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Practical Standalone Tuning: Step 9: Full Power Tuning

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Step 9: Full Power Tuning

17.06

00:00 - The next step of our tuning process is to begin performing some wide open throttle ramp runs to help fill in the areas of our fuel and ignition tables out at higher RPM that so far we haven't looked at in steady state.
00:12 Now what we're going to do here will be an iterative process.
00:15 Because we've only tuned out to 4500 RPM, we can begin by just stepping out slightly into those untuned areas and maybe performing ramp runs out to 5000 or maybe 5500 RPM.
00:27 As we start building up the fuel and ignition tables in those untuned areas, then we can continue our runs out further until we get all the way out to our rev limit.
00:36 Depending on your level of comfort with the dyno tuning process, you can either set the dyno to perform shorter ramp runs.
00:43 Or alternatively you can remember that if something isn't quite going right as you move out into those untuned areas, it's very easy to simply back off the throttle and abort the run, make the changes in the ECU software and then come back and revisit the run again.
00:59 What we're going to do here is start by leaving our ignition timing conservative and we're going to get our fuelling dialled in first. Once our fuelling's dialled in then we're gonna come back and we're going to optimise our ignition timing.
01:11 Before we do this though we do want to ideally start with conservative ignition timing.
01:16 We'd rather be a little bit rich with our fuelling.
01:20 So we're going to make a couple of broad changes here to the fuel and ignition tables that we've already looked at and let's just jump into our SCal Software.
01:28 For a start what I'm going to do is in the wide open throttle areas of the ignition table, in this case above 1400 millibars and above 2000 RPM, what I'm going to do is use the math subtract function, I'm going to remove two degrees out of the table there.
01:46 So this is just again, making the ignition table, just a little bit more conservative.
01:51 What we'll do now is we'll come out of our run mode ignition and we'll go into our run mode fuelling.
01:56 And we're going to broadly do exactly the same thing here, what we'll do is highlight the entire table above 1400 millibars, 2000 RPM.
02:05 We'll use the math multiply and we're just going to add in this case 3% fuelling so we're just going to richen the air fuel ratio just slightly.
02:14 OK so let's get our engine up and running and we'll perform our first run.
02:19 During this process we'll be using audio knock detection equipment just so I can monitor and listen for detonation.
02:59 So there's our first ramp run complete.
03:01 You can see that we ended up with 143.9 kilowatts at the wheels.
03:05 On the top here we've got our boost pressure in millibar.
03:07 We're just using this to monitor and ensure that our boost pressure is safe.
03:12 We've been targeting around 2000 millibars, one bar of positive boost pressure, we're not going to be focusing here today in our worked example on actually adjusting our boost pressure so that's simply for monitoring purposes.
03:22 You'll notice we've got our lambda or air fuel ratio, we can see this starts at about 0.95 lambda at the beginning of our run, and it drops down nice and smoothly until we get to about 0.82 at the end of our run at 6000 RPM.
03:36 Now it's important though to remember that we are running the Syvecs ECU in closed loop fuel control mode.
03:42 So with that active the closed loop control will be making changes to the fuel delivery in order to account for any errors that it's seeing.
03:50 So in order to get the full story what we need to do is actually have a look at what that closed loop fuel control multiplier is doing.
03:58 And we can do this by downloading and accessing or analysing the log file from the ECU, so let's have a look at that.
04:05 Firstly in the top group here we've got our blue line here which is our RPM so we can see this during the area of the actual ramp run.
04:15 Our purple line above this is our manifold pressure.
04:19 Then our next group down we've got our lambda, so this is our measured air fuel ratio.
04:24 That on its own isn't too much use though.
04:26 What we really want to do is have a look at the lambda versus our target which we've got down on this group here.
04:33 So the blue line is our measured air fuel ratio, and the yellow line is our lambda target.
04:38 So what we can actually see is that the two match really really nicely there, right at the end of the run there, we can see that our lambda is just a touch leaner than our target.
04:48 We have a target of 0.82 and our lambda's sitting at 0.822 Now that doesn't tell the whole story though, if we look our next group down we have our closed loop fuel multiplier, so this tells us what the closed loop control was doing in order to achieve that.
05:05 In this case with our closed loop multiplier, you'll remember a value of 1.00 means it's making no corrections so this is what we ideally want.
05:13 If we look at everything from the start of the run here, you can see right at the very start of the run, our closed loop multiplier is sitting at 1.02, so we're adding 2% fuel.
05:23 That's pretty damn close to our target.
