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Practical Diesel Tuning: 4. Optimise Tune

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4. Optimise Tune


00:00 - Alright so on our last module we went through and we built a base calibration, remember we have our 2017 F350, we're looking to add about 80 rear wheel horsepower.
00:09 We went through and added fuel, added boost, talked about timing, talked about limiters.
00:12 Basically got a base cal set up so that we can get that flashed in and give us a good start on the dyno.
00:18 So the first thing I'm going to do is key the truck on and get that tune flashed in.
00:25 Key to the run position.
00:30 Click on the vehicle writer.
00:33 So I'm just going to write calibration, I don't need to do a full reflash of the truck.
00:36 Because we didn't make any changes to the TCM, I'm not going to write the TCM so I'm just going to click do not write.
00:42 Go ahead and write, that's going to take a few minutes.
00:44 So today we're operating on the dyno and not everybody has a dyno.
00:48 So I'm going to show you a log file of the stock tune, something you can do on the street with HPT and I'm going to show you the things that I would look at to validate the gains that we're talking about if you don't have a dyno so that you can tell, did the changes that I made in the base cal, did they get me roughly to where I want to be for the power output? It's important to take into concern the fuel rate and the boost rate.
01:13 You can look at mass airflow but looking at the fuel rate, you'll get a really good idea of if the truck is making that extra power that you're asking it to make or not.
01:22 So on this Ford we have a fuel rate PID.
01:25 I'll show you on the scan tool what that looks like as far as on a run.
01:32 We'll look at that maximum fuel rate in that fuel rate PID and then we go to run that bigger tune on the dyno, we'll be able to tell, OK did the truck make 20% more fuel? If it did then there's a good chance that it made that extra torque and that extra horsepower.
01:47 OK so we've written the tune file, it's prompted me to go key off for 3 seconds.
01:52 Key back on.
01:55 Press OK.
01:57 So we have the modified file in the truck.
01:59 I've taken the liberty earlier here of running a stock tune file on the dyno.
02:08 And I just want to look at our log file real quick here 'cause this is something you could do on the street or on the dyno but it's good to have a baseline run of the truck, just so you know what kind of health it's in, you know what kind of fuel rate it's making.
02:18 So I've put up some nice PIDs here.
02:21 I have RPM, I have accelerator pedal position, speed and then the power producing PIDs.
02:26 Alright we have timing, we have commanded boost and actual boost, mass airflow, EGR percentage, I just put that on there so I can see what's going on.
02:37 Fuel rate, that's a big one so if I want to validate my improvements on the street, looking at fuel rate's going to be a good indicator of that.
02:44 You'll remember in the tune file we went in and we looked at that torque to fuel table and we added 20% to that.
02:51 So I'm going to look for about 20% more fuel from our stock run.
02:54 You can see this red line here, it's not a perfectly straight line but we're looking right at the end here, 2700, 2750, somewhere around there is where the truck's going to make peak power so I kind of look at that bump at the end and I see OK 120 mm³ or 120 mg, so I'm looking for about 24 more right, so 144, somewhere in the mid 140s would indicate that we added that 20% fuel rate.
03:21 If we see that on the street we can be pretty sure that we added 20% more torque.
03:26 So we're not just relying on our butt dyno.
03:29 But because we have a dyno of course we're going to compare the stock run on the dyno to our modified tune so we'll see if that base cal's close.
03:37 We're going to be on a Mustang dyno today, we're going to be doing a loaded test, so you guys who are running on the street, I'll give you kind of the simulation that we're using, you can do a similar test on the street.
03:47 But for our dyno test, we're going to be running in manual mode, tow haul on.
03:51 Turn traction control off, we're going to be running in 5th gear and that will give us good bite on the roll set, nice long sweep, it'll be about 8 seconds.
03:59 We're going to start the run at 1800 RPM and run out until about 3300.
04:04 We might stop a little short of that.
04:06 That should give us a nice picture of the torque curve and the horsepower curve.
04:09 Now remember we have the modified tune file in, we're looking for about 480 rear wheel horsepower, our stock tune netted us 398 horsepower and 922 foot pounds.
04:18 So if we can get up in that 480 number, somewhere over 1000 for torque, that'll be a win.
04:25 Now of course we're going to be logging this as we go.
04:28 I have HP Tuners datalogger open.
04:31 I'm going to connect to the vehicle.
04:36 And then I'm going to start scanning.
04:39 All my PIDs should populate, I made some nice charts here and it just helped me kind of get a good picture of what I'm doing.
04:44 I'm ready to go ahead and turn the fan on.
04:46 I have warmed this truck up prior to the run, if you haven't, make sure your truck is up to operating temperature, you don't want to dyno a cold truck.
