Compared: 2017 Vs 2012 Toyota 86 - What difference has tweaked electronic driving aids had?

What effect do electronics have on performance driving in the new 2017 Toyota 86, and how much have they improved over five years?

ELECTRONIC AIDS on cars are here to stay for several reasons. The first is safety; either preventing a dangerous situation, or helping recover from one. Then there’s convenience – making life easier and, finally, driver assistance which is where the aids help the driver to drive.

What we’re looking at here is the effect of aids on performance driving. On public roads, that’s not even a rational debate – all the aids should stay on as if you lose control of your car it’s not just you and your property at risk, but the safety of others. Also, you simply shouldn’t be driving so fast on public roads that modern car electronic aids hinder progress.

But a closed, private track is a different matter. There you have a choice; leave them on so it’ll be safer and you’re more likely to drive home yourself than see the remains of your car loaded onto a truck as you watch from an ambulance. On the other hand, the point of track driving is the thrill of mastery, and to be honest the risk as well. If the electronics are helping you that takes a lot of the enjoyment away for many drivers.

So here we have the 2017 Toyota 86, and my older 2012 model too. The biggest change to the MY17 is the calibration of the electronics; Toyota claim they’re more effective and smoother than before, so we thought we’d put it to the test and compare the new 86 with the old. The cars are:

2017 Toyota 86, manual, stock standard with 215/45/17 Michelin Primacy tyres, 500km on the clock
2012 Toyota 86, manual, KYB Extage suspension (set to soft), Dunlop Sport Maxx tyres in 215/45/17 with two track day’s worth of wear, 70,000km on the clock.

The MY12 has a grip advantage with the Dunlops, but the MY17 has slightly lower gearing. The objective of the test isn’t to compare the speed of the 17 against the 12 as the tyres and to a lesser extent the suspension mean it’s not a like for like. We have a full roadtest of the MY17 model here, and that includes a comparison of the 17 against the earlier models.

Instead, we want to look at the relative effects of the electronic systems. So we set up a 22 second figure-of-8 lap with top speed of around 80km/h on a skidpan:

trackmap — When we ran the track those bollards and vehicles weren’t there, but you get the idea!

Two experienced drivers were used, and each of them ran each car as follows:

All traction aids on (“all-on”);
VSC Sport (MY12) / Track Mode (MY17); and
All aids off.

A full explanation of the 86/BRZ’s electronics can be found here.

d11d8578 — Section 4 above. You can see how the track has been cleaned by the cars. We did a few laps to ensure consistency before timing started.

The drivers were under strict instructions to aim for consistency, and not to slide the car but to aim for smoothness.

What we did

After familiarisation, each driver completed six laps in each car in each mode, and the totals have been averaged:

	MY17			MY12
	All on	Track Mode	All Off	All on	Track Mode	All Off
Av time	22.356	22.002	22.021	22.309	21.803	21.692
Diff to all-on		0.355	0.335		0.506	0.617
Diff Track/VSC to Off			-0.020			0.111

We used a Vbox timing device to measure the laptimes, and used the tracklog to create the map you see above. The results bears out what most drivers find in practice, and also Toyota’s claims of improvement. But first, some background.

Slip, speed and electronics

Whenever a car is driven it is slipping ever so slightly in several ways – a slight sideways drift around the corner, a slight wheelspin. The faster the car drives, the greater the slip.

d11d8548 — This car is slipping a little, not so much it’s lairy and sideways, but the angle of its travel is not quite the same as its tyre direction.

The extent of the ideal slip for maximum speed is dependent on the friction of the surface, the grip of the tyres and various other factors; at one extreme, Formula 1 cars with high aerodynamic downforce and very grippy tyres barely slip at all, whereas rally cars with little aerodynamics operating on low-traction surfaces slip a great deal; the reason rally drivers slide the car around corners is because it’s faster for their scenario, and the reason circuit racers don’t slide (or at least, not so a spectator would notice, there is slip going on) is because it’s faster for their scenario. Older racing cars, with less aerodynamic downforce and less grip always slipped more than today’s modern vehicles too which is why they looked more spectacular, although were slower.

The nature of the course is also a factor; slow speed, tight courses require more slip than high-speed courses. This is why the fastest way around a first-second gear motorkhana is to use the parkbrake to spin the car..but that’s definitely not the best way to drive a fourth-gear corner on a racetrack!

So some element of slip is essential to going fast. The 86’s electronics in all-on mode are calibrated to detect slip beyond what would be expected in normal driving, and correct it. That means individual application of each wheel’s brakes, and throttle reduction. All that is explained in this post.

The results

Both cars are slowest in all-on mode, and drivers reported that VSC activated even though they were being as smooth as they could be. This is because VSC is calibrated to permit less slip than is ideal for a fast laptime.

