Practical Reflash Tuning: Step 6: Confirm Calibration on the Road
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Step 6: Confirm Calibration on the Road
15.53
| 00:00 | - For the sixth step of our process, we've taken our car here to Highlands Motorsport Park to put it through its paces on the racetrack. |
| 00:07 | What we're looking for here is to make sure that everything we saw on the dyno stacks up under real world conditions. |
| 00:13 | We're likely to see some variations sometimes between the air/fuel ratios that we saw on the dyno and what we see under real world conditions on the road or the racetrack due primarily to the airflow and temperatures that we see on the dyno compared to real world conditions. |
| 00:29 | Particularly with turbocharged vehicles as well, it's very common to see problems with the boost control compared to what we had on the dyno. |
| 00:36 | Under steady state ramp run conditions on the dyno it's very easy to get very accurate and stable control of our boost but under the transient nature of driving under real world conditions, this may not always stack up, particularly under gear changes we can sometimes see over boost conditions so those are the sort of things we're going to be looking for. |
| 00:56 | While we're here on a racetrack, where obviously we don't need to worry about oncoming traffic and we don't need to worry about pedestrians, this can still be done on the road, albeit you do need to understandably take some care. |
| 01:08 | Your primary focus should always be driving the car and for this reason it's a good idea to make use of a friend to help with the tuning process. |
| 01:17 | One person can then drive the car, concentrating solely on the driving operation, the other person can operate the laptop as required. |
| 01:25 | Our task however is made a little bit easier when we are reflashing like this because we're going to be leaning heavily here on RomRaider. |
| 01:33 | This allows us to gather the data using the RomRaider logger out on the track where we can solely focus on driving the car, we don't need to worry about the laptop at all, once we've gathered all of the data that we want, we can then come back into the pits or stop on the side of the road and then analyse our data and make any necessary changes as required. |
| 01:53 | The other aspect that can be helpful while we are confirming our tune on the road is having access to a boost gauge. |
| 01:59 | In this case we've got a boost gauge sitting here on the dash so we can monitor that out of our peripheral vision and just make sure that we don't have any dangerous overboost conditions going on. |
| 02:09 | Likewise if we've got a wideband air/fuel ratio meter that is visible to the driver, this can be helpful. |
| 02:16 | We don't need to be staring at this, again we're concentrating primarily on driving the car. |
| 02:20 | But we can glance at that wideband air/fuel ratio data out of our peripheral vision, particularly when we're under wide open throttle acceleration and just make sure that the air/fuel ratio is on track for what we're expecting. |
| 02:33 | So now we know what we're trying to do, let's head out onto the track and get started. |
| 02:38 | Now our first job once we actually get the car moving is to allow the car to come up to normal operating temperatures. |
| 02:46 | Particularly here with the start of this module, we've had the car sitting idling for an extended period of time and what that's going to do is result in heat soak. |
| 02:54 | In particular this is going to affect our intake air temperatures and they're not going to be particularly realistic. |
| 03:00 | And while of course the ECU is going to account for this, before we start gathering our data and really diving down deep into the quality of our tune, we're going to want to let our air temperature come back down to normal conditions as well as our engine coolant temperature. |
| 03:17 | So we're just going to put in half a lap or so now and allow that to happen. |
| 03:21 | Alright we've got rid of that heat soak now, our engine coolant temperature and our inlet air temperature are both in the normal operating range so we can now press record and start gathering our data into a file. |
| 03:33 | It's important while we are gathering this data as well to be a little bit mindful of the way that we drive the car. |
| 03:39 | What we want to do here is drive the car using smooth throttle inputs. |
| 03:43 | This is going to reduce the effect of any transient enrichment that can give us some data that's not exactly clean and realistic. |
| 03:52 | The other thing we want to understand is what sort of data we're trying to gather. |
| 03:57 | For the first part of this, what we're going to be doing is looking for the sort of operating conditions that we're likely to see under steady state cruise. |
| 04:06 | So what I'm talking about here is anywhere from around about 2000 or 1800 RPM, up to about 3500, maybe 4000 RPM and we want to be going from low in our vacuum, basically to the point where our throttle is essentially closed and we want to be going all the way up until we're starting to transition into boost. |
| 04:27 | And we want to gather a reasonable amount of data, we want to get as many hits on those zones as we can so we're going to do a couple of laps here. |
| 04:35 | If you're out on the road, probably suggest driving for somewhere in the region of between five and 10 minutes to gather a solid amount of data. |
| 04:43 | And the more data we can get, the more hits on all of those points we can get, the more we can rely on that data being accurate, so let's just go ahead and do that now. |
