Nürburgring Driver Dirk Schoysman on developing the Nissan GT-R R32

Posted: March 29, 2022 Read time: 60 mins

On this podcast, Colin chatted with Dirk Schoysman, Professional Development Driver, whose association with the Nürburgring in Germany is known globally. If you search Google for Nürburgring and Ringmeister, Dirk’s name always comes top. He’s also been involved with Nissan from the very beginning, when they created a technical centre in Europe in 1987. His background includes racing, mainly karting and Formula Ford 2000 in the UK, after which he became involved in tuning cars for European markets. He has 30 years’ intensive driving experience, and Colin asked Dirk how his association with the Nürburgring first began…

Listen to the podcast or keep scrolling to read the transcript.

Dirk: Well, in the late 80s, the Nürburgring was not so well known. You have the traditional companies such as BMW and Porsche - they were making intensive use of this special track because, let's not forget, it was actually designed in the year 1927, as a test track and a racing track. And so, then the Japanese brands – cars as well as tyre manufacturers – they got interested in European markets, and it was Bridgestone, in fact, that was starting to use the track intensively. That was all just before the internet, so the number of people using the track was quite limited compared to today. And Nissan then became one of the first after Bridgestone, to start to use the track to develop the cars and to tune the suspension and so on. I was there and I witnessed it from the very beginning, and that has allowed me to get to know the place very well and to do a lot of laps. And one thing took me to another thing. So it is now like looking back to a thick book with lots of stories and lots of things happening.

Colin: Lots of history with the Nürburgring racing and testing. Before we move on to the testing side of your career, perhaps we can just touch on the motorsport element. Every time I see a Falken racing car, I always think of you because, to me, you are associated – you’re tied hand in hand – with that brand. Did they have an influence on your racing career – because that seemed to be a relationship that lasted a very long time?

Dirk: Yes, indeed. I have done the Nürburgring 24-Hours eleven times with Falken and four times with other teams. It was through my job with Nissan that I got introduced to Falken. In fact, it was the other way around – Falken wanted to do the race and they had asked Nissan, because there was some association on the technical side. They had asked Nissan if they could help to get introduced to the right people and so on, and I was chosen to assist Falken in the very beginning, to make a plan and to get to the place and to get organised. And so, of course, I didn't want to lose the opportunity to get to drive. So I told them, look, you want to use a Japanese car, a Nissan car, a GT-R at the time, and I was associated to Nissan on the technical side for road cars, with a good number of laps already at the Nürburgring, Well, I'm here if you want – I would be delighted to join the team as a driver. And so there were three Japanese drivers and myself. The first time out was in 1990. But prior to that, of course, you cannot get into such a professional team straight away. There is another story , which starts in quite a classical manner . Being a boy, 11 or 12 years old, I asked my Dad, please let's go and watch motor racing, I was of course fascinated by all of that, and that led to karting where I was doing quite well straightaway, and that led to Formula Ford 2000 and then later on Touring cars.

Colin: OK. It's interesting. I've started to accumulate several of these podcasts and they're going to become a regular thing, obviously, as long as people want to listen to them. But there's always some kind of association at a young age, it seems, so far in my investigations and discussions with podcasters – that something sows a seed, doesn't it, and it seems to stay with us for life.

Dirk: Yes, I think the kind of job that you are doing or myself, it can only be done when you have a passion for the subject. It's something you need to be highly motivated, and from the outside it looks like having fun and it is, of course, true that we enjoy the work we do, but behind that there is, of course, a serious basis to deliver the products, and there are a few rules that you have to follow. Whether for production cars or in racing, you are a small part of a big system and you have to comply to a certain number of rules. But it is, of course, interesting from all points of view.

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Colin: When you joined Nissan, was your intention to join Nissan and develop your racing career? Or was your interest in engineering and racing and it evolved obviously organically as you're describing? What was your motivation to get to Nissan and engineer vehicles?

Dirk: Well, like most people in that area, my motivation was mainly that I wanted to drive as much as possible and to learn as much as possible with that. And when I joined the company, I was happy to become a test driver for cars, to drive all around Europe and even outside of Europe. In the beginning, I was not thinking so much about racing, but after a short period of time, as I was employed in that company, I saw an opportunity, which was very simply that the few production cars we had, they came obviously from Japan at the time – I'm talking about the late 80s – and they either had to be sent back to Japan, and of course that involves quite high costs, or they had to be destroyed, you know - that was just the rule with Customs. I don't know much about the background, but that was the rule. And so I could convince my boss at the time that that’s really a pity, how much time do you have before you have to destroy the cars? Because that's the choice they have made instead of sending them back to Japan. And apparently, there was some time that we could keep the car. So after all the testing, I said, why couldn't I use that car and then throw it away later on, and so I was allowed to use it. The first time it was an N13, if you remember, that was a Sunny GTi at the time, to participate in some of the races in Belgium and then from there it developed further, and I got actually, if you like, a factory seat in 1990 in the Spa 24-Hour race in a GT-R Skyline, at the time the R32 Group N. And then from there, there was also racing part parallel to my development activity. But my profession really was developing cars, and on the side there has been, let's say, a semi-professional activity in motor racing.

