Practical Standalone Tuning: Step 9: Full Power Tuning
Watch This Course
$229 USD $114.50 USD
-OR-
Or
8 easy payments of only $14.31
Instant access. Easy checkout. No fees.
Step 9: Full Power Tuning
1.02.57
| 00:00 | - Alright we can now move onto the 9th step of our 10 step process where we're going to be addressing the full power ramp run tuning and we're going to be doing this in a couple of parts. |
| 00:10 | We're going to begin by roughly or coarsely optimising the VTEC changeover point. |
| 00:16 | We're not going to have it perfect at this stage but we're just going to get it in the ballpark, ideally it'll be within a few 100 RPM of the correct VTEC changeover point. |
| 00:26 | The reason we want to do this is it's going to save us wasting time needlessly optimising the VE and the ignition tables and areas that we're not going to operate in once we'e got the VTEC changeover point correctly set. |
| 00:41 | For example, no point optimising the low cam operation at let's say 4500 RPM if we were to find that the VTEC changeover point was in fact at 4000 RPM and vice versa. |
| 00:53 | Before we jump into that, we'll just have a look at a couple of other elements we're going to be using in the MTune software to help us with our ramp run tuning. |
| 01:02 | Understandably we can't make live tuning changes during a ramp run so we will be relying on the built in logger functionality. |
| 01:10 | This is a really nice feature in the MTune software and it is really powerful so let's have a look at how that works. |
| 01:16 | Up to this point we have been using the real time tab here down the bottom showing real time values for all of the channels that we're interested in but to the left of this, we'll see the logger tab and if we click on the logger tab, we see a real time view of the current channels that we're logging, these are over here on the left hand side. |
| 01:36 | Now as it stands at the moment, this is quite a small logger and while it's adequate, we can see what's going on, we can choose to actually drag this little bar up here on the left hand side and expand it to suit our requirements. |
| 01:49 | Now let's have a look at the channels we are logging, we've got lambda, manifold pressure RPM, throttle position and lambda target which really is enough for our fuel tuning, optimising our VE table. |
| 02:02 | Now if you want to add another parameter or maybe change those parameters, what we can do is come into the logger screen, right click and click on select channels so let's say we wanted to add lambda target, if we just type in lambda and if we spell it correctly that will also help. |
| 02:19 | We can see that we've got lambda target as one of our options and of course that tick box is already ticked because we've got that parameter already displayed. |
| 02:28 | The other element that you may want to change is the scaling on some of these channels so if we again right click and we click on channel setup and then we can come into, for example our lambda here and we can select the colour that we want that channel to be, we can also select whether we want it to auto range which is this little tick box here, or we can manually set the scaling. |
| 02:52 | Now by default the auto range tick box will be selected and while this will work, what I find is that the range that is selected then will be so great that it loses some of the detail in our lambda plot, makes it hard to see when we're maybe too rich or too lean so I like to scale that manually, I'm using 0.7 to 1.2 lambda and it gives us a reasonable range in our scale. |
| 03:17 | Now a nice feature with the logger as well is on the right hand side we can see that this little button here is saying live and it's green, we click on that it goes pink and it says pause and now what we could do is scroll back through this and see what all of the channel values were at any particular time just by scrolling over them with our mouse. |
| 03:37 | Now while it's a little difficult to see with the engine running, this also brings up a red crosshairs on the VE table so let's shut down our engine for a moment and we'll see the live blue crosshairs disappears out of the way and now we can see our red crosshairs, it's also showing in red there what the lambda was at that particular point. |
| 03:56 | So this makes it really easy to be accurate, making pinpoint changes to our VE table or ignition table for that matter because we know exactly where abouts we were in the log file or the VE table from that log file. |
| 04:10 | Alright let's just shrink this down a little bit for the time being, we'll come back to this as we go through and we can get our engine back up and running and we'll perform our first ramp run. |
| 04:20 | Just before we do actually perform the ramp run though we'll just talk about what we're going to be achieving here. |
| 04:25 | And let's head across to our dyno and we'll have a look at our dyno setup. |
| 04:29 | Now we have our start RPM and we're going to be starting this ramp run from 2100 RPM and I've actually selected here to go out to 4800 RPM and we're going to be doing this at a ramp rate of 480 RPM per second. |
| 04:44 | Now just worth talking about this for a moment. |
| 04:48 | We know that we've only tuned under steady state conditions out to 4000 for our fuel and ignition. |
| 04:53 | Yes we've kind of taken a bit of a stab in the dark at what our fuel table should look like above that RPM but there's no guarantees that's going to be right or wrong. |
| 05:02 | So generally what I'd recommend is when you are just getting started with tuning I would only extend out into the untuned areas by perhaps 500 RPM at a time. |
| 05:12 | To speed this process up, I'm going to be taking a slightly larger chunk out of this, around about 1000 RPM at a step. |
| 05:19 | It is also worth just reiterating that while you're in a ramp run, you're going to be wanting to monitor the air/fuel ratio and if the air/fuel ratio is too rich or too lean and you're not happy with it, or for that matter if you hear any knock occurring, you don't have to stay in the run, you can back off the throttle, clutch in, come back to a stop, address whatever you weren't happy with and then go again, there is no requirement to stay in the ramp run until the end. |
| 05:44 | On that note as well we'll just close down our setup on the dyno and we can see that we're going to be logging our power down the bottom here of course. |
| 05:52 | Up the top we've got our lambda and you can see I've also put a reference line in here at 0.9 lambda so this will just give me a quick visual glance at whether we are above or below that 0.90. |
| 06:04 | I'm going to know at a glance really whether we are rich or lean. |
| 06:08 | So now that we know what we're doing, we'll get our logger unpaused, we'll get our engine up and running and our fan on and we'll get our first run out of the way. |
| 06:28 | OK we've got our first run complete there and we've made 94.5 horsepower at the wheels. |
| 06:33 | Obviously nothing to write home about at this stage but of course we're really not worried about the power at the moment. |
