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Practical Standalone Tuning: Step 8: Steady State Ignition Tuning

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Step 8: Steady State Ignition Tuning

22.22

00:00 - The next step in our tuning process is to perform our steady state tuning of the ignition timing.
00:05 Now this particular process is very similar to what we've just gone through with our fuel delivery.
00:11 What we're going to be doing is starting with minimum load and low RPM and we're going to slowly build up the load and then move and copy the column that we've just tuned out into the next RPM column.
00:24 Now this allows us to again build up a shape and a trend to our ignition timing table.
00:29 It's going to speed up our tuning process, it's also going to prevent chances of us ending up with damage because the ignition timing is overly advanced or unsafe as we increase our load and RPM.
00:42 Now again because this particular engine is quite noisy, it's quite hard for me to talk while we are doing the tuning process, I'm going to tune the 1500 RPM column, I'll explain what I'm doing and how I'm going about that using the torque feedback from our Mainline dyno to find MBT.
01:00 Once we've done that I'll explain the process of extrapolating those numbers out further into the untuned areas and then you'll be able to watch as I complete that tuning process out to 4500 RPM.
01:11 Now while we are tuning the ignition timing, we do need to be very mindful of monitoring detonation or knock.
01:19 I'm going to be using audio knock detection and once we go past that 1500 RPM column, I certainly urge you to do the same.
01:25 Remembering with this particular application, we are running on a 30% mix of ethanol.
01:31 Now this makes it a little bit less likely for the engine to suffer from knock but from previous experience we do know that the engine is still knock limited at 30% ethanol so we do need to be very mindful.
01:42 And in some instances, particularly around peak torque, this may actually limit the amount of ignition timing we can achieve or use and we may not be able to make it all the way through to MBT.
01:53 OK so let's jump into our laptop software here and we've got our very very conservative base ignition timing map and this is what we're going to be working from.
02:03 You can see we've still got the numbers we originally set.
02:05 We've got 15 degrees in the vacuum areas of our table and we've got that gradually dropping down until we've got five degrees at the top of our table.
02:15 Or actually the bottom of our table at our maximum load point of 3400 millibars.
02:21 OK let's get our engine up and running, we'll go back into fourth gear and we'll get to 1500 RPM and we'll begin the tuning process.
02:28 OK we're up and running here at 1500 RPM.
02:31 And you can see we're currently operating at around about 600 millibars.
02:35 Remembering that we can't really get too much lower in the load on our dyno than that point.
02:41 So what we'll do is we'll have a look at how we can go about steady state tuning that particular cell.
02:46 What we're going to be doing is using the torque graph here on our Mainline dyno.
02:51 One of the skills we do need to develop is just being able to read or average that torque graph.
02:56 So what I'm looking at is the point the torque graph is at just before and just after I make a change to the ignition timing.
03:05 So currently we're seeing around about 47, 48 newton metres of torque.
03:10 What I'm going to do is just enter a value of 17 in the ignition table.
03:14 Now that value, that change won't be active until I press enter.
03:18 So we'll press enter now and we'll look at what the torque graph does.
03:22 And we can see that that has been a really small but noticeable increase there to the torque just after I press the enter key.
03:30 So this means that we're moving in the right direction there.
03:33 So we've gone from 15 to 17 degrees.
03:36 And I'm making a two degree change here just so we can see a worthwhile change in our torque.
03:42 If we're only making very small changes, it can be harder to see.
03:46 So if I'm going in the right direction, provided we've got no knock occurring, we're just going to go in the same direction.
03:51 So I'm just going to go now to 19 degrees.
03:53 And again I'm looking at the torque graph just before and after I press enter.
03:58 So currently we're sitting at about 52, 53 newton metres, I'll press enter, and again we've seen a small but noticeable increase.
04:06 What I'm doing there as well is averaging out those oscillations just mentally, that we can see in that torque graph.
04:12 So we are seeing very small changes here.
04:15 So this probably means that we are also quite close to MBT for that particular cell.
04:20 We'll go a little bit further though, we'll try 21 degrees.
04:23 Again we're just looking at that torque graph before and after we press enter.
04:26 Trying to manually or mentally average those changes, those oscillations we're seeing.
04:33 OK I'll press enter now and again we have seen a small change, a small improvement there, despite those oscillations we are seeing so we're still going in the right direction.
04:43 Let's try 23 degrees.
04:47 At 23 degrees again we've seen it jump up, although it's actually settled back down to almost the same torque value, I'm just going to make sure that I am still central in that cell.
04:57 Now if we see a change like that and we're not really 100% assured that we have seen an improvement, we can always just go back to where we were.
05:05 So again we're just going back to 21 degrees, we're just going to have a look at what happens to our torque.
05:11 And at this point we're really seeing almost no noticeable change, so I'm gonna leave the timing for that cell at 21 degrees.
05:18 Now what I'm going to do is increase my throttle opening, we'll come down to 800 millibars.
05:22 So we'll just make sure we stay in the centre of that cell.
05:28 And we're going to do exactly the same process.
05:31 So we'll get in the centre of that cell, again we've got 15 degrees, we've seen obviously as I've increased my throttle opening, we've naturally seen an increase in the torque.
05:38 So what I'm going to do is enter a value of 17 degrees, press enter, we've seen a very small improvement in the torque so again, when I see a small improvement in the torque like this, I know that I'm probably pretty close to my optimal or MBT timing.
05:55 We'll go a little bit further, we'll try 19 degrees.
06:00 19 degrees again we have seen a very small improvement.
06:04 Just make sure we stay central in that cell there because you saw the torque drop away.
06:09 We'll try 21 degrees.
