Practical Standalone Tuning: Step 8 : MBT Testing ( Laptop )

Back to course

Watch This Course

$229 USD

-OR-

Or 8 easy payments of only $28.63 USD Instant access. Easy checkout. No fees. Learn more

Enroll Now
8 easy payments of only $28.63 USD

Course Access for Life

60 day money back guarantee

Step 8 : MBT Testing ( Laptop )

23.52

00:00	For the next step of our process we're now going to steady state tune our ignition timing.
00:04	Now, clearly this entire step, irrespective if you're using the laptop software or the touchscreen, is essentially irrelevant if you aren't running the HyperSpark distributor.
00:15	You don't obviously have the adjustability with your ignition timing if you're running a conventional distributor.
00:21	However, as I've already mentioned, that's not to say there isn't some ignition tuning that goes on but that will be addressed when we get into our full power wide open throttle ramp run step and under those conditions we're just going to experiment by swinging the distributor plus or minus a couple of degrees and see how that works out.
00:39	Essentially moving our entire ignition curve up or down as required in order to optimise it.
00:45	So, as we've done with the previous steps, we're going to start with our laptop tuning software and let's dive into that now.
00:52	What we can see here is we've already got our ignition table created and again this really just comes from what we saw in the base calibration that the wizard created.
01:04	We also, as we've discussed, have the option of having a full three dimensional table which is what we're using now or the simple mode where we only are able to select our idle, our cruise and our wide open throttle settings.
01:17	Because we have the benefit of the tunability here with the laptop software, it would make sense to use the table, I don't really see the point in using the simple mode but it does come down to personal preference.
01:29	Alright, so let's talk about what we're going to try and do here on the dyno.
01:32	We're essentially going to repeat what we did with our steady state fuel tuning.
01:36	So, basically start from low RPM and low load, we're going to again tune in blocks of nine cells so that we basically are eliminating some of this very high resolution in the table and so that we speed up this process and make it a little bit more sensible.
01:53	However, of course you have the ability to get a little bit more granular with this if you want to, as you'll see, there's probably not particularly with this application, there's not going to be much advantage to doing so so we're going to be using that technique along with some interpolation and smoothing to get the job done.
02:10	So, the process will be to essentially hold the engine in steady state on the dyno, we're going to be using the torque feedback from the dyno so once we're up and running we'll see that the torque value here, it's also displayed up here, the torque value will auto scale and what we're looking for is that graph of torque, when we make a change to our ignition timing, we want to see whether the torque increases which means we're moving towards MBT, if it does, we'll continue adding timing until the torque either plateaus or we encounter knock and then if that's the case we'll be retarding the timing.
02:47	However, if we add timing and it gives no advantage in torque, we will be removing that timing so exactly as we've basically demonstrated in the body of the course.
02:57	One complexity here with our automatic transmission and torque converter, if we start down in the 1400, 1600 RPM area, the lightest load that we can actually hold on the dyno, we find that when we try and add timing or remove timing, we get into a situation where because of the slip of the torque converter and the torque multiplication, as we remove timing or increase timing, we're actually getting the RPM change as well and there's no easy way of getting around that.
03:27	If we were in a manual transmission car, obviously that wouldn't be an issue but in this case it makes that area of the map just essentially impossible to really fine tune using this technique on the dyno so we're actually going to start with a little bit more load on board.
03:41	I will reiterate here as well that while I'm not going to be using knock detection equipment for this part of the worked example, I'm already very familiar with this engine, I know that given the octane of the fuel that we're running it on as well as low compression, that knock is just not a factor for this particular engine but of course we always recommend that you do use knock detection equipment while you're tuning the ignition timing and certainly as we've already discussed, even the fuel, just in case our base ignition timing table had been a little bit too aggressive.
04:12	Alright, so let's get ourselves up and running and we'll have a look at a few of these zones and see how we can optimise them using the dyno.
04:18	OK we've got ourselves up and running here and we're central on the 2000 RPM and 42 kPa cell, I've highlighted the surrounding cells so we're not really going to have any problems with interpolation.
04:29	If we look over at the dyno, you can see that our torque's sitting around about 340 Nm, obviously it's moving around and that's why we're using the graph here rather than the digital value because it's too hard to really see the trends when we make a change to our timing, the graph will show this, or at least should show this.
04:47	I'll just make a small adjustment here to get ourselves a little bit more central RPM wise, it's looking pretty good there.