05:24 As we move through the run we can look at what's happening and you can see here at 3000 RPM we're sitting at 0.99 so it's removing 1% of fuel.
05:33 So at the moment, nothing that I'm overly concerned about.
05:36 What we can see here though is there is an area where there is a positive trim being added and this starts at around about 4400 RPM and we can see that at the moment it's adding 4%.
05:48 We actually end up at 5000 RPM adding 7% fuel.
05:53 So we can use this data, we can use the MAP value here as well as the RPM value along with our closed loop multiplier in order to make changes to our fuel table so what we're going to do is start at the area where we just start beginning to add a little bit of fuel.
06:08 So in this point here, our fuel multiplier's 1.01 so we're adding 1%, not overly worried about that, but let's just have a look at what we can do.
06:15 At that point we're sitting at 3900 and basically 2000 millibars, so let's add 1% to that particular site.
06:22 We'll jump back into our SCal software.
06:26 So what we're going to do here is go to 2000 millibars and 4000 RPM.
06:31 And what I'm going to do is actually make this change from just slightly below that, I'm going to actually make the change from 1800 millibars and above and we're gonna use the math multiplier and I'm going to multiply this by 1.01 Let's move back to our SView software, and we'll go through to our next point.
06:48 What I'm going to do here is essentially just look at each of the RPM break points in our table.
06:53 So the next point I'm going to come up to here is 4500.
06:57 We can see that we're still at about 2000 millibars there.
06:59 And this time we can see our closed loop muliplier is sitting at 1.05 so we're now adding 5% so we're getting a little way off.
07:08 So let's move through to 4500 RPM, again I'm going to make that change form 1800 millibars and above and we'll use math multiplier and 1.05 We also can in this instance interpolate that change back down.
07:23 So we can come back and have a look at any of these areas if we are seeing a significant difference from what we actually found in steady state.
07:31 We're really focusing for this part of the tuning, on the wide open throttle operating area.
07:37 So we'll just continue here.
07:38 Our next point in our table, we come up to 5000 RPM, and we can see that our closed loop multiplier is now 7%, 1.07, we're still at 2000 millibars.
07:48 Now in this instance because we're now moving out to an area that we haven't tuned at all, rather than just making these changes in the wide open throttle operating area of the table, I'm actually going to make these changes right through the entire column.
08:04 So we'll just be adding fuel everywhere at this particular point.
08:08 Now this is because if everything works as we'd expect, if we're lean at 2000 millibars in this untuned area of our map, chances are we're also probably going to be lean at part throttle and the vacuum areas of the map.
08:20 Again we could be wrong here but we're just taking a broad guess.
08:23 We can come back later on and have a look at those vacuum areas of the map, but of course these vacuum at high RPM are areas we're only going to be transitioning through, so their accuracy is not quite as critical as the lower RPM regions.
08:37 Let's go back to our SView software.
08:39 And our next point we're going to come out to is 5500 RPM and we can see that at 5500 RPM, we're actually not adding quite as much fuel now this time, our multiplier is 1.053 Let's go back.
08:55 We are still at 1990 millibar, so close enough to 2000.
08:59 So I'm going to highlight the entire 5500 RPM column and I will multiply that by 1.053 So again we're just replicating what we're finding in our datalog.
09:10 The last point we're going to come out to here is 6000 RPM.
09:14 And at this point you can see our multiplier is also 1.05 OK let's head back to our SCal software.
09:21 So we're gonna make that change, but we're also going to extrapolate that change all the way out now.
09:27 So and for our next run we will be extending out to 7000 RPM.
09:31 So we know that we're a little bit lean, and we're just going to make that change out through the rest of the table.
09:36 With that change made, let's get up and running, and we'll see if that's corrected the errors that we were seeing.
10:05 So our second run's complete there.
10:07 And we're gone through to 7000 RPM this time, so this is as far as we're going to run the engine for our worked example.
10:14 We can see our lambda once we get up in the revs has tracked nicely along on our target of 0.82 lambda.
10:20 So again that's doing everything we'd expect, our boost is still under control.
10:23 But of course we still have that closed loop fuel control to consider.
10:27 Let's jump into our laptop software, we'll have a look at our SView datalog software from our second run.
10:33 And again what we're looking at here is our comparison of our target lambda to our measured lambda.
10:39 Again they're all matching very nicely but of course we want to look at what our fuel multiplier for closed loop control is doing.
10:46 We can see that this time our fuel closed loop control is always sitting very very close to 1.00 So of course depending on how fussy you want to be with your fuelling, you can go through and make further adjustments, for example, if we look at 4600 RPM we can see that at this point, the fuel closed loop control is adding 2.4% fuel.
