Resumen

En este seminario web, veremos cómo optimizar el arranque en frío con la plataforma Haltech NSP en la ECU Elite 2500. Para este seminario web, utilizaremos un Mitsubishi EVO 9.
00:00 Hey Team, Andre from High Performance Academy, welcome to another one of our webinars.
00:03 This time we're going to be looking at cold start tuning on the Haltech NSP platform and specifically I'm sitting here in our Mitsubishi Evo 9 and we're using a Haltech Elite 2500 ECU but this is going to be broadly applicable irrespective of what Haltech product you've got.
00:20 Now, as usual we will be having questions and answers at the end of this webinar so if you've got anything on the topic that maybe you want a little bit more information on or something that I don't cover that you wanted to know about, you can ask those questions in the chat, we'll get into those at the end.
00:36 Now, for me, when it comes to cold start tuning, this is actually one of the harder parts of tuning an engine and what I'm always trying to do is essentially replicate factory drivability.
00:47 So, what I mean by that is I don't really care if the engine is hot, cold, whether we're in the middle of summer and it's 35°C outside or maybe it's the middle of winter and there's snow and ice on the ground.
01:00 I'd like to ideally be able to reach in through the driver's door, turn the key and have the engine start and idle smoothly and consistently without me needing to nurse the thing on the throttle.
01:11 More on top of that though as well, it's not just about the idle and how the engine idles when we first start it, it's also about drivability off idle.
01:19 So, again if we jump in the car, there's ice on the ground outside, it's minus zero and we start the car, we want to also be able to immediately put it in gear and drive away.
01:30 Smoothly without it sort of lurching or basically being difficult to drive.
01:34 And this is more difficult than it would seem but I think on top of this, one of the reasons why so many aftermarket ECUs exhibit poor drivability and don't do all of those things that I've just talked about is that tuners don't take the time to actually do this job because it is time consuming and we'll find out there's some other caveats around this as well.
01:54 And on top of this, they probably don't actually understand the tables and controls that they have at their fingertips in order to actually make these changes.
02:03 So, we'll get into it and see what we can do to help improve our cold start drivability and our cold start performance.
02:10 I think it's probably safe to start with just a bit of a broad understanding of why we actually need cold start enrichment or a cold start system in the first place and this really comes down to the way fuel is combusted.
02:25 Most people think that we inject fuel, it gets atomised by our injector, it gets into the combustion chamber and then it burns.
02:32 A subtle aspect of this though is that liquid fuel actually doesn't burn very well and even the best atomisation from our injector, that still actually doesn't get the fuel into a form that's really easy to combust.
02:44 What we're actually relying on is that fuel evaporating, turning into a gaseous state or a vapour before it enters the combustion chamber or as it enters the combustion chamber.
02:55 And this is done because of the heat on the intake port wall.
03:00 The intake manifold wall and even the back of the valve.
03:03 Obviously, there's also a lot of heat in the combustion chamber once the engine's running.
03:07 So, we're relying on that phase change from a liquid into a vapour state or a gaseous state in order to make our fuel really easy to combust.
03:16 That's easy once our engine's up and running for all of the reasons I just said.
03:20 All of those parts of the engine are nice and hot and that promotes the vaporisation of our liquid gasoline.
03:27 That doesn't happen quite so easily though.
03:30 That happens when the engine is cold.
03:31 So, the elements or the components inside of gasoline will tend to vaporise at different temperatures so it's not just one temperature where everything goes from liquid to vapour.
03:42 This process sort of starts somewhere around about 40°C.
03:45 And obviously if we're starting our engine particularly in the middle of winter, we're not going to be anywhere near that and that's the problem.
03:52 So, we need to find a way or promote this vaporisation.
03:55 What we get instead when we cold start the engine is a lot of the fuel that's being injected by the fuel injector will actually condense out or wet out on the port walls, the back of the valve etc and then it tends to sort of run into the combustion chamber as a liquid.
04:11 Now, all's not entirely lost at this point, of course we have compression that works in our favour as the intake valve and the exhaust valves are closed, we've got our fuel and air mixture trapped inside the cylinder albeit a lot of this in liquid format as the piston comes back up to top dead centre on the compression stroke.
04:28 Compression creates heat and that can help with the vaporisation and of course the spark itself also helps to ignite the fuel.
04:35 But even if we can get the fuel to initially start combusting, we're going to be in the situation where a lot of the fuel that we've injected is not going to be in a gaseous form so we're going to end up with an air fuel ratio, an overall air fuel ratio that's too lean to burn.
04:52 If we're solely relying on the amount of fuel that we'd need to inject if the engine was at operating temperature.
04:59 Alcohol fuels make this much much worse.
05:02 Because they're a more pure, I guess, fuel in terms of the components that go into them, we find that essentially these do vaporise essentially almost all at one temperature.
05:13 It's much much higher than gasoline, maybe somewhere in the region of 60 to 80 degrees C.
