Practical Standalone Tuning: Step 9: Full Power Tuning
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Step 9: Full Power Tuning
23.49
| 00:00 | - Now with our steady state tuning complete for both fuel and ignition out to 4500 RPM, we can begin our full power ramp run tuning. |
| 00:09 | Now what we're going to do here is start initially by only running the car out to 5000 RPM. |
| 00:16 | So we're really only moving 500 RPM out into that untuned area. |
| 00:20 | And what this means is we can be reasonably confient through most of our run that our fuel and ignition should be on point. |
| 00:28 | Now of course if we're performing a ramp run and at any point anything isn't to our liking, either our air fuel ratio is too rich or too lean or we hear any audible knock occurring, in that case we can simply abort the run, back off the throttle, put our foot on the clutch, come back to a stop, make the necessary changes and then continue with another run. |
| 00:50 | There's no need to stay in the run if something isn't correct. |
| 00:55 | The other thing we'll find is as we become more confident we can start our run going out to perhaps 6000 or 7000 or even 8000 RPM and what we're going to do is simply stay in the run until we see our air fuel ratio start wandering rich or lean and we can back off there and this may in some instances allow us to see more of the tune in our first try. |
| 01:19 | OK so what we're going to do is just jump into our laptop software and before we make our first run, just for safety's sake, what I'm going to do is highlight the entire area on boost, so from 20 kPa of positive boost up and we're going to add 5% fuel to this area. |
| 01:38 | This just safeguards us, we should be starting with a safely rich air fuel ratio. |
| 01:43 | With our ignition map on the other hand, we've already made some really conservative numbers in the on boost area, so we're not going to make any further changes to our ignition timing. |
| 01:56 | Let's have a look at our dyno configuration and what we're going to do here is just have a look at the setup for our ramp run. |
| 02:06 | We'll click on the setup button and what we're wanting to do here, we're looking at our start RPM, we're going to be running from 2250 RPM, we'll select a ramp run rate, a ramp rate of 500 RPM per second. |
| 02:20 | This should be relatively realistic for fourth or fifth gear where the car is heavily loaded up. |
| 02:27 | And what I want to do initially though is we'll just bring our end RPM down and for our first run, as I said, we're going to go out to 5000 RPM. |
| 02:38 | So that's 100 km/h. |
| 02:40 | OK so we've got our setup correct, let's get our engine running and we'll do our first run in fourth gear. |
| 03:05 | So that's our first run complete and we're actually pretty close to the mark. |
| 03:09 | Let's just have a look at our results here. |
| 03:11 | And what we can see is first of all we've got our power at the bottom and we ended up with 124 kilowatts at the wheels at this point so we're not really too worried about our power right now, remember we are running very conservative ignition timing as well. |
| 03:25 | We can see we've got our boost being displayed here and for the purposes of this worked example we're just going to be running the engine at our base boost level of 15 psi, one bar of positive boost pressure. |
| 03:38 | And then our top line here is our lambda or air fuel ratio plot. |
| 03:43 | And what I've done is I've put in a reference line here at 0.80 lambda which is what we're targeting on boost. |
| 03:51 | And what we can see is actually the air fuel ratio was really really close, we're just very slightly leaner than our target as we move through and come up onto full boost. |
| 04:04 | So for our first run, that's actually a pretty good starting point. |
| 04:07 | And what we're going to do, before we adjust our ignition timing is we want to get our air fuel ratio dialled in correctly all the way through to 8000 RPM. |
| 04:17 | So with that first run, what I'm going to do is save it and we'll be able to reference that later, so we'll just call this tune one for now. |
| 04:29 | And before we start our next run we'll just have a look here at, from about 4500 RPM and above. |
| 04:38 | As you can see we're just a little bit leaner than our target, you can see our lambda was sitting at 0.81 and our target is 0.80. |
| 04:47 | So what I'm going to do is I'll go in and add another 2% fuel from 4500 RPM and above. |
| 04:57 | So let's jump into our laptop software and we're going to go back online with our ECU and what I'm going to do here, when I'm making changes in the areas that we haven't tuned in steady state, I'm going to make changes to the entire map. |
| 05:12 | So in this case in particular from 5000 RPM and above, sorry 4500 RPM and above in this case, we're going to add 2%. |
| 05:21 | So we'll multiply that entire area by 1.02. |
| 05:26 | Alright we can store that, let's get our engine running and we'll make another run. |
| 05:31 | But before we do that, what we are going to do is just increase our RPM range. |
| 05:36 | So we'll click on the set up button and this time I'm going to make a jump up to 6000 RPM. |
