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Practical Standalone Tuning: Step 10: Confirming a Tune on the Road/Track

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Step 10: Confirming a Tune on the Road/Track

16.28

00:00 - So the last part of the tuning process once we've got the car off the dyno, is to confirm the tune on the road and make sure that everything we're seeing on the dyno matches what we're actually seeing out in the real world.
00:13 Now there's two parts to that, one is confirming the tune, the other part is getting access to the parts of the map that we couldn't when we were on the dyno.
00:23 That's the very light throttle areas.
00:25 As I said, when we're on the dyno, you can't get down into those very light load areas which is what you'll be accessing when you're just cruising along the road, barely touching the throttle.
00:36 Basically if you take you foot off the throttle far enough on the dyno, the dyno just slows down because it needs a certain amount of inertia to keep it running.
00:44 So on the road we can access those areas and those are the parts that we're going to want to focus on.
00:51 The other thing we're going to be doing is making sure that the cruise mixtures that we saw on the dyno are correct.
00:57 If we've done our job properly on the dyno, everything should be pretty close anyway, but we just wanna confirm and make sure that everything's right.
01:05 Things to do while we're road tuning is to make sure that all of our throttle applications are nice and smooth.
01:14 If you make large abrupt changes to the throttle opening, what you're going to end up getting is acceleration enrichment coming in, and that's going to confuse matters.
01:23 When you're road tuning, you obviously need to be able to focus on driving the car foremost, that's the most important job.
01:31 And we've got a Motec CDL3 fitted to this car, which is displaying our lambda value right there on the dash so I don't need to be looking at a laptop screen while I'm driving the car.
01:43 Now it's helpful to have someone else drive with you while you're doing this so they can make changes to the fuel map, and you can just concentrate on driving.
01:54 The other option you can do is to drive the car, datalog what's happening, and then go back through your datalog file and make changes to the map based on that datalog file.
02:05 And that's what we're gonna do now.
02:07 So we'll just go for a drive and we'll see what exactly our air fuel ratio's doing as we're driving.
02:20 So what I wanna do, basically the car, because this is a road car, it's going to spend a good portion of its life cruising.
02:29 And that's the area we want to focus on first of all and make sure that we've got good fuel economy in that area.
02:37 The full throttle stuff, for a road car it's probably only going to spend maybe 5% of its time at wide open throttle so those areas aren't quite so dramatic and aren't quite so important.
02:52 One thing that is important when you are road tuning, is to make sure that you give the car a chance for all of the temperatures to settle while you're driving before you start making changes.
03:04 If you sit stationary for a long period of time, it's quite common for the fuel in the rails to heat soak and the engine bay temperatures to become quite hot and that can influence the mixtures when you first start driving.
03:17 So generally before I start making changes, I'll just drive the car at a normal speed for a minute or two and let all of the temperatures settle back down.
03:27 Now I'm just driving along at sort of a normal cruise and we're doing around about 2200 RPM.
03:34 And looking at the lambda that I'm seeing on the dash, we're sitting about 1.0, 1.01 and basically we're pretty much exactly where I wanna be on target, so it's doing a really good job, and that's what I'd expect.
03:49 If we were seeing a discrepancy between the target and our actual lambda, I would stop and make changes to the areas of the map that I've been accessing.
03:58 A little tip there is while you're driving, you can press the spacebar on this particular ECU and it will jump to the site or the cell in the fuel map that the ECU is accessing at that particular time.
04:13 So that means you don't actually have to keep your eyes on the laptop screen while you're driving it, you can use that function to figure out where exactly the ECU is accessing and make changes to that.
04:26 Again as with on the dyno, we do want to make sure that when we are making changes to the mapping, we are in the centre of the particular cell.
04:35 And we can use the datalogging to help with that.
04:39 So one part of the road tune is to confirm our cruise mixtures.
04:44 Now we're also chasing a moving target.
04:48 The air fuel ratio is never going to be 100% stationary so if we're targeting say for example lambda one, I would normally allow a small variation.
05:00 Maybe plus or minus 0.01 lambda, and that range I would call good, I'd be happy with that.
