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Practical Standalone Tuning: Step 8: Steady State Ignition Tuning

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Step 8: Steady State Ignition Tuning

14.16

00:00 - With our steady state fuel tuning completed, we're going to now go through exactly the same process, only this time we're going to be looking at our ignition table.
00:08 What we're going to be doing here is using the torque graph on our Mainline dyno to help guide us with our ignition tuning.
00:16 And we can see the torque graph right here.
00:19 Obviously at the moment it's showing nothing because the engine isn't running.
00:22 What we're going to be doing is using our MBT tuning technique, we're going to be making increases or advances to our timing and we're going to be watching where we end up making peak torque or where our torque stops increasing.
00:37 Now providing at that point, the engine isn't suffering from any knock, any detonation, in that case that would be where we leave our timing.
00:46 Now particularly as we move into the positive boost areas on this engine and at higher RPM as well, on pump fuel we know that there's a good chance with the high compression this engine is running that it will be knock limited.
00:59 So we're going to need to be very careful and monitor the engine for detonation using audio knock detection equipment.
01:08 What I'm going to do here is I'm going to run through the process, so I'm going to demonstrate a couple of columns of tuning and then I will fit my knock detection equipment and I'll complete the tuning out in this case to 4500 RPM, replicating what we did with our fuel tuning.
01:24 So let's get our engine running and we can get started.
01:27 So again I'm going to perform our tuning in fourth gear so we'll just get the engine into fourth gear and we'll get down to 1500 RPM where we can start our tuning process.
01:38 So just as we did when we were tuning our fuel, we want to start from our lowest possible load.
01:43 What we can see here, if I close my throttle down, we almost get into that 60 kPa zone, but if we look at our torque there's no load being placed on the dyno, the dyno is registering zero torque.
01:55 So we're actually going to have to increase our throttle opening and we'll start with our 80 kPa zone.
02:03 OK so at this point we can see our torque graph, we can see our dyno's registering around about 70 newton metres of torque.
02:10 Now I'm not really looking so much at the specific numbers, what I'm going to do here is make a change of two degrees, and what I want to do is see what happens to the shape of that torque curve before and after I make that change.
02:24 So let's just click on the cell we're going to adjust, I'll enter a value of 17, now that's not going to be locked in until I've actually pressed enter.
02:32 So we're looking at the shape of our torque curve right now, I'll press enter.
02:36 We can see that our torque did in fact increase.
02:40 So that means that we've moved towards MBT timing.
02:43 Let's go another two degrees, we'll enter 19.
02:48 Again we've seen an increase.
02:50 These are relatively small increases but we are moving the right way.
02:54 So we'll try 21 degrees.
02:58 21 degrees has again shown us a small but real increase.
03:03 So we'll go another two degrees and we'll try 23 degrees.
03:13 Alright this time with 23 degrees we really didn't see any noticeable change, so I'm actually going to remove that timing.
03:20 If we make a timing change and it doesn't show us any improvement then we're going to take that timing back out.
03:27 Of course we can make smaller adjustments of perhaps a degree at a time as well.
03:31 Here I'm just showing you the coarse technique.
03:34 Now once we've got that particular cell tuned, you'll remember we couldn't do anything in the cells above this at lower load areas because we can't get there.
03:45 We're not going to leave those cells alone though.
03:47 What I'm going to do is I'm going to set those also to 21 degrees.
03:50 Despite the very way the combustion process works, if we needed 21 degrees of advance at 80 kPa then it's likely that we're going to need at least 21 degrees of advance at load zones below that or lower manifold vacuum.
04:08 In fact it's actually likely the engine will need more advance as the manifold vacuum increases but in this case we can't actually optimise these areas so we're going to leave them set to 21 degrees.
04:21 Now what we can do is we can increase our throttle opening, we'll move up to 100 kPa and we'll tune our 100 kPa site.
04:29 Just make sure we're in the centre of that site before we make any adjustments.
04:34 Alright so we're going to increase our timing to 17 degrees, press enter.
04:37 Now we've seen a small increase but it's very minor.
04:42 So this suggests we're probably pretty close to MBT already.
04:46 We'll go another two degrees though, we'll try 19 degrees.
04:52 We still have seen an improvement there, we'll try 21 degrees.
04:59 This time with 21 degrees we've seen no improvement at all so I'll remove those two degrees and we'll go back to 19 degrees.
05:06 Now in this case we'll try and press our throttle but at 1500 RPM, we know that we can't get to the centre of the 120 kPa zone.
05:16 Now that makes it a little bit difficult for us to tune the ignition timing there.
05:21 What I'm going to do is I'm going to take notice of the trend that I've got going at the moment, it's a very small trend because we've only tuned a couple of cells.
05:31 And we see that we've got a variation of about two degrees per 20 kPa.
05:35 So in this case it's likely that the correct ignition advance at 120 kPa might be somewhere in the region of 17 degrees.
05:43 What I'm going to do though is I'll just take another two degrees out for safekeeping and we'll set our timing there to 15 degrees.
05:51 So that's tuned as much of the 1500 RPM column as we can.
05:55 Now what I'm going to do is copy that column across to our 2000 RPM column.
06:00 As we move from 1500 RPM to 2000 RPM, it's likely that our engine is going to want to take more ignition timing but I'm going to actually start with these numbers anyway, I'm not going to advance the timing before we move the RPM up on the dyno.
06:18 The reason for that is it's always safest to start with our timing retarded and be able to advance it rather than start and find that we're already over advanced and perhaps our engine is suffering from knock.
