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Practical Standalone Tuning: Introduction

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00:00 - In this worked example, we're going to be following the HPA 10 Step Tuning Process and applying that to a Link G4X plug and play ECU fitted to this V11 Subaru STi.
00:11 Now the car itself is going to be used as a rally car and there's a couple of elements that I'll just cover off here.
00:18 In paricular, those who are already familiar with rallying will probably know that a lot of turbocharged cars used for rally will incorporate an inlet restrictor on the turbocharger.
00:29 This actually has quite an important effect on the tuning process, and particularly the boost curve that we need to run.
00:37 In this case the car is not equipped with an inlet restrictor and that's going to be important when we are dialling in that boost curve as we go through our worked example.
00:46 The engine itself is a stock standard EJ20, it does use variable cam control or AVCS on the inlet cam only.
00:55 To keep this worked example as simple as we can and focus on the core principles of tuning and using that G4X platform, we will be completely ignoring the AVCS or variable valve timing element of this tune.
01:10 If you do want more information on the variable valve control, because that is quite a large topic and a worked example in and of itself, we do have a completely separate course covering variable valve timing, configuration setup and tuning that you can follow to get a little bit more information on that process.
01:29 The ECU itself, as I've mentioned, is the G4X which at the time of filming this, is the current generation of ECU from Link.
01:38 This, for all intents and purposes, shares a lot of DNA from the previous Link G4+ and the Link G4+ is a platform that we have got extensive coverage and worked example material on already.
01:51 So there's going to be a lot of similarity, however the G4X does also have a few idiosyncrasies and differences and we will be focusing on those as we go through the worked example.
02:04 In terms of what we're trying to achieve here, really the owner of this car just wants a reliable and mild tune so we're not going to be really shooting for the moon in terms of power levels.
02:16 We're probably going to be running this to around about 18 to 20 psi peak.
02:20 Due to the fact that it is still a factory turbocharger, we'll almost certainly find that the boost will start to taper off as we get higher in the rev range.
02:29 Couple of elements that are worth discussing here, the factory boost control solenoid has been switched out for a conventional mac three port solenoid.
02:38 The factory boost control solenoid is a bleed style arrangement and generally this results in less than accurate boost control and also can limit the amount of boost that we can achieve in the top end.
02:51 So for better control, always a good idea to swap one of these out for a three port solenoid.
02:55 In terms of the fuel system, we're running with an aftermarket fuel pump fitted inside the tank, the factory STi injectors and we've got a adjustable fuel pressure regulator.
03:07 While the adjustable fuel pressure regulator is not strictly an essential element, it does give us that flexibility to vary the base fuel pressure up and down as we see fit.
03:16 Given our power aims, we should still have plenty of headroom in that fuel system so I don't believe that we're going to be stretching that but of course we'll see how that actually pans out as we get through our worked example and get stuck into the tuning.
03:29 Another element here that's just worth discussing is the fuel that we are running on.
03:33 This is a locally available fuel from NPD called 100+ and in my experience, this has been a great combination for a pump based gasoline, no ethanol content so to speak, to run on turbocharged engines.
03:48 For the most part, we should be able to get very close to tuning this car, this engine, to MBT timing without the onset of detonation.
03:57 If you are tuning on a lesser grade fuel, you need to be very very mindful of the knock propensity of the EJ20, it is an engine that will knock on low grades of pump fuel.
04:08 Even on our 100+, it's quite likely we may get to that situation and knock will very quickly destroy one of these engines so absolutely essential that you are using audio knock detection or some quality knock detection system to make sure that the engine isn't suffering from knock.
04:24 The other element I will mention here is that once the tune is complete on this vehicle, it will be set up for competition use on a rally stage with anti lag, I won't be covering that in this worked example, again for exactly the same reason as the variable valve timing element, just trying to keep this simple and focus on the core elements.
04:43 The plug and play ECU side of things here is relatively straightforward and really easy to get one of these vehicles up and running.
04:52 It simply requires us to remove the factory ECU from its case.
04:56 The Link G4X plug and play board then bolts straight into the factory enclosure.
05:01 It's got the factory Subaru header plug so everything can just plug straight in.
05:07 One little word of caution here and this is of course covered in the installation manual, there are set of jumpers on the PC board and these need to be configured to suit STi or WRX.
05:19 It's actually not even quite that straightforward but it's again covered in the installation manual.
05:24 The reason I say it's not quite that straightforward, this is to do with the pin outs for the immobiliser and basically if you get yourself into a situation where the ECU won't power up and the engine won't run, it is very likely that that will be your problem so make sure that you read the instructions, of course as always.
05:42 One other element is that the factory ECU case does need to be modified slightly with a slot or a hole that you can pass the tuning cable through as well as the excess connector if required.
05:54 Another point that is worth making here is that the factory STi MAP sensor that is fitted, in this case to the throttle body, this does limit our maximum amount of boost.
06:04 These are capable of reading up to around about 23, 24 psi, about 1.6 bar of boost.
06:11 In our instance, we're not going to be aiming for anything quite like that so we should have enough headroom above our target boost pressure that this will be absolutely fine.
06:20 If you are really going to be pushing one of these engines through, of course it's simple enough to add an auxiliary or external MAP sensor and wire that up to the factory MAP sensor plug, set that up in the ECU which we'll look at and then you can fit a three bar, four bar or for that matter whatever you want to suit your particular application.
06:40 Only other change that's worth mentioning here and pretty standard fare, is that the car has been fitted with a full turbo back three inch exhaust system so that should help improve flow and definitely help improve power, because we aren't running the mass airflow sensor, the factory mass airflow sensor has also been removed with an aluminium intake pipe and pod filter.
07:02 Now that we've got a bit of an idea of what we're going to be focusing on and some of the considerations that we do have to keep in mind, let's move onto the first step of our process.

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