| 04:54 | Now while we're gathering this data as well, it does give us the opportunity to get a feel for how smooth the car is. |
| 05:01 | It's obviously pretty important, if we've got our tune on point, the car should be smooth, we shouldn't have any hesitation or any jerkyness as we are moving through the RPM range and as we're moving in and out of the throttle. |
| 05:16 | If we do sense any jerkyness or any erratic behaviour then that's an area that we'd want to dive in a little bit deeper and see if there's a reason for that, given our air/fuel ratio may not be quite accurate in that region or also there may be something strange going on with our ignition timing. |
| 05:33 | The other aspect here and this may not always be possible, on the racetrack obviously we don't have any traffic lights to worry about, we don't have any stops to worry about so this allows me to gather my data in one single gear. |
| 05:47 | So here I'm using third gear which allows me to expand through that rev range that I'm looking at, remember around about 1800 to 2000 RPM in the low range, through to about 3500, 4000 RPM in the high vicinity. |
| 06:00 | Using one gear like this rather than constantly cycling between gears and using the clutch, this gives us cleaner data because on a gear shift we're going to see our air/fuel ratio move around. |
| 06:12 | Now that's not to say we can't filter that out using the likes of MegaLogViewer HD but if we don't have to filter that data and we've got clean data to start with, that's likely to give us a better result. |
| 06:24 | Let's continue now with our data gathering. |
| 06:26 | Alright I'm pretty happy with the amount of data that we've gathered now under our simulated steady state conditions so we're going to stop our log file right there and this is going to allow us to review that particular section of our log independent of the next one we're going to create. |
| 06:43 | This allows us to look specifically at what's happening under closed loop conditions where we can use our short term and long term fuel trims to give us an indication of how close our MAF scaling is as well as our load compensation. |
| 06:56 | The next part of our testing, we're going to start our logger again and what we're going to do now is we're going to simulate a wide open throttle ramp run on our dyno and here I'm just going to use the longest section of straight track and we're going to do a full power acceleration run in fourth gear here. |
| 07:15 | We're going to try and go all the way from 2000 RPM through to 7000. |
| 07:20 | Particularly here we want to take note of our boost and if possible our air/fuel ratio while we're doing this, just to make sure that nothing is going outside of our normal operating conditions and we're happy with everything. |
| 07:32 | Now let's just go around our last corner onto our front straight and we'll just get down here to about 1800 RPM and we can just go to full throttle and go all the way through to 7000. |
| 07:59 | Alright we've got our test complete there so we can stop our logger. |
| 08:03 | Again we can review this data back in the comfort of the pits and we'll be looking at our air/fuel ratio, our boost pressure and also we'll be able to analyse our knock feedback and see what was happening there. |
| 08:18 | For our last piece of data here we're just going to have a look at the transient performance of the tune. |
| 08:25 | We're looking at two aspects here, we're going to be looking at how crisply the engine responds to throttle input. |
| 08:32 | In other words is our transient enrichment or acceleration enrichment on point? And we're also going to be looking at the boost performance on a gearshift. |
| 08:40 | When we do this, what we want to do is make sure that we're actually beyond the boost threshold which is the RPM range above which we can actually reach full boost and what we want to do is either perform a gearshift there, or we can either go full throttle, allow the boost to reach its peak, roll out of the throttle and then jump straight back into it. |
| 08:59 | And that's again going to replicate our gearshift, making sure our transient boost response is under control. |
| 09:06 | We'll just get around this next hairpin onto a straight section of track and we'll be doing that in third gear. |
| 09:13 | Alright so we're just going to accelerate here up to about 5000 RPM. |
| 09:17 | We'll get off the throttle and then straight back into it. |
| 09:27 | OK so the engine is responding nice and crisply to throttle input so transient acceleration enrichment there, really good. |
| 09:35 | Also our boost wasn't spiking above our target so straight away just looking at the boost gauge, even before I have a look at the data, I know that our boost is actually pretty well under control so everything's looking good. |
| 09:46 | I'm happy with how the car feels and of course, that is one of the most important aspects. |
| 09:51 | Let's head back to the pits now, we'll have a quick look through our data and see if there's any improvements that need to be made. |
| 09:57 | Let's start with our first piece of data loaded up where we looked at our steady state testing. |
| 10:02 | And what we want to do is exactly what we did on the dyno, we want to analyse this in two separate ways, looking at our mass airflow sensor scaling and then we're going to have a look at our load compensation table as well using our histograms. |
| 10:16 | So looking at our first one here where we're looking at our mass airflow sensor data. |
| 10:20 | And in particular what we want to do is look mainly at the low RPM and the very high RPM, skirting around those areas through the mid range where we know we've got that fuel system issue. |
