're looking at here.
13:56 For safety as I go higher in the load as I mentioned and RPM I'm going to now revert to using my knock detection system so I can audibly listen for knock.
14:05 We're going to go through and complete this process up to about 4500 RPM so you can watch as we go through and complete that.
15:53 Alright so we've completed the steady state process up to 4500 RPM so a few takeaways there.
15:59 First of all we did need to stop a couple of times just to allow the engine temperature to stay under control.
16:06 This is pretty normal as the RPM rises so always we need to be vigilant of our coolant temperature.
16:12 Also a good idea to stay on top of your intake air temperature and just make sure that those are both staying realistic compared to what you'd expect to see out in the real world, otherwise this can skew your results.
16:21 So that being said, the rest of the process was pretty straightforward.
16:25 We very quickly start to build up a bit of a picture of what's happening as we move from one RPM column to the next.
16:34 Particularly to start with, if we look at what's happening through here at about 120 kPa, we can see that as we move higher in the RPM, initially we are stepping up about 2° every 500 RPM.
16:46 So this gives us a bit of a feel of at least what we could expect as we go from let's say 2500 to 3000 RPM.
16:54 Now turns out that that hasn't stayed the same and particularly as we get up to 3500 and then 4000 RPM and above we can see that change actually plateaued and we ended up pretty consistent at 4000, 4500 RPM there with the same timing.
17:10 That's not always going to be the case but we generally start to build up a bit of a picture of what the engine wants and what we can expect as we move into these unchartered areas.
17:20 Likewise we can see that down here in the lower regions which I couldn't get to, we've just extrapolated those changes and added any timing that we were adding up in the areas 80, 90 kPa which we could get to.
17:33 Now again of course we're not going to be perfect but we're going to be there or thereabouts, we're going to be pretty close to MBT, particularly at such light load where the throttle's essentially closed.
17:43 First of all, if we don't have every last newton metre of torque out of the engine that's probably not going to be that critical and we also certainly don't need to worry about knock occurring, the likelihood of that at such low load is very very slim.
17:58 It's also probably worth mentioning that up to the point we've tuned so far, around about 140 kPa, 4500 RPM, we haven't had any knock so we were actually able to tune to MBT and the RB26 in general on a good quality fuel is not overly knock sensitive until we start raising the boost so exactly what I expect there.
18:20 Alright before we can move on though we've got a little bit more work ahead of us, what we're going to do is start by copying our 4500 RPM column and we'll simply extrapolate this out to the right here, moving it through.
18:31 Now again as our RPM increases, we could rightly expect the timing the engine will want or will take could increase.
18:39 But for safety's sake we're going to start with the same timing, a flat timing map and we'll address this as we get out there.
18:46 This now leaves us with the low RPM region and obviously we didn't tune below 1500 RPM.
18:51 And strictly it's not that neccessary, of course if you want to you could probably load the engine up quite happily at 1250 RPM like you saw me do with the fuelling.
19:00 Struggle to do that at 1000 RPM, the engine's probably not going to be that happy with it.
19:03 But what we can do here is just make some sensible adjustments to the map.
19:10 We don't want the big step that we can see in here, want nice consistent timing that's going to make the engine run nice and smoothly.
19:17 So the actual numbers we've got in here in the idle area, actually remembering that we are actually idling up around about 70 kPa so we're in here.
19:28 15°, nothing specifically wrong with that, let's just increase that a little bit though, we'll take that up to 16, let's say 18°.
19:37 Generally that's a pretty safe place for our idle timing to be.
19:41 What we want to do is make sure that we are below MBT so that our idle ignition control will work.
19:46 Now what we can do here is simply use the interpolate function so we will highlight the cells we want to interpolate.
19:53 Now the key that we actually want to use is the R key, however if you right click, if you don't remember that, if you go down to the interpolate you can see your different options there.
20:02 So that gives us a nice smooth section down here as we transition from idle.
20:07 What I'm going to do now is essentially repeat that process with our higher load areas.
20:14 In the high range here the high region here, we don't really need to be too thorough because we're not going to actually ever be able to run the engine down here at high boost and 1000, 1250 RPM.
20:27 But for the sake of consistency here, what I will do is just copy our columns from 1500 RPM and we can copy these across and then make the appropriate changes.
20:39 So what I'll do is I'll highlight the cells that I have changed there and we will remove 4° so again it's not super critical because we're not going to be operating in this region, it's just a case of trying to get us some numbers that are smooth and make sense and again, here I'm going to use the interpolate function.
20:59 So now if we look at our graphical representation over on the right hand side, we've got a reasonably smooth shape to this which is about what we'd expect from a well tuned ignition map.
21:09 If you are seeing any big holes or spikes in this, this could be an indication just like with our fuelling that maybe you've got a mistake in that area of the map and it's easy enough to just go back and revisit those sites and have a bit of a check and make sure that everything is ideal.