| 05:44 | And we'll see how our tune works out as we increase our RPM. |
| 05:49 | Let's get our engine running and we'll do our second run. |
| 06:07 | So that's our second run complete there and again we can see that everything's looking pretty good. |
| 06:12 | Our boost, nice and stable sitting on our 15 psi target. |
| 06:16 | We can see that our air fuel ratio is starting to nose over a little bit rich up at around about 5700 to 6000 RPM. |
| 06:27 | So that's means we're going to need to remove a little bit of fuel there. |
| 06:31 | Having said that though, it's still very very close to our target, we're sitting at 0.78 so we're only around about 2% richer than our target at that particular point. |
| 06:42 | And right now that may not actually necessarily be something that would stop us running the engine further. |
| 06:48 | What I'm going to do is I will save that run and we'll call this tune two. |
| 06:54 | What we're going to do is jump back into our laptop software, I'll just go back online with the ECU and we will make some changes to our tuning. |
| 07:05 | Now what I'm going to do here is at 5500 RPM and above, I'm just going to remove 2% fuel. |
| 07:14 | So to do that we can just multiply by 0.98. |
| 07:18 | So that should go some way towards correcting that slight rich area we're starting to see right at the top of the run. |
| 07:24 | OK let's go back to our dyno setup. |
| 07:27 | And this time we're going to extend our RPM range out to 7000. |
| 07:33 | Now of course you don't need to go in 1000 RPM increments and particularly while you're just getting comfortable with everything, 500 RPM increments are probably a lot safer, you're only going to see a small area of the untuned map in each ramp run. |
| 07:50 | Alright let's get our engine running, we'll do our third ramp run. |
| 08:13 | Alright so we've got our third ramp run complete there. |
| 08:15 | And we can see that there's a couple of areas that do need a little bit of work, particularly the area where I actually removed fuel, we can see now on this run we've actually gone a little bit lean. |
| 08:26 | So we've gone a little bit too far and then again we can see that above 6000 RPM we're dropping quite dramatically rich, in this case we've gone down from about 6250 RPM and above we're sitting at 0.75 lambda. |
| 08:43 | So we're around about 5% richer than our target. |
| 08:46 | So what we're going to do now is we'll go into our software and we'll make some changes to those particular areas. |
| 08:53 | So the first change I'm going to make is at 5500 RPM. |
| 08:57 | Again when I'm making these changes at this point, I'm making them to the entire column and the reason for that remember is if we have copied our trends across, then it's reasonable to expect that if we are a little bit rich or a little bit lean at 200 kPa, then we're probably going to follow that trend and be a little bit too rich or too lean right through that column. |
| 09:21 | Of course once we've completed this wide open throttle ramp run tuning, we can go and have a look at those part throttle areas and the vacuum areas of our map in steady state. |
| 09:31 | Remember those areas aren't a place that we're going to spend a lot of time so we don't need to be quite as accurate and fussy, that's why we don't bother spending the time to tune each of those zones in steady state. |
| 09:42 | Alright so what we're going to do is start by adding 2% in at 5500 RPM. |
| 09:48 | I'm also going to add 1% in at 5000 RPM, and then 6000 RPM we've already started to go a little bit rich so I'm just going to remove 1% from 6000 RPM, and then from 6500 RPM and above, I'm going to be removing 5% and we'd do that by multiplying by 0.95. |
| 10:15 | OK so this should get us something that's a little bit closer, let's store that into the ECU, we'll get our engine running and we'll make another pull on the dyno. |
| 10:43 | So that's our next run complete there and you can see we've picked up a little bit of power, we're now sitting at 161 kilowatts. |
| 10:48 | Again our boost is nice and stable so that's good. |
| 10:52 | We can see that our air fuel ratio still needs a little bit of work. |
| 10:55 | The lean area at 5500 RPM that I had used last time, that's gone some way to correcting it, we can see we still need to add a little bit more fuel at 5500 RPM and you can see the fuel that we removed above 6500 RPM, that's gone a long way towards correcting that rich area that we did have but we still are a little bit too rich at high RPM. |
| 11:22 | So the process of completing our fuel tuning is exactly the same as what we've looked at here. |
| 11:27 | What we're going to do is continue to perform ramp runs. |
| 11:30 | Any time we've got an error in our air fuel ratio from our target, we're simply going to address that particular area in our fuel map. |
| 11:39 | Now what we're going to go is continue this until we've extended our ramp runs out to our rev limit or whatever RPM range we want to tune to. |
| 11:47 | So with this in mind, I'm not going to go through every single iterative step. |