11:07 So if you want to go from the start making finer changes, you can.
11:11 For the purposes of our worked example though, we're going to continue, if you want to make additional fuelling changes, it is just a rinse and repeat of what we've looked at.
11:19 What we're going to do now is we'll jump back into our SCal software and we're going to go back into our ignition timing table, our base ignition angle one table.
11:30 And you'll remember that we started by removing two degrees from 1400 millibars and 2000 RPM and above.
11:39 So what I'm going to do is to begin by adding that two degrees back in.
11:43 Of course we are going to be monitoring this for detonation, and just to ensure that we aren't suffering from any knock.
11:50 We want to be very careful when we do start making these changes.
11:53 What we're going to do is another run.
11:54 We'll overlay this run directly on top of the run we've just done and we're going to see the effect of that additional two degrees.
12:00 So let's get our engine back up and running now.
12:27 OK we've got our third run complete there with the additional two degrees of ignition timing.
12:32 And you should've been able to see, during that run, the new run overlayed directly on top of our last run.
12:38 And in particular what we're looking for is any areas where we're either ahead or behind in terms of our power.
12:44 So in particular we can see when we're looking at our power delivery, while we've added that additional two degrees of timing from 2000 RPM, it wasn't until we got through to about 4000 RPM that that additional timing actually started showing an improvement.
13:00 And the further we went through the run, the more of the improvement we saw there.
13:05 So particularly from about 5000 RPM and above we're seeing quite a significant improvement.
13:11 Now provided we don't have any knock occur, if this is the case, what we're going to do, is continue and add some additional timing.
13:18 Before we do that though, while we have dealt with the fuel tuning, we always want to have a quick look and just make sure that our closed loop control is still accurate and this allows us to simultaneously if we like, make changes to our fuelling and our ignition timing.
13:32 So let's jump back into our SView software.
13:34 And again we're just looking at our closed loop lambda trim and we can see that we're always within 1% of our target, so there's no work needed there.
13:44 Also while I'm audibly monitoring for knock, we can also have a look at our knock control worksheet and in this case we can see this particular line here is our knock threshold.
13:56 So what we're looking for is any area where the noise levels from the individual cylinders exceed this threshold.
14:03 In this case we've got no knock being monitored.
14:05 This backs up what I'm getting audibly.
14:07 So what we're going to do is go back over to our SCal software.
14:10 Now for a start what I'm going to do is I'm just going to remove two degrees of timing again from that area below 3000 RPM.
14:18 That didn't help us, we didn't see any gain in torque there, so there's no point having that timing in there.
14:24 So I'm using the math subtract function, taking two degrees out from there.
14:28 Then if we look back across, it was from about 5000 RPM and above we really started seeing an improvement from that timing, so what I'm going to do there, is just add another two degrees.
14:38 Now I'm making quite a broad change here.
14:40 You can of course make finer changes, of perhaps a degree at a time.
14:45 The other thing you want to do is make sure that you don't end up with any large steps in your map.
14:50 So what I'm going to do here is just smooth this out, I'm going to also add some timing down into the lower load areas and then I'm going to add a degree through at 4500 RPM just to continue a smooth shape to our table.
15:04 OK with that second change done, let's get up and running again, and we'll see what the effect of that additional timing was.
15:31 So with our next run complete we can see that we have picked up a little bit more power, we're up to 155.7 kilowatts at the wheels.
15:37 Now importantly as well we can see that that additional timing that we added in there from 5000 RPM and above, has still shown an improvement in our power and our torque.
15:48 We can see particularly from about 5500 RPM and up, we're seeing quite a significant improvement in our power.
15:54 So with this in mind, provided that we're still not seeing any sign of detonation, we'd continue and go further and add more timing as we are moving towards MBT.
16:04 So this is simply an iterative process, we're going to rinse and repeat what we're looking at here.
16:08 Always being careful that we are monitoring for knock.
16:12 If we find that the engine is starting to knock, then we need to retard the timing and provide a safety margin there, just to ensure that the engine is going to remain reliable in operation.
16:22 So this concludes our full power ramp run tuning step of the 10 step process.
16:29 From here we'd take the car out into the real world, and perform some testing on the road, or in this case because it is a race car, we'd perform some data logging at the race track, just to allow us to confirm and back up everything that we've seen here on the dyno.
16:42 Particularly with the advanced data analysis inside the Syvecs ECU.
16:47 This makes it very very easy to both monitor our air fuel ratio by virtue of the closed loop fuel control multiplier, as well as the knock, using the built in knock control strategy.