| 06:39 | Looking at our lambda plot, we weren't too bad here, we can see we've got this lean area here, we move a little bit richer than our target but actually considering we are moving out into that untuned area, we're already actually pretty close to the money so not too bad there and that allowed me to stay in the throttle for that complete run. |
| 06:57 | Let's jump into our MTune software though and have a look at our logger for a little bit more detail and first of all what I'm going to do is just go to a 2D only view just so we're not going to be having our 3D table in the way and we'll just expand this out, we can get a better idea of what's going on, obviously our yellow trace here that I've just gone over is our RPM and our pink trace here is our lamba. |
| 07:24 | We've got our orange trace here which is our target so we can see that we've got a few areas that do need a little bit of attention here but for the most part we're actually pretty good. |
| 07:34 | We can see that we're a little bit rich here out into that untuned area though, out at sort of what are we, 4600 RPM, out to 5000 RPM, or 4900 RPM, we can see we're a little bit richer than our target so that's a nice safe place to be. |
| 07:50 | I will just mention here that despite the dyno setup showing we're only going to 4800 RPM, we can see our maximum RPM there was actually just under 5000 so not uncommon depending on your dyno setup to see small discrepancies like this. |
| 08:05 | OK so let's look at what we're going to do. |
| 08:08 | First of all we're going to fix some of these fuelling issues or at least try to. |
| 08:12 | So we can see our first area here that's a concern, 0.887, let's call it 0.89, our target 0.92 so we're around about 3% rich. |
| 08:21 | Now interestingly if I just come vertically up here that'll leave the cross hairs on our table and what we can see here is this is actually occurring right in between two of our cells. |
| 08:32 | We've got a column at 2000 RPM and a column at 2500. |
| 08:37 | Now let's have a little bit more of a detailed look here. |
| 08:39 | If we come to our logger where we are at 2000 RPM right in the middle, we are really close to our target, we're 0.908, let's call it 0.91 and our target of course 0.92 so we're only actually 1% rich here. |
| 08:52 | If we scroll through to 2500 RPM, we can see that again we're really close to our target, 0.90 vs 0.92 so that rich area is actually happening in between. |
| 09:03 | Likewise we've got this lean area here and that is occurring again exactly in between our cells. |
| 09:10 | That's no problem, we do see this quite often so let's have a look at how we can address this. |
| 09:14 | First thing we're going to do is add a couple of additional break points. |
| 09:18 | Let's add one at 2250 so we'll right click on the 2000 RPM column here and we want to click on insert column or row after. |
| 09:28 | Now what that will do is immediately interpolate so essentially the numbers in that new column are there, going to be in between the two at 2500, they have no impact on the tuning as they are so that change will have no impact on our running at the moment. |
| 09:42 | Before we make some changes, let's do exactly the same between 2500 and 3000 RPM which was our second break point that we had issues with. |
| 09:50 | Alright so we know that we are a little bit rich here at 2250 RPM, let's just leave our cursor in the right spot there. |
| 10:00 | 2250, what I'm going to do, I'm only going to highlight the wide open throttle operating area at 90 and 100 here, we're around about 3% too rich so what we could do is enter a value of 0.97, the multiplication symbol, press enter, that will take 3% out there. |
| 10:16 | Let's have another look here, and if we get back into the middle of our 2000 RPM, we are very slightly too rich there as well, maybe about 1% so let's make a small change there as well, 0.99, multiplication symbol will take 1% out. |
| 10:33 | What I'm going to do is essentially just scroll through now, we get into the centre of our 2500 RPM zone here, again we're very very slighty rich but we are on the way to going lean so I'm actually going to leave that for the moment. |
| 10:46 | Our lean spot here occurs at 2600, 2750 RPM, we're 0.97, target of course 0.92 so we will change that, we are 5% too lean so enter a value there of 1.05, multiplication symbol will add 5%. |
| 11:04 | And then when we get to our 3000 RPM zone, again we're actually just a little bit lean here. |
| 11:10 | But as we move through by the time we're at about 3100, we're actually back to our target so let's just leave that for the moment. |
| 11:19 | If we're lean, it's only going to be within a percent or so so I'm pretty happy with that. |
| 11:22 | Through this area here up to our 4000 RPM zone, we're pretty good, we do move rich here at 4000 RPM. |
| 11:29 | Remembering we haven't optimised our VTEC changeover point so if we do find that our VTEC changeover point wants to be 4000, kind of all bets are off here but we want to get a bit of an idea with the fuelling right, of what our power and torque will be so let's fix that up. |
| 11:44 | Again 4000 RPM is within our tuned area so I'm only going to make these changes to the wide open throttle operating area, we are 0.88 to a 0.902 target so that means we are 4% rich so 0.96 will fix that or should fix that with the majority of it. |
| 12:04 | Let's move out to 4500 RPM now and we can see 4500 RPM we actually pretty much come onto our target of 0.90 and then as we move above, 5000 RPM we are maybe about 1% too rich. |
| 12:19 | I'm not too worried about that but let's just for the sake of completeness, multiply the entire column here at 5000 by 0.99. |
| 12:27 | Now the reason I'm multiplying the entire column here is because remember we haven't steady state tuned here, we're working on the basis that if we are too rich at wide open throttle, that entire column is most likely to be too rich. |
| 12:40 | Don't worry though, we will be coming back and addressing this once we've got our VTEC changeover point optimised. |
| 12:45 | Alright so that's our first round of changes, let's get our next run underway and we'll be able to see if we've corrected those errors. |
| 13:01 | Alright we've got our second run underway, we actually ended up recording slightly less power this time but again we're not too worried about that, looking at our live trace of lambda during that ramp run, looked much closer to the mark. |
| 13:12 | Still got a little lean blip here but everything else is looking pretty good. |
| 13:16 | For a bit more detail though, let's jump back into our logger in our MTune software and what we can see here is that for the most part, if we just scroll through here, we are sitting within around about 1% of our target. |
| 13:30 | If anything through this region here, we're probably maybe a little bit richer than I need it to be, certainly from about this point here, 4300 RPM and above, we've gone a little bit rich there so we might want to address that. |
| 13:44 | We've still got this little lean hole here but realistically we could go and make some more changes to this. |
| 13:53 | What we can see now if we come up into our VE table is again frustratingly we are actually still now between zones, we're between 2500 and that new zone that we created at 2750. |