Colin: Yeah, I think you might be, I'm being cheeky now, I think that you might underplaying that a little, because if I Google your name and Falken, then I get pages and pages and pages of pictures and comments. So I think looking maybe from inside your world, I'm obviously not contradicting you, but from outside, being a UK petrolhead, it looks like there’s significant race success at the highest level. And I've enjoyed tracking your history, and certainly doing this podcast I've looked into your history. Obviously, we're friends and we have an association from Nissan, but you've been up on the Podium, I believe, you've won a Class, I believe, at the 'Ring - is that correct?

Dirk: Yeah. Well, I'm flattered with what you say because I don't regard my racing career as a very high-level thing, but it was not bad, you know. We had many Class wins in fact, but it is not like winning the 24 Hours of Le Mans. But at the Nürburgring I got a fourth, fifth and sixth place from scratch, which is not so bad, but it is just outside of the mainstream attention. And so it was not bad, but it is not really like winning. I was not winning a lot, but I was always in the top five, let's say, third, fourth position – that was my typical result in any kind of racing I’ve done. So I was always there, but not really winning a lot, except for karting. In the very beginning in karting, I won half of the races I did, which made me the highest champion of Belgium – and Benelux in 1980. But then in Formula Ford in '82, I was actually in your country, in the UK, living in a van in a paddock. It was so great, but you know, in '82 – and a lot of people find this impressive – in '82, I’ve done the six first races of the Formula Ford 2000 Championship. I don't know if you remember, but that was the year that Ayrton Senna won, I think, 15 out of the 17 races. So I have seen the man a few times in qualifying when he passed me – and, of course, it doesn't go away immediately. He takes a few seconds for laps, so you can see him, and it was perfect all the time. So this is one of the great souvenirs I had. Or when I moved over to let him go through. He lifted his hand to say thanks, and that's a few nice memories, like photographic memories, you know, like a picture in your mind – it stays there forever. It's just so nice to know that and to know how shocking it was also when he disappeared.

Colin: Yes, we all know the story, don't we? But in that era, they were the benchmark Formula, weren't they? Formula Ford, Formula Ford 2000 and then into Formula 3, and that really was your gateway into Formula 1, wasn't it? Not necessarily karting, as it seems to have evolved into today.

Dirk: Yeah, I think so. But what is interesting is that the year before in '81 when Senna was the British Champion, and normally people would then move on to Formula 3 straight away, and he didn't. He did one year of Formula Ford 2000. And apparently, there's a reason for that, which is that in '81 Tommy Byrne won the F 2000 Championship and Senna thought that Tommy Byrne was the only guy that could beat him. So, in order to avoid that defeat, he chose to do one more year in Formula Ford 2000 and Tommy Byrne became the champion of F3. And so one year later, in '83, Senna moved to F3, where of course, he had a great fight with Martin Brundle. But politically, he was clever, he did things in a very thoughtful manner.

Colin: He was a lateral thinker, wasn't he, and a political thinker, as you say.

Dirk: Those great champions, they are not only great drivers, they also have insight into how to do things. It's something I was missing, to be honest, when I was younger, I was not political at all.

Colin: Yeah, yeah. Well, I was the same. I did racing for fun, oval racing as a young man and into my teens, I was in a similar way racing at that time, and Ayrton Senna was an up and coming driver that made all the magazines and that everybody was talking about. And clearly was destined for better things. But yeah, he was way outside my world - club driving.

Dirk: Of course, that was another world, as you say. So it was not the thing that we are in that league, but there are a lot of activities in motor racing outside Formula 1, and the general public is maybe not always aware of that. You have Touring cars and GT cars, which is very serious racing as well. Or, as you mentioned with Falken, I have been able to drive first of all the GT-R and then later on the 350Z. And that was also fierce competition and a fantastic experience.

Colin: Yeah. Perhaps we can come on to that as we move through the podcast. I've got quite a flexible list of questions here, and we can certainly cover a bit more of that. What I'm also interested in is your engineering prowess at setting cars up. So you were known as, in the UK certainly, as Mr GT-R and I believe your 7:59 ’Ring lap in a GT-R was perhaps a turning point for how people viewed the ’Ring and perhaps how manufacturers viewed the ‘Ring. So my thoughts are that you were influential at that time in perhaps, projecting into the sports car world the relevance of the ’Ring, and it became very competitive amongst manufacturers. Could you just talk us through some of those experiences in the GT-R? Perhaps I could just paint a bit of a picture here. My belief is that the ethos behind that car was for Nissan to make a car that people could drive quickly and safely. You didn't have to necessarily have specialist knowledge, like driving a 911 GT3 or GT2, and you're the man who set those cars up on the ‘Ring. I wonder if we could explore that time of your life. Give us an idea of what you were looking to achieve and how you went about it.