04:53	So, for this first change here, let's just make a big change so we can really see the effect of this.
04:58	So, we can see that the central cell, the one we're actually accessing is 38.5°, just going to set all of these for the moment to 20° and we'll let everything stabilise and we straight away see on the graph that massive drop in torque so we know that we have moved away from NBT, we're making less torque.
05:15	So, just to make this really clear, let's start by making large changes.
05:20	I generally would make 2° changes, here we'll add 4° so we'll go from 20 to 24.
05:25	The change doesn't take place until I press enter so what we want to do is look at our torque graph, make sure that it's stable and when we press enter, that change will take place so I'm going to press that now and we want to look at the graph and we can see a nice obvious step up in torque.
05:40	So, we know that we've just moved towards NBT.
05:43	Let's make another 4° change at this time just so we can make this nice and obvious.
05:47	Again, looking at the graph before I press enter, I'll press enter now.
05:51	And again we see the torque increase.
05:53	Now, 4° is quite a big change but even between those two changes, hopefully you would have noticed that we didn't pick up as much torque that second time.
06:02	So, that's a hint that we're getting a little closer towards NBT but we still saw a change so let's try another 4° so we'll add 4 to that, 32°, again looking at our torque graph, I'll press enter.
06:14	So, you see again the torque increases but again not as much.
06:18	So, each of those three steps we've made, progressively the increase in our torque is getting less.
06:25	Alright, so let's try another 4°, we'll go to 36° here.
06:30	Again, looking at our torque, waiting for that to stabilise, making sure that I am still central to the cell, I'll press enter.
06:37	OK small increase there but very small so we're getting pretty close.
06:42	Let's try, just to see if we can either plateau or go too far, let's try 4°.
06:48	So, we're at 40° now so another 4° change.
06:51	Again, looking at our graph, I'll press enter.
06:56	Didn't see any change there at all.
06:58	So, essentially what we know is that our torque NBT point is probably somewhere between 36° and 40° there.
07:05	Let's split the difference and go to 38°, I'll press enter.
07:10	We see our torque's still flat lined so I'll go back down to 36°.
07:15	See a very very small decrease in our torque there but we are splitting hairs.
07:24	So, in this case, just for the sake of being a little bit more conservative, between 36° and 38° we really don't see any change so I'm going to leave 36° in there.
07:34	Alright, so we've tuned one cell essentially at the moment.
07:38	What we'll do is we'll just go up and load a little bit here and we'll highlight the next nine cells above.
07:44	So, let's bring ourselves up here.
07:49	I'll just get us nice and central in the centre of those nine cells.
07:59	OK everything's looking quite good there so we're sitting now just under 600 Newton metres of torque.
08:06	Alright, so we know that the cells that we just tuned, we ended up finding 36° to be NBT or pretty close to and as we've increased the load here, we're now a little bit more advanced, 38° so probably that's going to be over advanced here if our timing follows the usual trends that we'd expect.
08:25	So, let's just retard all of those cells back to 30° for the time being.
08:29	And we did see that our torque has actually dropped there a little bit, we're down to about 570 Newton metres at the moment.
08:36	I'll just make sure again with the throttle that I am as central on that cell as I can get.
08:40	Alright, so what we'll do now is we'll add, let's try 2° in increments now.
08:45	So, we'll go from 30 to 32, we're looking at our torque graph, I'll press enter.
08:50	I see a very small increase in our torque but almost insignificant.
08:56	Still going the right way though, let's try another 2°, we'll go to 34 here.
09:00	And again looking at the graph, I'll press enter now.
09:06	Tiny increase and we are just trickling over into the 600s now with our torque.
09:12	34, not a big change but is it changed? We'll try 36 here though.
09:18	Just press enter there.
09:20	36°, I can't pick up any noticeable change there so we'll go back to 34.
09:25	Alright, we'll just come back to idle now because at this point I'm going to speed up this process a little bit.
09:32	It's all just a rinse and repeat of what you've seen there so I'm not going to narrate the rest of these changes.
09:38	So, what we're going to do, we know that we really can't, because of the limitations with the torque converter and the transmission, we can't get down lower in either load or RPM.
09:47	So, there's going to be a little bit of hand smoothing that's going to be required both in the areas down below in load that I've just pointed out as well as we're going to have to do something to basically interpolate or extrapolate the values from our idle area into this light throttle cruise area.
10:04	We are also going to end up, just remembering that realistically all I've actually done here is tuned two cells.
10:12	We've been doing that in blocks of nine and the reason for that, just to reiterate, is so that we don't get any interpolation with surrounding cells affecting the accuracy of our tuning.
10:21	But of course we can't just leave blocks of nine cells like this so again we're going to be using the interpolate function there both vertically and horizontally once we're done.
