Practical Standalone Tuning: Step 8: Steady State Ignition Tuning

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Step 8: Steady State Ignition Tuning

21.52

00:00	Now, that we've got our steady state fuelling dialed in, our next step of course is to repeat this process and dial in our steady state ignition timing.
00:08	Again we're deviating from the normal technique that we teach in the course here because of course we are starting from a base map designed around our LS1 engine.
00:18	Now, again I'm doing this because I'm trying to replicate what I see as the most common use case for the Holley Terminator which would be to start with a base map selected for your particular engine.
00:28	However, you could also go about the normal process that we teach in the course and set the entire ignition table to 15° or something similar and then dial it in from there.
00:39	Knowing these engines like I do, these numbers that we've got here are probably pretty well in the ballpark and we should probably expect that around about 36° in the cruise areas is about probably what the engine will want.
00:52	Under wide open throttle you'll remember that we did have 26° in here and I've just pulled a little bit of timing out to make it safer, but again probably 26°, maybe 28° is about what I'd expect under wide open throttle high load operation.
01:05	Now, given that we are starting from this base map here and we've got such high table resolution, again I'm going to adapt our normal technique, I'm not going to be attempting to tune every single cell here, we'd just be absolutely here forever.
01:18	Instead, what I'm going to do is basically take snapshots within the table, tune the areas that I'm going to take these snapshots from and then interpolate between and you'll see how this works out as we move forward.
01:32	Of course, we're going to be using the torque feedback from our dyno here to help us optimise or find MVT.
01:38	Again we would normally be using audio knock detection here to help see or know when the engine is suffering from knock.
01:45	With the fuel that we're running, as I've already mentioned, knock is just not an issue with this stock relatively modest compression LS1.
01:52	So, let's get ourselves up and running and we'll go through the process.
01:56	Alright, so we've got ourselves up and running here, just allowed some time for our heat soak to dissipate and what I'm going to do here, because of our tight zoning, is I'm going to make changes to a block of numbers, we'll see how these work out and then if required we can do some manual smoothing of the numbers, just get ourselves as close as I can to 1400 RPM here.
02:17	OK, so we've got 18 degrees in there, looking at our torque, we're sitting at around about 27, 29 pound foot of torque, but really just wanting to look at the shape of this graph, what we'll do is we'll press the O key for offset, what I'm going to do here is add 2 degrees, now this won't take effect until I press enter, I'm just again adjusting our engine speed a little bit and I'll try and get as close as I can to the centre of that block of cells, looks like we're pretty good there.
02:45	OK, let's just wait for our torque to stabilise, sitting at around about 27 to 28 pound foot and I'll press enter and we see that our torque did jump up reasonably significantly there.
02:58	So, we've gone the right direction there, we're moving towards MBT, I'll press O again, we'll just again allow everything to stabilise, we'll offset by another 2 degrees and we'll press enter here and again we see our torque noticeably increase, so we're definitely still heading in the right direction.
03:14	Press the O key again, we'll add another 2 degrees here, so this is going to be coming up to 6 degrees of additional timing, we're up to 32, 33 pound foot, press enter.
03:24	Again an increase, but that was quite a small one, so I'd say we're pretty close there to MBT.
03:29	Let's go another 2 degrees though and just see the effect of that.
03:32	Here we'll just let everything stabilise, press O.
03:38	Yeah no real change, not enough for me to be worried about, so there we'll go back and offset by minus 2.
03:44	OK, so that's our first change made.
03:46	And what we're going to do, we can't get down into this lower load area, we just don't have the ability to keep the dyno running, so what I'm going to do is extrapolate the changes we've seen down here.
03:57	So, we'll copy those three cells, come down to the very bottom of our table, Ctrl V, paste those in and then we can just highlight those and by using the C we can fill those columns and that just makes it nice and quick and easy.
04:14	Alright, so rather than trying to creep up here, what we'll do again is just try and speed this process up a little bit and I don't know, we might not be able to get into the centre of these cells anyway, just with the auto, yeah, so that's going to want to change down there, so I'll just let it go back into third gear.