| 14:04 | So there's a couple of ways we could address this, of course we could add another break point, that'd be easy enough to do but we may have found that the 2750 RPM break point we added in wasn't quite where it needs to be, perhaps that actually wants to be closer to 2600, 2650 RPM. |
| 14:21 | That will give us the ability to remove that lean spike, however we also don't need to necessarily chase our tail on such a small lean spike there, particularly when it is down at only 2600 RPM, there's no real stress on the engine at this point, we're transitioning through it so quickly so I'm not actually particularly worried about this, it's close enough to the mark for my liking, for our purposes at the moment. |
| 14:49 | So what we will do though is now make some changes to our VTEC changeover point before we go and sort of chase our tail, really dialling in this fuel table. |
| 15:00 | Again all we're wanting to do at this stage is get our fuelling at least in the ballpark, we of course haven't even changed our ignition timing. |
| 15:06 | So what we're going to do is save our run and we'll come over to the dyno screen and do that and we will call this run VTEC 5000. |
| 15:19 | So this is important just to give it a sensible name so we can reference that later on. |
| 15:24 | Let's come back into our tuning software here, we'll get our live graph unpaused, our logger unpaused and we'll come into our VTEC output so we know we've got this at 5000 RPM at the moment and what we're trying to do when we are optimising the VTEC changeover point is generally I want to have the VTEC changing over much higher or at least higher than I expect the VTEC changeover point to ultimately want to be and then much lower, we'll end up with two graphs on our dyno that should cross and the correct or optimal VTEC changeover point should be where the two cross over. |
| 15:59 | There will be some fine tuning to go but again that's going to get us coarsely in the ballpark. |
| 16:04 | So you may be thinking at this stage, well we'll just set the VTEC changeover point to turn on at 500 RPM so it's on the whole time. |
| 16:11 | Well that's going to create some problems because the VTEC mechanism is engine oil pressure driven and if we're bringing it on too low, first of all we probably won't have enough engine oil pressure to actually function it and it does drain oil pressure away from the bearings which could potentially do some mechanical damage so what I want to do is just turn it on a little bit lower so let's say we want to turn that on at maybe 3500 RPM. |
| 16:36 | Generally in my experience, I haven't found a point where the VTEC will want to operate below that so that's probably a good enough test. |
| 16:46 | So let's get another run underway here. |
| 16:48 | Remembering that now we're going to be switching to high cam at 3500, this will affect the engine's volumetric efficiency so we need to be monitoring this. |
| 16:56 | If the engine does go lean which it might likely do we may need to back off and actually make some changes so let's see how we get on. |
| 17:14 | Alright so we've got our run complete there with our VTEC changing at 3500 and looking at our lambda plot, we can see that right at our VTEC changeover point, we've essentially seen our lambda go a little bit lean, 0.95, wasn't too worried about that but obviously if it goes too lean, that's a point where we'll back out, make a change and come back in and try again. |
| 17:34 | Let's have a look at our software, our MTune software and have a look at our logger and again we can see the lean spike here, we'll go up to about 0.96 lambda. |
| 17:44 | It does correct itself reasonably quickly, we actually got a little bit rich here and then we're right on our target. |
| 17:50 | Now when we are optimising the VTEC changeover point we are looking for the air/fuel ratio to go lean, that is actually a good thing because it means that the volumetric efficiency of the engine has improved So we're probably on the right track. |
| 18:03 | Before we actually try and optimise the VTEC changeover point though, I want to correct this fuelling so that we aren't being misguided by the actual power and torque because the fuelling isn't correct so let's come back to our fuel table and we can see the point where we go lean there is right on that 3500, of course that's because that's where our VTEC changeover point is and we are lean at 3500 and 4000 RPM. |
| 18:30 | So what we're going to do is make changes to those two columns. |
| 18:34 | Now here I will be making a change to the column at this stage because obviously if the VTEC changeover point needs to be 3500, that whole column is now going to be inaccurate. |
| 18:44 | Likewise 4000 RPM and you're starting to see why we didn't waste too much time steady state tuning too much further. |
| 18:51 | So in this case we were, let's just check again, 0.96, 0.97 with our target of course 0.92 so we want to add about 1.05 to that, or 5%, we'll enter that value, multiplication symbol, 1.05, let's do one more run and we'll just see if that's corrected our air/fuel ratio enough that we can start making some sense of the differences. |
| 19:25 | Alright so that's corrected our fuelling at least well enough for the purposes of our tuning at this point so we can see on our dyno, 96 horsepower this time around we can see that our air fuel ratio's still moving around a little bit but we're there or there abouts. |
| 19:39 | Pretty close to our target. |
| 19:41 | Looking into our logger, again we can see we've definitely got a couple of rich holes that we would want to be looking at and addressing but again for the purposes of our test at this point, I don't want to get too fussy with our fuel tuning, I just want to make sure that I'm in the ballpark, pretty close to my target so we can make sense of the actual power and torque values which is what we're going to do now. |
| 20:03 | So what we'll do is we'll save our second run there and we'll call this VTEC 3500 and we'll go and have a look and analyse these two logs, or two plots over the top of each other. |
| 20:17 | We've got three on the dyno screen at the moment, we want to get rid of our first tune where we were just running the engine out, getting our fuelling optimised and really what we're looking at here is our difference between our red run and our yellow run with our VTEC changeover point. |
| 20:31 | Now this is a little bit misleading, what we're looking for is the point where we see the two separate and obviously there is always some run to run variation. |
| 20:40 | We kind of see that there's a bit of a separation happening from about 3500 but if we actually look here, this is the point here where we actually start to see that yellow trace start to diverge and go up above the red trace so 3750, that's probably actually a little lower than I'd expect but let's start with that point and we're again going to come back and fine tune this. |
| 21:05 | This won't be the last time we'll be looking at this but this will get us at least in the ballpark so come back to our output configuration here for our VTEC and we're going to turn that on at 3750 RPM. |