| 11:51 | We've got here our completed volumetric efficiency map and if we look at it visually, this gives us an idea of what a properly tuned VE map should look like and we can see that we've got a shape to our VE map that's nice and smooth, there's no really sharp erratic changes in there and it's, particularly for a turbocharged engine, that's what we would expect. |
| 12:14 | If you've got a naturally aspirated engine that's running very aggressive cams, in that case we can start seeing some erratic areas creep into our VE tables. |
| 12:24 | Particularly at low RPM where the cam is not working efficiently. |
| 12:28 | This is a relatively normal or typical shape to a VE table. |
| 12:34 | So now what we're going to do is move on and we'll continue our tuning with our ignition table. |
| 12:42 | Before we do that, let's lay down a complete run out to 8000 RPM with our fuelling correct. |
| 13:10 | Alright so we've got our complete run there out to 8000 RPM. |
| 13:14 | We can see that we've still got a little bit of fluctuation in our lambda plot. |
| 13:18 | Really depends how fussy we want to be about that exact lambda target. |
| 13:22 | And of course if there is any further requirement for change, we can simply go back and follow the same process. |
| 13:28 | Now we can also see that at higher RPM, our boost is actually starting to increase. |
| 13:33 | And at this point I'm going to make an assumption that this is quite likely due to the fact that our ignition timing is very very retarded at this point. |
| 13:43 | At this point we're running somewhere around about 18 psi. |
| 13:47 | And if we jump back into our laptop screen, we can see that at the higher RPM, 8000 RPM and 220 kPa, we're down around the two to three degree ignition advance area. |
| 14:03 | So this can create excess heat in the exhaust manifold and this can in turn result in high boost levels on turbocharged cars. |
| 14:12 | Alright so we're going to save this and we're going to use this as our base run. |
| 14:17 | And this is going to allow us to overlay with this as we start making changes to our ignition timing. |
| 14:23 | And for the very first run, what I'm going to do is simply highlight our entire map here in the ignition timing, anywhere above, in this case, I'm going to go from 2500 RPM and I'm going to add two degrees to that. |
| 14:39 | I do wanna be a little bit careful because at very low RPM down around 1500 and 2000 RPM when I was running in steady state with the ignition timing we did find that the engine was quite heavily knock limited here. |
| 14:53 | So we want to be a little bit careful and make sure that we don't add too much timing down low. |
| 14:58 | So what we're going to do now is perform another run on the dyno. |
| 15:01 | And we're going to see how this additional two degrees affects our power. |
| 15:06 | So let's get our engine running again and we'll do another pull. |
| 15:31 | OK so that's our second run complete. |
| 15:33 | Now we've overlaid it with our base run, with our base ignition table. |
| 15:36 | And what we want to do is look at any areas we've seen an improvement. |
| 15:41 | Let's have a look at the overall run first, and the first thing we can notice is that at higher RPM where previously our boost was increasing quite dramatically, you can see that our boost is still tapering up slightly above our target of 15 psi, but it has been reduced and that's as a result of that additional two degrees. |
| 16:01 | We've removed some heat from the exhaust gas as a result of that. |
| 16:05 | We can see that for the most part our air fuel ratio has tracked along exactly as it did for our first run, no big surprises there. |
| 16:14 | What we can see is we've seen a dramatic increase in our power, particularly from about 4500 RPM where we first hit peak boost and above. |
| 16:25 | Now when we see quite a dramatic increase in our power, this means that we're probably quite a long way away from MBT. |
| 16:33 | So this straight away would indicate to me that it's likely that this engine is going to want even more timing than I've already added. |
| 16:42 | Now you'll remember that we added that timing from 2500 RPM. |
| 16:46 | Now we can see that it's not actually until we get to about 3000, 3500 RPM that we see any real advantage from that additional timing. |
| 16:57 | So any time we have added ignition timing to the table and we haven't seen an advantage from that timing we're simply going to pull that timing back out. |
| 17:09 | So let's go back into our ignition table now and what I'm going to do is exactly that. |
| 17:14 | Between 2500 and 3500 I'm just going to pull two degrees back out. |
| 17:20 | At 3500 RPM, we saw a mild increase, it's very very small but what I'm going to do is I'll just add one degree back in. |
| 17:30 | And really the aim I'm going with here is to try and smooth the transition. |
| 17:34 | At 4000 RPM, we are seeing a small improvement from that power, so we want that additional timing in there. |
| 17:41 | And I'm just smoothing the ignition map. |
| 17:43 | Now really the main improvements there though were from 4500 or 5000 really and above. |
| 17:51 | For this next run, what I'm going to do is just add in another two degrees above 4500 RPM. |