Dirk: Well, yeah, but that's a very long history. The lap record was, of course, yeah, it was important. It was in the early days that manufacturers started to use the 'Ring for marketing reasons. They wanted to show the whole potential, and that was reflected in the lap time of the car. But you know, you said Mr GT-R, it's just too much to say, I was just part of a big team. It was not only me. And there were always some Japanese test drivers, but at the time I was the only non-Japanese test driver, because the Japanese usually don't speak German, which is obvious, and to remain in that area I was a kind of sport for a lot of things. But being there and being the test driver on the Technical Centre I was, of course, allowed to drive the car in the beginning, and as a team, we made choices how to set up the car, because what is the client expecting? And you know, those are the fundamental questions. As I did so many laps, indeed, I was again getting the opportunity to do a lap time, and that resulted in a sub eight-minute lap, which was the first time that a production car got so fast. And yes, I think it made the reputation for the GT-R online for the next years. It was, of course, an honour to do that. Yeah, the ’Ring, still today, people try to go for lap times, but I think today it has not the same meaning. In the 90s it was more impressive, I would say, and today I think the cars are so fast that normal people, even with all the aid systems, they cannot do that. I think it is very dangerous, or maybe I'm just getting old now.

Colin: I think you're right. I think YouTube is littered with fails on the Nürburgring, isn't it? I try not to watch too many of them. But there are many mistakes on the 'Ring, aren’t there, and we teach safety and a way to go to the ‘Ring.

Dirk: And the faster cars – when one does a certain lap time, then another one wants to go five seconds quicker. But those cars move so far away from normal requirements, and you cannot use anything like that on the road. So what is the point? It's like they make racing cars, but you know, that is not for the general public.

Colin: Yeah. And in terms of the set up with the GT-R, can you give us an idea of how you went about that process? My experience of those cars is that we've had many GT-Rs through our doors for training, in fact, over 450 of all the models, and I always find the cars are very quick, and if they're set up correctly, they feel very safe and stable, they communicate to the driver. They're not a car that frightens you, unless clearly your technique is poor. How do you go about setting a car up to achieve that? What are the key areas you're looking to adjust or develop to achieve that goal?

Dirk: Well, I think you said the right thing: the target was actually to make a very fast car, efficient and not too difficult to drive. It was actually, let’s say, more or less a negative comment from certain people: they said it's too easy to drive but, let's not forget it is a road car. It was and it is a road car. So on the roads, you don't want to have a peaky car. So it is also the responsibility of the manufacturers to make a car that is not too peaky to drive because it is destined to use on the road. So the target was exactly that, and the active 4WD was a part of the reasons why we achieved this. So the setup was to have a car – efficient, fast and not tricky to drive, that was actually the main target – and I think we achieved that both in dry and wet conditions.

Colin: Yes. And how many laps of the 'Ring would you take as the programme? What time designation would you put to achieve that, with the R32, for example? I know there's history, and there are previous models, but I think the R32 was quite unique when it was launched and it was very successful in Japan in motorsport, and that obviously crossed over into the UK and Europe. How many hours of work are there on the 'Ring to achieve that set up until it's signed off and until it's achieved its design intent?

Dirk: In hours it's quite difficult to say something, but in weeks I can give you an idea. I think it would take about 10 weeks of driving, but not consecutive weeks. They come one year, then they change things and so on, and I think it was about 10 weeks, to go around and also with the suppliers of the shock absorbers and things like that. Like you say, the R32 was a very special car because it was launched in '89, if my memory is correct.

Colin: Yeah, that sounds right.

Dirk: Yeah, and it was the very beginning of all of the electronics coming up. And, to my knowledge, it was the only car at the time that had an automatic 4WD system. You know, I think... was it the 959? So the two super sports cars of the final were the Ferrari F40 and then the Porsche 959. The 959 had also a 4WD system. But the bias was fixed. There was a switch with three positions, and so the driver could adapt to the conditions, but the GT-R did it all instantaneously. And that was new. It was all done by advanced electronics with a multi clutch, as you may know, it has a central diff. And so it was, as far as I know, the first car with the roll sensors, steering angle, speed and everything the ECU would need, to adjust the bias from front to rear immediately, and that makes it so special. And that is also a great compliment to Nissan, because they were the first to have this system. And then others later on, took over the same principle.

Colin: Yes. And in terms of that development, that's interesting, 10 weeks, and I'll bet that will surprise some people as well, when they hear you say that because, you know, if you're not involved in the motor industry, that might sound like a long time. But that just shows the level of investment in not only time, but also engineering to produce a product, doesn't it – and fine tune it once it's left the drawing board and become a product. I think it's different now, isn't it, because computer modelling and kinematics rigs and simulation may shorten that time, but 10 weeks, I would think for a layman that sounds like a big investment in time. How do you think that car influenced the car industry moving forward? Because that seemed to be really a stake in the ground for Nissan, saying, "Look, this is what we've done", and everybody else seemed to spend a few years catching up. Do you think that changed the design of other big brands like Ferrari and Porsche at the time?

Dirk: Without naming any brands, in a general sense, yes, I think it has influenced the car industry because, I remember a journalist asked me in the early 90s, "What do you think will change in the next few years?" And I said, "electronics". And ever since, we have seen that there is an increasing part done by electronics because basically almost everything is possible with electronics. It makes the cars more complicated, but also more efficient, such as a 4WD. And as we know, the R33 saw the second GT-R 4WD generation. It had also an electronically controlled rear diff, that made the car more efficient at the exit of a corner. And so you find electronics in all areas now. I think it's even too much, like these automatic braking systems with the radar. Sometimes it's a bit too sensitive and they start to brake too early and, you know, it's all down to the philosophy. But at the time, with the R32, the Nissan, I think there was a team behind it of real enthusiasts. It was not about people just doing the job. They had a well-defined target and they really went for it. And I remember at the time the presentation of that car - Paul Frère - he came, he was already maybe 75 or 73 like that, but he's a real great - he was, because he's not with us anymore – but he was a real fantastic person, and I had the honour to spend time with him and he was so enthusiastic about the car. And so that was also great to hear from a person with such broad technical knowledge and driving knowledge.