04:36	What we'll do is we'll come up here, this is the problem with an automatic, we don't have the complete control like we would with a manual gearbox, so we can't necessarily access all of these high load, low RPM cells.
04:53	Alright, we'll get ourselves central here, as central as we can, offset here and again we're looking at 2° and we're looking at our torque, so we're sitting currently at about 107, 108 pound foot of torque, we'll press enter here, we see that might have picked up one or two pound foot, let's try again, I don't really think we're going to see much of an improvement here, again we'll make sure we're central, press 2° here, no, absolutely no change, so we've now added 4° so what I'll do is press offset and I'll go minus six, so we'll see if we're maybe too advanced to start with, minus six here, OK, we definitely dropped some torque there, so we'll go back to where we started, press offset with two there, I'll just try another 2° there and just make sure we didn't see a change so 107 pound foot here, press enter.
05:58	Yeah we did pick up a very small amount, but we are starting to split hairs here.
06:03	OK, so let's just now do a little bit of smoothing before we carry on.
06:08	So, what we can do here, we've got 32° here, so safe to say that we're going to be able to accept at least 32° below this, we've got 24° here, what I'm going to, we've got 26° there so, we'll pull this down to 26° as well and now we're going to just sort of smooth these out so, 22° there, we'll go 20° here and then 18° here.
06:37	So, just a manual smoothing, but again remembering we've got such tight resolution here, this is not really too dissimilar to what we'd be doing normally with 20 kPa and 500 RPM increments.
06:48	OK, we'll increase our load again and we'll come up and see where we can get to.
06:53	So, again we see our RPM creeping forward and chances are, again just like we saw, I'm probably not going to be able to get back down to that 1600 RPM, no I'm not, not going to be able to get back down to that 1600 RPM column.
07:07	So, we'll just settle with 1800, once we get up above about 2000 RPM, everything's going to sort of work out a little bit easier for us, but at the moment we're just dealing with the torque converter slip at low RPM.
07:20	So, again we'll just make sure we are central in that set of nine cells there.
07:25	So, again we've got 30° where we're actually operating, we'll offset here by 2°, looking at our torque, we've got 181, 182 pound foot, we'll press enter.
07:40	Absolutely no change, so what we'll do is offset by minus four and just see if we were over advanced.
07:47	And it looks like we may have been, we didn't see any reduction there, so I'll offset again by another two.
07:56	OK, now we see the torque drop away a little bit.
07:59	So, it looks like we were a little bit over advanced there, so let's just come back to stationary and we'll see what we can do with that.
08:06	And what we'll do here is just use our fill column here and we will just smooth that out.
08:14	We'll probably be able to get in 22° there, 24° there and everything's looking pretty good there.
08:22	Alright, let's get ourselves back up and running and we'll have a look at where we can get to next.
08:27	OK, so again our RPM's crept up a little bit, 2000 RPM this time.
08:32	So, we'll just get central with our next cell that we want to adjust.
08:42	OK, so we've got 32° in there at the moment, my guess is that's probably going to be a little over advanced because of the trends that I'm seeing already.
08:50	So, what we'll do is we'll actually start by offsetting minus two and just see if we lose any torque, looking at our torque at the moment, about 236 pound foot, press enter.
09:04	Absolutely no change there, so we'll press O again and offset by another two, minus two.
09:13	236 pound foot still, press enter.
09:18	OK, so we've actually dropped a little there, we've gone down to 233, so we'll go back to where we were, add another two degrees in.
09:30	Very little change there, but we'll leave it at that.
09:35	Now, so we've found basically in those last two cells that we've tried that we have been a little over advanced.
09:42	Let's continue going and again as I increase the throttle here, we're going to find that our RPM creeps up.
09:54	OK, so we're at 2250 RPM here, about 26° in there.
10:00	Again I think we're probably going to find that we're a little bit over advanced here but let's just try pulling two degrees and see where we go to.
10:07	So, 272 pound foot, 273, again no change, we'll try pulling another two degrees here.
10:18	271, 270, we did lose there, so let's add two degrees back in, we might have been in the right, spot after all.
10:27	Add two degrees, yep we've picked up a little bit, we'll try going back to where we were with another two degrees in here.