05:07 If you try and chase a very accurate target of 1.00 you're gonna be disappointed and you're gonna be chasing your tail because the actual lambda is always going to move around a little bit.
05:20 So as long as I'm sitting within a range of 0.01 plus or minus, I'm gonna be happy with what I've got.
05:27 OK so once we've confirmed the cruise area, the next thing we're gonna be looking at is getting down into the very light load ranges of the tune which we couldn't get to on the dyno.
05:37 And for this example here, we're looking at 2500 RPM down at 30 kPa, and you can see that we're actually pretty good.
05:51 If we come down though to the next site down which is 20 kPa which we haven't tuned yet, you can see the number's quite large, 57 and I need a little bit more RPM just to get into there.
06:05 And you can see unsurprisingly as we come through that area, we're very rich, we're down at 0.82 so this is the area that's quite important to spend some time getting right.
06:16 And there's a few ways you can do that.
06:18 Again you can do it using datalogging, so you can actually just drive the car through those areas and use the datalogging to make adjustments.
06:26 You can also use the quick lambda function here on the M150 which I've found really helpful and we saw I was using that on the dyno as well.
06:36 So we'll just drive through there and we can press the Q key and that's going to get us close.
06:46 Just like when we're on the dyno though, before we actually made changes to that particular site, we could've sped up the process by copying the number from the load zone we've just tuned above it, copying that number down, as we reduce load we can expect our volumetric efficiency to decrease.
07:05 So we know that the number in that particular 20 kPa site is probably likely to be at least the number from the 30 kPa zone or lower.
07:18 So you can see now we've got down to about 0.92 so we're getting quite a lot closer to our target.
07:24 So it's just an iterative process of driving along and making changes to those particular sites, until we've reached our target.
07:35 And what we'd do is we'd concentrate on getting all of those sites in the low load areas that we couldn't access on the dyno, tuning those, and getting them spot on to exactly what we want to see.
07:46 There's a good amount of fuel economy to be gained in making sure that those areas of the map are perfect.
07:53 Again these are the areas that a road car's going to spend a lot of its time driving in.
07:57 So I'm not gonna do the whole map now, that's gonna take a lot of time, and we don't need to see it all, it's just an iterative process.
08:07 The next step I'm going to do is we're gonna look at the full throttle wide open throttle tuning.
08:12 And fortunately this car's not particularly powerful and that makes our job pretty easy from a wide open throttle tuning perspective.
08:20 Just for the example here, we are on a public road, and we're going to make sure that we stay under the speed limit.
08:28 I recommend if you've got a powerful car, that you do this tuning on a closed road or a racetrack and I recommend that you use the datalogging to aid you with that tuning.
08:42 And we're gonna just see exactly how easy that is now.
08:45 So all we wanna do is get into normally sort of third or fourth gear but just to keep our speed down I'm going to use second gear, and again this car's not overly powerful so traction's not an issue.
08:57 And we want to datalog a full run, basically replicating what we saw on the dyno.
09:02 I'm gonna go one step further though, I'm actually going to do a gear change and go into third gear.
09:07 So we're gonna start from 2000 RPM and basically all we need to do is go to full throttle.
09:26 OK so that was run through second gear and just a little bit into third gear.
09:31 And all we'd do now is stop and we can review the datalog file and make any changes based on that.
09:41 Now normally while we're doing that, I would be listening for knock.
09:47 This particular car as we already know, has a fairly accurate electronic knock measuring system and we can see that on the laptop datalogging as well.
09:58 So I don't need that, but for normal cars, we'd be using knock detection equipment.
10:02 So now if we look at the datalog file, and we can zoom in on that.
10:06 The things we're going to be interested in looking at is our exhaust lambda versus our fuel mixture aim.
10:15 And we can look at that, we've got our throttle position here, and we've got our engine speed here.
10:22 We can look at that fuel and lambda and decide if we need to make changes to our fuel map.
10:30 And you can see for the most part in the low area of the map we cycle pretty closely around our aim lambda.
10:38 And again I'm using that same sort of plus or minus about 0.01 tolerance or range for my tuning to make sure that there is gonna be some fluctuation that I'm going to tolerate.
