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Practical Diesel Tuning: 3. Configure Base Tune File

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3. Configure Base Tune File


00:00 - Alright so so far we have read the stock file out of the truck, VCM and the TCM.
00:06 We've talked about preparing the vehicle for tuning so talking about what kind of shape the vehicle should be in, what kind of things you want to look at to make sure before you tune the truck that it's in good shape and there's not going to be any surprises with either the truck or the customer.
00:21 And now we're finally to what I would call the fun part which is configuring the base tune.
00:24 So for this exercise we're going to be working in HP Tuners VCM Editor Suite.
00:29 We have the ECM file in front of us here along with the TCM.
00:33 We're going to jump into the ECM tune here and talk about how the ECM logic works and how the ECM's going to look up the fuelling rate for the truck and then how we're going to go about adjusting that.
00:47 OK so I click on the engine icon and that brings me up to the general page for the engine.
00:51 There's all sorts of tabs on here, don't be overwhelmed.
00:55 Let's just go through and look at the logic here.
00:58 So as I think about how the truck is picking its horsepower number or making its power using the ECM, I like to start with my driver wish and that is how I push the throttle down, that's the start of things.
01:09 I want power, I push the throttle down.
01:11 So let's look there.
01:14 Under torque management, we'll go to desired torque.
01:18 And that desired torque normal engine is where everything starts and what this table is is across the top we have an axis for RPM.
01:27 So whatever the RPM, the engine speed vs the accelerator pedal position.
01:33 So as I push the pedal position down further, up to 100 I'm requesting more and more torque.
01:39 And the shape of this curve should look pretty normal so as I push the pedal down, the torque number goes up and as the RPM goes higher in the rev range we call for less torque.
01:50 That's because less torque is needed to maintain a consistent horsepower number which is really what we're looking for, consistent feel on the pedal and that consistent feel comes from a consistent horsepower number so I'm going to right click on this graph and move it around a little bit.
02:02 But as you look at the shape of this graph, understand this is kind of the normal shape of this graph and this is what I would call a consistent pedal position or a consistent throttle feel.
02:11 Meaning you push the throttle 30%, you're going to get a consistent horsepower number all the way through.
02:16 So what do I take away from this graph? Well the interesting thing I see here is in the bottom row.
02:22 I'll draw your attention to row 100% throttle.
02:25 And we know this truck makes its peak power between 2800 RPM and 3000 RPM.
02:32 Interesting things here is that we're calling for between 825 foot pounds and 735 foot pounds of torque.
02:38 What does that mean? Well the engine control module is trying to keep track of the torque number and it's trying to do that so that it knows what it's transferring to the transmission and all the modules are in sync and communicating, this is the right torque number, let's look back and see how we get that power number.
02:53 OK so we know what kind of power we want to make, now we have to look that up.
02:56 So how do we make that power? Well we need the ingredients to make the power.
03:01 We need engine speed, we need fuel and we need air.
03:04 Ignition timing or spark, or start of advance, start of injection for a diesel.
03:11 But let's talk about the 2 basic ones, fuel and air.
03:13 So fuel is the most important one in my opinion in a diesel.
03:17 The rest of it is turbocharger, let's jump into the fuel side.
03:20 So at 2600, let's just make it simple, let's call it 3000 RPM.
03:25 735 foot pounds, so know that number, 735 foot pounds, 3000 RPM.
03:31 From there I'm going to take you to the torque to fuel quantity.
03:34 This torque to fuel quantity, is the lookup for the fuel rate.
03:38 When I say fuel rate, I'm talking about a fuel volume and that's a fuel volume that's injected on every power stroke.
03:44 So as that piston comes up towards top dead centre on the compression stroke, goes into the power stroke, this is the amount of fuel that the injector's going to inject.
03:53 You can see down here at idle, we have very small amounts of fuel, so low RPM, low engine torque, we have low amounts of fuel on the order of 7-10.
04:07 At higher loads, so at 1032 foot pounds at 3000 RPM, we're looking at 123 mg.