10:35	Yeah it did pick up a little bit, so let's just try going a little further.
10:39	Go to 28° so again just looking at our torque, 274, 275, nah we didn't gain anything, so go back and take those two degrees back out.
10:51	We'll come back up now to, we can go to wide open throttle.
10:55	Now, I'm going to tune all of these cells, now I expect here we will be under advanced because we pulled that timing out, so let's just try, because it's all the same number, we'll just directly enter 24 here.
11:06	We're sitting at 330, 332, press enter, yep picked up 335, so we've definitely gone in the right direction, we'll try 26, our original number before we double the map down.
11:21	It picked up a little bit again, not much, we'll try 28° but I don't expect we're going to see any gains here.
11:29	Yeah we're splitting here, so we'll go back to 26° where we started.
11:33	Alright, so we've kind of taken a bit of a trajectory through this map that looks a bit like that and we do need to do a bit of hand smoothing in here or at least some smoothing but we'll leave this for the moment because we will just simply rely on our smooth function later on, actually I take it back, we will do a little bit of hand smoothing here because we can take this section here, it's probably a bit of a moot point because we're probably never going to actually be in this region, we're probably unlikely to be at 1200 RPM and high load, we'll just flare through the torque converter and increase our RPM instead but for the sake of completeness we'll just smooth everything out a little bit around this area.
12:16	So, this area here, we'll take this up to 14°.
12:19	I'm going to use the smooth function anyway, so this is just sort of making sure everything makes sense and we'll have a look, these ones here, we'll try adding those to 22 and then we can probably take these to 20 and we've got this area here where our numbers don't really increase smoothly or make sense.
12:38	Alright, we'll press the C key to fill column there.
12:43	It's all looking OK, 26, 26.4, so we step up here a little bit.
12:47	So, again I'll just use the fill column there just to smooth that out, make sure that we are decreasing our timing numbers as we increase the load.
13:01	And again here we'll do exactly the same.
13:05	Right, OK, so we've got everything pretty well sorted there.
13:08	What we're going to do is now come into this sort of low load cruise area, we'll increase our RPM and see how 36° works out.
13:16	Again I'm expecting this to be probably pretty well on the money.
13:19	So, we may be in a situation where we have to start by removing timing to see if we can actually affect our torque, so let's get up and running anyway.
13:29	OK, we're up and running, but if you see with the torque that's on the dyno at the moment, we're only seeing 5-7 pound foot, so we don't actually have enough load to really actually, be able to see a noticeable change in the torque.
13:41	So, we're right on the lower limit of the dyno's load cell there, so we'll just increase our throttle position a little bit, now we're sitting at about 24, just get ourselves back in the centre of that cell.
13:55	20, 21 pound foot, I don't think we're going to see much of a change here.
13:59	We'll start by pulling 2° out and just see what happens here.
14:05	Absolutely no difference, that's because I haven't pressed enter.
14:11	OK, really didn't see any difference there, we'll try offsetting by minus four, let's make a bigger change, so we can really see the effect of this.
14:20	This time we definitely saw a change, we're down to 18-20 pound foot, we still really are on the low side of that load cell though, so not getting repeatable results here.
14:31	Let's just try offsetting by 8° so we'll go 2° beyond where we started.
14:36	Let's press enter now.
14:42	It's up to 22 pound foot.
14:45	As expected I think really where we were is about right.
14:48	We're starting to get into a situation of splitting hairs here.
14:51	When you don't see a noticeable change in torque then you are sort of really chasing something that doesn't really make any difference.
15:01	So, in that case I would prefer to be a little conservative rather than a little aggressive with my timing.
15:06	We'll try another point though.
15:08	Now, that we've got a little bit more load on and we're sort of 56, 57 pound foot, we might see a bit more of a difference here, so let's start again by just pulling some timing out, we'll go to 30° just to really show a difference.
15:20	Just again taking note of where we are, 52, 62 pound foot, no I've just crept up a little bit of load on my throttle.
15:27	We'll get back into the centre there.
15:30	57, 58 pound foot, press enter.
15:34	And yeah we've dropped down to 54, but it's again quite a small change.
