Practical Standalone Tuning: Step 9: Full Power Tuning
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Step 9: Full Power Tuning
16.30
| 00:00 | - Now that we've done the steady state tuning, it's time to have a look at the full power tuning on the dyno. |
| 00:05 | Now that steady state tuning as you can see, it takes quite a while to do. |
| 00:09 | And it's really worth spending your time there because basically we're tuning the entire engine in three dimensions. |
| 00:16 | What that means is, doesn't matter what combination of engine RPM and load you use, the ignition timing's going to be optimised, as is the air fuel ratio. |
| 00:26 | So you're gonna get good fuel economy, you're gonna get good power and good torque out of the engine, and most importantly it's also going to drive smoothly. |
| 00:33 | Now that's really important and it's an area that 90% of tuners just don't focus on. |
| 00:40 | Once we've done that though it's time to actually do the power runs. |
| 00:44 | This is the glory part of tuning where you finally get to see some power numbers up on the dyno screen. |
| 00:49 | And I'm going to show you how that all works. |
| 00:52 | Before we actually get into the tuning, there's a couple of things I would do to the maps just to get us ready. |
| 00:58 | So we're still on the ignition timing map here. |
| 01:01 | What I'd wanna do is we just want to start off and make sure that we're safe. |
| 01:06 | So we wanna be conservative and creep up on the peak numbers. |
| 01:10 | So what I'd start by doing is taking two degrees out of the top two rows of the ignition map. |
| 01:16 | We'd also swap through to the fuel map. |
| 01:19 | And likewise I would add in either sort of 3% to 5% of additional fuel to those top two rows. |
| 01:28 | I'd like to start out rich and with a conservative ignition timing. |
| 01:34 | OK so that gets us ready there. |
| 01:35 | Now if we swap over to the dyno screen, I'll show you how we would set that up for a dyno ramp run. |
| 01:43 | Now we want to replicate as closely as possible the way the car accelerates down the street. |
| 01:50 | I've personally found that a ramp run length of around about one second per 500 RPM is a good starting point. |
| 01:57 | And we can set those parameters in here. |
| 02:00 | However we don't wanna start, we've only tuned our engine fully out to about 5000 RPM. |
| 02:05 | So we know we should be pretty safe out to there. |
| 02:08 | We don't wanna go all the way to 7000 on our first run. |
| 02:12 | So what we'll do is we'll just cover the areas that we've done on our steady state tune. |
| 02:18 | So we're going to go between 2000 and 5000 RPM over a six second ramp run. |
| 02:36 | OK so once we've done our ramp run, first of all what we're going to do is forget about the ignition timing and we're basically going to treat this the same way we did the steady state. |
| 02:44 | We want to get our air fuel ratio correct first. |
| 02:48 | So if we cycle through, we can look at the air fuel ratio that we got during that run. |
| 02:54 | And you can see that we've got quite a bit of variation from where we want to be. |
| 03:00 | The scale that I'm using on the dyno though does make that look a little worse than it is and if we sort of zoom out a little bit, we can see that it's actually not too bad at all. |
| 03:21 | OK so what we can see is that we're a little bit lean between around about 2500 RPM, and also at around about 4750 RPM, we're also a little bit rich which is what we'd expect because we added some fuel at around about 3500 RPM. |
| 03:40 | So what we could do there is we can just use our have over want formula. |
| 03:46 | So we'll start with 2500 RPM, so we'll go to that area. |
| 03:51 | Generally I would concentrate on the top two rows here. |
| 03:55 | And we're around about 5% too lean. |
| 04:00 | So we'll multiply that by 1.05 to add 5% to it. |
| 04:06 | At 3000 RPM we're actually very slightly too rich. |
| 04:10 | We're about 2% rich so we'll multiply that by 0.98 At 3500 RPM we're about 5% rich. |
| 04:21 | So we'll multiply that by 0.95 At 4000 RPM we're actually bang on our target at 0.90 So at 4750 RPM we're lean. |
| 04:37 | And then again at 5000 RPM we are bang on. |
| 04:41 | Now this highlights what I was talking about earlier, where we're quite good at 4500 RPM and also we're quite good at 5000 RPM but we're lean at 4750. |
| 04:54 | So how we can address that is we can simply press the A key and we can add in another row at 4750 RPM. |
| 05:04 | If we press OK that'll automatically interpolate those numbers. |
| 05:07 | But what we wanna do is leave, for the most part, everything alone. |
| 05:11 | Right up in the top end where we're lean, we're going to add 5% in there. |
| 05:16 | OK so that should be pretty much good to go. |
| 05:19 | What we're going to do is we'll extend our RPM for the next run out to 5500 and we'll add another second to our run length, and we'll do another pull on the dyno. |
| 05:55 | OK so if we swing back and have a look at the air fuel ratio you can see that we're now quite a lot better than what we had before. |
| 06:03 | We're still a little bit rich through this area here from 3000 through to about 4000 RPM. |
| 06:10 | We're about 2% rich. |
| 06:12 | At 4500 and 4750, we're about 3% lean, so let's just sort those two areas out first. |
| 06:20 | So we'll go to 3000 and 4000 and 3500 and we'll multiply that by 0.98 So we'll take 2% out. |
| 06:32 | Then at 4500 and 4750, we're going to add in 2%. |
| 06:41 | OK in the top end there at 5500 we are a little bit too rich but we're pretty close, we'll just take out 2% there. |
| 06:50 | OK we're looking pretty good so we will increase our run length through to 6000 RPM. |
| 06:58 | And again we'll add a second and we're good to do another run. |
| 07:19 | OK one of the great features of the M150 is the onboard logging. |
| 07:25 | If I just press the T key we can see here we've actually got our target lambda and our measured lambda is logged. |
| 07:34 | And we can see any differences in the target versus actual here. |
| 07:40 | So we can use this as well as we can use the dyno. |