| 21:18 | Coming back to our fuel, VE table here. |
| 21:23 | This brings us to another point, we're going to need some finer control across that VTEC changeover point so we've got zones at the moment or break points at 3500 and of course 4000 RPM. |
| 21:35 | But we want to add one in here at 3750. |
| 21:39 | So let's do exactly that, we'll add one in and we're going to actually make this, we're going to add two in here, we'll do one at 3750, at this point the VTEC has changed over so I'm going to actually add another one in here as well and we're going to change this one, by default it'll interpolate the value between but what I want to do is actually make this one 3700 so we can double click on that, 3700. |
| 22:10 | So what we've got is really tight break points around our VTEC changeover point. |
| 22:13 | At this point, this is probably a little bit irrelevant because we will be coming back and optimising the VTEC changeover point and almost certainly it's going to move a little bit from where it is now. |
| 22:23 | So typically I would leave this step until we've actually found our optimal VTEC changeover point but just for the sake of completeness, this is the process that we're going to follow. |
| 22:35 | Now we're going to look at optimising our wide open throttle full power tuning for both our fuel and ignition. |
| 22:41 | At this point we obviously have our VTEC changeover point approximately in the ballpark and know that we can run the engine out to 5000 RPM. |
| 22:49 | Obviously our fuelling is approximately where it needs to be, we're going to fine tune that and we're going to creep our engine RPM out to around about 8000 RPM at this point and then we're going to go ahead and optimise our ignition timing. |
| 23:03 | So for our next run, given that our fuelling is in the ballpark out to 5000, we're going to extend our RPM on the dyno so let's head across to the dyno software and we'll click on our setup here and at the moment we've got it coming out to 4800, let's just extend that out, 5500, we'll go a little bit further, let's go to 5700 for our next run. |
| 23:27 | So again just as we've already talked about previously, if the air/fuel ratio moves too rich or too lean, we don't like anything, it's very easy to just abort the run and make the appropriate changes and try again. |
| 23:39 | Let's get this run underway and we'll see what needs to be done. |
| 23:54 | Alright looking at our result on the dyno, 121 horsepower, little bit better than what we had previously. |
| 24:00 | For the most part our fuelling looked pretty good. |
| 24:02 | Into the untuned areas above the 5000 odd that we got to before, you can see we're moving a little bit rich but nice and safe so I'm not particularly worried, that's why I didn't back off there. |
| 24:13 | Let's jump into our MTune software and have a look at our actual results and we'll start making some adjustments. |
| 24:19 | So what we can see is first of all we've got this quite rich area here down at 3700 so this is immediately after our VTEC changeover point and then the rest of the run is looking pretty good, we've still got our little lean area that we've discussed here, right down at the low RPM area and then right at the top here we see that we start to move a little bit richer and at the top of that run there we got out to just under 6000 RPM so let's start by addressing this high RPM area here so we'll come down into our 5000 RPM zone. |
| 24:53 | 5000 RPM we're actually pretty good, we're pretty much right on our target so we'll come up to sort of 5500 RPM there, we're sitting at 0.86, 0.87 and our target 0.90 so we need to make a bit of a change to that point there. |
| 25:12 | So this time again because we're in an untuned area, we're going to make the change and apply it to the entire column instead of just our wide open throttle running area so we were, I'll just check again, we were at this point here, 0.87 so we are 3% richer than our target so 0.97 multiply, that's going to correct that error. |
| 25:38 | Now we didn't quite get into the middle of that 6000 RPM column but we know that we are heading now quite rich and if we're looking here, 0.80 so we're about 10% rich at that point. |
| 25:50 | So I'm not necessarily going to want to take an entire 10% out, if we end up over estimating then we could end up a little lean so it's again just safer to be a little conservative and this change I'm not going to just make to 6000, because we've got that shape that we've added into the curve, I'm going to actually make this change at 6000 RPM and all of the cells above. |
| 26:11 | So we'll start by taking out let's say 6% so not as much as we theoretically should but again should get us close to the mark and this will help us not go too lean. |
| 26:23 | Now let's just have a quick look here and again there's not a lot of point being super fussy at this point because we may still be moving our VTEC changeover point around but at this point you can see we're around about 7% too rich so let's just address that at 3700, so this is just before the VTEC changeover point. |
| 26:43 | So at this point I'll just address the top zones, so 0.95, let's take 5% out instead of 7% and we'll press enter, make that change. |
| 26:54 | We will just see if we can do anything to just address our little lean area here that we've already talked about, we're 0.96 on a 0.92 target so around about 4% there, that's happening at about 2700 RPM. |
| 27:08 | So again we're going to add this time, 1.04, multiplication symbol and just to get a sense of what's happening there, let's just get our logger out of the way, we'll bring in our 3D table as well and we can actually move this around so we can get a sense of what the shape of this is. |
| 27:29 | Let's just get this into something we can actually see, that makes sense, so we can start seeing, we've got a few areas in this table now that are showing some outliers. |
| 27:41 | Got this area here which is showing the outlier here, I'll just get our graph unpaused, where we have pulled some fuel out. |
| 27:50 | Nothing untoward here, there is a urban myth that a properly tuned fuel and ignition map must be perfectly smooth and that's not always the case, we do want to give the engine what it wants and quite often, particularly with a naturally aspirated engine and moreso once we start running aggressive cams, we will find that there will be some peaks and troughs, particularly low down in the RPM. |
| 28:12 | Higher in the RPM which we can see here, obviously we haven't got all the way through yet, we would tend to see this being a little bit smoother. |
| 28:18 | Alright so next round of modifications is made, we'll just again disable our 3D view and pull our logger back into view and let's get another run underway here on the dyno and we'll also creep our RPM out another 600 or 700 RPM as well. |
| 28:53 | Alright our next run complete there, 156 horsepower at the front wheels, we can see our air/fuel ratio was pretty good until again we start creeping out into that untuned area, we've gone rich, again exactly how I'd like this to be so no danger there so I did stay in and completed that run. |