04:52 I'm full against the brake.
04:55 Release the truck.
05:14 OK so after the dyno run, I like to save the scan because it's nice to have that data saved and if you go ahead and log another one it might log over that one and you'll lose that data.
05:23 So good to stop, save that log file as, that was log, V 1.0 and I looked at the dyno, it was 460 horsepower and 1085 foot pounds.
05:36 460, 1085, not 1800, 1085.
05:46 Well that's encouraging, we've picked up quite a bit of power, we went from 398 up to 458 or 460.
05:51 Call that about 60 horsepower.
05:54 So we were looking for 80, we got 60, we're off to a pretty good start, can't complain.
05:59 So what changed compared to the stock run? Well we certainly got more power and torque.
06:04 But stuff that I'm noticing here as I'm looking at the log file is if you remember that stock run, right around 2750 RPM, 2800 RPM, we said we had 119 or 120 mm³.
06:17 Or mg, whatever our fuel rate, mg sorry.
06:22 And remember what I told you was that if you see that extra fuel rate, we're looking for 20% more so 20% of 120 is 24.
06:31 So we're looking for about 144 mg on our modified file.
06:36 So if we see that on the street, if we see it on the dyno, we should be getting pretty close to our power number, we might have a few other things to optimise but the encouraging part is that we're 142.37.
06:47 So we know our method to changing that torque versus fuel table worked.
06:52 Our method for adding more fuel worked.
06:55 Now we just need to do a little bit of tweaking.
06:57 So other things that are kind of drawing my attention, I'm going to look at timing.
07:02 So timing on the stock file is about 7°, we're about 9.5 now so we did add timing, remember that in the previous module, nice to see that come through.
07:11 Our boost pressure, we're a little short on boost and the reason I say that is I think, pull up the stock file.
07:21 OK I have a stock file pulled up and we're about 39.7 pounds of boost on a command of 43.
07:26 We have something interesting happening here, my vane position says 2.4 and I'm not sure if that's just a bad PID or if the truck is truly at 2.4% vane position.
07:37 The truck seems to drive decently on the street and comes up relatively well on the dyno.
07:41 I know I have a back pressure sensor that's kind of reared its head since we started dynoing it so I did have a code for that, we didn't get to change that so it's possible that the vane positon's back but in any case, 39.7 on the stock file and 41.8 on the mod file.
08:00 OK so we did see a significant bump in boost.
08:03 Yeah that's right around our command.
08:07 So what are some things we can look at in getting this truck up to that 480 number? Well we have a few options.
08:14 We can go back in the tune and we can continue to add fuel using the method that I showed you earlier which might be 1 prong.
08:23 We can also tinker with the timing a little bit.
08:27 So we can go in there and add a degree or 2° of timing up on the top end of that 2600, 2700 RPM and see what that does.
08:37 I would prefer to do that after we add the fuel just to see, if we're making changes, let's make 1 change at a time.
08:44 And then we'll be able to see on the dyno, did the timing net us the power or did the fuel net us the power? We don't want to make multiple changes at once and then we don't know exactly what our limiting factor was.
08:55 Remember this truck does have a lambda limiter on it so if the truck gets too rich, it's going to hold the fuel rate back.
09:04 But we do have airflow sufficient to match our desired fuel rate so I'm not too concerned about adding boost at this point.
09:11 The truck seems to be moving enough air to reach its desired fuel rate.
09:15 So airflow wise, I'm pretty sure we're OK.
09:18 So let's jump back into the tune, we'll go into those diesel fuelling tables that we were in before and we can see looking at the table here, that we were at 142 mm³ at around 2800, 2700 so right in here, right in here.
09:35 So we were somewhere between this 128 and So we know that if we're modifying that what we did before which was modify these bottom rows from 663 up, that that worked.
09:48 Now a simple way to get us from 480 to 460 would be to find out the percentage difference between those 2 and I do that by opening my calculator app.
10:00 Simple enough right, 480 divided by 460.
10:08 4.3%, so if I add 4.3% to here, that should get us pretty close to that 480 number.
10:15 I'm going to round up and I'm going to 5%.
10:18 1.05 multiplied, OK and remember just like before, we want to do that to the other configs as well.
10:31 And I'll just show you on this one kind of some fast tricks for that.
10:35 If you copy this here, control C, control V.
10:46 Click select and mutliply.
10:48 Nice thing about HPT is it shows you which maps you've already modified so you've got the red maps which I've already modified and then I'm going to go through and hit the other configs as well.
10:59 It's kind of a tedious process but by doing this, you'll ensure that no matter what mode the truck is operating in, so whether it's operating in a cold mode or a warm up mode, or desoot mode, whatever it's in, you'll have the extra power over stock.
