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Practical Reflash Tuning: Introduction

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00:00 - In this worked example we're going to be using the Hondata K Pro tuning platform to tune this DC5 Integra Type R, endurance race car.
00:09 Now as far as the engine goes, this car's actually relatively standard.
00:13 The engine is just fitted with some basic bolt ons including an exhaust system and an intake system.
00:19 We're going to deal with those modifications in a couple of step's time and delve a little bit deeper into how they're going to affect our tuning strategy.
00:28 For now though I just wanted to give a basic introduction to the Hondata K Pro system and discuss how this system works.
00:36 The K Pro system is a daughter board that's fitted inside the factory Honda ECU and essentially this converts the factory ECU into something that's tunable by us, via the Hondata K manager software interface.
00:50 In this respect, we are treating the Hondata K Pro system as a reflash of the factory ECU.
00:58 Even though there are some similarities to an aftermarket standalone ECU.
01:03 As you move through this worked example you're going to find that we have adapted the HPA six step process slightly to better accomodate the Hondata K Pro system.
01:14 Before we get started with the six step process, we're just going to take a few minutes now to talk in a little bit more detail about how the K Pro system works, and really this is all focused around how the factory Honda ECU deals with the tuning on the K20 engine.
01:30 The K20 engine is fitted with Honda's VTEC mechanism which is a switched cam system where there are low cam lobes which are optimised for low RPM engine performance and high cam lobes which are optimised for high RPM engine performance.
01:45 We can switch between these two cam lobes based on engine RPM and engine load.
01:51 The VTEC system is a relatively mature technology now and should be pretty familiar to most people experienced with tuning Honda engines.
01:59 It's the i VTEC system that's incorporated on the K20 engine however which is a little bit unique.
02:07 This is a continuously variable cam control system, where the intake cam can be moved through 50 degrees of rotation, while the engine is running.
02:16 This allows the cam timing to be optimised throughout the engine's lobe and RPM envelope.
02:23 The continuously variable cam control system does present a few challenges for tuning, particularly because Honda have used a speed density tuning system, where instead of directly measuring air flow into the engine using a mass air flow sensor, air flow is calculated using a manifold absolute pressure sensor and the ideal gas law.
02:44 In order for the speed density system to provide accurate results, it does rely on the engine's volumetric efficiency remaining fixed.
02:53 And of course with a continuously variable cam control system, as we adjust the cam timing, the engine's volumetric efficiency is changing.
03:02 Now Honda have addressed this by providing a range of maps inside the ECU for both fuel and ignition.
03:09 Firstly the fuel and ignition maps are split up based on the VTEC operation.
03:14 We have low speed fuel and ignition maps and high speed fuel and ignition maps.
03:20 These are then further split up based on the intake cam position.
03:24 We have a range of maps, in this case actually we have six maps for both fuel and ignition on the low speed, and another six maps for fuel and ignition on the high speed.
03:35 Let's jump into our K Manager software and we'll see how all of these tables are laid out and how we can access them.
03:42 So this is our tables view where we've got our fuel and ignition and we can move between all of our tables by using the four icons in the top left hand corner.
03:52 Right now we're looking at our ignition table for our low speed cam position.
03:56 We can move across to our high speed ignition table by clicking here.
04:01 And then if we move across to the right we have our low speed fuel and then our high speed fuel.
04:07 Of course on the right hand side we have a graphical representation of all of these tables as well so we can visualise what the tables actually look like.
04:15 We can select between two dimensional and three dimensional view using the little buttons at the top here.
04:22 At this point we've looked at our low speed and our high speed fuel and ignition tables based on VTEC point, but of course we also have multiple tables based on the cam position as well.
04:32 We can access this by clicking on the little drop down icon here, and we can see we've got tables for zero, 10, 20, 30, 40, and 50 degrees of inlet cam position.
04:45 So for example if we click on 20 degrees we can see all of the numbers in our high speed fuel table that we're currently on have changed to suit that particular table.
04:56 Now this is where the tuning on the K Pro system does become a little bit tricky and a lot of novice tuners that aren't familiar with this system can potentially come unstuck.
05:07 When we are making tuning changes, it's very important to make sure that we are adjusting the correct fuel and ignition table.
05:15 So it's important to look at what particular cam angle the engine was operating at during a log or while we're running it and make sure that we select that particular cam angle from our drop down box.
05:27 If we don't do this, we can find that the changes that we've just made will seem to have no effect.
05:33 But worse than this we can also find that those changes have actually been made elsewhere and may have unintended consequences later on that we can easily overlook.
05:43 Now there are also two ways we can make changes to the fuel and ignition tables.
05:48 If we want to be very accurate and just adjust one particular cam angle, we can do so as we've just looked at.
05:55 In this case let's say for example, we want to make changes to our low speed ignition timing at 40 degrees of cam angle.
06:03 What we would do is start by clicking on our low speed ignition table, and then we can select our 40 degree cam map, and then we can make changes inside this table that will only have effect at 40 degrees of inlet cam position.
06:19 The other way we can make changes though is to edit all of the tables, or all of the cam angle maps simultaneously.
06:26 We can do this by highlighting and clicking on our little edit all tables box here.
06:34 So if this little tick box is ticked, this means that if we make a change to our low speed ignition timing, let's say in this particular area here, that change that we make, let's say that we add two degrees, that will be added to every cam angle, at that particular RPM and lobe point when we are on our low speed cam operation.
06:56 So there's no correct or incorrect way of using this feature, it depends exactly what we're trying to do at the time, and you'll see how we use that as we move through our worked example.
07:06 As well as our fuel and ignition tables we also have our cam target tables.
07:11 And we can select those from this area here.
07:15 And these are separated into cam targets for low cam operation or low VTEC operation, and high VTEC operation.
07:24 It's important to mention here that while we only have six sets of fuel and ignition tables, we can target cam angles in between those tables.
07:33 So for example we have a cam table at 20 degrees for fuel and ignition, we also have one at 30 degrees, we can target 25 degrees.
07:42 And in this position the ECU will interpolate between the 20 and 30 degree tables for both fuel and ignition.
07:51 The last aspect that I want to touch on here is the numbers that we have inside the fuel tables.
07:58 The Honda ECU is not a VE based ECU, so these are not volumetric efficiency numbers, these are simply a raw number.
08:06 Essentially the ECU uses an injection time based fuel table, and if we double the numbers in the fuel table this will double the length of time that the injector is open for.
08:17 Essentially delivering twice as much fuel.
08:20 So now that you've got a better understanding of how the K Pro system deals with a continuously variable cam control and the VTEC system, we're ready to get started with the first step of our six step process.

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