05:18 And that is why if we're cold starting on ethanol based fuels or full methanol, cold starting particularly in winter climates where we get temperature changes, down below maybe about 5 degrees C positive, that's where I start to find that it can be difficult and in some cases impossible to get good cold start performance on ethanol, essentially no matter how much effort you put into it.
05:40 Sort of a side note here, this is why when we look at pump gasoline, sorry pump ethanol, pump E85, in parts of the world where we do get very cold climates, they're called E85 but the specification actually allows down to I think off the top of my head, about 60, maybe 65% ethanol.
05:59 So, winter blends of pump E85 can actually have a reduced ethanol component and there are other gasoline based components that are more volatile and by volatile I mean that they will evaporate more easily and that helps promote good cold starting.
06:15 So, a little bit of a sidebar but essentially what you need to know is if you are running on a pure E85, by pure I mean not that pump E85 with the reduced ethanol content, you may find that at very cold climates, no matter what you do, you're simply not going to get adequate cold start performance and that is why.
06:36 Alright, so we've talked about why we need it.
06:39 There's a number of parameters here that will also influence how much cold start enrichment we need or how much additional fuel we need to provide.
06:48 A lot of this comes down to the design of the intake track and where the injector is placed.
06:53 Injector atomisation and spray pattern can also affect this.
06:57 Essentially we've got our injectors placed a long way away from the intake port, then there's much more intake track that will allow that fuel to wet out, condense against the port wall, so it makes the matters worse.
07:10 Fortunately most modern port injected engines do tend to have the injectors placed right up by the port and essentially facing the back of the intake valve.
07:19 So, that's less of an issue but just a consideration if you've got an engine where the injectors are further away.
07:26 We've got a throttle body injection which I guess you could consider the worst case scenario here.
07:30 So, ultimately what we need is additional fuel and we need this in a few different forms.
07:36 What we're going to need we'll find is we're going to need additional fuel during cranking to initially get the engine to fire up cleanly.
07:44 Then we're going to need warm up enrichment which is essentially going to depend, I like to set this up as a three dimensional table, it's going to depend on our load or more specifically our airflow.
07:56 And it's going to depend on our coolant temperature.
07:58 We'll get into this and we'll have a look at some of these tables in a bit more detail but essentially what we find is that as our load or airflow increases, and I certainly don't recommend that you take your car out when it's stone cold and automatically go straight to, or immediately I should say go straight to full throttle, that's obviously not advisable, but essentially if you did that, the additional enrichment you would need at maybe part throttle 2000 RPM versus the additional enrichment you would need at 2000 RPM in wide open throttle, very different.
08:29 The higher airflow sort of promotes better fuel air mixing and we don't need as much enrichment.
08:36 So, where possible, I like to set up a three dimensional table.
08:39 Otherwise you're going to essentially be too rich at higher airflow values for the same temperature or you're going to be too lean at lower airflow values.
08:49 It's going to be an impossibility to get everything right.
08:53 OK.
08:53 So, let's jump into a few of the problems around this as well before we jump into the actual tables.
08:58 It's important to sort of have a basis of this before we jump into the software and look at what's going on.
09:03 So, the first problem we have is that in most instances the cold start tables work as modifiers or corrections to our base fueling or our base VE.
09:14 So, what this means, simply put, is that we need our base VE table to be properly tuned before we get started.
09:22 So, let's just jump across to the tuning software for a moment.
09:27 We'll just have a quick look at this.
09:28 Now, despite this being a cold start webinar, our evo here is actually at operating temperature.
09:34 It's going to be impossible for me to properly demonstrate cold start performance anyway so I'm just going to talk you through things.
09:41 But what I wanted to show here is at the moment we're idling, we can see we're at about 900 RPM.
09:47 We've got our coolant temperature at 88 degrees C and our air temperature at 60 degrees C.
09:53 Over here on the right hand side we can see we've got our target lambda is 0.95 and we're matching that really nicely with our measured O2 or lambda at 0.95.
10:02 Obviously, it's moving around a little bit but we're there or thereabouts.
10:06 What I wanted to show you here, and there's a bit of a heat soak here going on so this has actually changed since I started the car but we are running in closed loop and we can see that at the moment we're pulling around about minus 4% fuel out.
10:18 It's a moving target obviously.
10:19 It's probably about as much as I'd like to see being pulled out but essentially before we start going into tuning our cold start and our warm up enrichment, what we want to do is make sure that this VE table is dialled in as accurately as we can because if it isn't, if we're seeing trims here of maybe plus or minus 15%, our base VE's just kind of not in the ballpark at all, we're going to be, essentially that's going to be, we're trying to fudge errors in our VE table essentially with our cold start enrichment.
10:51 And this works irrespective of whether we're using closed loop control or not.
10:55 So, it doesn't matter whether you prefer to use it or you don't, we just want to make sure that the fuelling in our VE table is on point.
11:04 Now, another subtle aspect that goes into this as well, when we're talking about cold start enrichment we're obviously mainly prioritising our fuelling but this really goes hand in hand with our idle speed control as well.