Colin: Yes, yes. And how has that evolved into the R35? I think, as you touched on earlier, that received, I believe, mixed remarks and opinions from car enthusiasts. It was clearly well received when it was launched in the UK and into Europe. What's your view on that car now as the, shall we say, the evolution of the GT-R? Do you feel that's gone the right way? Is that something that really epitomises the GT-R brand in your thoughts?

Dirk: Well, to be honest, yes and no – at the same time.

Colin: Ah OK, that's interesting.

Dirk: The yes is because it was a car designed from scratch, so it was a completely new concept. It was, as you know, with the transaxle, the gearbox was in the rear and it made the car also a little bit complicated. It was very, very efficient. The potential of that car was enormous, but the little no I just mentioned is because of the weight. The more complicated you make it – because to get the 4WD, from the engine there was of course the main shaft going to the rear gearbox, but then there was another shaft going to the front again, to the front diff, you see. So it is very complicated and it all adds weight and weight is, of course, as you know, quite the enemy of performance. Even then, it was about 1.7 tonnes or something just over that. And I remembered that a lot of effort was put into the tyres, in fact, the tyres were absolutely top level, and they helped a lot to make the car so efficient. But again, when you have a lot of weight, it translates into bigger brakes, and of course the fuel consumption was not so good, to be honest. So it was quite an expensive car in that sense, but absolutely fantastic to drive, I think.

Colin: Yeah, I think so, too. A small number of people in the UK sort of complain that they drove themselves, but I've never agreed with that statement. I think if you drive one well and you understand – if you can reduce the steering lock on the exit of a turn, you get the 4WD intervening and you've got a very, very quick car around a circuit. I really like them. I think also what I found was really clever, and I'd really value your view on this, it that it seems that where modern cars have advanced, engineering through damping and suspension and spring rates, when a car is heavy, manufacturers seem to be able to make the car feel lighter in your hands. And perhaps the weight appears when you're asking for perhaps low speed directional change. But through a corner, I always think a GT-R doesn't always feel 1700 kilograms, and I think that's incredibly clever, like driving perhaps a Bentley or a heavier vehicle. Would you agree with my thoughts or have you got an opposing view?

Dirk: No, I do agree because, as you say, you don't feel the weight when you drive the car fast. And that is, of course, through a combination of things like steering rack, which is quite quick, and of course, the effort, the tuning of the steering, the way it loads up and the balance from the rear is not only because of the suspension setup, it is also because of the ETS or the electronic torque speed, the bias from the rear is very, very important to get the balance right, but the exit speed of the corners in an R35 is absolutely enormous and I would say, especially in the wet. My personal wish has always been to have a little bit more bias to the rear. I do remember the setup of the suspension is really very important. I mean, it has to be spot on, and when it is spot on, then you have a fantastic car, and when it is a little bit out, then you may have a little bit too much understeer for my taste. So when the car is good, then absolutely fantastic at the exit of the corners, then you don't have much understeer. And even then, with the tuning of the 4WD, it is easy to slide and to maintain it and to exit, at fantastic speeds.

Colin: Yeah. My experience of those cars is that the car crabs in a corner at grip limit. The lateral acceleration, the forces on front and rear, seem so equal that it doesn't feel like oversteer, it just feels like a very predictable four-wheel slide when you get used to them. And I found that fascinating. On the steering pad at UTAC Millbrook with customers it’s really a big learning point, because it gives drivers confidence to push knowing that obviously there's some assistance from the car, but it's quite a comfortable feeling. You don't need to be frightened of it is what I'm saying. I'm assuming that's also built into the design of the car. That is the intention of the design?

Dirk: Yeah, it's the combination of the weight distribution and the 4WD tuning. And of course, you have to have a good suspension as well to maintain stability. And that is exactly what the car is doing again. When the alignment is really spot on, it is the most efficient car. I've never driven anything that efficient at the exit of the corner. That is the most impressive part. I'm not saying there is no other car doing the same, but I have not been in such a car.

Colin: Yeah, that's a testimony, isn't it? That's a testimonial from yourself, which means a lot. Interesting. OK. Thanks, Dirk. That's a good background on your history with the Nissan GT-R brand. I wonder if we could get stuck into this subject: when we speak to our clients who aren't associated with the motor industry, they don't quite understand what goes on during Pool days. It seems like this magical, mystical place where manufacturers develop cars. I wonder if you can give us an understanding of what actually happens on Pool days. Why do manufacturers use the 'Ring, and what would be a typical day for a test? Clearly, there are lots of things we might want to test, but why are we using the 'Ring and what's the attraction for manufacturers?