| 17:58 | So let's get our engine running again and see what that results in. |
| 18:02 | Now of course any time we're doing this, particularly on a turbocharged engine that is knock limited, we want to be listening for detonation, we want to be very careful that our engine is not starting to suffer from knock. |
| 18:14 | Particularly any time we are advancing the timing like this. |
| 18:17 | Alright let's do another run. |
| 18:35 | So that's our next run complete there and remember we've added some additional timing, in this case from 4500 RPM. |
| 18:42 | Remember we also removed that timing that we added in down at the start of the run, down around 2500, 3000 RPM, 3500 RPM. |
| 18:51 | And again we've seen no decrease from removing that timing. |
| 18:54 | So we know that we're OK there. |
| 18:57 | So we've seen an increase in timing but what we'll notice is that at 4500, and particularly at 5000, 5500 RPM, through this area where we first come up on full boost, while we have seen an improvement in power, this time it's been relatively small. |
| 19:13 | Now as we see smaller improvements in the power, this is suggestive that we're getting towards MBT and the engine may not require too much more ignition advance. |
| 19:22 | What we have seen though is particularly from about 5500 RPM and above, we've still seen a continual increase and quite a dramatic increase, particularly right at the top of that run around about 7000, 7500 RPM. |
| 19:37 | Again just indicating that the engine does want some more ignition timing. |
| 19:42 | So what we're going to do is again we'll try adding some additional timing. |
| 19:47 | Now I'm going to leave the timing there at 4500 RPM alone and the reason for this is we are getting to a point where the engine is quite knock sensitive. |
| 19:56 | So particularly around peak torque, this is the area that the engine is going to generally be very very prone to knock. |
| 20:03 | So in order to provide a safety margin there, I'm not going to advance my timing any further, the gain that we've seen from that last two degrees, while it is a real gain is also quite minor. |
| 20:15 | So I know that while advancing the timing further may continue to show an improvement, I'm happy to compromise here in order to maintain some safety with our engine. |
| 20:26 | So let's highlight our entire table here from 5000 RPM and above and this time I'm going to add another two degrees. |
| 20:35 | So let's store that change, we'll get our engine running and we'll perform another full power run. |
| 20:58 | OK so that's our next run done there and we can see now we've picked up quite a chunk of power, we're up to 201.7 or 270 wheel horsepower. |
| 21:06 | In particular you can see that we've seen quite a large gain right here at the top of our run. |
| 21:13 | And we also saw this was coupled with the boost just continuing to drop as I add timing, remember again that's to do with the added timing reducing that exhaust gas temperature. |
| 21:24 | Now we've seen an improvement, remember we added timing there from 5000 RPM and above. |
| 21:29 | Now really the process now is just to continue this iterative process of adding ignition timing while we're seeing gains in power and torque, provided of course that we don't run into any problems with detonation. |
| 21:44 | Now in this particular engine, given the high compression ratio and pump fuel, detonation was a limiting factor. |
| 21:50 | So what we're going to do now is have a look at the completed ignition table that was a result of this tuning process and let's see what we can deduce from that. |
| 22:01 | What we can see is that at high RPM and 200 kPa, our full boost target, we ended up with 15 to 17 degrees of ignition timing. |
| 22:10 | Now if we look at the map graphically we can also see that the ignition table has a nice smooth and consistent shape, this is relatively common, this is what we'd be expecting to see, there's no sharp spikes or erratic profiles to the ignition table. |
| 22:27 | What we've got it our general trends where as RPM increases, we can see that our ignition timing smoothly increases and as our boost pressure or load increases, our ignition timing reduces. |
| 22:38 | Now let's have a look at our dyno and I've loaded up our final run which in this case was 216.8 kilowatts at the wheels. |
| 22:49 | And we can see that for the most part our run overlays our last dyno plot up to about 5000 RPM. |
| 22:57 | After that we've continued to advance the timing and the main gains we've seen really are up around about 7000, 7500 RPM. |
| 23:04 | And that also resulted in a nice flat boost curve, we're holding exactly our 200 kPa target. |
| 23:11 | So this concludes our full power tuning step on the dyno and from here we'd take the car out onto the race track and confirm our tune, make any further adjustments that we need to. |
| 23:22 | What we're looking for on the race track from our datalogging is to confirm and ensure that everything we saw on the dyno is what we're seeing out in the real world. |
| 23:31 | If you do have any questions about the steps in this worked example, please ask them in the forum and I'll be happy to answer them there. |