11:17 So, there's a bit of to-ing and fro-ing here.
11:20 What I mean by this is that right now as we've discussed, we're sitting at a normal operating temperature with a idle speed of around about 900 RPM.
11:29 It would be typical for an engine like this with stock cams that maybe at 0 to 20 degrees C we would target a higher idle speed, maybe in the vicinity of 1200 to 1300 RPM and we'd gradually taper that off as our coolant temperature comes up to our normal operating temperature.
11:48 So, on that basis what we want to do is not only make sure in our VE table here that our VE values down at 850, 900 RPM are correct, we also want to focus on these areas up at 1000, 1250, maybe even slightly higher.
12:07 So, a way of doing this because obviously once we're up to temperature and we're tuning, we are now, as we've discussed, at 900 RPM.
12:17 We want to target a higher idle speed even with the engine operating at normal coolant temperatures and allow us to make sure that we've got those areas dialled in really tightly.
12:26 Otherwise again we're going to get ourselves into trouble when it comes to these correction factors that we're applying.
12:31 Alright, so that's the main fuel table, the main VE table and what we need to do there.
12:39 So, the other thing we want to also do is just make sure, and this is something that's caught me out a few times.
12:45 A little bit again aside from our main topic but if we come into our corrections here and we've got our coolant temp correction table, we'll go to this.
12:55 Always a good idea to just check before you start your actual tuning on the dyno or on the road to make sure that under the normal areas, normal coolant temperatures that we expect to be operating, we want to just make sure that we don't have any corrections going on in this table.
13:12 Typically that should be the case but particularly if you're dealing with, with a map that someone else has created, you absolutely do not know for sure that that's going to be the case.
13:22 So, you might find out that at 70 degrees or 75 degrees C, there's a correction there.
13:27 Maybe your radiator's really effective and you're actually dropping in and out of that correction temperature and that'll drive you nuts wondering why on earth is the fueling changing under conditions that it shouldn't be.
13:41 So, that's our first place to start there is making sure that we're actually checking that we have our VE tables dialled in correctly and that we don't have any weird corrections going on.
13:52 The second problem that trips people up with cold start enrichment is understandably if we want to tune our cold start performance, the engine has to be truly cold.
14:03 And the problem with this is we're going to naturally come off the end of a tuning session, be that on the dyno or the road and obviously at that point the engine is up to operating temperature.
14:15 And realistically if you want to get a decent crack at this, you are going to need to let the engine cool down overnight.
14:23 It's difficult because a lot of tuners want to move a car through, get it on the dyno, tune it and get it out same day and that's just not going to allow you the opportunity to have a really good look at the cold start performance.
14:35 So, when I ran my old tuning shop, when we had cars dropped off for a tuning session, it was always a two day operation.
14:43 We would do the dyno work the first day and any road tuning and then we'd allow the car to cool overnight and we would address the cold start performance the next morning.
14:53 This often still needs two attempts and there's a bit of to-ing and fro-ing here.
14:58 I've already mentioned that idle speed comes into this, I'll talk more about that as we go.
15:03 And you've got a few tables that we're going to need to dial in so two attempts would probably be pretty typical but if you are relatively new to this and you're a little bit slower, because obviously you've got a very short window before the engine is actually up to operating temperature.
15:18 So, if you're a little bit slower, this may take three to five attempts.
15:21 No big deal if it's your own car but if you're doing this for customers, then that's difficult to get that done quickly and easily in just one session.
15:32 Another problem that you also need to consider is that if you live in an area where there's quite a significant difference from summer to winter in Queenstown where we're based on the classic example, in summer we may only get down to maybe 12 to 15 degrees C in the morning, we're probably seeing temperatures in the high 20s to even low 30s occasionally later in the day.
15:56 In winter it's not uncommon to see temperatures of minus 5 to even minus 10 in the morning.
16:01 What I mean by this is if we are doing a tuning session in the middle of summer, we can extrapolate the results we're seeing out to those lower temperatures but we obviously aren't going to be able to test that.
16:13 We're going to test the performance at minus 5 degrees C.
16:15 So, this can mean that while the engine will operate perfectly in the middle of summer, once we get into these colder climates, colder temperatures in winter, we might start to find some problems with our idle speed, control, our cold start enrichment.
16:28 So, again this really comes down to just educating the customer and setting expectations.
16:34 Again, as my old shop, I would always tell customers under those circumstances, hey look, this is what we've done, we can only deal with the temperatures we've got, it's in the middle of summer, if you do find that in the middle of winter the performance is a little bit questionable, bring it back and we're happy to adjust that free of charge.
16:51 It just means that when the customer finds that maybe the cold start performance isn't as good as it was in summer, they're not going to sort of blame the tuner, they're going to understand why that's the case and they know that they can bring it back for free and get that sorted out.
17:04 So, always a good idea to go through that process.
17:08 Alright, let's jump back into the software here and we'll talk about the different features and options that are available.