| 07:43 | You can see up here at 6000 RPM we were targeting 0.89 and we've actually got 0.84 so we're around about sort of 5% too rich there. |
| 07:55 | So I can use the data logging to basically do the same function that I'm doing with the dyno. |
| 08:02 | So I'll multiply the 6000 RPM area by 0.95 You can see while we've got some small fluctuations up and down around our target, we're actually pretty good right through most of the map there and we can see exactly the same result if we look at the lambda plot on the dyno. |
| 08:23 | OK so I'm pretty happy with that, we've made a change at 6000 RPM. |
| 08:26 | We're just going to increase that out, just for speed I will go out now to 7000 RPM and we'll increase our run length to 10 seconds, and we'll see what we get. |
| 09:00 | OK so again everything's looking pretty good until we get into that area of the map that we haven't accessed so far, and you can see we go very rich above about 6500 RPM. |
| 09:13 | So what we want to do there is highlight those particular areas, 6500 and 7000 RPM, and we'll just copy that, translate that through to the rest of the map. |
| 09:24 | We're around about 6% too rich there. |
| 09:29 | So we'll multiply that by 0.94 and we'll do one more run and see where we're at. |
| 09:59 | OK so basically everything is looking pretty good for most of that run there. |
| 10:06 | We're still a little bit rich at 6500 and 7000 RPM. |
| 10:10 | So I'll just make one more change at 6500 RPM. |
| 10:16 | I'll multiply that by 0.98 And at 7000 RPM and above, multiply that by 0.95 OK so you can see we can really quickly use that have over want formula to dial in our tune and get our air fuel ratio close really quickly. |
| 10:39 | Now most tuners won't do that, what they'll do is they'll do a run, see they're a little rich, they'll make a small change, maybe one or two numbers, do another run, see if that worked, and it takes a long time to dial the tune in that way. |
| 10:52 | Using the have over want formula, particularly if we've got a well programmed fuel model like the M150, and our injectors are properly characterised, we can get this done really quickly. |
| 11:04 | OK so now we've got the fuel dialled in, what we can do is we can have a look at how we can do that same with the ignition timing. |
| 11:14 | Now what I'll do, just to show you how that works, we've already taken two degrees out of the top two rows of our ignition map. |
| 11:21 | I'm just going to take another 5 degrees out, and I just wanna show you how quickly and easily we can dial in that ignition map. |
| 11:29 | So first of all what I'll do is I'll clear the dyno and we're going to lay down a base run, so we've got something to compare against. |
| 11:54 | OK so first of all we are down on power over the numbers we were seeing just before. |
| 12:01 | What we can see though is that last little change that I made to the fuelling, has pretty much cleaned up that last remaining difference and we've got basically exactly what we're asking for. |
| 12:11 | 0.90 tapering off to 0.87 And you can also see, which is another thing a lot of people don't understand, is that change that we made in the ignition timing which was quite dramatic, 5 degrees, has made no difference to our air fuel ratio. |
| 12:27 | So now what I'm going to do, is I'm going to do another run, and I'm going to add two degrees back into the ignition map, the areas that I just removed the timing from. |
| 12:38 | And we're going to do another run. |
| 13:01 | OK now once we've done that, what we wanna do is jump across to the dyno screen and we can compare both the torque and the power. |
| 13:10 | And you can see from the torque graph here, we're comparing the initial base run, which was red, with this green run we've just done. |
| 13:17 | And you can see basically everywhere from about 2500 RPM right the way through the entire rev range, we've picked up torque. |
| 13:25 | What that means is that extra two degrees has moved us closer to our MBT timing. |
| 13:32 | Basically the engine has wanted that extra timing everywhere. |
| 13:36 | We haven't seen a massive improvement down below 2500 RPM. |
| 13:41 | If I was to do a run like this and see that change, what I would do is I would take that two degrees back out below 2500 RPM. |
| 13:53 | But above 2500 RPM where the engine has responded, I would add another two degrees and do another run and see if the torque continues to increase. |
| 14:05 | So we'll do that now. |
| 14:29 | OK so when we compare the blue run that we've just done with our green run, again you can see that basically we've picked up torque everywhere right though the whole rev range. |
| 14:40 | Now again that suggests we're still creeping up on our MBT timing, the engine's still responding, it still wants to see more ignition advance. |
| 14:49 | So I would continue to add two degrees throughout the entire map. |
| 14:54 | So we're going to do another two degree increment now and just see how the engine responds. |
| 15:03 | OK we'll do another run. |
| 15:28 | OK so what we can see, again we've picked up more torque, although if you look at the difference between the purple and the blue run, you can see that we haven't picked up very much. |
| 15:38 | What that means is we're getting very close to our MBT timing through this mid range area of the RPM range. |
| 15:46 | However in the top end it has picked up quite a considerable amount. |
| 15:50 | And that's shown through in the power output as well, we've picked up some power at the rear wheels. |
| 15:56 | The problem was right at the top end of that run, we did actually encounter some detonation. |
| 16:01 | So again we're basically running an engine that's high compression on a fuel that's really too low in the octane rating and that's limiting us. |
| 16:09 | So what we'd do there, because we've had some detonation, we'd remove that two degrees of timing back out to a point where we know it's safe. |
| 16:16 | So using this technique of doing ramp runs, adjusting the ignition timing, and seeing how the engine responds, it's a really quick way of actually optimising our ignition map and you can get the results very quickly. |