11:18 I won't bore you with doing the rest of these, sufficed to say we're going to hit every table in here.
11:51 So you may be asking yourself, Nick why are you only modifying the 663 and up? Why don't you modify this entire table? And I'll tell you that the reason I don't modify the entire table is because remember the truck is using this table for more than just your full throttle control.
12:04 It's also using the table for idle and transitions off of idle.
12:08 So as you're running in this area down here, if you start to modify those areas you're going to potentially mess with the quality of the idle on the truck and you may also mess with the feel of the throttle as it comes off of idle.
12:21 In general the truck has a pretty good feel in my opinion, coming off of idle and the idle quality's very nice.
12:27 I don't see any reason to modify the low speed operation.
12:29 When you modify that low speed operation you may impact areas of emissions controls.
12:34 So not changing those areas with emissions controls would be in everybody's best interest.
12:40 After I modify that file I'm going to go ahead and save it.
12:43 So save as, version 1.1.
12:52 The thing I'd recommend is going in and renaming your last version.
12:55 So not changing the name entirely but adding a subtext to it or a post script that says what the horsepower number is.
13:01 Nice thing about doing that is so if you go back and look in the past and say version 1.0, man I don't know what that was about.
13:08 Well now when you rename the thing, you can know, OK when it says 460 horsepower, OK yeah that was a 460 horsepower file.
13:21 It might even be nice to know how many mm³ it made on the dyno.
13:26 Alright nice to have that stuff.
13:28 OK so we now have V 1.1, we're going to do this again, key to the run position.
13:42 If you're flashing and logging and flashing and logging it's important to disconnect your scanner.
13:47 The request for the interface connectivity, if it's hooked up to the scanner and you don't disconnect the scanner, it won't allow you to flash.
13:53 So I just went through and found the scanner and disconnected from the vehicle so that we're not using the scanner and HPT knows it's time to flash.
14:00 Alright we're going to connect to the scanner again.
14:12 Go ahead and start the truck and get a bunch of beeping and messages at me, all sorts of service track and whatever faults.
14:19 It's OK to just click through those, they'll go away as soon as you get off the dyno, nothing to worry about.
14:23 OK so I have the scanner started, I'm going to go ahead and turn the fan on and then make another dyno pass here.
14:55 OK so we finished that dyno pass, let's compare that dyno pass to the previous pass we made.
15:00 The previous pass peaked out at 460, this pass looks like 480 all the way across up top here.
15:11 If you look at the shape of the lines you can see that there's a consistent difference across the run.
15:18 We should see that difference in the log file as well.
15:20 So as I pull up the log file, I'm looking for fuel rate.
15:24 Again remember our run started at about 1800, 1900 RPM.
15:30 Previously we were at that 140 for our fuel rate.
15:34 Now we're seeing 148, high of 148 and we have that 480 horsepower.
15:39 So we also had a little bit more boost, we're up in the 42.3 range here.
15:44 Is this the final revision for the truck? Well if all you want's 480 horsepower, by all means this could work.
15:52 However what I would like to do from here is hone in on making the most out of this fuel rate.
15:59 So it's possible that even though we have 148 mm³ that we could make more power by adding a degree or 2 of timing.
16:07 Possibly adding a little bit of boost to it.
16:09 I would like to start with timing and that may net us 5 or 6 horsepower and we may have to pull back the fuel rate a little bit.
16:16 This is not a 1 size fits all tune, this isn't something where we may one iteration and call it great.
16:23 We're going to go through and make sure we make the most out of that fuel rate.
16:27 So we want to keep the truck as happy as possible, we want to be as efficient as possible.
16:32 Along those lines we're going to iterate in this process.
16:36 It's OK to make those changes.
16:38 If you're making changes to the timing number, to the boost number 1 or 2 psi. rerunning the truck, making sure that it's seeing that change in timing or seeing that change in boost, you're doing it the right way.
16:49 Especially if you have a dyno to show you exactly what's going on.
16:52 As I work on the timing curve, something I'm going to look for is as I add timing, am I getting a diminishing return? So certainly 1° of timing netting us 5 or 6 horsepower would be a nice return.
17:05 If I add 1° of timing and power changes by 1 horsepower, I wouldn't call that a good return.
17:13 So we want to make sure that the additional stress that we're putting on the motor by adding timing or by adding that extra airflow, is making sense.
17:21 That's something that only you and your risk profile can justify.
17:29 That's why it's nice to have a good set of gauges on the truck, be aware of EGTs, be aware of air/fuel ratio etc but for this one, I think this customer's going to be happy, this is a good start for us.