04:16 So mg is milligrams.
04:18 Milligrams is the weight of the fuel, you'll hear me call it mm³, it's just stuck in my brain, mm³ would be the volume.
04:26 Either way this is the fuel rate.
04:29 So if we want to get more torque out of the engine, more torque at RPM meaning more horsepower into the engine, we'd have to find a way to increase this fuel rate.
04:37 This fuel rate is directly correlated to the horsepower output of the engine.
04:41 So we talked about in the previous video that we wanted to add about 80 horsepower to this truck.
04:46 Start on these trucks is about 395, 390 depending on cab configuration, tyres, age of the engine etc.
04:53 Let's just round it up, let's call it 400 rear wheel horsepower.
04:56 So if we want to get 480 rear wheel horsepower we're talking about an extra 20% output.
05:01 If the truck is currently making X fuel rate, we want to do 1.2 times X as our base cal to get us started towards that extra 80 horsepower.
05:11 Remember the 735 we just talked about earlier so 735 foot pounds at 3000 RPM is roughly what the engine's calling for.
05:20 Let's go down here, so let's cross reference.
05:25 737's pretty close.
05:28 3000 RPM.
05:30 81 mm³ and then the previous one I think was 830 so it's running right around here, right around here.
05:39 So somewhere between 80 and 100 mm³ or mg sorry as the truck is calling for that fuel rate.
05:45 So in this file, as I look to add more power I have a multitude of ways I can do that.
05:50 Some are better than others.
05:52 There's ways that I can cheat the system, there's ways that I can work in perfect harmony with the system and there's ways that I can do a little bit of both.
06:00 I'm going to show you the grey area, I'm going to show you a little bit of both because it's probably going to be the most useful to you as you go past 80 extra rear wheel horsepower.
06:09 If I only need to add 20 rear wheel horsepower to a truck, I can easily do that by simply requesting more torque in that driver demand table and then making sure that I get that extra torque by finding the limiting tables and adding to them and I'll show you those in a bit.
06:23 However in a situation where you're looking for a substantial amount of extra fuel, you're going to find that there's torque limiting tables that you're not going to be able to get past.
06:33 Let's say you want to make an extra 150 or 200 extra rear wheel horsepower, you're talking about 400, 500 extra foot pounds of torque.
06:42 There's limiters in the ECU and TCU that are not mapped in this software and you simply won't be able to get past those limiters.
06:50 So I'm going to show you kind of a way to work around that that's still effective as far as maintaining lambda, maintaining a clean truck, maintaining a good running truck.
07:00 In the situation we're in here we're looking for an extra 20% fuel.
07:05 As I look at this table, I know I'm running in this row at 3000 RPM at full tilt so as long as I hit this row and I add 20% more fuel there I should be able to get my extra 80 horsepower.
07:22 So what I'm going to do is I'm going to ensure that I get there by selecting the row above it, selecting 663 down to 1032 and these are all these torque lookups for all these RPMs.
07:34 Then I'm going to go in the adjust bar, I'm going to type 1.2 for 20% and I'm going to multiply.
07:43 When I hit that multiply button you'll see that fuel call jump.
07:47 It's now 97.
07:49 So we're calling for quite a bit more fuel and that's all the way through the rev range here.
07:54 So any time the truck is operating in the blue range it's going to get 20% more fuel than it previously was so any of those torque numbers are now going to be at 20% more fuel.
08:04 If you look at the map you can see that there's a little bit of a chasm here.
08:07 And I just want to address that real quick by showing you one of the smoothing functions, this is called straight line interpolation.
08:13 You can come in here and grab the 516 to the 663, interpolate between those vertical bounds and if you watch that chasm it closes right up.
08:22 So now what I've done is I've said any time the truck is over a 663 foot pounds, or really over 590, go ahead and give it 20% more fuel than previous.
08:35 Now I've done that for config mode zero, keep in mind these are all torque to fuel quantities so you have to do a similar operation to these dozen or so tables.