06:15 And we have seen actually our torque's basically stayed plateaued so again I'll try going back, we'll try going back to 19 degrees, and we'll see what the effect on our torque is.
06:26 Get back into the centre of our cell.
06:28 Now essentially we're seeing almost no difference there from 19 to 21 degrees.
06:32 It's also important to note that we are expecting a relatively consistent trend.
06:36 So as I move from 600 millibars down that table there to 800 millibars, as we increase the load, we know that the trend we're likely to see is that the ignition timing will retard.
06:49 So I'd be a little bit suspicious if I see a value that wants to be maybe 21 or 23 degrees at 800 millibars, that would make me want to go back and recheck what I actually had at 600 millibars.
07:02 And sometimes there can be a little bit of tooing and froing here just to get the optimal value.
07:07 You do also need to be aware though that when you're starting to split hairs over just one or two newton metres, the actual percentage effect that we're chasing there is very very minor.
07:17 So let's increase our throttle opening and we'll come up to 1000 millibars.
07:27 OK we're looking at our torque now, we're sitting at around about 180 newton metres.
07:32 So we'll try increasing our value, our ignition timing there to 17 degrees.
07:37 Just looking at the value before and after I lock in that change.
07:42 OK so we've seen an improvement there but very very minor so we're probably already pretty close to MBT.
07:49 We'll try 19 degrees and see if we get an improvement and in this case 19 degrees has made absolutely no change to our timing so we'll come back to 17 degrees.
07:59 So again this really follows the trend that we've seen with the cells we've tuned.
08:03 We've gone from 21 down to 19, down to 17.
08:07 So we're seeing a trend of around about two degrees of retard per 200 millibars of additional load.
08:14 So what that means is when we move up to 200 millibars, our next cell, that, I would expect to be somewhere around about 15 degrees.
08:24 OK so we're at 1200 millibars now, what I'm going to do is try advancing the timing, we'll go from 14.16 to 16 degrees.
08:32 Made that change and we've seen absolutely no effect on our torque.
08:37 So we'll come back and we'll actually retard the timing further, we'll try going to 12 degrees.
08:41 And we'll see what happens there.
08:43 As I go to 12 degrees we do see that the torque drops off very slightly.
08:47 So in this case 14 degrees for that particular cell is our optimal ignition timing.
08:52 So let's come back down to idle now and we'll just have a look at what we've achieved there.
08:57 So in this case because we're at such low RPM, we've only been able to tune four cells there.
09:03 We've tuned our 600, 800, 1000, and 1200 millibar cells.
09:07 And we've got a really consistent trend there.
09:09 Every time we've increased the load there, we've basically been retarding the timing approximately two degrees per 200 millibars.
09:19 So what we're going to do now is use that trend to help us fill out first of all the lighter load areas up at the top of this graph here.
09:26 The areas that we haven't been able to get to.
09:28 So what I'm going to do is simply extrapolate that trend, as we go from 600 to 400 millibars, I'm going to advance the timing two degrees.
09:36 As we go from 400 to 200 I'm going to advance the timing another two degrees.
09:40 And this last break point here we're going from 200 to 100 millibars.
09:45 So I'm going to advance the timing a further degree.
09:48 Now while we can't get down past 1200 millibars, we can't produce more boost than that, it's also a good idea to just follow that general trend that we have been seeing, just for the sake of completeness there.
09:59 So in this case what I'm going to do is just highlight the rest of my table here, this might not be the final values I end up using, but I'm just going to use the math subtract function and I'm going to retard the timing a further two degrees there just for a little bit of safety.
10:14 Now again we don't need to be too worried about these areas right down the bottom of our table, we're clearly not going to be able to produce 2400 or 3400 millibars of positive boost pressure with such low RPM, so we're just doing this for the sake of completeness.
10:30 What we're going to do now is we're going to highlight that entire column that we've just tuned now, use the control C function, we'll come across to the 1750 RPM column, and we're going to paste that in, and just like we did with the fuel, in this case because our break points are quite short there are quite tight, I'm also going to extrapolate that across to the 2000 RPM column.
10:51 OK so now you can sit back and watch, we're gonna go through and we're going to complete the steady state tuning of our ignition timing out to 4500 RPM.
11:00 It's important to note here that while as we move from 1500 out to 1750 RPM, we could rightly expect that we're going to need a little bit more ignition timing at 1750, I'm going to play it safe, play it a little bit conservative there, and I'm going to just copy those numbers across.
11:17 Let's get on and we'll complete the tuning of our ignition timing.
20:47 OK so we've gone through there and we've completed the steady state tuning out to 4500 RPM.
20:51 And hopefully you've been able to see that by extrapolating or copying the trends that we're seeing or the columns that we are tuning, by the time we get up to sort of 4000, 4500 RPM, there's very little, if any change.
21:03 So it really speeds up the tuning process.
21:05 What I'm going to do now before we move on and start our full power ramp run tuning, is I'm just going to copy our 4500 RPM colum and I'm just going to extrapolate that out through the rest of our columns here.
21:18 So again we can expect as the RPM increases, we can expect that our ignition advance angle may want to increase, we may want to advance the timing with RPM, however in this case we want to start from a conservative standpoint, so we're going to just plainly copy out those numbers that we've already seen, out into those untuned areas.
21:41 The other thing that I've done there as I've started to build up that map and built out a little bit further into the boost areas, is I've made some changes into the higher boost, lower RPM areas that we can't reach.
21:53 I've just followed the trends that I'm seeing in the higher load areas.
21:57 Now this just means that if we do by some chance end up running a little bit higher in the load, a little bit higher in the boost than what we've been able to get during the steady state tuning, while our ignition timing might not be quite right, if we follow that same trend that we are seeing, we're probably going to be very close.