| 10:33 | In particular though just looking at this, we can straight away see that the numbers are all looking pretty good. |
| 10:38 | For the most part we're within about plus or minus 2%, we've got a lot of areas here where we're right on our target. |
| 10:45 | There's a few little areas where our errors are in the 3-5% vicinity but for the most part, this is actually looking really really good, I'm quite happy with this and based on this alone I wouldn't necessarily make any changes to my MAF scaling. |
| 11:02 | Let's jump across now, we'll change our histogram here and we'll come across to our map comp histogram. |
| 11:09 | So our map comp histogram, we've got our RPM here on the vertical axis and we've got our manifold pressure on the horizontal axis. |
| 11:18 | So this allows us to see how well our map comp table or map compensation table is set up and again just using this exactly the same way we looked at it on the dyno. |
| 11:29 | Again for the most part we can see that everything's looking really good on this table, we've got numbers really close to our target of 0% trim, nothing again untoward here, nothing that I would really be too concerned about making changes to. |
| 11:45 | It is important here to understand that this isn't always going to be the case and tuning always us an iterative process so if we see any areas here that we are concerned about, if you're starting to see significant areas where we've got +/- maybe 4-5% trims or greater then we'd want to dive into those areas in a bit more detail. |
| 12:06 | We're going to use the same process that we used on the dyno, we want to first of all highlight if the issue that we've got is related to our mass airflow sensor scaling and there primarily we're looking at the mass airflow sensor scaling, our trims, 2000 RPM where we know that there's not a lot of problem with that fuel system and then 4000 RPM and above if we've got that data. |
| 12:26 | If that's all looking good then we know that the problem's in relation to our map comp table and that's where we're going to be making our changes. |
| 12:34 | Again in our instance, everything's looking really good here so we can move on and look at our next piece of data. |
| 12:41 | Now looking at our ramp run here, the key things we want to look at first of all, is our air/fuel ratio under control? And we can see that we're basically within about 1% of our target right through that ramp run. |
| 12:55 | Not too concerned if we've got some small discrepancies as we ramp up onto boost and we see that our air/fuel ratio starts to, or target starts to track richer, what we're really looking for is making sure that once we got to our rich target and we are at peak boost, that our air/fuel ratio is tracking nicely and we can see that it is so that's our first tick of approval there, that is doing what it should be doing. |
| 13:16 | The next aspect we want to analyse here is our ignition timing or more specifically our knock activity and here what we want to look for is an ignition advance multiplier that's sitting at 1.0 the whole way through our log file, it's exactly what we've got here. |
| 13:32 | We also want to make sure that our feedback knock correction and our fine learning knock correction basically aren't pulling any timing. |
| 13:40 | Now in this case we haven't got any timing being pulled so this means that the ECU isn't detecting knock. |
| 13:46 | We've got no knock happening so we're comfortable that our timing is under control. |
| 13:51 | The last aspect we want to look at here is our boost control, we want to make sure that our boost is hitting its target without any overboost or any oscillation. |
| 13:59 | Here, everything's looking quite good however what we can see is that at higher RPM we're actually slightly above our boost target. |
| 14:08 | Now that's something, unfortunately in this situation we can't address. |
| 14:13 | The reason for this is that if we look at our primary wastegate duty cycle we can see in the area where our boost is above our target, the duty cycle's already at zero so this is actually a mechanical limitation of the wastegate spring pressure. |
| 14:25 | In this case though, because our air/fuel ratio is still under control and also we've got no problems with knock, I'm not necessarily worried about this and it is a relatively small increase over what we did see on the dyno. |
| 14:38 | This just shows you though why it is so important to actually check and see what your boost is doing out on the road or the racetrack because it's not always going to be identical to what you saw on the dyno. |
| 14:51 | Now we can load up our third and final log file and we're looking at our boost control on those transients. |
| 14:58 | We already saw from our boost gauge on the dash, there's nothing really untoward going on there and we can see that everything is stacking up quite nicely. |
| 15:05 | We can also analyse our air/fuel ratio but often on our transients we aren't going to see the air/fuel ratio nicely track our targets anyway. |
| 15:14 | And this is something that we're going to be doing more from feel. |
| 15:18 | We know that the response out on the racetrack was nice and crisp so I've got no concerns there. |
| 15:24 | And at this point essentially everything's stacked up really nicely with what we saw on the dyno. |
| 15:29 | We've got good control over our fuelling, under cruise conditions as well as wide open throttle ramp run conditions. |
| 15:35 | We've got good control over our boost and we've got no knock activity occurring. |
| 15:41 | So at this point our tune is complete. |
| 15:43 | If you've got any questions on this worked example, please ask them in the forum and I'll be more than happy to answer them there. |