10:52 However what we can see here is up in the top end, particularly up here at what is about 6500 RPM, we're actually quite rich, we're at 0.863 whereas our aim lambda's 0.89 So we're around about 3% rich there.
11:08 And you can see again when we go into third gear, we're also still a little bit richer than target.
11:15 Now we can use that datalogging, if we drop back to the main fuel screen, the main VE table, we can see that there is a cursor that'll actually come up here, this little ghost cursor, which shows us the exact area of the map that was being accessed at that point in the datalog.
11:35 So if we look at our point here at 6500 RPM that we were at 0.863 lambda, we can go through and we're right here unsurprisingly at the 100 kPa zone at 6500 RPM.
11:51 So we've got some options there, we can use our have over want equation.
11:55 I know we're around about 3% rich there, so I would multiply that particular zone by 0.97 press the multiply button, and that's going to correct for that particular point.
12:07 We'd then go and do another run on the road and make sure that our lambda matches our target.
12:12 So it's an iterative process, exactly the same as what we did on the dyno, and you can really accurately zero in on your target lambda and get your tune dialled in perfectly just from the datalogging.
12:25 It's a nice safe way to do it because you don't have to worry about the actual laptop, you can just drive the car normally, and then pull over to the side of the road, and review your datalog and make the changes based on that.
12:37 So it'll take you a little while to dial in that map.
12:39 What's important though is you're now tuning the car in the real world.
12:43 So you're on the road, you're getting the same air flow, the same load the car will obviously see on the road and sometimes that does vary slightly from what you see on the dyno.
12:54 That's why I really like to back up the dyno tune on the road.
12:57 Now the last part of the puzzle we talked about is tuning in the transient throttle response.
13:03 I'm not gonna go through this on the M150 because the fuel film model is quite different, quite unique to the M150 and it's not like any other ECU you're likely to come across.
13:15 The process you would go through though, would be to just drive the car at each of the load zones the you have access to in the fuel film.
13:25 Or in the acceleration enrichment mapping.
13:30 And I normally do this in second gear.
13:33 So I'd be starting from quite low RPM around 2000 here and what you wanna do is go from a steady state cruise and then just instantly open the throttle all the way to the floor.
13:45 And you wanna be watching what the air fuel ratio does as you make that change.
13:50 And also feeling how the car responds.
13:53 Sometimes the delay, it's only a very small delay, but the delay in the reading from the air fuel ratio sensor won't match exactly what the engine's actually doing, so it's important to feel whether the car is responding crisply or whether it's bogging in when you open the throttle quickly.
14:14 So basically you wanna check that at each point in your map so I would go from 2000 RPM to 3000 RPM and basically do exactly the same procedure there, just open the throttle sharply, and see how well the lambda tracks the target.
14:36 Again once you've done that, you can actually review that in the log file.
14:43 And we'll have a look at that.
14:47 And you can see here from cruise, our aim lambda drops down to 0.92 We actually go slightly rich there, we go to around about 0.86 which is a little richer than ideal and then it drops back to our target pretty quickly.
15:02 You can actually see here once I come off the throttle here, the ECU actually goes a little bit rich.
15:10 So that's a decel enleanment function that would need to be addressed there.
15:16 But what we're mainly concentrating on is this amount of enrichment.
15:19 Now with the acceleration enrichment, you don't need to be super critical here.
15:25 While it's gone slightly richer than our target to 0.86 frankly that's not gonna cause any issues.
15:32 As long as it's not going so rich that the engine's bogging, I wouldn't really be too worried about that.
15:37 So we're really concentrating more on a feel thing than tracking an absolute lambda number.
15:43 It's just important to make sure that the engine is running smoothly when you put the throttle down to wide open.
15:51 So use the lambda values as a guide, but really you're concentrating on the feel.
15:58 So now that we've completed the road tune, basically that's going to give you a car that's gonna drive smoothly and perfectly everywhere in the entire map.
16:06 It's gonna give you a finished result that's better than probably what 90% of professional tuners are going to do.
16:15 Hopefully that explains the whole process and gives some more practical experience as to what you're learned from the course as well.