08:47 If you want to ensure that any time the truck is operating at any altitude under any conditions you get that extra fuel.
08:53 Now odds are it's not going to be operating in majority of these tables for the majority of the time but unless you're logging it to see which modes it's operating in and really targeting those modes, the shot gun approach works.
09:06 So I'll save you the time of editing all these and we'll move on from here.
09:10 So while we're on the topic of fuel quantities, I want to draw your attention to the injector pulse width table.
09:16 This table is the lookup for injector on time.
09:18 You'll hear this a lot in diesel tuning, it's a very common table to manipulate.
09:22 This table tells the injector how long to energise for a given fuel quantity lookup.
09:29 So for instance we talked about 81 or 97 mm³, or mg, let's call that 100, now this table's going to say based on the actual rail pressure, so there's a rail pressure sensor on a common rail, based on what that sensor is reading, how long to energise the injector? The temptation for a lot of guys is to go into this table first and modify it by 20%.
09:55 So they'll go in and they'll say OK well I know the truck is operating somewhere up here during its normal operation and I want more fuel.
10:03 So 1.2, multiply, boom the injector stays on 20% longer, boom more fuel, now we're really going to make some power.
10:13 Now I'll just caution you against that right out of the gate because once you do that, truck no longer is able to calculate its fuel rate and when it can't calculate its fuel rate it can't maintain lambda.
10:23 Can't maintain lambda, you can't keep emissions equipment happy, you can't control your smoke output accurately.
10:28 So I'm just going to control Z that change out and show you my considerations in this table.
10:34 In the previous table that we adjusted, the torque to fuel quantity lookup, you can see that the maximum in there was somewhere in the 140s.
10:40 Now we're looking for an extra 80 rear wheel horsepower.
10:43 But maybe in the future you're looking for an extra 150, 200 rear wheel horsepower, 300 rear wheel horsepower.
10:49 Something where you're going to need 200 mm³, 220 mm³.
10:53 If that's the situation, you're going to be beyond this axis so if you're ever calling for more than 160 mm³, you're going to have to modify this axis.
11:06 You can do that by coming in here and adjusting the axis.
11:11 Let's say you want to run it out to 80, or 180 I'm sorry, or 190 more easily.
11:17 If I wanted to run it out to 190, that's fine, but I need to adjust this column out here to define what 190 is 'cause remember currently this column is defined under 160 'cause that's what it was previously.
11:30 The difference between 160 and 190 is pretty similar to the difference between 130 and 160, talking 30 mm³, if I take this row, copy, paste and subtract.
11:49 Then I copy this quantity, control Z those changes out.
11:57 Paste and add.
12:00 I've just taken that 30 mm³ difference in injector on time and I've added it to the 160 which was that column and now I have a fairly accurate representation of what 190 mm³ would look like on this truck.
12:12 I'm going to leave it in there because if I ever want to in the future, it's there, I can go to 190.
12:18 OK so we've added fuel, we've added that 20% fuel, let's talk about the other important ingredient, airflow.
12:24 Head over to torque management under turbocharger and I'm going to show you some things in the boost control.
12:31 So this truck is equipped with a variable geometry turbocharger meaning that you can command boost.
12:37 It's not a wastegate deal, it's a variable geometry unison ring control setup so there's no wastegate but you can command a certain boost pressure up to a point.
12:45 So if I'm adding 20% fuel, I want to make sure that I have the ability to match that 20% extra fuel with the extra airflow that's needed so that we can run at that stoichiometrically appropriate level.
12:57 The reason we want to do that is so we can control particulate emissions.
13:01 If we can keep the truck from smoking, we can keep the DPF happy at that higher power level, we can keep everything operating the way it's supposed to.
13:09 So let's take a look through here.
13:10 The labelling on some of these tables leaves a little bit to be desired so let's just talk about some of these tables here.
13:15 You've got boost control 3, any time you see in the boost control a table ranging from 0 to 100 it's probably a vane position control table.
13:25 Now this table appears to me to be a feed forward vane position table.
