Practical Standalone Tuning: Step 8: Steady State Ignition Tuning
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Step 8: Steady State Ignition Tuning
14.15
| 00:00 | - OK so now that we've got the fuel side of the map tuned, it's time to have a look at the ignition timing. |
| 00:06 | Now we're gonna basically be using the same process of driving the car on the dyno and accessing each site in the ignition map and tuning them individually. |
| 00:15 | Now this time we're going to be using the MBT timing method. |
| 00:20 | Basically what that relies on is the torque reading from the dyno. |
| 00:24 | Now you can see the torque reading on the Dynapack dyno is displayed here and it's called axle torque. |
| 00:29 | And this is the value that we're going to be looking at as we run the car on the dyno. |
| 00:33 | Basically what we want to do is start with a conservative ignition timing. |
| 00:38 | We want to slowly advance that until we maximise or optimise that axle torque and then we can move onto the next site. |
| 00:47 | So again we want to start with as little load and as little RPM as possible. |
| 00:52 | We're going to start at 1500 RPM and I'll just show you how the process works. |
| 00:56 | So if we get the engine up and running on the dyno. |
| 00:59 | I'll just bring the target back on so we can see that. |
| 01:05 | And we'll get it running here in the middle of our 60 kPa row. |
| 01:11 | Now if we have a look at the dyno screen, you can see that the axle torque figure's sitting around about 250 newton metres. |
| 01:19 | Now what makes it a little bit difficult is you can see that that number does fluctuate quite a bit. |
| 01:24 | And that makes it a little harder to judge whether the change that we're making is increasing torque or not. |
| 01:32 | So what I like to do is make changes in two degree increments. |
| 01:37 | That's enough that we should be able to see the change. |
| 01:39 | But what we wanna do is enter the numbers. |
| 01:42 | So I'm going to enter 17 in there, but I haven't pressed enter yet, so that change hasn't been locked in. |
| 01:49 | Now what I want to do is look at the axle torque value and I'll keep the engine nice and stationary, and I look at the axle torque value, just before and just after I press enter. |
| 02:06 | OK so what we saw there is we had a jump of around about 15 newton metres when I added two degrees. |
| 02:14 | So that's a positive change, we know that we picked up torque, so we're going to enter 19 and we're going to do the process again. |
| 02:23 | OK so again we picked up some torque, this time it wasn't as much, probably about five to 10 newton metres. |
| 02:29 | Still we went the right direction, so we're going to add another two degrees. |
| 02:37 | OK again we picked up torque, and again the amount we picked up was a smaller increase so we're probably getting reasonably close to that MBT value. |
| 02:46 | As we get closer to MBT the amount of torque change will reduce. |
| 02:51 | So we're going to try 23 degrees. |
| 02:57 | OK again we saw a change but now we're almost down to the point where the amount of change is basically about the same as the amount of normal fluctuation that we're seeing in the torque value. |
| 03:08 | So there wasn't a gain in that timing change and realistically it's not worth having. |
| 03:15 | What I'm gonna do now though is I'm going to increase the timing further and you'll be able to see when we go too far the torque actually drops off and reduces. |
| 03:25 | So if we enter 30 degrees in here, you can see we're sitting at around about 305 newton metres, 310 newton metres at the moment. |
| 03:33 | OK so we picked up a little bit and then it dropped straight back off so we're basically sitting stationary at around about the same amount of torque. |
| 03:43 | So if we enter 40 in there, you can see actually now we've dropped off. |
| 03:49 | So we've gone past that plateau and we're down at 280 newton metres. |
| 03:53 | So we'll go back to 23 where we known it peaked. |
| 03:56 | OK so I can't access these sites down here below at 40, 20 and zero kPa. |
| 04:05 | Because of the way ignition timing works, as the load decreases, so as our manifold vacuum increases, chances are we're going to have at least 23 degrees, if not more, so what I'm gonna do is just copy 23 degrees into those sites. |
| 04:22 | What we'd do normally is we'd go back down into first gear so we can access those lower load areas and we'd optimise as much of that map as we can, but for the time being I'm just going to leave them at 23. |
| 04:32 | Now the next area we're going to access is the 80 kPa load area. |
| 04:37 | So we know that we're probably going to be higher than 15 degrees, probably less than 23, so what I'll do is I'll enter a value of 20 in there before we access that zone, and then we'll just increase the throttle position until we get into that particular site. |
| 04:53 | So once we're centred on that cell, we'll look at the torque on the dyno again, and we're sitting at around about 480 newton metres. |
| 05:01 | Now we'll enter a value of 22. |
| 05:06 | We did pick up a little bit of torque but really nothing. |
| 05:10 | That suggests to me that 21 degrees where we were, that's probably a pretty good place to be. |
| 05:17 | I'll just enter 24 degrees and we'll see how that changes things. |
| 05:23 | Again we didn't see any change there at all. |
| 05:25 | So I'm just gonna go back to 21 degrees where we were. |
| 05:28 | OK so the next site up is our full load row, at the moment we've got 15 degrees in there. |
| 05:33 | So I'm going to reduce the timing we had from 21, we're going to start with 18 degrees. |
