Practical Standalone Tuning: Step 10: Confirming the Tune on the Road/Track
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Step 10: Confirming the Tune on the Road/Track
23.46
| 00:00 | - For the last step of our tuning process, we've brought the car here to Highlands Motorsport Park. |
| 00:05 | We're going to head out on track and put the car through its paces and essentially make sure that everything we saw on the dyno stacks up under real world conditions. |
| 00:13 | In particular, we're looking for our air/fuel ratios to still track our targets, we're going to make sure that the car is smooth to drive, we're going to make sure that our boost control is on point, in other words we are seeing the same boost levels that we were seeing on the dyno and of course we'll want to check and make sure that we're not getting any knock that wasn't present on the dyno. |
| 00:35 | And while we'd like to think that our tune would be reasonably consistent between the dyno and the road or the racetrack, often we do see some minor differences so it always pays where possible to check and make sure that everything is still exactly what you saw. |
| 00:49 | Before we head out on track we're going to just discuss the process we're going to go through here. |
| 00:54 | And essentially we're going to be looking at 2 different parts of the tune. |
| 00:58 | The first step I'm going to do is I'll head out on the racetrack, we'll allow the engine to dissipate any heat so it can get down to normal operating conditions, temperatures, that's really important to make sure that we're not going to have heat soak adversely affecting our results and I'm going to spend some time in the cruise areas of my map. |
| 01:15 | So here, typically I'm going to be between about 2000 and about 4000 RPM. |
| 01:22 | Probably anywhere from about 5-10% throttle up to about 25-35% throttle. |
| 01:28 | So this replicates the cruise areas or light acceleration that we're likely to see out on the road. |
| 01:35 | And what we're trying to do here is just make sure that our air/fuel ratios are neatly tracking our targets. |
| 01:41 | Now while we're doing this as well, we're not going to need to be pinned to the laptop keyboard or laptop screen watching what's going on. |
| 01:48 | Obviously our main priority here is actually controlling the car. |
| 01:52 | So we're going to be making use of the onboard logging or the PC logging here with the EMtron and this will allow us to gather that data and then analyse that data back in the comfort of the pits where we don't need to worry about others cars or pedestrians etc so it's a nice safe way of gathering our data. |
| 02:08 | Once we've analysed that data and we're comfortable that everything is correct or made any changes as necessary, we're going to head back out on the track and now we're going to look at our full throttle area of our map. |
| 02:19 | So basically we're going to replicate what we did on the dyno with some wide open throttle acceleration pulls. |
| 02:25 | When we're doing this, what we want to do is carefully choose a gear where we're obviously monitoring our maximum speed here, the benefit of being on a racetrack we've got no speed limit so that's helpful. |
| 02:36 | On the open road obviously you do need to be mindful of your local speed limit so that's a really big consideration here. |
| 02:44 | On the other hand though we don't want to be doing our acceleration runs in a really low gear, perhaps first or second gear, we're not really going to be loading the engine up properly so we're not going to get a good indication of what's going to be happening in the higher gears so here I would typically use third gear and we're going to use a long section of the racetrack so where I can really accelerate from low down, perhaps about 1800 to 2000 RPM, all the way up to our rev limit out around 7800 RPM and that's going to give us data that's going to be just as good as what we saw on the dyno. |
| 03:15 | The whole time I'm doing this, if possible we would be monitoring out of our peripheral vision, the air/fuel ratio if we've got a wideband that we can put on the windscreen, that's perfect, we don't need to watch the wideband the whole time, we can watch the road and just glance at this out of our peripheral vision, allowing us to back off if we see our air/fuel ratio isn't where we want it to be. |
| 03:37 | While I won't be doing this for the purposes of our worked example here, I'd also typically be audibly listening for knock while I was out on the racetrack as well doing these wide open throttle acceleration runs. |
| 03:49 | There is another consideration here when we're doing our wide open throttle acceleration runs. |
| 03:53 | Just because of our ITBs plus turbo, what we want to do is start on our minimum boost level and what we're going to be doing if any changes need to be made to our VE table, we're going to do that at our minimum boost level. |