| 29:09 | Let's dive into our MTune software and have a look here. |
| 29:13 | Now we are still a little bit rich here, this time at 3500 RPM. |
| 29:17 | The 3700 RPM as well still a little bit rich. |
| 29:22 | For the sake of not wasting our time with optimising our VTEC changeover point, I'm actually going to leave that at the moment, we're essentially within a few percent of our target anyway, this isn't going to be affecting our power and as I've mentioned, we're going to need to come back and readdress our VTEC changeover point anyway. |
| 29:38 | Everything's looking pretty good, we've got a slightly rich area here but if you look, this is again right between our cells here, right between our break points at 5000 and 5500. |
| 29:47 | I'll leave that again and as we come out at 6000 RPM here, now we are quite rich, we're 0.84, let's round that 0.85, so we're about 5% rich there, so let's correct that, again of course we are going to be making this change to the entire column, 0.95 and the multiplication symbol, it will fix or should at least fix most of that. |
| 30:11 | Let's come out further to 6500 now and at 6500 we can see that we are sitting around about 0.80 so again we're around about 10% rich there so again I'll underestimate that correction, we'll go 0.92 which will be an 8% correction and we're also looking at the numbers here, are these making sense, are we getting a nice consistent trend? We've gone, at 100 kPa for example at 6000 RPM from 81.3 to 86.9 so we're jumping in the right direction, reasonably smooth, we can of course look at our 3D table as well to get a sense of that. |
| 30:51 | Let's see as well, right at the end of that run, we're just getting up to 7000 RPM and now we're very very rich, we're at around about 0.77 lambda with our target at 0.88. |
| 31:06 | So we're around about 12% rich there so what I'm going to do is highlight the 7000 RPM column and I'm going to make this change all the way out as well. |
| 31:18 | In this case 0.90 and the multiplication symbol will take 10% out of this, again if we look at the step, this makes sense, we're going to from 86.9% to 90.2. |
| 31:29 | So again we haven't touched our ignition at this point, let's now get another run under way, this time we'll extend out another 800 or so RPM. |
| 31:57 | Alright our next run complete there, 168 horsepower. |
| 32:00 | Again what we can see is the same trend, essentially we're fixing the air/fuel ratio in the area that we've done from the last run, we're at least getting it pretty close and then of course as we move out into this untuned area again, we move a little bit rich and let's jump across to our MTune software to see the magnitude of that. |
| 32:17 | So in this area here we are 0.80, 0.81 and of course our target there is 0.88 so we're definitely a little bit too rich there so what we can do is take a, let's take 8% out there, that should get us pretty much on the money, we've still got that entire area highlighted so 0.92, have to highlight that again. |
| 32:44 | 0.92 multiplication symbol, that's taken another 8% out there so we've now made our adjustment from 7000 RPM and above, let's look at our 6500, we didn't quite get onto our target there, we can see that we're sitting in this case 0.86 with a target of 0.90 so we are around about 4% rich there. |
| 33:07 | 0.96 multiplication symbol enter, that should get us pretty close there. |
| 33:14 | We're around about 1% too rich here at 6000 RPM so we'll make a correction there, 0.99 and that should get us pretty close and then if we come back down here, 5500 and 5000 RPM, looks like 5500 RPM was probably a little bit rich as well there, probably in the order of just a couple of percent there so we'll try and address that as well, 0.98 multiplication symbol. |
| 33:45 | Alright so at this point we have got our engine running out to let's see we are about 7700 RPM. |
| 33:54 | So we're going to simply repeat this process and go again, this time we'll try and get ourselves out to around about 8500 RPM, maybe 8300 and that's probably about as far as we're going to need to go, we should start to see our power nose over so let's make the appropriate changes to our dyno and perform another run. |
| 34:33 | OK our next run complete there, we're up to almost 177 wheel horsepower. |
| 34:37 | We can see our air/fuel ratio on the dyno looks pretty good, just started to move a little bit lean towards the top end there so again we'll jump into our MTune software and see what's going on and yeah we can see probably from 8000 RPM and above we're sitting probably about 2% too lean. |
| 34:54 | So that's easy, what we'll do is correct that, I'll actually make this change again all the way out and we did see a pretty consistent 8000 RPM and above, we went to about 8200 on that particular run so we'll add 2%, 1.02 multiplication symbol, that should fix that, we can see we've got some inconsistencies still down here but notice it's all generally between cells but again for the sake of our demonstration at the moment I'm pretty happy with what we've got there. |
| 35:22 | What we'll do is make one more run, we still see that our power hasn't quite peaked, I'd like to just get us past peak power so it's starting to fall away, I'm quite happy to rev this engine to 8800 or maybe even 9000 if we absolutely needed to so let's perform one more run and get ourselves out a little bit further in that rev range. |
| 36:01 | OK so we've now got our engine power just starting to nose over and if we look in our MTune software, we were running out to about 8500 RPM so I'm quite happy with that, we'll leave it at that for our dyno runs in terms of how far we're running in the RPM. |
| 36:19 | Now looking at the lambda, we can see again, we're just a little bit lean in that top end there and let's have a better look at that in the logger and we can see yeah we're sitting at about 0.94 with remembering our target being 0.88 at this point so that's 8500 RPM, again I'll make that change at 8500 and above so we want to add, we were, just to confirm again, yeah 0.94, we do need to average that a little bit and probably more like 0.92 so let's add 4% to those zones, 1.04 multiply and enter, that'll make that change and we're probably just about 1% leaner than I'd like to be from 7000 through to 8000 as well so again well highlight all of those cells, 1.01 and multiply and we'll press enter. |
| 37:15 | So from here we're just going to jump ahead a little bit. |
| 37:18 | The process is just an iterative case of what you've seen so far, we'll go and make a run and any rich or lean areas we'll correct those using the techniques that you've just seen so let's jump ahead and look at our final dyno run and our final log file for this point of our tuning. |
| 37:36 | Right we've gone ahead and cleaned up the remainder of our fuelling so let's have a look at those results. |
| 37:42 | Firstly on the dyno we can see our peak power at the moment, 179.7, again not really too worried about the power at the moment, we've seen a little bit of run to run variation but we're there or there abouts. |
