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Practical Diesel Tuning: Live Tuning vs Reflashing

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Live Tuning vs Reflashing

02.49

00:00 - One of the hardest aspects to get used to for those more familiar with tuning aftermarket ECUs is that in most situations the tuning changes we want to make can't be performed live.
00:10 What I mean by this is we can't run the car on the road or the dyno and make adjustments to fuel or ignition and see those results instantly as we could expect with any aftermarket ECU.
00:21 Instead the tuning process requires us to make a test run on the dyno or road, make any required changes to the mapping, shut the engine off, flash the new map into the ECU and finally test again to confirm the effect of our changes..
00:35 This is necessary because the maps in the ECU are stored in read only memory and this information can't be altered while the engine is running.
00:43 On the face of it, this sounds like it might be quite an inconvenience and potentially a very slow and time consuming way of tuning.
00:50 In reality though when we are reflashing a factory ECU, we can often confine the area of engine operation that we need to make adjustments to, to only the high load areas unless we've made dramatic changes to the engine configuration such as adding a larger turbocharger or injectors, camshaft or heads.
01:06 Often the idle and cruise areas of the engine operation will need little to no adjustment.
01:12 It's important to understand that unlike tuning an aftermarket ECU, we will be starting with a calibration or tune that is very well matched to the stock engine.
01:20 This means we aren't starting from scratch with no fuel or injection maps.
01:25 It's important to understand that unlike tuning an aftermarket ECU, we'll be starting with a calibration or tune that is very well matched to the stock engine.
01:32 This means we aren't starting from scratch with no fuel tables or injection timing maps.
01:37 The required tuning process will largely depend on the level of modification performed to the engine.
01:43 Stock or lightly modified engines, our work could largely be focused in the high load areas of the mapping.
01:49 We'll typically only need to adjust high power areas and in this case, the process isn't that much different to a standalone ECU.
01:57 We'll make a pull on the dyno or on the road, look at the results in the datalogging, make sure the adjustments to the tune worked and then confirm the results.
02:05 With an aftermarket ECU we can enter these changes into the map while the engine's running but in the case of reflashing, we need to perform one further step which is to shut the engine down, flash our changes into the ECU.
02:18 Of course there are situations where we'll need to make more drastic changes to the engine tuning.
02:23 But by far the majority of reflashing will still mainly focus on high load operation only.
02:27 We've talked about general rules for reflashing.
02:29 In general you can't make changes on the fly to a factory ECU.
02:33 However there are some exceptions.
02:36 There are some factory ECUs and some aftermarket hardware and software providers where you're allowed to make changes on the fly.
02:44 Some changes can be made in ram and fuelling timing and specifically power generating maps can be adjusted and logged in real time.