| 04:07 | From here we're going to leave our VE table alone and we're going to step up our boost pressure levels and once we go up in our boost pressure levels if we see any discrepancy at the higher boost pressures, we're going to be doing that in our secondary load table. |
| 04:19 | That's really important because if we start modifying our VE table at our higher boost levels, this is going to adversely affect our low boost so it's really the same process that we went through on the dyno, we set up our VE table on our minimum boost level, started stepping up our boost pressure and then if we saw any discrepancies at the higher boost pressure, those changes were made in the secondary load table so exactly the same process. |
| 04:41 | Alright so now that we have a bit of an understanding of what we're trying to do here, let's get up and running and we'll head out on the track and start gathering some data. |
| 04:50 | Alright so we're out on the track now. |
| 04:52 | I've only gone through a couple of corners, again just allowing our heat soak to dissipate, watching our engine coolant temperature and our air temperature and we just want those to reach our normal operating temperatures before we start gathering any data. |
| 05:04 | However, just glancing at our lambda graph at the moment on the screen, we can already see that our measured lambda is tracking right on the top of our target lambda so this is a really good starting point and of course this is exactly what we'd like to see. |
| 05:19 | So we'll just go through a couple more corners here and our temperatures are pretty much where I'd expect them to be so what we can do now is start our datalogging. |
| 05:30 | Now with our datalogging, all we need to do here is press F8 and we'll see a little blue status symbol on the bottom left corner, that's going to show PC log active so this means we are now logging. |
| 05:44 | Now we're just going to complete a couple of laps of the track gathering data. |
| 05:48 | It's important to understand what we are trying to achieve while we're doing this because it is a bit of a case of garbage in, garbage out so what we're trying to do is cover as much of that area of the map that I talked about previously as we can. |
| 06:01 | Remember 2000 through to about 3500 maybe 4000 RPM, 5-10% throttle at the bottom end through to maybe 25-30%, just the area where we're starting to come into positive boost and we're starting to see some mild acceleration. |
| 06:16 | It's also important while we're doing this though to make sure that we are very smooth on our throttle inputs and the reason for this is we don't want to be bringing any transient acceleration enrichment or for that matter, deceleration enleanment because that will affect the accuracy of our air/fuel ratio data so smooth is key here. |
| 06:40 | Where possible, and it's easier on a racetrack, we also want to try and avoid gear shifts. |
| 06:46 | Now of course that's not going to always be feasible however where we can if we can leave it in one gear and cover as much of the map as we can, it's just going to eliminate any errors that we're likely to see as we close the throttle and get back into the throttle. |
| 07:01 | There's always going to be some ugliness in our air/fuel ratio data when we're in complete overrun, particularly if we are using overrun fuel cut and likewise as we get back onto the throttle, we're almost inevitably going to see some acceleration enrichment come in there. |
| 07:17 | Alright so let's carry on, we'll just gather as much data as we can, using the techniques that I've just discussed. |
| 07:57 | Alright we've got a reasonable about of data there, certainly enough to demonstrate how we're going to use that data. |
| 08:04 | So what we can do now, we'll press F8, that's going to stop the data logging and download it so we can view it. |
| 08:10 | We'll head back into the pits and we'll see what we can learn from the data we've gathered. |
| 08:15 | OK so on the laptop screen at the moment we've got all of our raw data in a time graph which in itself isn't overly useful but let's just dive into it anyway. |
| 08:23 | So first of all we need to understand the channels that we are looking at. |
| 08:27 | These are listed up here in the top left, we've got the key ones that we're interested in, engine speed, our target lambda and our measured lambda, our throttle position and our manifold pressure. |
| 08:36 | So this is for the entire outing. |
| 08:38 | So little hard to really know what to do with this, there's a lot of data there so it's hard to be specific. |
| 08:46 | What we can see though, straight away which is pleasing is that the general trend for our data, particularly the lambda versus our target, we can see is pretty close so pinpoint there that I've just chosen, we can see that our target was 0.997, our measured 1.005 generally, rounding to 2 decimal places is absolutely fine so essentially no error there, lambda 1 target, measured lambda 1 so absolutely where we want it to be. |