06:30 Now let's increase our RPM and we'll move up to 2000 RPM.
06:43 This time I'm going to bring my throttle back down and we'll see if we can get down to our 60 kPa site.
06:50 And this time we can, we see that we're sitting there at 60 kPa and we've got around about 43 newton metres of torque.
07:00 Now I can't reduce my throttle and get down to that 40 kPa site, we get the same problem where the dyno just slows down.
07:07 So I'm going to make the changes here to the 60 kPa site and the ones above that in our table here as well.
07:15 OK so we'll try adding two degrees, let's see what happens.
07:20 You can see that our torque did increase very marginally, so we've gone in the right direction, we'll try another two degrees, we'll try 25 degrees.
07:29 Again we've seen a small but noticeable improvement, we'll try 27 degrees.
07:36 Again a very small improvement.
07:39 But we've seen the improvement has been decreasing as we've added that timing so I know that I'm probably very close to MBT there.
07:47 I'll just bring my throttle back down and get back in the centre of that site before I make a further change, we'll try 29 degrees.
07:55 Yeah and this time we've seen no improvement so we'll go back to 27 degrees.
08:00 Alright now we'll increase our throttle opening and we'll tune our 80 kPa zone.
08:10 We'll try adding two degrees, we'll go to 23 degrees.
08:15 See our torque increase but again, very marginal so again we know when we see a very small improvement in our torque, we know we're probably very close to optimal.
08:25 We'll try 25 degrees though.
08:29 And here we've seen really no change so we'll go back to 23 degrees.
08:33 We'll increase our throttle and go to our 100 kPa zone.
08:43 And once our dyno stabilises we'll try adding two degrees, go to 21 degrees.
08:52 We've seen a small improvement there but again very very minimal.
08:56 We'll try 23 degrees, and we've seen no improvement so we'll go back to 21 degrees.
09:03 So I'm expecting at this point just with the trend that I'm seeing, at 120 kPa, I'm probably going to want to see somewhere around about 19 degrees.
09:12 Remember we've retarded the timing just a little further for safe keeping.
09:18 We can almost get into the centre of our 120 kPa site so we'll try adding two degrees, we'll go to 17.
09:27 Seen our torque improve there, only small though, I'll try 19 degrees.
09:34 And again we've seen an improvement there.
09:36 So provided we're not getting any knock occurring, we can leave our timing at 19 degrees, we'll just try 21, we've seen no improvement so we'll go back to 19 degrees.
09:48 OK so now I'm going to fit my audio knock detection equipment and you can follow through while I complete the tuning on the remainder of the map.
10:30 So that completes our steady state ignition tuning and we've gone there to 4500 RPM.
10:35 There's a couple of things that I wanted to note here.
10:38 Now first of all as we saw with the fuel tuning, as we got higher in the load and RPM, we need to take care of the engine coolant temperature and make sure that wasn't getting too high.
10:48 So this again just requires a few periods of allowing the engine to come back to normal operating temperature.
10:54 As expected under boost, we were knock limited, particuarly as we came up in the higher RPM ranges at boost.
11:02 And in this instance it's a trade off, we obviously can't tune through to MBT, we must make sure that we avoid knock, so if we encounter any detonation that's audible, what we need to do is leave a safety margin, I like to leave a buffer there of about two to three degrees, just depending on exactly how hard the car's going to be used.
11:21 Now what I've done there is very broad, obviously we've only looked at making two degree incremental changes to our ignition timing but the same process can be applied if you want to get a little bit more precise and a little bit more fussy and make smaller changes of perhaps one degree at a time.
11:36 The other thing that we saw there is as we got higher in the rev range, we see the ignition timing, particularly in the cruise areas start to stabilise or plateau and we don't see such large dramatic jumps.
11:50 So what this means is that for a lot of our map, once we've actually got a bit of a trend developed and we can see what's going on, it's not strictly necessary to tune every individual zone, we can copy our trends across and then take a few sample cells through a particular RPM column.
12:07 See whether these need to be advanced or retarded and use that to guide us in our tuning, it's not strictly necessary to tune every cell.
12:14 And obviously this comes down to how fussy you want to be and how much time you want to spend with your tuning.
12:21 What we're going to do is look at what we can do from here to complete our table, ready to move onto our full throttle tuning.
12:28 And first of all what I'm going to do is simply extrapolate the numbers that I had at 4500 RPM, all the way out through to 9000 RPM.
12:37 Now I am expecting to be running around about 200 kPa in this particular car.
12:44 We're only just starting to get up towards that at 4500 RPM, this is where the engine is able to make full boost.
12:51 So I'm just going to safeguard myself a little bit, particularly above the 200 kPa column here, what I'm going to do, sorry kPa row there.
13:02 What I'm going to do is retard the timing a little bit.
13:05 So I'm just going to highlight the entire row and I'm just going to take out three degrees, I'll copy that down to 240 kPa and we'll do exactly the same.
13:15 This is just again, setting me up with conservative, safe timing once we actually start tuning those zones.
13:22 The other thing I want to do here is take my 1500 RPM column and I'm just, for the sake of completeness, I'm going to copy that back across into the lower RPM ranges.
13:34 And we want to generally have our ignition timing somewhere in the region of about 16 to 18 degrees in our idle region so I'm just going to bring that back down 'til we're at that point.
13:46 Now if we look at this graphically, what it should do is give us a reasonably smooth shape to our ignition table, and this is sort of what we're expecting to see.
13:55 There's no unusual big steps in our table, there's nothing particularly erratic going on in there so this should give us something that's going to provide good drivability, obviously we're going to be completing this table when we move into our next step which is our full throttle tuning.