13:29 This is not something I want to modify right now.
13:32 Any time I've leaving the factory turbocharger on the truck, I'm going to leave this feed forward vane position.
13:37 Really all this table does is tell the turbocharger what position it should be in at the start of that particular load and that particular RPM.
13:45 So what vane position should I be at, 516 foot pounds and 2800 RPM.
13:52 It's tempting to want to adjust this table first, my recommendation would be not to.
13:56 And the reason I say not to is because the turbocharger works on what's called a PID loop meaning that it's targeting a certain boost pressure so if you tell it what boost you want, it'll go to that feed forward vane position first, sure but then it'll tweak itself a little bit to get that desired boost.
14:12 As long as you're within the min and max limits of the vane control.
14:15 So let's look at the other boost set points.
14:19 Ah this looks a little more like it.
14:20 OK so this is a very common map for boost control.
14:24 What this is is a PSIA graph of desired boost.
14:29 I say PSIA because ambient's included in there.
14:33 So at idle, 14.5, your first clue when you see 14.5 in the upper left hand corner here near idle should tell you that's a sea level boost control table.
14:45 I say sea level boost control because at sea level, ambient air pressure's right around 14.5, 14.7 thereabouts.
14:52 So any time I see that I think sea level boost control and then the table is based off of the axis of torque and then the axis of RPM.
15:02 So at a certain torque level, say 1033 foot pounds and a certain RPM, say 3000 RPM, we're looking at 43.5 PSIA.
15:13 If you subtract that 14.5 ambient air pressure out of there you get about 29 pounds of boost commanded so that's the total boost command at 1033 foot pounds and 3000 RPM.
15:29 Now remember we didn't skew any of our torque numbers, all we did was add fuel for a given torque lookup.
15:36 So remember it started right around 664 and went to 1033 in our torque to fuel quantity lookup.
15:44 What we did was we told the truck at those torque levels we're going to add 20% more fuel so what we should do likewise is add something like 20% more air.
15:55 That's going to get us pretty close to start for our stoichiometric situation we want to be in.
16:03 So what I can do is highlight those same columns and come in here and add 1.2 multiply and that'll put us in an airflow situation that's going to be pretty favourable as long as the turbocharger can keep up.
16:17 Now again when I did that to the boost table it does something similar to what it did in the torque to fuel quantity lookup, we have that chasm.
16:26 And that chasm exists between 590 and 664 foot pounds.
16:32 So what I want to do is bridge that chasm.
16:34 And I'll show you another way to do that here.
16:36 It isn't the interpolate but rather smooth.
16:41 So these 2 buttons here are the interpolate buttons.
16:45 These ones over here are the smooth buttons.
16:48 For this particular job, I'm going to smooth between horizontal bounds.
16:52 So you can see that I have chosen my 590 to 738 and I'm going to click smooth between horizontal bounds and I want to draw your attention to that chasm as I click.
17:06 You can see how that chasm dropped, the 664 boost call dropped a little bit and put us right in line, a nice smooth boost call up to where we need to be.
17:16 Now remember our truck is running somewhere between 835 and 735 foot pounds at full throttle.
17:23 So our boost call is going to be somewhere between this 41 total, pull 14 off of that, so we should see boost somewhere in the high 20s as far as this truck goes, 27, somewhere around there.
17:42 27, 28, we'll pay attention on the scan tool as we start to dyno the truck and optimise this file.
17:49 You might be thinking, well Nick, couldn't we have just run the truck out to 1033 foot pounds and got the same effect? Yes, the answer is yes we could have gone through and commanded higher torque from the truck via the driver demand table and then the truck would have looked up that higher boost number because there is 1033 foot pounds available here.
18:13 Remember I was showing you the way to do this, if you want to go higher and higher, if you're simply going to adjust the torque number to stay within the lower bounds of adjustment, you may not even need to adjust this table.
18:29 For the sake of our method it's important to adjust this table.
18:32 You can see also that there are multiple boost set points.
18:35 There are boost set points for low altitude, medium altitude and high altitude.