| 09:13 | There are a few areas where we see some discrepancies so this particular area here, looking at our target lambda 1, measured 0.97 so we're about 3% rich there but for the most part what we are seeing is everything's looking pretty good which is quite pleasing. |
| 09:30 | And we do want to be mindful of some of these errors could be brought in by deceleration enleanment etc or acceleration enrichment as I already mentioned so again it still comes down to the quality of our data, trying to be smooth on the throttle. |
| 09:43 | However again very difficult to be pinpoint accurate with this data on where do we go and make changes. |
| 09:50 | And really we want to gather a lot of data so that we can analyse it all together so let's have a look at another way of analysing our data now. |
| 09:59 | What we'll do is we'll come over to our mixture plot and this allows us to view the data in a slightly different way so we need to understand how to set this up initially and by default this will be set up with the left plot over here for lambda 1 and the right plot over here for lambda 2. |
| 10:18 | Perfect of course if you do have dual lambda. |
| 10:20 | We don't of course here so I've set this up to view the data in 2 different ways. |
| 10:25 | On the left of the screen here, we've got lambda on the vertical axis versus our engine RPM and the colour axis here is our throttle position so I've spanned that out here on the right hand side, we can see that colour code. |
| 10:38 | We've spanned that between 10% throttle and 40% because that's the area we're interested in. |
| 10:43 | So we can see we've got a lot of data here represented by these blue traces which as we can see is sort of down around the 13 to maybe 16% throttle. |
| 10:52 | We've got some data here in green as well that is up around, looking at about 25% throttle. |
| 11:00 | So this gives us a good indication of how, what our lambda is doing versus our throttle positon and RPM but of course this isn't taking into account our target air/fuel ratio so for example, are we tracking our target? We're not seeing that from there because it's just representing or reporting on our lambda value. |
| 11:18 | On the right hand side, for this particular purpose, not particularly useful but we are now using manifold pressure as our colour axis so this will be useful once we start doing some wide open throttle ramp runs but how do we use this data? Well what we can do is use this to automatically correct our VE table. |
| 11:36 | So let's right click here and we'll click on setup. |
| 11:40 | So first of all we can have our plot settings. |
| 11:43 | Pretty straightforward here, we can define the X parameter, in this case our engine speed which is by default. |
| 11:50 | We can also choose the minimum and maximum. |
| 11:52 | So I've just narrowed this down a little bit here given we are only really worried about our cruise areas for the time being. |
| 11:58 | Then we have our Y parameter so our vertical axis of course we've got lambda 1 here and again we can choose the range for that Y axis so nothing particularly special there. |
| 12:12 | On the right hand side we've got the Z axis or the colour axis so of course we're using throttle position as I've already explained. |
| 12:17 | The correction settings and the filter settings though are quite important here. |
| 12:22 | This is how we can use this data to automatically correct our VE table. |
| 12:26 | So first of all we'll go to the correction settings. |
| 12:29 | So we can choose the table to correct which in our case we're going to be correcting our VE table or fuel table 1. |
| 12:36 | The measurement source there is our lambda 1, so again pretty straightforward here. |
| 12:41 | The target, so this is the important part because for our correction, what we're doing is looking at the measured lambda versus our target lambda so target source of course is our target lambda table and then the calculation method, it's going to calculate a lambda correction. |
| 12:58 | So that's what going to be applied. |
| 13:00 | So this just does a lot of the heavy lifting for us automatically and we'll basically look at, for all of our data how close were we to our target, what was the error and then apply that error into the table. |
| 13:12 | Now that's all well and good but as I've already mentioned, garbage in garbage out here and we can do a lot of work here to give us good quality data. |
| 13:20 | At the end of the day we're likely to still get some outliers and that's where our filter settings come in. |
| 13:27 | So we come across here to our filter settings tab. |
| 13:29 | We can choose to filter this data in a number of ways. |
| 13:33 | Now for example here I've got 1 set up for throttle position already. |
| 13:38 | So we can filter for example, we don't want to allow anything below 5% throtte. |