| 37:52 | Looking at the lambda plot here, nice and smooth, pretty close to our target of 0.90, our little reference line, let's have a look at what that looks like in the MTune logger though and we can see now we've got a reasonably smooth lambda plot that's nicely following our target. |
| 38:08 | Now obviously there is a little bit of oscillation in this and we do need to do a little bit of mental smoothing, there's no need or point for that matter chasing down every one of these tiny little peaks and troughs, we just are not going to achieve anything by doing so and it's absolutely not necessary. |
| 38:26 | In order to achieve this result I did end up adding a few more break points into the table which we'll see if we look at the RPM axis in our VE table up here but essentially the process that we've used, exactly the same as you saw during the worked example so far. |
| 38:45 | Now what we're going to do is move on and have a look at our ignition tuning and the process is again similar to what we looked at during our steady state ignition timing tuning, we're going to be making changes of 2° at a time, looking for either the point where we achieve MBT, see no gain in power for additional timing in which case we'll back that back off, or alternatively if we were knock limited, if we get any sign of detonation, we're obviously going to back the timing back off and provide a safety margin. |
| 39:16 | Let's head over to our ignition table now and what we can see is the ignition table as we left it here, you will remember from the body of the course, and I discuss this in the steady state tuning module, that typically I recommend we back the timing off a couple of degrees before we start doing our ramp runs just for safety. |
| 39:35 | As I explained, we didn't do this so the first step normally would be to add that 2° of timing back in and obviously we don't need to do that. |
| 39:43 | What I do want to do though is just see how the engine responds to additional 2° of timing everywhere that we are running the car under ramp run conditions. |
| 39:51 | So we'll highlight the two top rows of our table here and 2000 RPM and above and what we'll do is we'll add an additional 2° in here. |
| 40:02 | Let's get our engine up and running and we'll perform a ramp run and overlay this with our last run and see what that additional timing does for us. |
| 40:31 | OK so we did actually see in that live run which of course was overlaid with our final tune for our fuelling that we did pick up some power and torque but not everywhere. |
| 40:41 | So at the start of the run there really wasn't much noticeable in terms of a difference so in order to really highlight that and see what we need to do with our ignition timing, let's just analyse those two runs one on top of the other. |
| 40:52 | OK so in this instance, our blue plot is our final fuel tuning with the base timing and then with our red run, that's where we've added that 2° right the way from 2000 all the way through the run. |
| 41:06 | And what we can see is that essentially up to 4000 RPM the plots are really no different, in fact right down in the bottom end we see that the blue run with less timing actually made a little bit more power. |
| 41:18 | However there is a noticeable difference from 4000 RPM and above so that we're going to do is remove that 2° from 4000 and below, below 4000 I should say and because we've seen a gain here, we're going to add another 2° above that point so let's jump into our MTune software. |
| 41:36 | So what we want to do for a start is highlight the zones up to 3500 RPM and we'll pull the 2° that we added back out. |
| 41:49 | Now 4000 RPM we did see a change. |
| 41:51 | Now remember we did steady state tune this but we steady state tuned this before we optimised our VTEC changeover point so we were optimising the steady state ignition timing on low cam, we're now on high cam so that explains why we can see a change. |
| 42:05 | Now we actually saw an improvement with an additional 2° at 4000 so I will try another 2° from here and above. |
| 42:14 | However what we're now getting is quite a significant jump here, between 3500 and 4000, I wouldn't typically want or expect to see a 5° change across 500 RPM. |
| 42:26 | Let's just run the car though and see whether that's actually realistic or whether we need to pull a little bit of timing back out at 4000 RPM. |
| 43:00 | Alright our next run complete there, again we saw quite a nice jump in our power, particularly at higher RPM. |
| 43:06 | Let's save this run, overlay it with our last and we'll dive a little bit deeper into where that additional power came from and what we might want to do with our timing for our next run. |
| 43:16 | Alright so diving into this, we can see in the bottom end really no difference in our two curves, I'm overlaying here the run that we've just completed with the previous run where we'd added 2° right the way through from 2000. |
| 43:29 | So what we can see is at 4000 RPM here where I added an additional 2°, we've got no additional power so that really comes down to that jump that I talked about in our ignition table, let's come back and have a look at that. |
| 43:42 | So that is this particular site right here or step right here between 3500 and 4000 RPM so essentially what this means is we added 2° into this particular site, the engine didn't need it, it doesn't want it so we're simply of course going to take that back out. |
| 43:58 | And now we're starting to get a more realistic step change, here we've got 3° over 500 RPM which is a lot more in line with what I'd expect. |
| 44:07 | Let's have a look back at our dyno plot though and see what happened with the rest of our run. |
| 44:11 | So essentially from around about 4500 RPM, actually we've still got very little change there, we've gone from 93.6 to 94.3 so that additional 2° that we've got there has done a little bit but not too much. |
| 44:27 | That would suggest to me probably it's not going to want to take any more and then from 5000 RPM and above, particularly when we get up to 8000 RPM and above, the engine has responded to that additional 2° so we're going to go again here, let's jump back into our software. |
| 44:43 | As we discussed, 4500 RPM we only saw a really minor change from that 2° so I'm not going to add any additional timing there but from 5000 RPM and above, again we'll add an additional 2° and again just based on my experience with these engines, we're starting to probably get closer to the timing I would expect the engine to be taking. |
| 45:04 | Probably in the sort of 26 to 28, 29° vicinity, maybe as high as 30 at higher RPM is where I'd expect it to be. |
| 45:13 | So let's get another ramp run underway and we'll see the effect of that change. |
| 45:39 | Alright so our next run complete there, again we've seen a nice little bump in our power. |
| 45:42 | Now the gains that we're seeing are starting to get a little bit less significant though and that's another sign that we are probably getting pretty close to MBT timing. |
| 45:53 | Again we'll save this, overlay it with our last run and just see what we can learn though. |
| 45:58 | Alright so looking at our two plots, below 5000 RPM they essentially overlay one on top of the other. |