18:41 The easiest way to check and see which table you're in is to look in the upper left hand corner and see what that boost call is at idle.
18:50 If you're seeing somewhere between 14 and 15, you're probably in sea level table.
18:54 If you're seeing 10 to 11 you're probably high altitude, if you're seeing 12 to 13 you're probably medium altitude.
19:00 Medium altitude's usually about 5000 feet, high altitude would be 7500 plus.
19:05 Sea level would be 0 up to about 5000.
19:12 Remember you're going to interpolate between those tables as the truck moves between altitude so your boost call might not be exactly what you put in, it might be a blend between low altitude and medium altitude if you're at 2500 feet above sea level.
19:26 Couple more things I want to draw your attention to while we're in here.
19:29 We're not going to need it at the level that we're operating on this truck but there are some limits in here, so some maximums that you need to be aware of.
19:38 One of those is a maximum boost set point so 50.8 psi, again pull 15 off of that you're looking at about 35 psi, 36 psi for your max call.
19:49 If you're ever running a modified VGT turbocharger or something where you're going to be running boost pressures higher than 35 psi, you're going to want to be aware of this and potentially raise it.
19:59 Also we have some maximum pressure ratios.
20:02 Those max pressure ratio tables are going to want to limit boost potentially based on airflow so pressure ratio would be the multiple from the face of the intake, the face of the compressor wheel into the discharge pipe.
20:18 This table for instance based on airflow may limit your maximum boost or maximum pressure ratio based on airflow.
20:25 So I'd just be aware, any time you're operating in here, take a look around and see OK is there any boost tables, is there anything, any maximums that are going to be inhibiting my call.
20:35 Similar to the torque to fuel lookup table, there's many boost lookup tables.
20:39 I want to go through and adjust all these boost lookup tables.
20:43 I'm not going to bore you with that right now but using the same method that we just used, we're going to add 20% to those boost lookup tables from 664 foot pounds up to 1033 foot pounds.
20:54 All those columns we're going to add that 20% and blend.
20:56 That way we have higher boost at medium altitude, at high altitude etc so we're not limiting the ability of the truck to only operate at sea level.
21:06 At that extra power we're also making it resiliant at higher altitudes.
21:09 OK so let's also, let's flick into the torque model a little bit.
21:14 'Cause there's other things you may want to do besides just add power to the mid range, you may also want to widen the outwarding range.
21:21 On an emissions equipped truck I haven't found this particularly useful but if you're looking for a competitive situation you may want to raise the ability of the truck to make power.
21:34 Remember we talked about 735 foot pounds at 3000 RPM.
21:37 Now that's our call from the driver demand table.
21:40 That's our ask so you can see we're limited to that in this torque limit table.
21:46 This is what the factory call a lug curve so this defines the shape of the torque curve for the engine.
21:52 Remember this is no longer going to be the real torque curve in the engine because we fattened it up by 20%.
21:57 However, if you want the truck to pull harder after 3200 RPM or 3400 RPM or 3600 RPM, let's say you're truck pulling and you want to stay in 3rd gear and really rev the truck out to 3800 or 4000 RPM.
22:11 On our dyno graph when we go to dyno this truck we're going to see a pretty sharp decline after 3200 RPM.
22:16 If I want to widen that operating range, what I might want to do is take this table, might want to copy it, control C and then widen it one cell.
22:27 And then I can blend it between and what that does is allow the truck to run out a little bit further in the rev range so now it's going to pull up to 3400 RPM or so, 200 extra RPM.
22:41 How you modify this table is up to you but just keep in mind that tables like this, these max torque tables by RPM, they're going to have a big implication on the ability of the truck to rev, hit the rev limiter, rev out, whatever you want to call it.
22:55 So be aware these limiting tables are real and they are something I want to talk about.
23:01 So that's a lug curve.
23:03 There's multiple other limiting tables and you'll see limiting tables of a variety of sort in the tune.
23:09 Let's talk about what some of them do.