10:31	Again, I'm going to do this just like we did with the fueling, out to 3500 RPM and just to also remind you, we want to be careful, mindful of our coolant temperature here, particularly once we get up sort of 2500, 3000, 3500 RPM and higher in the load, we're going to want to just be mindful that we're not having our engine overheat.
10:54	The other thing just to mention here is as we've already found here, 34° was NVT for the last cell that we tuned which looks like it's about 53 kPa, 2000 RPM.
11:06	So, because we know that as we increase the load, we would expect the timing to need to be retarded, what we can do is just be a little bit more conservative here, we can highlight these cells up here above and for the purposes of our demonstration here, what we'll use is the offset and let's take 10° out of all of these cells.
11:27	Haven't changed the wide open throttle ones here just yet, when we get up to that point we'll deal with that based on the trends that we're seeing.
11:35	Alright, so let's go ahead and we'll get ourselves tuned for the 2000 RPM column all the way to wide open throttle and we'll come back and talk about what we've found.
12:11	Alright, so we've just gone ahead and completed tuning of our 2000 RPM column but as I mentioned we've got some big blocks now and we want to do a little bit of smoothing with this.
12:22	So, the first thing to talk about here is the area below where we could tune on the dyno.
12:27	And we can kind of extrapolate the trends that we're seeing here and for the most part, as we increased and stepped through those cells, I was basically removing about 2° every step.
12:40	Not quite always but that was about where it ended up.
12:43	So, we could kind of extrapolate this down and we know that probably as we reduce the manifold pressure, we're going to want to increase the timing.
12:52	You'll also notice though that the step changes once I got close to NBT were very very small, we're probably talking about a percent or less of torque, 2-4° either side of NBT.
13:04	So, there's no real necessity here in chasing the absolute last newton metre of torque out of this.
13:12	I always want to err on the side of being cautious, while I've already discussed the fact that this engine is not knock limited, that doesn't mean to say that every engine we're going to come across will be.
13:22	So, basically what I'm going to do is just be a little bit more conservative here, we'll highlight the section down below here and this is only going to be light light throttle anyway, we're going to add 2° there, 38.
13:33	Chances are maybe, maybe NBT might have been at 40° but again we're only going to be talking about a percent or so so it's really not that critical to be super fussy here.
13:44	Likewise, we've got these cells up here that are into boosted areas, we're not obviously going to be getting into there.
13:51	You can choose to leave them as they are or for the sake of making everything look nice, you could extrapolate the ones from the cells that we actually tuned there, 24° in the wide open throttle NA area.
14:05	OK now that we've done that extrapolation here and we've essentially got a fully tuned column for our 2000 RPM column, what we're going to do is copy that column and we're going to copy that out to 2500 and 2750 so let's go ahead and do that now.
14:25	At the moment I'm going to leave those steps in that we've created but don't worry, we're going to deal with that a little bit later on once we've done the rest of our steady state tuning and if we pop across to our base timing graph and we just manipulate this a little bit so that we can actually see the area that we've created these steps in.
14:46	Yeah, you can see those in there.
14:49	Not the nicest but realistically we could leave that as it is but don't worry, we'll smooth that out to make it all nice a little bit later on.
14:57	OK so now we're going to repeat this process at 2500 RPM.
15:02	Typically with the fuelling we know that we added some additional fuel because we're expecting the timing, sorry the VE of the engine to increase with RPM.
15:10	We know that also as our RPM increases, typically NBT timing will increase.
15:16	We're going to stay conservative here though so we're going to leave the timing as what we found to be optimal at 2000 RPM and this should in theory mean that we're starting a little bit conservative.
15:27	So, from here we're going to speed this up again and we'll continue this process out to 3500 RPM and then we'll come back and talk about what we're going to do next.
17:12	Alright, we've completed our steady state ignition tuning there to 3500 RPM.
17:17	And realistically it's followed the exact trends that we'd expect, it's not that sensitive to timing so again there's no point really chasing that last 0.5% of torque.
17:28	It is fairly broad with the area around the NBT curve at the top of the plateau so that's quite wide is what I'm getting at there, we don't need to be pinpoint accurate with our actual ignition timing.
17:42	Alright, so what we do want to do though just for the sake of completeness is smooth out some of these steps that we've created.
17:48	So, what I'm going to do first of all is start by using our 3500 RPM column, the last one that we just completed.
17:55	Worth just mentioning as well that when I found that the timing in the areas that we could steady state tune needed to be stepped up, I also extrapolated those changes down into the light load areas.
18:08	Alright, so what we're going to do is use the S key here to smooth that vertical column.
18:13	And what that's going to do, you can see it's just changed some of those numbers in there in between the areas that we've actually been able to tune.