| 46:05 | However as we move beyond 5000 RPM we can see that we start to get a nice little bump in our power. |
| 46:10 | So what that suggests is probably at 5000 RPM we're pretty close to our MBT timing, I'm not going to add additional timing at that point but let's just try another 2° at 5500 RPM and above and we'll run the car again and see the effect of that change. |
| 46:50 | Alright we've completed our next run there, we've got another small jump in our power, we're up to 189 horsepower but you can start to see those gains are beginning to diminish again just suggesting that we are really really close to the top of our timing or our MBT timing point. |
| 47:08 | But again let's just save this run and we'll overlay it with our last and see again if we can learn anything from that. |
| 47:14 | OK so looking at our two plots overlaid, we can see that we start to see a bit of a separation here between our white plot which is the last one we completed and our previous green plot. |
| 47:23 | From around about 6000 RPM, 5500 RPM and above, so the engine has responded to that timing. |
| 47:30 | We can see in the top end though, very very small difference there, we're only talking around about one horsepower at the most. |
| 47:38 | Just for the sake of completeness, we'll do another run and we'll add another couple of degrees of timing. |
| 47:44 | It does look like the engine responded from about 5500 RPM we started to see that separation but it gets more significant from 6000, again what we'll do is we'll make this change this time from 6000 RPM so we'll go into our table, add another 2°, let's run it again and see the effect of that change. |
| 48:22 | Alright so this time we can see we didn't get any gain in power, in fact we've actually lost a very small amount in the top end so this suggests we are at or now potentially very slightly beyond MBT. |
| 48:34 | Easy enough though, we'll just go back into our ignition table here and we'll remove the 2° that we just added. |
| 48:40 | So you can see how quick and easy it is to actually optimise our ignition table using this process. |
| 48:46 | Now while we've got our timing dialled in and optimised at wide open throttle, we haven't completed the job yet. |
| 48:53 | Looking at our table, we know that we've only been making these changes here to the wide open throttle operating area and that leaves the area down here and below. |
| 49:03 | Now obviously we've steady state tuned up to around 4000 RPM as we already know, we did find that at 4000 RPM, the engine actually did want a little bit more timing. |
| 49:13 | There's a couple of ways we can deal with this. |
| 49:15 | What we could do is when we're making our changes, above the area we've tuned, much like we did with our fuelling, we could have made those changes to the lower areas as well, essentially copying down the changes that we're making if we find that the engine wants 2° at wide open throttle, basically making that same change at the lower load areas. |
| 49:35 | However I don't really want to be going and adding a huge amount more timing in the very light load areas down here above 4500 RPM at light load so we're already at 38°. |
| 49:48 | Generally there's not going to be much to be gained by advancing the timing beyond this. |
| 49:53 | Although in saying that we also don't necessarily need to be too worried about knock in these areas as well. |
| 50:01 | So what I'm going to do, just because we don't really run the engine in these areas, it's not as critical, I'm going to just take what we've learned here, we've added 2° at 4000 RPM, we're going to bring the timing here at 4500 up to 40° in our overrun areas and what I'm going to do then is then just using our shift an arrow keys I'm going to highlight the block of cells between and what we can do then is use the interpolate vertical and that's just going to give us a nice smooth shape to the ignition table in those areas. |
| 50:31 | So we can have a look at that with our 3D view and we can see yeah we've got an ignition table that has a pretty typical shape, this is what I would expect to be seeing. |
| 50:40 | Now our job isn't complete at this stage, we have only at this stage coarsely dialled in our VTEC changeover point and now we want to go back and just see if there's anything to be gained in maybe moving that up or down a few hundred RPM so we're going to perform some more ramp runs here, let's go first of all back into our outputs and we'll go into our VTEC one, we know that the shiftover point at the moment is 3750 so let's try making a couple of changes here. |
| 51:10 | And just for simplicity here, let's make these changes in 250 RPM increments so for a start let's try dropping this down to 3500 RPM, we'll do another ramp run now, overlay it with the run we've just completed and see the effect of that change. |
| 51:46 | OK so we've made that change to our VTEC changeover point. |
| 51:49 | Visually I couldn't really see any noticeable difference there. |
| 51:52 | We've actually dropped a little bit of power just probably more down to a run to run variation, obviously the timing essentially is identical, the last run we'd added timing gained no power from it so I'm not too worried about the peak power number, obviously what we're looking at here is just that VTEC changeover point so to get a better view of that, we'll save this run and we'll compare it to our last. |
| 52:15 | OK looking at these two runs overlaid on top of each other, it's really really hard to pick a winner here, really the sort of changes we're seeing here are more in line with run to run variations than anything. |
| 52:27 | If we look at our point here, 3900 RPM, we're above the VTEC changeover point in both but we've actually got a small variation in power that shows our last run with our lower VTEC changeover point to actually be a winner but of course we know that we're running on high cam in both of these positions anyway. |
| 52:48 | Looking down at 3600 RPM, the ignition final run does actually show a very slight improvement but again we're talking run to run variation so I didn't really see anything significant there, certainly not enough to warrant making that change. |
| 53:06 | Let's try going up though so we were at 3750, we've dropped it down to 3500, let's try 4000 RPM and see if we can notice a change with that so we'll run the car again now. |
| 53:41 | OK so looking at these two runs overlaid, to this is our ignition final with our 3750 RPM VTEC changeover, vs changing that to 4000 RPM. |
| 53:52 | Realistically again we're splitting hairs, there's almost no discernable difference. |
| 53:57 | What we can see though here at 4000 RPM or 4060, remembering our dyno is reading actually about 100 RPM too high so at this point we can see that the blue run, our 3750 RPM VTEC changeover point, is actually showing a little bit more power. |
| 54:15 | So it looks like we actually had it pretty close with our very first attempt at 3750. |
| 54:21 | Of course you can get a little bit more granular with this if you want to and start making changes of 100 RPM but you're going to quickly find there's diminishing returns to this so we'll go back to 3750 and call our job done there for our VTEC changeover point. |
