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Professional Motorsport Data Analysis: Step 5: Analyse Chassis

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Step 5: Analyse Chassis

08.10

00:00 - Step 5 is all about going and analysing the car and chassis itself.
00:05 Now with this particular data set because I'm not there at the track with them and I don't have their debrief notes, it makes it a little bit difficult so the way I usually tend to manage getting the most out of the chassis is really starting with the driver feedback so that's a case of going through them with the track map, going corner by corner, understanding what the car's doing at each point on track and what they need more of in order to go faster.
00:28 So the quality and the level of the driver is going to make a little bit of a difference here as to what sort of feedback you get from them and how useful it is.
00:35 Of course like we went through in the main course body, the way they're driving the car also has a massive impact on both the grip and the balance whether it's to do with the way they're trail braking the car, what I mean by that is how they're adding steering, particularly brake forces.
00:52 Whether it's how aggressively they're getting on the throttle and how they're turning in, how they're exiting the corner, stuff like this.
00:57 The way they're using their driving lines as well, all this stuff has a massive impact on the balance and grip of the car.
01:04 Now in this particular case, I'm not going to get too detailed into looking at the chassis balance, there's a couple of reasons for that and that's because I don't actually have, without having the information from the drivers, it's really difficult for me to properly correlate and make proper calls on what's going on and the other thing is this car's actually relatively basic as far as the number of sensors we've got on it.
01:23 So it makes it a little bit more difficult to truly get into a proper chassis analysis, particularly not having things like damper pots on the car to understand how much it's pitching, how much it's rolling which certainly gives us a lot wider picture of how the car's actually being driven.
01:38 I'd also say just based on the driver analysis that we looked at, there's so much time to find there just in terms of the driving technique and as I said, that tends to be the area that we find the most gains.
01:50 Now that's not to say that we can't find gains for the chassis, it's just that I would tend to be concentrating most of my efforts on the way the driver is driving the car before moving onto trying and tuning the chassis.
02:01 That goes to say as long as the chassis' not doing anything really serious, really evil as far as being really difficult to drive, as long as it's roughly in the window, in my experience you're far better to concentrate most of your efforts on the way the driver is driving the car before you attack the chassis too much as far as trying to make improvements for it.
02:18 Certainly as we went through in the course, there are a lot of times when the driver can actually be inducing something into the car so you really want to be making sure the driver is able to use all of the performance envelope you've got available for that car before ou try and actually start making changes to the car because you'll often find you end up going backwards if you're trying to fix a driver issue with a chassis change.
02:38 One of the things I've seen by going through the data that we can look at is the timing of our shift lights.
02:43 So let's jump in and look at how the driver is making use of the shift lights and how that's affecting their acceleration.
02:49 So what I've got is a preset display set up here called an upshift workbook so I'm just going to jump across to that and we'll have a look at what we've got going on here.
02:58 So I'm just going to zoom out to that full lap again.
03:01 The thing we want to understand here is making sure both drivers are upshifting in roughly the best place on track.
03:07 Now a little bit of this is going to be down to how they're using the shift lights.
03:10 What I mean by that is how they're interpreting the shift lights.
03:13 So that's one thing you do need to get clear on with your drivers to make sure both of them, in this case we've got two drivers in the car and it's quite different how they're doing their shifting is to make sure they're both interpreting the shift lights in the same way.
03:24 So there's a whole lot of different ways you can set up those shift lights but generally they'll be coming on in stages and you need to make sure that they understand the timing and what that timing means with respect to the gear shift.
03:33 So I mean if you've got 4 stages of shift, does it mean that they should be shifting on the 4 stage or does it mean that they'll go through 1, 2, 3, 4 and then shift? That's often something that can trip people up as far as just not following the same convention as far as what the shift lights mean.
03:49 So I've got a couple of different plots here.
03:52 We're looking at the same 2 laps we were looking at before.
03:55 At the top I've got the speed trace, below that I've got the gears, below that I've got the engine speed and below that I've got the time variance as well.
04:02 It's pretty clear looking at some parts of this lap that the orange driver in this case is shifting quite differently or revving the engine significantly harder than the blue driver.
04:13 Now that's not necessarily to say for a start that that's the best way to do it, just wring the neck of the engine just to get the most performance out of it.
04:19 That's going to come back to the optimum shift points that we went through in the course, you can use that spreadsheet tool that I gave you guys to work out the optimum place to put all of your gear shifts.
04:29 So you're going to know for each gear position what the optimum place is to actually shift gears and again you want to generally concentrate on the most important straights.
04:38 It's usually the longest straights, so the ones that are going to make the biggest difference to your lap time.
04:44 So let's dig into some of that now, let's have a look.
04:49 OK so looking at this straight here, this is I think the slowest corner on track and we've got this relatively long straight before we head down into another chicane before we continue on with the lap.
04:59 Now one thing that's clear to see is that one driver is definitely shifting significantly earlier than the other as they move up here and we can see the same thing, it's pretty well reflected in the engine RPM trace so we can see here, down here I'm not too worried, this section down here, just because this is typically a place when you've got that really low speed and you're exiting a slow corner, you'll typically be traction limited so I wouldn't be reading too much into where they're shifting there.
05:23 Often people will be shifting up in order to suppress a little bit of wheel spin in there.
05:26 But once we get further up in the gears, so at this point we're in 3rd gear and then we're in 4th gear.
05:33 So in this 3rd to 4th, and 4th to 5th gear shift here we can see one driver is definitely shifting significantly earlier than the other so let's have a look at the cursor values here, we've got 6700 for the blue driver and we've got let's say 7000 roughly for the orange driver then at this 4th to 5th shift we've got 6600 for the blue driver and roughly 7000 again for the orange driver.
05:58 Now you can see some pretty good trends here in the speed trace as well.
06:04 If we just zoom in, actually I'm not going to zoom in any further there because maybe it makes it a little bit clearer without it but you can sort of see the way that these two speed traces diverge here as well.
06:13 So we can see here that if we hover from this point where my cursor is, you can sort of see the orange driver does tend to, does have a little bit of a gain as far as a little bit of extra acceleration down that straight there and I think, definitely some of this is coming from the blue driver shifting too early and they're dropping down into that next gear too early and they're losing some torque available to the tyres as a result of it.
06:37 And this is a bit of a trend that we've seen throughout the lap is that those early shifts are probably costing that blue driver a little bit of acceleration.
06:45 And the best way to see that, well you can see it in the time variance but also you can see it in anywhere that speed trace diverges where you've got one taking a bit more of a steeper approach than the other.
06:55 Let's have a look at another part of the lap here, so there's a previous relatively straight section, it's actually a large constant, quite a large radius corner, you're actually turning the whole time but it's relatively close to the straight and we see something similar here with the blue driver shifting significantly earlier than the red driver so we're down to 6400 as far as the shift point there.
07:15 Versus a 6900.
07:18 Now a little bit of this difference in the speed trace we see up here is to do with that lift that we analysed during the driver section but what I really want to concentrate on here, before we get to that lift is that again we see that divergence here in the speed trace up here and again that just comes down to that blue driver shifting too early so what I'd be doing here is first understanding how each of those drivers interprets the shift lights before I go ahead and make changes to the shift lights.
07:42 Before that even you should really be doing those calculations as far as understanding the optimum place to do your shift.
07:47 Once they both understand where they should be shifting, then that can be a case where you can move onto actually tuning the shift lights as far as shifting the shift lights back and forward a little bit to help get yourself in the window so you are tuning them for the shifts in the right place.