18:20	So, from here what we want to do as well, we're basically doing that for each of the columns that we have tuned so 2000, 2500 and 3000 so let's get that done now.
18:33	If we quickly have a look over at our timing graph we can see now those columns that we have smoothed are nice.
18:41	If we jump over to our timing graph, now you can see the difference between those columns that we have smoothed and the ones that we haven't with the steps in them.
18:49	So, everything's working quite nicely in that respect, we'll come back to our timing graph and now what we want to do is essentially use the interpolate function horizontally to fill in the columns that we haven't tuned.
19:00	So, for example we know that we tuned the 2000 RPM column and we've also tuned the 2500 RPM column.
19:08	So, if we highlight all three columns here and we right click and we use the fill row values, what that's going to do is interpolate horizontally so let's do that.
19:19	And we're just going to repeat that now, we need to do 2500 through to 3000 RPM so again we'll highlight those columns.
19:26	And this time we'll use the R hotkey, it's done that job.
19:31	And then again we're going to do the same out to 3500 RPM, press the R key.
19:38	OK so again we'll have a quick look at our timing graph, manipulate this around a little bit so we can actually see the area that we're interested in.
19:48	And again we can now see we've got relatively nice smooth shape to the graph which is what we're wanting.
19:56	Alright, got a little bit more work ahead of us though.
19:58	So, what we want to do as well is basically have a bit of a guess ahead at what these values are here to the right.
20:04	Again, as I've already mentioned, we can expect that the timing will want to probably step up a little bit from what we've got at 3500 RPM but for the sake of starting conservative, we're just going to make all of those columns exactly the same.
20:18	So, let's copy that out now.
20:25	OK so we're pretty close now, we do have this one other area here where we haven't really been able to steady state tune.
20:32	And we can see that the numbers that we've got in here now are actually quite a lot more advanced than the surrounding numbers of what we actually have tuned.
20:39	So, how we can deal with this here, we know that we've tuned our 2500 RPM column, oh sorry 2000 RPM column here.
20:46	So, what I'm going to do is highlight that and we'll highlight all the way back out to 1000 RPM and again here I'm just going to use the R key to interpolate those values.
20:56	So, again these might not be quite right, we might be two or three degrees away from MBT but we're going to be there or thereabouts.
21:04	The reality again, we're going to be chasing very very small percentage changes under those conditions anyway, we've got no way of steady state tuning on the dyno under these conditions with the automatic transmission so that's why we've done this.
21:17	Of course, if you're in manual transmission we could get lower in the RPM and you'll have less of this sort of guesswork and smoothing to do.
21:24	Alright, let's have a quick look at our timing graph again from a graphical standpoint and we'll just have a look at how that looks now.
21:30	Alright, so what we can see is I've actually made a mistake here, we can see that we've actually still got these steps in here so we're going to now go back and just copy out our smoothed column as opposed to an unsmoothed column.
21:42	We've also got, not that this is really a big issue here but we can see we've got sort of some inconsistencies in our timing here down in that low RPM area.
21:51	We see that our timing sort of steps, let's just get rid of that, it sort of steps up and then as our load increases it steps back down so not very realistic.
22:01	I'm going to deal with that only from a standpoint of sort of OCD really, it's not going to have any impact in the actual running of the vehicle so let's go and deal with both of those.
22:11	First of all, the timing step, so what we want to do is actually take our nice smooth 3500 RPM column, not the 3750 RPM column that I copied, we'll copy that and repeat the process.
22:26	And also we're going to deal with our timing down in this low RPM area, we can see here where it sort of steps up so what I'm going to do here, and again this is being fussy, it's not really critical to the running of the vehicle, all we can do is actually highlight this entire area because we're only talking differences of half a degree or thereabouts and we'll set them all to 20 and then I'm just going to grab the values from here.
22:53	And we'll just extrapolate those up, we'll right click here and all we're going to do is fill column values this time.
23:01	Alright, let's have a look at our graph now and see how that's all panned out.
23:05	Alright, we've got a much better result down here in our low RPM area, everything's following the sort of trends we'd expect.
23:11	We do also still have a bit of a jump here and really again this isn't going to be very critical to the actual operation of the engine but for the sake of completeness, let's go back and we'll address that as well.
23:28	Alright, so at this stage we've really taken care of our steady state tuning using our laptop tuning software, we've got a nice smooth trending graph doing exactly what we'd expect and we're ready to move on.
23:39	Before we get into our wide open throttle tuning though, we'll just have a look at the process of using our touchscreen to optimise our timing and steady state conditions.