| 54:36 | Now one thing I will mention, if you do happen to find that you do indeed need to move that VTEC changeover point from what we found when we were doing it coarsely, if we head back to our fuel table this may require you to then rejig the break points, you'll remember we added these break points to be either side of our VTEC changeover so you may need to move these around as well just to give you that fine fuel control at the VTEC shifting point. |
| 55:03 | So from here our job is essentially complete. |
| 55:06 | What we do have is one last little task that I'm going to go through here quickly. |
| 55:10 | Remember that we have steady state tuned the engine now in areas that we were on low cam which we're now on high cam so for the sake of completeness, I'm going to go through and redo those areas at 4000, 3750 and 4500 RPM. |
| 55:27 | I'll also take a look at some of those higher areas and just see if we need to make any across the board changes to those higher RPM, low load areas. |
| 55:35 | Remembering in these areas we don't run the engine there under sustained operation, we're only passing through them so while we can't just have any numbers in there, we don't need to be quite so critical there and generally I'm going to be happy if we're maybe just a little bit richer than our target so we'll speed this process up, it is just a repeat of what we looked at in the steady state fuel and ignition tuning so let's go through that now. |
| 57:14 | Alright so we've gone ahead and made some changes there to our steady state areas of our fuel table and there's a couple of takeaways that I wanted to just point out here. |
| 57:24 | What we can see if we look at the shape of the VE table here, we've now got quite a significant step down in VE particularly of course at lower load so we can see that that step's quite apparent there. |
| 57:36 | And assuming that our points are still properly tuned at 3700, which they should be because you'll recall that this was steady state tuned on low cam, then this step is indicative that our VTEC changeover point does want to actually be manipulated relative to just, not just RPM but load and RPM and you'll recall I mentioned the windowing technique and how we can use that earlier in this worked example. |
| 58:05 | Now as I mentioned, and we're sticking to it, we are for the sake of simplicity here just using purely an RPM switchover point but when we see this drop off, and let's just turn our table around a little bit so we can see that, when we see this shelf here, what this suggests to me is that the VTEC changeover point at lower load, actually wants to be shifting out to higher RPM. |
| 58:28 | If we look on the other hand, let's just move it around again, at our VTEC changeover point here at wide open throttle, we can see we've got a step but it's a relatively small step so this means that our VTEC changeover point is pretty close when we've got such a small step there. |
| 58:43 | So technically this is why we would want to use manifold pressure or throttle position as a load input to that VTEC changeover point instead of just purely RPM. |
| 58:53 | The other aspect that's just worth mentioning here is before I went and steady state tuned the 3750 RPM column, what I did do is go back into our VTEC control and I temporarily dropped this down to 3000 RPM. |
| 59:08 | I'm going to put it straight back where it should be now at 3750. |
| 59:11 | The reason I did that, if we come back to the fuel table, is that if we were sitting in these cells here, and even without hysteresis, we're likely to have the RPM wandering around a little bit on the dyno, we're going to be in and out of VTEC so this just makes sure that while we're in that zone, in that column, the VTEC is actually engaged. |
| 59:31 | So now I've put that back how it should be. |
| 59:34 | So this gives us a bit of a problem though because we've obviously got this area here in the table which is now almost certainly going to be too rich. |
| 59:43 | And we don't want to go ahead and steady state tune each of these cells. |
| 59:47 | Instead what I'm going to do is just take a look at a few of these cells in here and I'm going to make some broad block changes to this area of the table, remembering again we don't operate in it, we don't need to be super fussy here, we just want to have the numbers in the ballpark and I'd always err on the side of being a little bit rich so we want to be mindful here because at high RPM our engine temperature will start to build up quite quickly so we'll go into a few key sites and just make some block changes that we'll extrapolate out through that rev range just to get our fuelling at least in the ballpark in these areas so let's go ahead and get that done. |
| 01:00:46 | Alright so at this point, the work on the dyno is complete, that last little step there, what you saw me doing is using the dyno to get ourselves out to the higher RPM areas. |
| 01:00:55 | Again no need to steady state tune every single cell, what I was doing there is just making some block changes and what you saw or would have seen is that I did need to take quite a large amount of fuel out of these areas in the overrun area of the map simply because we were too rich and this really just comes from our original extrapolation of the lower RPM areas. |
| 01:01:16 | Obviously with the VTEC changing over, that also affects the volumetric efficiency and the fuelling requirements, particularly at low RPM so when we've got a cam switched engine like this, the technique that we'd use on a conventional engine doesn't work quite as well but it's easy enough as you saw there to just go in and make some block changes. |
| 01:01:35 | And we don't need to tune every cell, only need to use maybe one, sorry maybe two or three RPM ranges and then I can choose some key load points and just vary that with the throttle, just get a quick snapshot of what the fuelling's doing and then make some block changes to account for that. |
| 01:01:51 | Looking at the VE table, other than the step which we've already discussed with our changeover for our VTEC, in that lower RPM area, everything is looking pretty much like I'd expect, we've got a reasonably smooth shape, we do have these little peaks and troughs down low, as I mentioned though, this is not uncommon with a naturally aspirated engine, this would tend to get worse as well with larger more aggressive cams so it's pretty typical. |
| 01:02:19 | Particularly we will see this down at low RPM and what we can see is that in fact the whole VE table does start to get a lot smoother once we get higher in the RPM. |
| 01:02:30 | So at this point our work on the dyno is done, we would not take the car off the dyno and complete the tune out on the road or the racetrack. |
| 01:02:38 | This would also help us gather some data in those higher RPM lower load areas and we may find that we need to fine tune that once we actually get out on the track and gather that data. |
| 01:02:49 | If you do have further questions on this worked example, please ask them in the forum and I'll be happy to answer them there. |