23:11 Under main injection limit, we have what's called our lambda limit table.
23:16 So these are static, static 1, static 2.
23:19 Truck will toggle between these depending on which mode it's running in and these are lambda limit tables so this is the richest the truck is allowed to run.
23:26 So if you are running down the road in 6th gear for instance and you go to cram the throttle and you ask for that full torque, you want to make big power, you'll get the fuel that's available up to a certain point and usually the first limit that you run into is called a lambda limit.
23:42 So I mean there's not enough airflow to inject the fuel that you want.
23:45 We have to wait for the turbocharger to spool up in order to get these.
23:49 These tables keep the truck clean, they keep the truck from excessive regeneration frequency by keeping soot out of the DPF, keeping the particulate matter concentrations low in the exhaust.
24:01 If you want the truck to run cleaner what you can do is raise these values.
24:05 I usually work in increments of 0.05 or 0.1.
24:10 If you want the truck to run dirtier you can subtract from this table.
24:14 The only time I'd really look at this table in a situation for performance would be under high air loads where I would be considering OK if we're out of air, so let's say we're 200 horsepower in and we're out of airflow, the ECU will pull the fuel rate back in order to keep the truck above a certain threshold for air/fuel ratio.
24:38 So you may want 180 mm³ but it's only letting you get 160, 163 because in this case 1.079 lambda limit.
24:51 Another limit I want to draw to your attention is under torque model.
24:54 You have the torque calculation atmosphere correction limit.
24:57 So I showed you the lug curve limit under max attainable.
25:00 I'm going to show you the atmospheric correction limit.
25:02 What this table does is limit the amount of torque the truck is able to make based on the barometric pressure.
25:09 So barometric pressure would be altitude.
25:12 So 100 kPa would be sea level, 30 kPa would be really really high altitude.
25:19 Usually we see a lot more protection at high altitude on trucks.
25:24 This Ford does not have a particuarly aggressive limiting table.
25:29 If you're using this example as a model, just keep in mind there's a reason the trucks have protection at high altitude.
25:37 High altitude makes the trucks susceptible to turbocharger overspeed, you don't have a lot of cooling because the air is not dense enough to pull heat off the cooling stack.
25:46 Things happen very quickly at high altitude.
25:48 So if you're looking for power at sea level, and you're going to remove limits.
25:53 For instance I'm just going to put an example to that, so let's say I want this limit totally out of the way.
25:59 OK the limit's totally out of the way at sea level.
26:01 The fairly irresponsible thing to do in this situation would be to eliminate the limit at high altitude as well.
26:08 One because you're not testing it on the dyno, you're not running at high altitude, we're not running at high altitude today.
26:14 So it's important to just keep in mind that as you're sending this truck out the door for the customer, remember what's happening not only here at sea level but what's happening at high altitude.
26:23 If you're going to mess with limits, especially anything barometric pressure related, pause, does it make sense? It doesn't in this case so I'm going to go ahead and back these limits out.
26:32 The next thing I want to peak at is timing.
26:34 I just want to look at it because I want to see is the truck set up to time out to the power level that we're talking about? So any time we add more fuel and more air, we need to consider our start of injection.
26:46 Is it appropriate, does it need to be advanced slightly? What's the factory up to? So I'll take you in this scenario, we talked about 738 foot pounds at 3000 RPM.
26:59 Remember I said that what we did by adding 20% to the fuel is very similar to bumping the truck up to that 900 or 1000 foot pounds without cheating the fuel call in the torque to fuel lookup.
27:13 So a good clue here is to look, what's the timing number at 3000 RPM? 8.7, 738, we know we added more fuel so what did the factory do when they had more fuel to add? Well they added about 2°, interesting.
27:28 So what we could do, come in here and copy, notice I selected this whole row at 1033, control C, copy.
27:40 Control V, control V.
27:43 And then I use the interpolation between those rows.
27:50 And what that did was get us that 10° of timing at 735 foot pounds.
27:56 To be more in line with the fuel rate that we're running now that we have 20% more fuel.