17:14 And if we look over in our fuel tuning, we'll find all of these under fuel tuning here in our dropdown menus.
17:21 So, if we expand that out, let's just close down our engine functions for a moment.
17:25 Go to our fuel tuning and what we've got for a start is our fuel prime pulse and our cranking.
17:33 So, these two tables work to help get our engine initially started up.
17:39 And they kind of work hand in hand.
17:43 It's a little difficult to explain but let's go through it and see what we can do.
17:46 So, we'll start with our fuel prime pulse and I like to sort of consider this to what you'd do if you had an old carburetted engine.
17:54 Generally, when we go to start those engines, we'll give the throttle a pump and the throttle pump will then basically provide fuel to start wetting out the port wall.
18:05 So, that just helps get the engine started.
18:07 This is essentially doing the same.
18:08 So, what this does is it provides an initial pulse of fuel.
18:13 When engine RPM is first detected.
18:18 So, it's one single pulse from all of the injectors and that will just help wet out the port wall and allow us to get the engine started quicker.
18:26 And we can see that this is a two dimensional table versus our coolant temperature.
18:31 And this is actually just the base Evo 9 map.
18:35 I'd always start with a default map and then adjust this if necessary rather than sort of trying to come up with these numbers from scratch.
18:43 We can see that we've got larger numbers down at colder temperatures and then of course these taper away because we don't need so much of a prime pulse when the engine is truly hot.
18:53 What I'd also do with this particular table, we can't dial this or our cranky enrichment in realistically with a wideband air fuel ratio meter.
19:03 So, both of these are really done by sort of feel and how crisply the engine starts up.
19:09 So, I'll talk about some processes we can go through on this in a second.
19:13 We'll jump down to our cranking enrichment.
19:15 And this again is a two dimensional table versus our coolant temperature.
19:19 So, this table though occurs while the engine is considered to be cranking.
19:24 Again, we're going to need more fuel when the engine is cold and less as we get up to temperature.
19:29 So, how do we deal with this? Again, we can't use our wideband necessarily.
19:34 We can look at what happens on our wideband immediately after the engine's fired but this is a little bit messy.
19:42 And realistically, I prefer to tune these just based on how the engine's operating.
19:46 Now, if you want to isolate these, what we can actually do is completely disable our coolant temperature correction here and we can disable our post start correction.
19:57 And this just means that we're only working off our VE table and the prime pulse and our cranky enrichment.
20:04 So, this is a good way of just making sure that we're not getting sort of a good cold start or cranking initially and start up based on some combination of these other tables.
20:16 Remember if our engine is stone cold, if we've disabled these two corrections that I've just pointed out, we will find that once we get our prime pulse and our cranking enrichment dialled in, the engine will crisply start up and immediately die because there's no connection between the additional fuel that we've got for that cranking and then what we need to get to our hot running enrichment.
20:39 So, personal preference.
20:40 A lot of this I should have mentioned as well.
20:42 There's no black and white method for how you must dial this in.
20:46 I'm just simply showing you the process that I go through.
20:50 Alright, so how do we make changes to these? Generally, I would start by leaving the fuel prime pulse as it is but the default value's in the table.
20:58 I find that most of the changes that I'm personally making will be to the cranking enrichment.
21:02 There's potentially, there might be considerations with injectors mounted further away from the ports or throttle body injection where a larger prime pulse may be beneficial but when we've got the injectors fitted very close to the valve, I generally find that that's not the table I'm spending the most time with.
21:21 It will be this cranking enrichment table which we've got up now.
21:26 So, the way I will generally go about this is disable those other tables which I just mentioned and try cranking the engine and see how well it starts.
21:35 Now, if it sort of coughs and splutters and doesn't really fire, we could be in a situation where, most likely we're going to be in a situation where we're a little lean or under-fuelled though.
21:46 And we don't really know necessarily the scale of the changes that we need to make.
21:52 You're going to have to do this a little bit by feel.
21:55 So, essentially here what I would do is start by making big changes, big bold changes, double the numbers and then see how that affects it.
22:06 So, don't worry you're not going to end up damaging things, you're not going to be ball washing the engine, you just need to get a sense of whether you need to add more fuel or whether you need to reduce fuel.
22:20 And again, this is a trial and error process.
22:23 So, these big bold changes are going to help guide you quickly in the direction you want to go.
22:28 If you come into this table and you start sort of making changes of 5-10%, it's not going to show you, it's not going to guide you in the right direction very quickly and you can end up a little bit lost.
22:37 So, what I'd do is start by doubling these numbers, see how that works.
22:42 And if it gets better, maybe try doubling them again, you probably shouldn't need to do that.
22:46 Maybe if it gets better though, you find that when you double it a second time, the performance drops away.
22:51 OK we've gone too far, we've got too much fuel.
22:53 Go back to where you were, now maybe halve that number so you're sort of between your starting point and the first set of changes.