| 05:40 | So we're just gonna go into the full throttle zone here, and we've got 18 degrees in there at the moment. |
| 05:45 | If we look at the torque on the dyno, we're sitting at around 710, 715 newton metres. |
| 05:52 | I'm just going to increase the ignition timing up to 20 degrees. |
| 05:57 | Now you can see we really didn't have any change in the torque at all. |
| 06:02 | You also saw, you may have seen down here, we actually had a knock warning come up. |
| 06:07 | So we're right on the limit there and realistically the extra two degrees didn't give us any more torque, so I'm just gonna take it right back out, and we're going to leave it at 18 degrees. |
| 06:18 | So that basically tunes that entire 1500 RPM column. |
| 06:23 | What we can do now is we can control C, copy that, and paste it across to the 2000 RPM row. |
| 06:31 | Now chances are that when we get to 2000 RPM, the engine will probably accept some more ignition timing. |
| 06:38 | We always want to start with the timing retarded and then advance it up. |
| 06:43 | So we're just going to leave it like that. |
| 06:45 | We'll increase the RPM on the dyno up to 2000, and again we'll just go back to our minimum load, so we should probably get into that 60 kPa area or maybe even down into the 40 kPa row, yep we can. |
| 06:59 | And we'll just see what happens when we increase the ignition timing. |
| 07:03 | So we'll go from 23 degrees, and we've got 125 newton metres so we'll add two degrees. |
| 07:14 | Basically we didn't see any advantage from that extra two degrees. |
| 07:19 | I'm just gonna increase the throttle now up to that 60 kPa row. |
| 07:24 | So we're at 312, 314 newton metres. |
| 07:28 | So again we'll just try another two degrees. |
| 07:33 | We actually did see a little advantage there, I'll try 27 degrees. |
| 07:42 | And 29. |
| 07:46 | So it looks like around about 27 was where it actually peaked. |
| 07:50 | I just wanna drop back down 'cause it's unusual for me to see timing like that increase as load increases so just wanna drop back down and we'll just recheck what we actually had at 40 kPa. |
| 08:03 | So we'll try 25 degrees in there. |
| 08:07 | OK so now we actually did see an advantage there, we picked up to 140 newton metres. |
| 08:12 | So I'll try 27 degrees. |
| 08:16 | OK so we've picked up to 150. |
| 08:20 | At 29 degrees, yep we've got 170. |
| 08:27 | 31 degrees. |
| 08:32 | OK so we're still seeing a small increase at 31 degrees. |
| 08:37 | Try 33. |
| 08:42 | OK so we didn't really see an advantage there so I'm gonna set that at 31 and again because we can't get to those lower rows, I'm just gonna copy that in down below. |
| 08:51 | We'll now come up to the 80 kPa row which we haven't looked at yet. |
| 08:57 | And we're sitting at around about 500 newton metres. |
| 09:01 | So we'll try 23 degrees. |
| 09:05 | OK we've picked up a little bit of torque but it's a really small change so I'd probably be guessing that we're about right at 23, I'll just try another two, OK and we saw no advantage so I'll set that back to 23 degrees. |
| 09:20 | And now we can go to full throttle where we've got 18 degrees. |
| 09:25 | OK so we're at 780, 785 newton metres. |
| 09:30 | I'll just try 20 degrees in there. |
| 09:34 | OK and we've got our knock warning come back up. |
| 09:37 | So while there was a small improvement in torque from that, we have to protect the engine and basically what that means is on this particular octane of fuel that we're running on at that RPM we're actually knock limited. |
| 09:53 | So I'm using an electronic knock detection system through the M150 Motec. |
| 09:58 | Normally we'd be doing this audibly with a headset. |
| 10:01 | So that's the process we go through, again it's just a case of repeating this throughout the rest of the map. |
| 10:08 | I'm just gonna go through now quickly and do the rest of the map up to 5000 RPM. |
| 12:00 | So that gets our engine tuned out to 5000 RPM. |
| 12:05 | And what you can see is particularly under light load, once you get out past about 4000 RPM, the engine actually not particularly fussy about the ignition timing. |
| 12:15 | You can actually vary it backwards and forwards over quite a large range and it doesn't make a lot of difference. |
| 12:20 | Under wide open throttle though, it is still quite sensitive. |
| 12:24 | You can see I've been battling a little bit with detonation and that's made me in some areas, I've actually been a little bit more conservative on the ignition timing and I haven't been able to get all the way through to our optimum ignition timing to maximise torque. |
| 12:39 | So from 5000 RPM and up at this stage, all I'm going to do is copy that particular row and we'll just paste that through the rest of the map. |
| 12:50 | Now again as RPM increases, generally the engine will accept more timing. |
| 12:55 | So I know that's probably going to be pretty safe. |
| 12:58 | What I would do is just use my knock detection equipment and just have a look at those different rows, make sure that the engine is safe. |
| 13:06 | I'll just quickly do that now so you can see how that looks. |
| 13:39 | OK so we can see there that's basically looked at a couple of rows of the map. |
| 13:43 | We actually had, at 7000 RPM, we had a little bit of detonation come in there that was just picked up. |
| 13:50 | So what I'd do, whether I'm doing that electronically or manually, that would just get me to pull some timing out and what I'd do is basically highlight the areas that that occurred in, and remove two degrees and test again. |
| 14:03 | So that's how we go through the steady state ignition timing tuning. |
| 14:08 | Once we've done that we can move onto our full power tuning. |