Dirk: Well, yeah, there is nothing mystical. I would say it's a confidential thing, so people are not allowed to see the cars because you have prototypes going around. That is maybe why people say it is mystical, but there is nothing mystical, in my opinion. It’s just that it is a closed area and only car and tyre manufacturers are allowed to use the 'Ring during those so-called industry pool days. Yet, all manufacturers from all over the world use the 'Ring: the Americans, the Japanese, the Koreans, they all use the ’Ring because it is the only road known in the whole world where you have all possible situations. And the classic expression I use in this connection is that a car cannot keep any secrets within the 'Ring. The amount of information you can get when you test a car over there is enormous, in a relatively short space of time, and that allows you to make a good product. That is the reason why people are testing at the 'Ring. And as you will have noticed, most manufacturers they have their own workshop close to the 'Ring. So also Jaguar Land Rover, they have their own workshop since a long time, since 20 years, and it is the place to be. But you have several activities. I think you have tests where you tune the whole car, not only suspension but also transmission, and then you have durability tests. That is also important because when a car is launched on the market and they discover a weakness, whether important or not important, it has to be fixed by a recall. And that is, of course, extremely expensive and also not so good for the reputation of the brand. So therefore, there is a lot of durability driving on the 'Ring, and that means that if there is a weakness, it will show up and can be fixed before the car is sold to the market. So those are the main activities on the ‘Ring.

Colin: And then if you were a durability driver on the 'Ring – and we can come on to Top Line soon, your development company based at the Nürburgring – if you're a durability driver, what does your day look like? Is that 20 laps? Is that 60 laps and is it done to a lap time? I know peoples will find this fascinating: I'm going to work, I'm a durability driver on the 'Ring – how is my day structured?

Dirk: Well, about 30 laps is more realistic because you have to know, in theory, it is possible to do a few more, but not many more. I mean, 35 is probably an absolute maximum. You have to imagine when you do that in a whole week or two successive weeks, then you know you will have some backache. Yeah, physically, it becomes quite a bit heavy. But for the lap times, indeed for durability, normally you have a target lap time. First you will go out and go as fast as you can, which is then showing the maximum potential of the car. And then you will add whatever the manufacturer's wishes: 10 or 15 seconds to that, and that will be then your target time for durability. So it means that you use the car hard – much harder than people would ever use it on the road or even through mountain passes. So it means that you are above the normal use of the car. And so it allows you to discover, for example, heat problems, which is one of the most common problems that show up. Some element of the car may become too hot in that case. And, of course, brake capacity, that is also a very important item that you can see on the 'Ring when you do durability. But of course, the whole car is monitored. You can have more than 200 sensors to register pressures and temperatures in a lot of systems. And so it's a pretty broad picture of everything the car is doing, and maybe to show an area where something needs to be improved.

Colin: OK, and then based on those high wear rates, I'm assuming now you've got a team of people around you to engineer the vehicle – brake pads, tyres, accruing data – how many people would be involved in that test for, say, a single vehicle?

Dirk: I would say between five and ten engineers from the car manufacturer’s side, so my company is delivering five or so. So it would not be possible to engineer the car because we would not have access to all the data. We are not specialised in that, so of course, it is working together. But with the years of experience, all the drivers working for Top Line, they of course, they have a lot of experience, and they describe certain characteristics, and all of that may support the development team to improve other things, such as a suspension setup or steering feel, you know. So it is always working as a team and working together with the same target, which is to make the best possible product.

Colin: Yeah, I understand. And then I hope I'm not going to embarrass you, Dirk, when I say this, but people might not be aware that I completed my training to drive on the Nürburgring with yourself. You signed me off and I had training with you out there and you've just described Ayrton Senna driving past and waving and thanking – that's instilled in your memory. Well, the first few laps you gave me around the 'Ring on my training day – you've given me a similar lifelong memory. And the reason I say that is relevant to the conversation. You really set the scene for me. Although I was at Nissan and still learning how to evaluate and test vehicles, what’s really stuck in my mind ever since is not only the ease at which you drove, but the consistency, the repeatability and the way that every lap was identical. You really helped me there, and I realised then - the penny dropped on how to evaluate and test and the technique needed. I wonder if you could explain that also – the difference, perhaps between a racing lap, if there is one, and an evaluation lap, because in my head there are subtle differences depending on the objective of the lap. I wonder if you could talk through that.

Dirk: Well, yeah, that's a very good point. But first of all, thank you for saying that you enjoyed the training at the time. That's a long time ago.

Colin: Yes, that really was instrumental in me understanding how to test and evaluate – your lap. I realised after a few laps that your driving was on a level I'd never seen, and that really was the benchmark forevermore for me. And I still maintain that today when I think of driving a clean lap on the Handling Circuit, to evaluate or show someone how to evaluate, it's those early laps that stick with me. So yeah, thank you.

Dirk: Well, no. Thank you for the compliment. I think it's because in the beginning, when people come, when they don't know the layout of the track so well, then it may be impressive, because at the time I knew the track very well. That makes the whole difference because a lot of sections are blind and then you may be impressed. But after a day or so, you will be less impressed because you get used to it.

Colin: The interest is in the repeatability. What people might not know when you evaluate cars – you need to be consistent. You're the constant. The car is the variable and if you're not consistent, then it's very hard to come to an objective or a subjective decision on a characteristic or an improvement, etc. And I wonder if you could just talk us through laps on the 'Ring in terms of whether you're in a race or you're evaluating. Can you highlight the differences?