22:59 So, by doing this doubling and halving it allows you to really quickly dial in where you need to be and get that engine up and running crisply.
23:07 Another trick that I will do here is because the danger to cranking, too much cranking enrichment is not necessarily you're going to bore wash the engine or anything like that.
23:19 But more that if you are repeatedly cold starting the engine, and this goes for your cranking enrichment as well as these other tables.
23:27 What you can find is that if you've got too much enrichment over time, maybe 5-6 cold starts in a row, you can end up with the spark plugs becoming fouled.
23:37 Obviously, is a problem, then the engine won't start and then the only solution is to remove the plugs, clean them or replace them.
23:44 So, no one wants to be in that situation.
23:45 So, we always want to be basically providing just a bare minimum amount of fuel in order to get the engine to fire up.
23:52 Now, again because this table is two dimensional, what we'd want to do is check this down at our cold start up temperatures, maybe 0 to sort of 10 degrees C.
24:01 But also we want to sort of look at another couple of data points here, so maybe 40 to 50 degrees C.
24:06 And then obviously the sort of, it's very easy to check this when we're at our operating temperature as well.
24:14 So, you don't have to tune every cell, very easy to just put maybe three or four points across this table and then interpolate between them.
24:21 This table is not super critical, it's not super fussy, so it's kind of a case of we just need to be in the ballpark and that's going to be good enough.
24:31 Alright, so that's our cranking enrichment.
24:33 Once the engine is initially fired, then as I've discussed we need to have sort of some additional fuel until we reach our operating temperature.
24:42 There's a couple of ways that we can essentially achieve this.
24:46 And this again comes down to personal preference.
24:49 So, we basically go through the process of next dropping into our post start correction.
24:54 Now, interestingly, Haltech actually recommend in one of their videos to only use this post start enrichment and we can see this runs out to 30 seconds of operation.
25:05 But you can of course adjust the axis breakpoints here and you can add your own breakpoints out to sort of whatever run time you want.
25:16 It's two dimensional so we've got our coolant temperature on the vertical axis in this case and we've got our run time on our horizontal axis.
25:26 The problem that I see, and again it's up to your own personal preference, the problem I see with only relying on this post start correction for all of our cold start enrichment is that this essentially does not allow us to add a fourth axis where we can account for that airflow or load which I already mentioned.
25:46 Just to reiterate, when we're at higher airflow for the same coolant temperature, we're going to find we need less enrichment.
25:53 When we're at lower airflow, maybe idle or part throttle cruise, we're going to need more enrichment.
25:58 So, to me this table on its own is not going to be enough to get the job done.
26:03 And I like to also use our coolant temperature correction.
26:09 Let's come back to our post start correction though and we'll just talk about how we can use this.
26:14 So, first of all, no matter how you're using this table and what you've done with the axis breakpoints, what we want to do is ensure that the last column here is filled with zeros, otherwise we're just going to retain any enrichment values that we've got in this table.
26:30 So, we want to make sure that we're set up like this.
26:31 What we can see here is that at lower temperatures, we start with higher enrichment and then by the time we're up to 30 seconds run time, this drops away, in our case, to zero.
26:42 It could be very different depending on your specific engine.
26:45 Interestingly though, what we can also see is that even at operating temperature, we are still using this table.
26:52 So, when the engine is hot, and particularly when it's heat soaked, we've sort of got another problem which is very similar to cold start enrichment where we may find that we're not able to get around that heat soak, we need some additional enrichment.
27:05 So, that's what we've got here going on in this table.
27:09 At this point though, our engine is in fact running, so what we can do now is start using feedback from our wideband air fuel ratio sensor to help guide our tuning efforts.
27:21 This table will work on top of our coolant temperature correction though, so generally what I'd like to do is start essentially with our coolant temperature correction, and we'll have a look at this table here.
27:33 Again, we've got the three dimensional table, we've got our manifold pressure, so load, in this case on our x axis, and we've got our coolant temperature on our vertical axis.
27:45 So, what we want to do is basically start the engine, we've already got our prime pulks and we've got our cranking enrichment dialled in to get the engine started crisply.
27:56 Now, because we're going to deal with this table first and then we're going to come back to post start correction, we're going to find that probably for the first 10 or 15 seconds, we may find that the fuelling isn't quite right and the engine's running a little bit lean.
28:10 What I want to do is basically allow everything to stabilise so that we would be running mainly, or completely I should say, on our coolant temperature correction table.
28:19 And then we're going to be just taking note of our wideband reading here versus our target, and we're going to be making corrections in this table as required.
28:30 So, I've also got quite broad breakpoints here on our load axis.
28:34 You can get a little bit more granular with this if you want but we don't need to be too fussy with it.
28:40 So, we're probably going to be starting somewhere down around here at idle, we'll just allow everything to stabilise and then we're just going to basically tune the particular cell we're accessing.
28:50 And then obviously at idle we're just going to move up this column.