28:03 Just like in the boost tables and just like in the torque to fuel quantity lookups, there are a lot of timing tables.
28:10 You can go through and look at each one of these and make a similar call based on the different timing tables.
28:15 As I look through the timing tables, I just want to kind of look in the mid range, look in this range here so medium torque output and medium RPM.
28:25 This range gives me a lot of clue as to what the factory's doing so when I see low numbers here or negative numbers here it makes me think heat up, so I may be using the situation to heat up the SCR or the DPF.
28:38 If I see really low numbers here like maybe -8 to -14, maybe a regen map.
28:44 So be thinking in your head OK is the factory using this timing map for any situation that might not be something I want to mess with.
28:52 Is this for a regeneration map, do I really want to mess with this map? The temptation's usually there in new tuners to advance timing globally on on the whole map across the board.
29:04 And I'll tell you that if you do that, you might run into a situation where you're making excessive knocks, your knock sensors are going to pick that up and they're going to alert the ECU that hey at cruise we're seeing a lot of extra knocks and then you're going to get fault codes, you may see excessive ammonia consumption or diesel exhaust fluid consumption.
29:25 On a tune like this on something that's a reasonable or durable setup, modifying the timing numbers at light cruise or idle or anything like that, it's not advisable.
29:39 And the last thing I want to jump to is fuel pressure.
29:42 So we talked about timing, let's talk about fuel pressure because fuel pressure is part of that strategy that the ECU's going to look at to make fuel volume.
29:51 And that fuel volume's going to translate to torque, it's going to translate to horsepower.
29:55 So one of the temptations I see often in new tuners is to jump into this fuel pressure set point which is under fuel system, fuel pressure.
30:07 I'll click on mode 0.
30:11 Now what this table is, is a lookup for fuel pressure.
30:16 And remember that pulse width lookup was based on fuel pressure and fuel quantity.
30:22 So fuel pressure and fuel quantity.
30:28 So as the truck runs higher load it's going to look for higher fuel pressure and it does that because it can get more fuel in a shorter operating window, better atomisation.
30:43 In general, better performance at higher fuel pressures.
30:46 So the temptation on a lot of new tuners coming in here in the mid range, just like the timing table, and bump up the fuel pressure in the mid range.
30:53 Thinking they're going to get better mileage, better performance in the mid range.
30:56 Remember the factory is trying to balance noise vibration harshness, NOx emissions, which can be negatively impacted by high fuel pressures.
31:04 They're also trying to keep the parasitic load of the pump within reason.
31:10 So remember the higher fuel pressure you run, the higher load runs on the pump.
31:14 Think of a pressure washer when you really turn that regulator up and work the thing hard.
31:18 What I would caution you against is if you can't justify raising fuel pressure, don't touch the table.
31:26 For the most part it's not necessary on emissions equipped trucks running that extra 100, 150 horsepower, not until you're really pushing the truck, you're really trying to stretch the fuel system or keep the injection window tight.
31:38 We're not at that level at this 80 horsepower number, in this case I would not advise changing the fuel pressure.
31:45 From here the only other thing I would look at would be the speedometer setting.
31:48 So maybe the customer wants a little bit higher a speed rating, maybe they changed tyres on the truck, they want 106 mph speed rating, you can go in here and adjust that, there's a bunch of other little things you can go through and click on and look through.
32:02 OK so once I go through and I look at everything I want to do, I get all my, I'm going to go back and knock out all those boost tables and torque to fuel lookup tables, I'm going to save this file.
32:12 So save as, so this is my first mod revision.
32:15 I'm just going to name it what it is.
32:19 So this is an extra 80 plus horsepower, version 1.0.
32:27 I'm going to save it in the same folder as my stock ECM and TCM and the duplicates.
32:32 Now that it's saved, the next step is going to be flashing that file on the truck, then we're going to optimise that file on the dyno by running the file, logging it, getting the fuel rates, seeing how close we are to that 80 extra rear wheel horsepower number.
32:43 We'll do that next time.