Dirk: Yes, but that is exactly the point. The way you say it is exactly right, the car is the variable and the driver must be the constant because of the repeatability. To drive the same every time is important because otherwise you would not notice any change to the car setup. So whenever you change something to the car, you must be able to feel it and to describe it, and therefore you need to drive in the same way all the time. But of course, a race lap is different. To define a race lap is quite easy. It's to go as fast as you can without breaking the car, whereas to evaluate a car, you will not go that fast because you will do some manoeuvres – you know, breaking through the corners, for example – to see if the rear is stable or slipping out and how it is slipping out. Is it easy to drive? Is it difficult or whatever? So there's a lot of things coming together, but you will repeat the same manoeuvres in the same place in order to get certain information. You know, nowadays I still do a lot of tyre testing, actually only tyre testing for the moment, for road cars I mean. And, of course, we drive on specially designed test tracks such as MIRA or Millbrook. I've never been to Millbrook, I've been to MIRA and usually use IDIADA in Spain for that. And, of course, repeatability is extremely important because otherwise you wouldn't notice any differences. So to evaluate, you will also look at certain systems. I mentioned tyres, but it can also be, as we talked about with the GT-R, the bias of the four-wheel steering, the setup of the differential because it changes the turn in and it changes the acceleration of the corner. And usually you work on a system and we'll try to get the system right, and then you move from one to the next system, until everything works together. And when it works together, then you have completed the job of developing your car.

Colin: On the 'Ring, is there a lap time element to that? Or is that a secondary consideration?

Dirk: When you tune suspension, there is no lap time to be achieved at all. All that happens is when everything is finished, you can do a lap time to see what the potential of the car is, and that may give you an indication. Is it being efficient or not? And especially, how can you position the car compared to competitors? If you want to position the car above something else, then it cannot be slow, so to say. So it is about that. But the driving style for racing and evaluating is, of course, very much different. But again, for a race car, you need to have a setup so that the car is not too peaky to drive. You must feel at ease, especially in a 24-hour race, because it's very long. It would be hard to drive a difficult car, whereas when the car is very efficient, it is not so hard and therefore safer, and therefore also you have a better result at the end of the race, I would say.

Colin: Yes, OK. Is perhaps the reason behind the differences when we race – sometimes we're a little over grip limit a little under and we're searching out the optimum grip continually – does that create in your mind another element of skill? Is that something that the test driver may not be as polarised into? Clearly, you need to be able to control the car over limit to test, but a racing driver lives at the limit of adhesion, and that brings with it an element of variation, I assume. Would that be a fair statement?

Dirk: Yes, I think so. The grip that changes is mainly, of course, when in a long-distance race, again, when the weather conditions change. And that is very difficult when you're on slicks and it starts to rain and especially after rain, when it is only on part of the circuit that is wet then it is really difficult. But then you have to adapt to it and try to make the best out of it, and especially to avoid any trouble and not to destroy the car.

Colin: You touched upon there the changes in grip, depending on the condition. I constantly read, and obviously I've done nowhere near as many laps yourself, but I've done enough laps around the 'Ring to know that the surfaces almost, seem to change hour by hour, minute by minute almost. There's something very unique about the 'Ring. Is that something we can discuss in terms of safety for people going out there? Would you agree with that statement? It just seems such a changeable surface.

Dirk: Well, it doesn't change hour by hour. Not really. I mean, when it's dry, then it is OK. And the differences between corners are not so big. They renew the tarmac every year in a few places, but to do the whole circuit would be too much work and too expensive, I guess. So every year, basically for maintenance, they change the tarmac in certain corners. And then of course, you have more or less grip (well, more grip normally) than in the more polished corners with an old tarmac. So in the wet, it makes a really big difference but in the dry not so much. So in the wet you really have to know where it is slippery, because it may catch you out when you don't know. And the differences are really, really big, especially on road tyres. Again, on racing cars it's another story because they cope better with low adhesion surfaces. But on road tyres, the difference may be really very big. You need to walk and, after that, you can run. But first you have to discover everything. Before you try to go fast, you have to discover everything and to know everything, and then you can start to build up speed.

Colin: Just while we've been talking about evaluation and testing, you touched on tyre testing. I believe that really is the pinnacle of subjective and objective evaluation and testing in terms of driving skill. Could you just give people an understanding of what you would be developing on the 'Ring with the tyre? What are the criteria you are actually testing, evaluating, developing?

Dirk: Well, that is mainly safety related now. Not many people realise, I believe, that tyres, they determine, let's say, 40% of the handling of a car. That starts with steering feel and straightability and of course balance, but also ride comfort for impact, shock and even noise. Then the car manufacturer asks the tyre manufacturers to have especially good grip in the dry or in the wet, or a good compromise. I think the wet is more important because you can easily reach the limits in the wet, whereas to reach the limit in the dry on the road, you have to be driving like a fool. But not all do. Some manufacturers say, "Oh, wet is not so important", which I find really amazing. I cannot agree to that. And I thought a lot about that. Why? Why do they say it because they must realise that the risk to have an accident in the wet, to lose control, is much higher for the normal driver than in the dry? And the only answer I can find – but that is again my very personal opinion, I have no information whatsoever – is that they can put into the brochure a very short braking distance, if it is good. And that will show people, for example, from this car: "Oh, that must be a safe car", without thinking of the performance on the wet and I think this is a bit misleading. So my opinion remains that the wet is so important. You need a lot of finesse for the subjective evaluation of tyres. Again, repeatability is important and to pick up small things is quite difficult. And I can tell you that some manufacturers, they are working in a really small window. It means only perfect is good enough, but perfect is very theoretical. If you want to have crisp steering, then you will have a stiffer tyre and then comfort may be a little bit less. So you cannot have both at an extremely high level, so you have to make choices. And some manufacturers are quite realistic and others are less realistic in that.