| 13:44 | So this will help eliminate some of our gearshifts or if we're sitting stationary. |
| 13:48 | Likewise here I'm only looking at our cruise areas. |
| 13:52 | So we could eliminate anything above 60% throttle. |
| 13:55 | We can also and this is quite powerful, eliminate anything where we're seeing a rate of change greater than +/- 10%. |
| 14:04 | So you can choose these to suit anything you like and basically what we're trying to do here is eliminate any sharp throttle transitions that would bring in transience, so that's quite important. |
| 14:15 | We can also bring in another 2 filters here and these can be anything you like, maybe you want to filter when the engine temperature is below a certain level or the air temperature is above a certain level, whatever you want, basically to focus in on getting really good quality data there so that's quite important. |
| 14:33 | The other option we've got available here and I won't dive into this in too much detail but we can also filter based on how far away from the centre of a cell we are. |
| 14:43 | And this is just a case of reducing the effect of interpolation if the data that we're gathering is basically between 2 of the adjacent cells then it's hard to get good quality data so we can basically define how close to the centre of the cell we must be. |
| 15:00 | So once we've got all of that, we'll click OK there and basically we can right click here and we can then go apply correction. |
| 15:09 | So when we apply correction it'll correct that fuel table 1, if we come back to tuning and we can see now the area where we've got changes that have been made, all of those changes are highlighted and that will automatically change the VE numbers in our table. |
| 15:26 | Now this is a really good way to make quick coarse changes to a lot of data and again the more data we'e got, the more accurate we can be with this. |
| 15:35 | It is however still an iterative change so you're unlikely to get everything absolutely perfect in just one set of adjustments so you might need to do this 2 or 3 times. |
| 15:45 | It may also require some smaller manual adjustments but this is a really good way to get your data into the ballpark or the VE table into the ballpark quickly under real world conditions. |
| 15:57 | It's also important to be a little bit realistic on what we're expecting here with the air/fuel ratio numbers because they are not going to track perfectly our target under all conditions. |
| 16:09 | So generally if I'm within about +/- 1-2% of my target air/fuel ratio, I'm going to be pretty happy with that, I'm going to call the job done. |
| 16:19 | So that's the process we go through there to fine tune the cruise and transition areas of our VE table. |
| 16:26 | We're going to go out now and gather some data under wide open throttle conditions and see how we can use this to highlight and modify the wide open throttle areas of our VE table so let's get back out on track now. |
| 16:40 | Alright we've got rid of our heat soak just like we did previously. |
| 16:42 | Coming up to a long section of straight here, we've got our boost controller turned off to run wastegate spring pressure. |
| 16:48 | Just coming up to the last corner leading onto the straight, I'm in third gear so we'll just get us down below 2000 RPM and what I want to do here is smoothly go to wide open throttle. |
| 16:59 | We're going to just use the graph logger here that we used during our ramp runs on the dyno. |
| 17:16 | Right so we've gathered that data there and again we could have used the logger, the F8 function to log to our PC just like we did for our cruise areas of the map but in this case we're really looking primarily at our air/fuel ratio data initially. |
| 17:32 | So we can just use the laptop tuning software, the EMtune software the same way we did on the dyno, just focusing on the time graph that we have on our tuning page. |
| 17:43 | So again let's head back into the pits and we'll have a look at that data and see what we can learn. |
| 17:49 | OK so looking at our graph here we're of course looking at how closely our green line here follows our magenta line here which is our target and we can see for the most part it's actually doing a pretty standup job here. |
| 18:03 | We can see that right up the top here we are possibly just a touch richer than our target, we'll click on that and we can see our target there, 0.80, 0.78 is our measured so we're about 2% rich there right in the top end and we start to move there from around about 6200 RPM. |
| 18:24 | So generally if we've got a repeatable situation like this, we can come up to our VE table here, look at the areas where those changes need to be made, probably make these changes at 100% throttle and we'll follow that down to 80% throttle. |
| 18:41 | We'll highlight through and in this case it's from about that point all the way through and we'll enter a value of 0.98 and the multiplication symbol there and that will follow that change through. |