28:54 Now, again if you want, depending how fussy you want to be with this, obviously if you want to treat this as a three dimensional table and get the results that I was talking about where we don't need as much enrichment at higher air flows.
29:07 And we can sort of see that if we look at one of these rows.
29:10 You can see at minus 10 here, we're sort of starting at 44.5.
29:13 By the time we're at 100 kPa, so we're in positive boost here, we're down at 13.6.
29:19 Now, I can't necessarily say that's right, I haven't gone to one bar of boost at minus 10 and I absolutely don't intend to.
29:26 But you can sort of see the trend there.
29:30 It can, as you can hopefully understand here, take a reasonable amount of time to get this all dialled in.
29:36 Now, one little trick that's worth mentioning here as well is that if you are running in closed loop, obviously the closed loop control system is there to correct any errors in the fuelling that we have.
29:48 So, if we aren't sort of displaying what our short term fuel trims are like I've got here, it can be really easy to look at our measured lambda and say to ourselves well we're on target so no need to make any changes.
30:01 So, either make sure that you're paying attention to the short term fuel trims like I've got or alternatively it may be easier for you to place the engine into open loop while you are dialling this table in.
30:13 Alright, so a little bit out of order here.
30:16 So, we've at this point should have our coolant temperature correction table dialled in.
30:21 Once we've done this then I would come back and start looking at our post start correction.
30:26 So, we again need the engine back to being completely cold and we're going to go through the same process.
30:31 We've got again our cranking enrichment dialled in to start the engine crisply.
30:36 We know that for a given coolant temperature, once the engine's sort of stabilised and reached equilibrium, our coolant temperature correction is dialled in.
30:44 So, now this table here becomes the last part of the puzzle that we want to dial in to sort of trim the fuelling if you like between the initial start up and once we're dropped into our cold start, our coolant temperature correction.
30:59 So, again, a lot of moving parts here and it does take a little bit of time.
31:06 Essentially initially you're going to be sort of moving between tables and it gets a little bit frantic because you're trying to catch all of this before the engine comes up to temperature.
31:15 But again if it's your own car, no big problem.
31:17 Have another look at it the next day and the next day take your time and get it dialled in.
31:21 It's really more of a problem for professional tuners who don't necessarily want to be around the workshop for, you know, maybe three to five days.
31:30 They want to get it back to the customer and keep the customer happy.
31:33 A few more things that we're going to deal with but at this point I'll just mention if you've got questions now is a great time to put them into the chat and we'll get into those in a moment.
31:44 Alright,, one other aspect with our coolant temperature correction here is we can see that up here at 110 degrees C and 120, particularly under the sun, under load, we've got some positive trims so we're now actually adding fuel back in.
32:00 So, this is not for obviously any cold start enrichment consideration, this is more engine protection.
32:06 If our engine's starting to overheat, it can be beneficial to start adding a little bit of additional fuel, rich in that air fuel ratio to help sort of prevent the onset of detonation or not potentially.
32:19 There's a couple of considerations though with this.
32:21 If we are running in closed loop, then obviously when we get up to this point, this section of our coolant temperature correction table, the closed loop control is simply going to be removing that fuel.
32:34 So, it's not actually going to achieve the aim.
32:37 Likewise, at the flip side of that, when we are targeting perhaps lambda 1.0 at idle and cruise, which would be pretty typical, we may find that when the engine is very cold, we actually get better performance by targeting slightly richer, perhaps 0.95 under idle and cruise until we're up to maybe 50 degrees C or something like that.
32:58 Some implications on emissions here, but I won't get too derailed on that.
33:03 So, what we want to do as well is come over and have a look at our lambda corrections.
33:07 So, we'll open that up.
33:10 And if we look here at our coolant temperature correction, we can see that I have done exactly that.
33:16 Basically, we've removed a little bit from our lambda target table at 120 degrees C and likewise we've removed some down below 20 degrees C.
33:25 So, that's just going to richen our targets and we need to consider that based on the numbers that are in our base lambda target table.
33:33 So, that's just going to be an adaption on the numbers in this table.
33:38 Obviously, we know the two numbers, we can figure out what we're actually going to be targeting.
33:43 So, that's one thing that again a lot of people get wrong.
33:48 Just basically not adjusting the lambda target table to suit, trying to add in these corrections and then finding that essentially the closed loop control undoes all of what they're trying to achieve.
34:01 Obviously, not an issue if you are running in open loop.
34:06 Now, the other thing that is a consideration here is our idle speed control, which I've mentioned a few times.
34:12 So, let's close down our fuel tuning for a moment and we'll come to our engine functions and our idle speed control.
34:18 So, again we're sort of trying to tune the fuelling and our idle speed control hand in hand.
34:23 What we want to do is start with our target RPM and make sure that this makes sense.
34:28 So, we can see here down at 20°C and below, we're targeting at 1300 RPM idle and then when we're out at our normal operating temperature, 850 RPM.
34:39 Worth just mentioning, a little aside from our cold start tuning, we do need to just make sure here that the target idle speed is sensible for the engine.