Colin: Yes. And if you were testing on the ’Ring for a day, tyre testing, what does your day look like? Is that three sets, five sets, six sets of tyres you're evaluating?

Dirk: Yeah, more or less - six sets, but you normally have a reference tyre – a control tyre. Something which is already approved by the manufacturers and they say, "Look, this is a tyre which is good for us. Can you try to improve in this or that area?" And then we have a number of prototype tyres and we compare and we try to select one that is according to the requirements of the car manufacturer. And then we present that tyre, but that takes a long time normally. It is several loops. It's not done in one day because, again, it's learning the car. The tyre engineers, they need to know how the suspension works on the car. And then they may make changes in the design of the carcass and all the elements and the beads, and of course, compounds are important. And since a few years, the rolling resistance is very important, which means usually stiffer compounds, so you lose out a bit on the wet. It is really very, very difficult and very technical for the designers to make a really good car. It's fascinating.

Colin: Yeah, I can appreciate that. And when you left Nissan, Dirk, you started your own company Top Line. I believe from our conversations, you're semi-retired now. Would you just like to mention Top Line?

Dirk: Well, yes Colin. Back in 1999, Nissan was not doing so well and then Carlos Ghosn, who was then the CEO, he decided to close down the technical centre in Brussels, Belgium, where I used to work. At the time, I have to say the management was very good with all of us, because they gave the opportunity to most of us to continue to work at Renault, because there was already the alliance Renault-Nissan. I thought, well, shall I move to France and work with Renault? It was a fair proposal, I think, to continue, but I thought, no, I'm going to try and become a freelance driver, and I created my company. They had also said that they would still hire my services from time to time, and that has been true for another 11 years. And then that faded away because I guess that people I used to work with, would have either retired or they move along. So it fades. Life goes on. That was then back in 2000, and what also made me decide to take the step was that I was approached by Hankook Tyres from Korea. And I still work with them. So that is 21 years that I do testing with them. I knew that I had a number of clients to make it possible. Ever since that year 2000, my company has grown a lot. We have about 10 drivers working with us, especially at the 'Ring, all really nice people and specialists on the 'Ring and other things. Most of them with a racing background, but not all. And yes, as a team, we have a lot of durability driving for several clients at the 'Ring. I continued, mainly tyre testing and some chassis tuning.

Colin: OK. And where are you now? I know we've spoken and you're semi-retired, so is Top Line still running?

Dirk: Well, almost three years ago, I actually sold all my contracts to an old friend who is Hans Wilms. He took over the contracts of Top Line and I kept one myself, which is the best tyre contract. So I work not full time anymore, but the team is still going around, which is the most important thing that all of those really fantastic people still have their jobs and that they continue, so that the logo and the name still exists and can be seen at the 'Ring from time to time. So myself, I am now 63, so I am not working all the time anymore.

Colin: Yeah, I understand. And if people want to reach out to Top Line, how do they get hold of them?

Dirk: Well, the easiest is just to go onto the website https://www.topline.be and there you can find information about what the activities are, and whenever somebody wants to be in touch, it is possible through that site.

Colin: That's good. Good to know because we have a lot of engineers in the motor industry that we work with, and I'm sure there'll be engineers listening to this broadcast. Yeah, I'm glad your business continues. Having started it, it's always nice for it to continue isn't it?

Dirk: Yes, the same for you. You have created your company and it is great to see that it has been such a success and that it is growing, and it is so satisfying that it is possible, isn't it?

Colin: Yes, it is. And I'm 62. I'm sure my age will catch up with me soon, but I'm not quite ready to retire yet. I can see you need an exit strategy because we're not getting any younger, are we?

Dirk: No, but it shows your enthusiasm and that is very nice indeed. I wanted to do less, but I don't want to give up completely. You see, I think it is normal at this age that you don't want to travel all the time and so on, because it's a lot of energy - so many years always to be on the road, or in a plane, or whatever it is.

Colin: Agreed. I think also, once you've been involved in the motoring world and there's perhaps an element of adrenaline and excitement in your general working day – obviously not every day, I don't think anybody can cope with that – but I got that feeling there's something missing if you're not driving a car and doing what you do. And I think I need to come down from that. I'm thinking about it, but I haven't yet perhaps implemented it into my life.

Dirk: Yeah, that is true. And it's also a great privilege that we have to be part of that, because it’s interesting work and we live our passion and it is really a great privilege to have been part of that. We have met so many interesting people and yeah, when I look back, I'm really very happy to have had this opportunity.

Colin: Yes, I concur with that totally. I think CAT Driver Training for both Jo and I is more than the sum of its parts. We've met so many lovely people. I've made close friends. I met yourself through Nissan and we all walk a similar path, don't we? And it's really nice to be part of it.