When the vehicles were switched to VSC Sport and Track Mode the electronics permit a little more slip, beyond what you’d get in normal driving, so we go faster. That’s why we see a laptime improvement of 0.3s for the MY17 and 0.5s. for the MY12. Could we measure that accurately? Well, that’s an average of 12 laps. Both drivers were running their six laptimes within 3/100th of a second, lap after lap, and there were more than a few laps identical to the thousandth of a second, so the variance is small but significant.

Now you may ask if a 0.3 second difference is significant. The answer is yes; this was a 22-second lap. The average racetrack takes the 86 around 1.2 to 2 minutes to complete, so four to seven times longer than our track. Multiply that 0.3 difference by say five and you have 1.5 seconds…which is a significant laptime difference. For example, I turned VSC on at a track and ran a low 1.13…turned it off and dropped immediately to a mid 1.11.

We also see that the difference between the MY17’s all-on and Track mode is smaller than the MY12’s all-on and VSC Sport mode. This is because the MY17 electronics are smoother in operation, intervening less and earlier, robbing the car of less momentum. In fact, the MY12’s electronic interference can actually unsettle the car by unwanted sudden weightshift, whereas that never happens with the MY17.

Driving fast with VSC Sport, and to a lesser extent Track mode is interesting. When the car gets out of shape the driver, and the car will both correct. This may lead to unintended consequences where too much correction is applied, leading to further problems. I actually managed to near spin the MY12 by correcting a back-end slide at the same time as the VSC decided to do the same and there was an overcorrection as a result.

Alternatively, trusting the electronics only to make the correction is dangerous, as one day they will be switched off and then the driver is left wondering why they have speared off backwards into the armco.

Then we come to the all-off mode. In the MY17 there’s barely any difference at all. This shows that the MY17’s Track mode was allowing the drivers to reach the optimum slip angle for speed. However, there’s a small but significant difference for the MY12, reflecting the harsher, less optimal calibration of the VSC system.

Here’s two graphs showing the sample laps, collected with a GPS-based Vbox system. Using GPS is not the most accurate way to do this sort of testing, but it served our purposes well enough. First, the MY12:

And now the MY17:

The traces are; green all on, yellow VSC Sport/Track Mode, Red all off. The top part of the graph shows relative speed over position on track. The second part shows the positon/time difference to the all-on green baseline.

So at any given position on the circuit, the top traces show the speed in each mode, and lower traces show how long it took to get there in each mode relative to baseline. For the top traces, higher is better – higher speed and for the lower traces, lower is definitively better – lower laptime.

What can can conclude is:

The MY12 has fairly distinct differences between all three traces, whereas the MY17’s are all much closer. That means there is less difference with the MY17 for the electronics being on or in Track Mode compared to all-on.
The Track Mode and all off for the MY17 is virtually identical.
In the MY12’s green all on line there are distinct jaggies – these are as a result of the VSC system harshly applying the brakes.

Track notes

The track itself yielded some interesting observations. Turn 2, the big left-sweeper was possible to take flat out in all-on mode…but the car would reduce the throttle and use VSC to keep on track so while the throttle may have been maxed, the engine power was restricted. Novice drivers often confuse the degree to which the throttle is pushed with speed, so while safe it’s not a great teaching point.

With VSC Sport/Track mode on it wasn’t possible to drive flat out without major understeer, or sometimes oversteer if you were really slow to correct. In all-off mode there’s no way it was flat; keep the throttle pinned and you’d have to drift it, fun but slow.

Turn 3 was a tight right and it was useful to be able to get on the power and slightly drift the car’s back end. This wasn’t possible in all-on, and not really in the MY12’s VSC Sport mode not least due to inconsistency. It did work in the MY17’s Track mode, and of course easily so in all-off. And similar to Turn 2, Turn 4 was designed to promote understeer…and it did, but all-on kept the car on track every time.

What the drivers said:

“Didn’t feel the MY17 cut in so much, less noticeable”

“There’s more consistency of power with the MY17, it’s more predictable”

“The MY12 would cut throttle where the MY17 wouldn’t, or if it did, you didn’t notice”

“The MY12’s VSC will actually unbalance the car. Not so the MY17”

“The differences with the MY12 between modes are more pronounced”.

Conclusion

Toyota have done a fine job with the MY17 electronic driving aids and it is the primary reason to buy the car over the previous model. The MY12’s electronics in all-on mode were too harsh, and slowed the car too much to be useful in any motorsports scenario, although they did offer a great deal of safety. The MY17 is a far more pleasurable car in all-on mode when driven hard, and quicker too. In the new Track Mode for the MY17 it looks like it’ll be no quicker than in all-off mode, with minimal interference although more extensive testing on a range of tracks would be required for a definitive answer. Regardless, this is good news as it means the driver can get the most from the car while still enjoying a safety net of electronic protection. However, it must be remembered that no system can defy the laws of physics and once switched off…you’d better know how to anticipate, notice and handle over and understeer all by yourself!

Compared: 2017 Vs 2012 Toyota 86 – What difference has tweaked electronic driving aids had?