34:48 And what I mean by this is if we're tuning let's say an LS2 with a stock cam, that's probably going to idle quite happily at 650 RPM, maybe even a little bit lower.
34:58 Put a really aggressive cam in there and it's probably going to need to idle at more like 850 or even 950 RPM for big race cam that's not streetable, maybe even higher again.
35:10 So, what I'm getting at here is if you've got a really aggressive cam with a lot of overlap and you're trying to make it idle at the target idle speed for a stock camshaft, you're going to be chasing your tail here and bashing your head against the wall because you are simply not going to be able to get the engine to do what you want.
35:26 So, make sure that your targets are sensible.
35:30 What I'd also do with this when you are dialling in your idle speed control is I would place it in open loop so that you are not going to have the ECU trying to fix the problem in the background.
35:41 What we want to do is essentially come down to our closed loop or base table here, idle speed target, sorry, this is our stepper motor position actually.
35:51 So, we want to basically tune the numbers here, so let's say we're starting at 20 degrees.
35:56 This has got vehicle speed on an axis for some reason, I don't necessarily think we need that.
36:04 This could easily be a two dimensional table but what we want to do is basically make sure that at 20 degrees C, the numbers in this base table actually achieve our target idle speed of I think that was 1300 RPM.
36:17 If not, we need to correct it.
36:19 There is to-ing and fro-ing with this though because the idle speed's also going to be affected if our air fuel ratio is excessively rich or excessively lean.
36:28 So, in both situations, that'll drag our idle speed down.
36:32 So, we want to make sure that both our fuelling is correct and then we come back and we adjust our idle base output table in order to achieve that.
36:42 So, again as you can see, we're flicking backwards and forwards between these and the faster the engine warms up, the quicker we're going to have to work.
36:52 The other consideration here is with our ignition tuning, I don't tend to make too many changes to this but we can see under corrections, we have a coolant temperature correction and we can see that actually lo and behold, this has got some positive numbers in here from a base table.
37:11 So, what that's going to actually do is add some ignition timing at cold start at idle.
37:20 We may find that once the engine is started up, a little bit of additional timing can actually help.
37:27 If you've been following HPA and you've understood our tuning process, you'll know that what we're trying to do is essentially for idle ignition control, we want to make sure that our base ignition timing in our table is below MBT.
37:43 And why we want to do that is because if we've got say base timing of let's say 16 degrees, that means that we can advance the timing and gain torque which ultimately will raise our idle speed or we can retard the timing and that will reduce torque and that will drop our idle speed.
37:59 So, we're using ignition timing there to help control and we can sort of see, if we look at our ignition advance angle here, that's exactly what's going on while I'm talking here.
38:08 Ignition timing's flicking backwards and forwards between positive and negative and that's making really fast instantaneous changes to our ignition timing to get our idle speed where we want it to be.
38:18 So, the problem with this though is that if we're in a situation where we're struggling to get the engine to initially fire up and let's say we've got 10 or 15 degrees of timing, what we'll actually find, and this is more important as well with alcohol fuels which are much more difficult to light off at cold temperatures, what we'll actually find is that we need to, or we will get better results if we retard the timing to let's say maybe zero degrees top dead centre or maybe five degrees before top dead centre.
38:48 So, the reason for this is the closer we fire that spark plug to the top of the stroke during cranking, the more compression we have and essentially the more heat we're creating.
39:00 So, as I mentioned at the start, that is a big help to start vaporising that fuel.
39:04 So, just considering what we're doing with our ignition timing, and we do have the ability here of course as well to have our cranking timing set independently, so yeah we might find that at cold temperatures, we may find that we get a benefit from retarding that to zero degrees.
39:20 Five degrees which I've got on this map here, it's probably a little bit more retarded than I'd normally run, so maybe at operating temperature here, I'd typically have this more around 10 degrees.
39:31 If we go too far, we can get a situation where we start getting the engine sort of kicking back, particularly if we've got a big aggressive cam in it.
39:39 So, there we go, that's hopefully the process, I'll just quickly recap before we jump into questions, so the important thing to consider here is we must have our base VE table diverted, dialed in accurately first because these warm up corrections all modify or work on the base fuelling.
39:55 So, if we don't have that dialled in, all bets are off.
39:57 We also need to make sure that our engine is truly cold and just again we need to allow the engine to cool down potentially overnight and those considerations of a summer tune versus a winter tune come in there.
40:10 We're going to start with our prime pulse which as I mentioned, typically I don't find I need to adjust in the r-cranking enrichment, making those large block changes to see how the engine responds because we're not really reliant on our wideband.
40:25 From there we're going to zero out or turn off our post start enrichment.
40:30 We're going to dial in our coolant temperature correction and once we've got that dialled in, we're going to re-enable our post start enrichment.
40:37 Basically, bridge the gap between when the engine first fires and when it drops into smooth operation under equilibrium on our warm up enrichment.
40:45 Hopefully that all made sense.