15:38	We'll try 34° and just see where we end up there.
15:45	So, that's picked us up to 55, 56 pound foot.
15:50	Yeah I think we're sort of again in a situation where we're splitting hairs.
15:56	Probably could leave that at 34°.
15:59	Let's just be a little bit more conservative.
16:02	We'll see what we end up with up here.
16:08	Just a little bit of adjustment to get us in the centre of our RPM zone.
16:12	OK, so at the moment we're sitting at about 82, 84 pound foot.
16:20	So, let's go to, let's offset by minus four, again we'll start by pulling timing out.
16:29	And we see we lose torque, so we'll offset, we'll go 6° and see if we gain anything.
16:35	So, this is two above where we were.
16:39	Again we're really just going round in circles here and seeing differences of only a couple of pound foot.
16:47	Let's increase our load and we'll come up into this section here.
17:01	So, 32° in the actual cell I'm central on here.
17:05	So, we'll press our offset, looking at our torque at 133 pound foot at the moment.
17:12	We'll add two degrees here.
17:15	Crept up to about 130, 140 even, press enter.
17:23	Absolutely no difference, we'll try minus four and see if we lose a little bit.
17:30	Yeah and we do, so again we happen to be pretty much bang on where we were.
17:36	So, let's come up to full load now and we'll creep up to this section right here, or as close as we can get.
17:49	So, again we're expecting this probably will want to be about 26°.
18:02	So 276, let's add two degrees.
18:10	Yeah 279, we have picked up a little bit, not really very much, we'll try 26°.
18:16	Yeah we're up to 280, let's try 28°.
18:22	No change, so 26° turns out is the magic number there.
18:27	So, let's have a look now, we'll do a bit of hand smoothing before we carry on.
18:30	So, we've dropped these cells here to 34° and obviously as we increase the load, we're going to expect that we're going to want our timing to be there or lower.
18:40	So, what we can do here is we'll just highlight those across, use our fill column, and that's got those lined up quite nicely.
18:51	Now, we're going to repeat this process, I won't narrate this, now we're going to go through to about 4000 RPM.
18:57	I'm really not expecting to see any change in this area.
19:00	It'll be more just a couple of pinpoint areas that I'll check just to confirm for a sanity check, but yeah as I already said at the start, 36° is about what I expect this is going to want in the cruise area and as you've already seen, other than at wide open throttle, it's pretty unresponsive for not that sensitive to timing anyway and any time we've got this situation where we find ourselves chasing a one or two pound foot of torque with a couple of degrees, I'd prefer to be conservative there and just be a little bit safe with a little bit less timing, so let's get this underway.
19:58	Alright, so we've got through to 4000 RPM there and pretty much everything's tracked just about exactly like I'd expected to see there.
20:07	So, this is a much more condensed approach than what we normally take.
20:11	We've only really taken a snapshot of a handful of cells there, but again we're obviously, working from a base map and again the engine is one that I kind of already know what I expect to see in terms of timing.
20:23	So, now we've got a little bit of hand smoothing to do here.
20:28	You can see we've got a few cells here that don't really make sense with the general trend, so we're going to come in here and clean up anything manually that needs to be cleaned up, so we'll set those back to 26°.
20:39	These ones in through here as well, we also want those to be at 26°.
20:45	And then we can also use the smooth function.
20:51	Before we do that though, we're just going to set these cells back here.
20:55	We've got 26° at 4000 RPM, we can be pretty confident that we're going to need at least 26° above that as well at wide open throttle.
21:04	So, everything's looking pretty good there, so let's press Control A to highlight the entire table and we'll just give it one smooth and we'll just have a quick look at that graphically and see what everything's looking like.
21:16	We can also rotate this, so we can sort of get a better sense of what everything looks like, but basically we've got a nice smooth table, everything should be pretty sensible anyway, obviously we've started from a base map and haven't made dramatic changes to it, but it's always a good idea just to visually inspect the table and make sure, that everything sort of checks out with what we expect and we can see that that's exactly the case.
21:41	So, at this point we've got our fuelling and our ignition timing both dialed in under steady state conditions and we can move on to the next step of our process.