Dirk: Yeah. And the backbone of all of that is the passion for something that, by the way, is going to change its character. I mean, with electric cars and autonomous cars, maybe, but I don't think it's for tomorrow. I think it will take a very long time before we see those on the road. But everything is changing. We have just been part of this very nice area with combustion engines, right?

Colin: Yeah, agreed. Yeah. I'm open to the change, but I can't help facing the change with a degree of remorse. I think we've got to move forward. I totally understand that. But I think if you're a petrolhead and you like the sound of a piston engine at high revs and tyres working – I think there's a degree of sadness that that might be coming to an end.

Dirk: Yeah, yeah, I agree.

Colin: Before we finish Dirk, I wonder if we could just give people the benefit of your advice. Clearly going to the 'Ring, for many, is a great experience and an exciting one, but also for an amount of people who go, it ends in perhaps an expensive crash or at worst tragedy. So could you give people the benefit of your experience? If someone's heading to the 'Ring and they've not been before and they enjoy track days, what would your advice be to prepare?

Dirk: Yeah. Well, it's an important question, in fact, for people that go there for the first time. My first advice is start in a modest car. Don't go in a fast car straightaway. Take your time to learn the track and especially all the humps and the bumps that may upset the car. You really have to line up the car to drive over a hump at high speed because it gets very light, and you should therefore open up the steering wheel and reduce the cornering force, otherwise you may have a big surprise. You should do at least 100 laps in a modest car and then you can move up to something faster. You know, I've been so lucky, also in my Nissan days, I could use a Primera GT. The first generation Primera GT at the time was a fantastic car. It was one of the best cars around I think. I have done hundreds of laps in the beginning in that car. That was really the basis to get to know the track well and to be safe enjoying fast cars. But first walk and then run, take your time to learn it, and go and look at a PlayStation to know the layout of the track. It means you will know what corner is ahead, but it will not get you familiarised with the humps. Or hire an instructor for a day. It may cost some money, but you will gain a lot of time, because when you learn it on your own it will take days, but with an instructor it will go faster, then you will enjoy driving much sooner.

Colin: That's good advice. And in terms of the car, are we into similar preparation as we would be on a UK track day? Thinking of brakes and tyres, I believe my advice is always not to have a car that's too stiff, and you need a compliant car. What would be your advice on that?

Dirk: You're right, it shouldn't be too stiff compared to smooth tracks. I think you have some bumpy tracks like Thruxton, Castle Combe or something like that. But the car should indeed not be too stiff for the brakes. The Nürburgring is not really so hard for the brakes unless people well, in the beginning, some people brake too much because they, of course, they have to discover the track. But once you're OK, then it is not so hard on the brakes. I would really, as you said, go for a not too stiff suspension and then step by step.

Colin: Yes. OK. And what about your thoughts on driving in the dry and driving in the wet? Obviously, we’ve touched on that through our discussions through the podcast, but it can be exponentially more slippery than the road outside of the circuit. What would be your advice on driving on a wet Nürburgring day?

Dirk: Yeah, that it's really quite dangerous. The wet in the beginning, you have to build up speed. Again, you have to discover where it is very slippery or not. And in a number of corners where the surface is polished, it is better to be off line and to use the wet line, so to say, which means a late entry and a very late apex, and then unwind the steering sooner and more, when you start to accelerate. And pedals are not really a big problem, I believe again, it will be so important, especially in corners where the braking is downhill, to adapt your driving to that, because the rear is light and in the wet when the car starts sliding, it may not come back immediately. So you have to take your time to discover all of that, and there may be some kerb stones - you really have to be careful to avoid them. But even in the dry, I've never been a fan to jump over kerb stones. It's quite hard for the car and there's no real need for that. Exceptionally, when you are in the qualifying lap in a race, you can do it. But otherwise I'm really not a fan to use the kerb stones.

Colin: Yeah, and some of the kerbs are very high, aren't they?

Dirk: Yes. In some places, they are quite high. And I've seen, we all have seen, I guess, on YouTube, some footage where cars literally take off. And that is, of course, very dangerous. So again, it is so important not to make mistakes, to do maximum, not to make mistakes and to learn it slowly. My experience is you need about 50 laps to know the layout and you need about 50 more, so 100 laps in total, to become reasonably fast.

Colin: Yes, OK. And then if it was your first visit, how many laps would you look to do in a day? If you're a complete newbie to the 'Ring, it's really tiring and it's exhausting, as you said earlier, just getting moved around in the car and the G loads and the changing topography. How many laps would you recommend for a first session?

Dirk: I think 20 or 25 is possible? Yeah, you can do that in a day without any trouble, I think.

Colin: Dirk, I think that might be a good place to wind up our conversation. Your insights are fantastic. I’ve really enjoyed listening to both your racing and your engineering history. And we’d like to thank you for taking part, and hopefully in the future we can do another one.

Find out more about Dirk and Top Line Development at https://www.topline.be/en/

CAT Chats Cars Podcast

Join Colin as he explores the automotive world with a diverse range of car enthusiasts and professionals as they share their passion and life stories. Search ‘CAT Chats Cars’ on your favourite Podcast app or browse our episodes here.

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