| 18:52 | Again this can be a little bit iterative so we're going to want to gather some data, make a change like that and then go out and confirm that change, we might need to do this a couple of times to get us onto our target. |
| 19:04 | And again if we have done our job properly on the dyno, we should be pretty well close to our target anyway, it should be there or thereabouts but this is why we're here at the track because we do often see some minor discrepancies. |
| 19:16 | Notice the rest of that plot though, everything's looking pretty good here. |
| 19:20 | We're always within about 1 or 2% of our target so I'm pretty happy with that. |
| 19:25 | So from here I'd go out and confirm that change. |
| 19:29 | We're going to jump ahead a little bit here and we'll look at our higher boost settings. |
| 19:33 | As we've already seen on the dyno we've got multiple boost settings here. |
| 19:36 | For simplicity though I'm just going to jump straight to our maximum boost setting and we'll go out on track again and see what our data looks like under those conditions so let's do that now. |
| 20:02 | Alright we've got rid of our heat soak, we're coming back up to the long straight section of track here. |
| 20:07 | Back into third gear, making sure that my boost controller setting is on the highest boost setting, we'll get back down to 2000 RPM and we're going to get around this corner and again just go through to full throttle and have a look at our data. |
| 20:36 | Alright so clean run all the way through to the rev limiter there and in fact we just touched the rev limiter. |
| 20:43 | We've paused our graph logger, let's head back into the pits and we'll see what our data shows us. |
| 20:49 | Alright let's start by having a look at our air/fuel ratio data. |
| 20:52 | And we can see that for the most part, it's pretty good, it's pretty close to our target. |
| 20:57 | We do have just a little lean spike here, if we click on that we can see that we're about 0.80 for a target of 0.78. |
| 21:06 | Likewise right in the very top end, we are actually very slightly richer than our target, 0.78 target, we're 0.77. |
| 21:15 | Now again we do need to be a little bit realistic here. |
| 21:18 | If I'm within about 1% of my target I'm going to be pretty happy and you do need to understand that just due to small variations from one run to another, we're not always going to see exactly the same air/fuel ratio data. |
| 21:31 | However, when we are on boost in particular, while yes we'll see some variation, I'd like to keep my target as the leanest air/fuel ratio we're likely to see. |
| 21:40 | In this case, 1% I'm not going to be too worried about in the top end. |
| 21:44 | We're going to head back out on track though and just confirm if the lean area down here at lower RPM, in this case specifically that little spike there, occurred at about 4700 RPM, if that is realistic and it is consistent then I'd be inclined to go back and make some adjustments to the secondary load table at the boost that we are seeing. |
| 22:08 | At the same time it is also worth just understanding what boost pressure we are seeing here. |
| 22:13 | We can see at that particular point our manifold pressure there sitting at 270 kPa, that is around about our peak there. |
| 22:20 | We can move through there and see what our boost did, we can see right at the top end just like we saw on the dyno we're dropping down to about 250 kPa or around about 22 psi. |
| 22:31 | So again just making sure that our boost pressure is meeting our targets. |
| 22:35 | Likewise we will just head over to our ignition and our main ignition table here and while again as I've explained during the worked example I'll be audibly listening for knock, this is a good quick representation here to make sure that our knock data is not exceeding the threshold, it'll be individual cylinder knock data is not exceeding the threshold, we can see that it isn't so at this point I'm comfortable the ignition control, the ignition timing is under control, we've got no knock occurring. |
| 23:02 | Our boost pressure is under control. |
| 23:05 | For the most part our fuelling is under control and again that is just an iterative process, it's likely we may need a couple of goes out on the track to get the air/fuel ratio exactly where we want it at each of our boost set points but it's just a rinse and repeat of what we've seen so far. |
| 23:21 | So at this point our worked example is complete, we've got a car that's been properly tuned on the dyno delivering great power and torque, we've confirmed that everything we saw on the dyno stacks up under real world conditions here at the track so our job is complete. |
| 23:37 | If you do have any further questions on this worked example, please ask them in the forum and I'll be happy to answer them there. |
