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Practical Standalone Tuning: Road Tuning Introduction

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Road Tuning Introduction

03.45

00:00 - Now that we've seen how the 10-step process can be applied using a chassis dyno, we're going to see what changes we need to make to these techniques in order to perform your tuning on the road or the racetrack.
00:12 Now, if we're not going to be using a dyno for our tuning, there are some advantages, and there actually some disadvantages in comparison to dyno tuning.
00:21 I just want to discuss those briefly before we get started.
00:24 We'll start with the obvious, which is the disadvantages.
00:28 Now, when we're tuning on a dyno, we've got power and torque figures being displayed by the dyno.
00:33 This makes it very easy when we're tuning, in particular, the ignition timing, because we can instantly see the results of any change.
00:41 We know if we're going in the right direction, we can very accurately tune our ignition table to MBT.
00:48 On the road we don't have the benefit of this feedback, we don't know exactly how much power or torque the engine's making.
00:56 So this involves some compromises, particularly as it applies to tuning the ignition timing, and we're going to talk about those a little bit further into this section of the course.
01:08 When it comes to tuning the fuel, we actually have some advantages, and we've already discussed in the main body of the course that even when we are tuning on a accurate dyno, it's always beneficial where possible to take the car off the dyno after the tune's been completed and confirm the tune out on the road or the racetrack.
01:28 And there's a couple of reasons why I recommend this.
01:31 First of all, even with a very well designed and very well built dyno bay, it's difficult, if not impossible, to replicate the airflow that we're likely to see out on the road or race track at high speed.
01:45 Perhaps 100 to 150km an hour.
01:48 This can affect the airflow through the engine bay at the operating temperature of the engine, the intake air temperature, and this in turn can affect the tune.
01:59 So it's always beneficial once we've completed our tune on the dyno to take it out in the real world and confirm that the air/fuel ratio still matches our target and that the engine isn't suffering from any detonation.
02:12 The other aspect that's often overlooked is that on the dyno it requires a certain amount of engine torque in order to keep the dyno spinning.
02:21 What this means is that when we're trying to access the very light load areas of our fuel map in particular, when we take our foot off the throttle to try and get to these areas, often we'll find that the dyno will just slow down, and the engine RPM hence also slows down.
02:37 This makes it impossible to get to the very light load areas.
02:41 On the road, however, when we take our foot off the throttle, the inertia of the car rolling on the road keeps the engine RPM up and we can now access areas of our fuel and ignition maps that we couldn't get to on the dyno.
02:54 For a drag car or a circuit car, this area of the map probably isn't that relevant but particularly for a street-driven car this isn't an area that we're likely to be accessing a lot.
03:07 So it's great to take the opportunity to confirm the air/fuel ratio in these areas on the road or the race track.
03:14 For this particular demonstration we're going to be using our Nissan 350z fitted with a VQ35, 3.5 liter naturally aspirated V6, and we're using the link G4+ ECU.
03:27 However, it's the concepts that I'm going to be focusing on, and the platform, the ECU platform in the engine aren't that relevant.