40:47 Let's jump into our questions and we'll see what we've got in there.
40:51 If you've got any more questions, keep them coming.
40:57 VK1's asked, do you generally alter the coolant bias charge temperature tables from the supplied default values during cold or hot starts? Charge temperature tables are a tricky one.
41:08 These are generally beyond most people to actually dial in because how do you know how to adjust that table? So, most people leave these at the default values and I don't typically change those for cold start.
41:24 We do have a webinar if you want to learn more about how I approach charge temperature tables.
41:33 For those who aren't aware, charge temperature estimate table essentially biases between the coolant temperature and the air temperature sensor based on RPM and load.
41:44 The premise of this is what we're really trying to do is model the temperature of the charge as it goes past the intake valve and clearly we can't directly measure that.
41:54 So, typically in the past, everything's been done purely off the air temperature sensor.
41:59 Which does make sense, it's measuring the air temperature but of course when we're at idle, we've got low air flow, particularly if we've got the sensor mounted in the intake manifold and it's a cast aluminium intake manifold, we end up with a lot of heat soak that's passed into the air temperature sensor.
42:16 So, we can end up with a skewed result.
42:19 It's not really giving us the true charge temperature that we want and under those conditions, the coolant temperature can actually be a better model for what the charge temperature's going to be because the charge has basically been picking up heat from the intake manifold, the intake ports etc.
42:36 So, under those conditions will bias towards engine coolant temperature.
42:41 High load, high RPM, we've got a lot of air flow now, there's not so much time for it to pick up temperature from the intake manifold and port will, so under those conditions, the air temperature sensor's more relevant.
42:52 So, hopefully that helps with an explanation for you.
42:56 Next, question, Troy has asked, my S15 with an RB25 running drive by wire on a Haltech on E85.
43:03 Issue I have with cold start is the drive by wire doesn't open at all.
43:06 Have to push the pedal about 10% in the car for it to start.
43:09 Took out fuel but then it won't start.
43:11 Haltech told me that it's normal after they looked at my tune file.
43:15 Is there a fix for this? Starts perfect and idles on its own after about one minute of holding the gas pedal.
43:20 It sounds to me from that, it's interesting that Haltech have said that's normal.
43:24 I would absolutely not have said that's normal.
43:26 It sounds like perhaps you haven't got sufficient range with the drive by wire idle speed control.
43:34 It's not fresh on my mind so I can't give you the specifics.
43:38 Again, we've got a idle speed control Haltech webinar which goes more into detail on this.
43:43 But essentially with drive by wire you're setting your range so the base table will be a 0-100% and you're setting what 100% is relative to in terms of drive by wire throttle opening.
43:59 So, why we want this is obviously we want good resolution so we don't want a massive range.
44:05 If we just allowed a full range of drive by wire movement then the base table would be, would have very poor resolution.
44:13 We don't want to have really bad control.
44:15 So, it would be typical maybe to limit the drive by wire opening to maybe 8-10%.
44:20 In some instances though you may need maybe 12-15%.
44:24 So, I would say that's where I'd probably look.
44:26 That's definitely not something that I've encountered and not something that I would consider to be normal.
44:33 Next, question, Haltech or MoTeC for a built 04 STi pushing around 450? I'm just worried that the MoTeC will end up being too much for me doing this as a hobby.
44:42 The MoTeC seems like it has a stronger trans control.
44:45 I was just told that MoTeC is harder on the DIY tuner than Haltech.
44:49 This becomes really a personal preference.
44:52 I think for a lot of tuners, particularly novice tuners, that the MoTeC is quite a daunting system.
44:59 We do have a lot of worked examples on the MoTeC platform, both, well not both, the M1 platform specifically and we do have an M1 software tour, software guide.
45:09 So, that would be helpful.
45:12 Both ECUs are going to be more than capable.
45:14 There's absolutely nothing between them in terms of whether the Haltech or the MoTeC is going to be better and realistically the power is not that important.
45:23 When you say stronger trans control, I'm not 100% sure what you're referring to there.
45:28 I'm going to assume you're talking closed loop gear control for sequential or paddle shifted transmissions and if that's what you're referring to then yeah absolutely, I couldn't agree more.
45:37 The MoTeC is closer to a professional motorsport grade ECU for that.
45:42 But if you're running a conventional 5, 6 speed gearbox then there's really nothing to it.
45:49 I think you would probably find that Haltech has broader support from more tuners.
45:55 And so if you're not tuning it yourself, you're probably going to find more tuners that you can take your car to.
46:02 And if you're learning yourself, again there's probably just a broader range of knowledge on the Haltech system.
46:09 Again, we've got worked examples for our practical standalone tuning and a heap of webinars on both of those platforms.
46:16 Alright, that's all the questions we have so we will leave it there and as usual if you're watching this in our webinar archive at a later point and you do have further questions, please ask those in the forum and I'll be happy to answer them there.
46:29 Thanks for watching and we'll see you all next time.