Practical Standalone Tuning: Step 8: Steady State Ignition Tuning
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Step 8: Steady State Ignition Tuning
17.51
| 00:00 | - So now we're going to go through the same steady state tuning process, only this time we're going to be doing the ignition timing. |
| 00:06 | And here what we're doing is looking at the torque on the dyno and we want to optimise the torque by increasing the ignition timing until that torque reaches its peak. |
| 00:19 | Now the only thing I will say in this particular engine is I know from experience that at 1500 RPM it is knock limited. |
| 00:26 | Everywhere else in the map is fine but at 1500 RPM the engine is knock limited. |
| 00:31 | So we have to be a little bit careful about how far we can go. |
| 00:36 | What we're gonna do though is just start at 1500 RPM and as light a throttle as we can which is that 20% area. |
| 00:43 | We'll see how that process works. |
| 00:47 | OK so you can see at 20% throttle there, 15 degrees, we've got about 802, 803 newton metres of torque, so we'll just add two degrees and go to 17. |
| 01:04 | OK so we didn't actually really see much of a change. |
| 01:08 | Oh it's jumped up to about 808. |
| 01:11 | I'll try another two degrees and just see how it responds. |
| 01:17 | So we really haven't seen any change at all. |
| 01:19 | So I'd probably just take that all the way back down to 15. |
| 01:23 | And in fact if you see that, where you advance the timing, and there's no increase in torque, we can also try reducing the ignition timing and see if maybe we're already over advanced. |
| 01:34 | So let's try 13 degrees. |
| 01:38 | OK so when we went down to 13 degrees we did see a small drop off, so chances are 15 degrees is where the engine wants to be. |
| 01:46 | So we're gonna try that now at 40%. |
| 01:51 | OK so we're at 10 degrees now, 886 newton metres. |
| 01:57 | I've just tried 12 and we went up to 895. |
| 02:00 | We could try 14. |
| 02:04 | We're at 900, 16. |
| 02:09 | OK so I tried 16 degrees and there was no change, so I go back to 14. |
| 02:14 | OK we'll go up to 60% throttle. |
| 02:18 | So we're at 900 newton metres, I'll try 12 degrees. |
| 02:24 | Picked up to about 906, 908. |
| 02:27 | I'll try 14 degrees in there. |
| 02:32 | We've gone up to about 910, 908. |
| 02:38 | I'll try 16 degrees, there's no change, so I'll go back to 14. |
| 02:44 | And we'll try the 80% row. |
| 02:47 | So we're at 10 degrees now, 896 newton metres, try 12. |
| 02:55 | And 902, 904, try 14 degrees. |
| 03:01 | 908, I'll try 16, no change, so we're back down to 14. |
| 03:07 | And we're at full throttle. |
| 03:09 | So at 10 degrees we've got 870 newton metres. |
| 03:14 | So I'll try 12 degrees. |
| 03:18 | Picked up a little bit there, try 14 degrees. |
| 03:24 | Picked up a little bit again up to 885, we'll try 16. |
| 03:30 | And again there's no change there. |
| 03:33 | So we saw the best result there at wide open throttle at 14 degrees and we've got a fairly stable map really. |
| 03:41 | 15 degrees at 20% and you can see it was a flat line of 14 degrees basically everywhere else. |
| 03:48 | And that's the process that we use in the rest of the map. |
| 03:53 | Basically we just copy that through. |
| 03:55 | Now again just like the fuel map, there's areas that we can't get to. |
| 03:59 | And as we reduce the load, we generally expect the ignition timing to want to be slightly more advanced. |
| 04:07 | So at 1500 RPM and 0% throttle, we may expect to see the ignition timing advance by a couple of degrees, perhaps up to 18 degrees. |
| 04:17 | And we'd follow that general trend down in these lower areas of the map that we can't get to. |
| 04:23 | So again we'd start by copying the row that we've just done through to 2000, and again just like we talked about with the fuel map, if you're making large changes and your RPM's fluctuating, it can be worth moving that through the 2500 RPM map. |
| 04:42 | So you can just watch now and I'm going to do the rest of that ignition map in steady state up to 5000 RPM. |
| 04:50 | Just like we did with the fuel map. |
| 16:34 | OK so that's basically, that's got our ignition table tuned really accurately out to 5000 RPM in steady state. |
| 16:42 | You can see that it is difficult with this particular engine to control the temperature. |
| 16:47 | I need to wait quite a lot of time in between the runs or between the rows that I'm tuning to allow the temperature to come back down, otherwise the temperature would just get out of control. |
| 16:58 | You can also see that this particular engine is not overly sensitive or responsive to ignition timing. |
| 17:04 | I really haven't see much in the way of change between 3500 there and all the way out to 5000. |
| 17:11 | The ignition timing's really quite stable and we haven't see much advantage from changing the timing. |
| 17:17 | So from here what I'd do is just simply copy the numbers we've got there all the way out to the rest of the table and what we'd do is just using our knock detection gear, run the engine at 5500, 6000, and 6500 RPM and just gently accelerate through those columns, and just confirm that we're not seeing any detonation. |
| 17:38 | So once we've done that, we can move on, and we can start looking at our full power ramp runs. |
