The Brains behind the MX-5 Part I | Nobuhiro Yamamoto, Programme Manager

BY Burnpavement

When the new Mazda MX-5 was launched here, two of the most important figures in its creation were in attendance. In the first of this two-part series, we had a chat with the car's Programme Manager.

Nobuhiro Yamamoto has always been fascinated by engines and motor vehicles since he was a boy. As a young teen, he came across a newspaper article about the launch of Mazda's Familia Rotary Coupe, which piqued his curiosity about rotary engines. Once he read The Basics of the Rotary Engine, he was immediately hooked. Joining Mazda at age 18, he was appointed to the rotary engine division, and a scant three years later was placed in charge of racing rotary engine development. Since then, he has overseen the development of the FC and FD RX-7s, and, more impressively, was responsible for the 26B quad-rotor engine in the Le Mans-winning 787B. WIth a CV like this, selecting him to be the Programme Manager for the new MX-5 was probably a no-brainer.


BPYamamoto-san, we saw on your CV that you have an extensive history with Mazda, in particular with rotary engines and the company's racing programme. We'd like to know, will we see another rotary-engined Mazda? Is it possible to make a rotary engine compliant with today's tougher emissions regulations?

Yamamoto I can't really answer questions about the future, I'm afraid. But one thing is clear; the company will never stop developing rotary engines, as this is what we feel is in line with our customers' expectations. That's all I can comment about the future of rotary engines, I'm sorry.

BPHas Mazda ever considered another global motorsports program? Maybe in touring cars, GT cars, or even returning to Le Mans?

Yamamoto — There are many interesting racing series today, but we want to engage more in grassroots type of events. This is because this category of racing is very popular with our customers and we want to engage them more; that is how we take care of our customers. For instance, since 2002 we've had a MX-5 Cup race in Japan. For the new MX-5, we will have a new series starting from next year, so with this we really want to get closer to the customers.

BPOk so for Mazda Cup races, where will they take place? How many different championships will there be?

Yamamoto — We are going to make an announcement at the Tokyo Motor Show, where we will also display the car. But in the US, they've already announced the pricing. So far we have been making preparations for the US, Japan and also Europe. That’s the plan so far, and we really want to get the races started next year, but for now it's still under development.

BPOne thing the NA MX-5 was very famous for was excellent steering feel. Was it difficult to engineer the same kind of steering response and feel with the electric system in the ND?

Yamamoto — The NA, NB and NC all used a hydraulic steering system, because you get more direct feedback, and we believe that was a great system. But now we have to meet environmental regulations. We also wanted to include more steering feel across a wider range of speeds, so we believe the EPAS (Electric Power Assisted Steering) system is quite effective, because it allows a lot of flexibility for fine-tuning. But we still really care about the details, so we have a dual-pinion EPAS system that is attached to the column for more feedback. Normally this system is quite expensive, and our management even asked us, "Why do you use such an expensive system? Why don't you just use the system from the Mazda 2?" But I told them it has to be this design, otherwise you cannot get the same type of feedback.

BPSo, related to that, were you able to achieve all the goals and ideas that you wanted to use on the car? Was there anything that the finance department considered too expensive or complicated to approve?

Yamamoto — Hmmm, allow me to explain. On this car we have LED headlamps, which we had already decided three years ago we wanted to use. But LED technology was very expensive back then and management didn't like it. But like I said earlier, you have to make a priority, you have to look at the vehicle as a whole, then divide the vehicle in to two parts: areas where you need to spend more money, and areas where you can save some money. So we always had a priority of how to use the money. The more you spend, the more the customer has to pay to buy the car, and it is not good for them. For example the door handles, air-con controls and air-con vents are the same as on other models, so in those areas we used carry-over parts to make sure the costs weren't so much.

BPWe read from an earlier interview you had with a British magazine that you felt very strongly against adding a turbo to the MX-5, because of how it would change the car's characteristics. So as an engineer and designer of a car, how do you feel about people performing engine swaps? For example people in America swapping V8s into RX-7s or turbocharging MX-5s.

Yamamoto — There are many different types of fun you can get from an MX-5, and one of them is when people customise their car. The MX-5 has to be authentic in the hope that we are able to enhance the essence of driving. However, all customers are different, and they will all have different ways of enjoying their cars; for example some of them only want to go fast in a straight line so they add a supercharger or turbo rather than enjoying the cornering. It's ok for them to customise their cars; I don’t mind it, because that’s their fun. But if we added a turbo to the MX-5 as a mass-production version, that will deviate from the authentic essence of the car. So we don't add a turbo to the car ourselves, but it is ok if the customers want to do it, no problem. Same thing for the handling, if they want to fit bigger tyres or stiffen the suspension, they can do what they like for their enjoyment. Even though performance will then be quite biased in a particular direction…

BPWhat is the one aspect of the new car that you are most proud about?

Yamamoto — There are a lot of things that we can be proud of when we developed this vehicle. Of course there is the steering and handling, the performance, they all come close, but a roadster has to look cool and beautiful at first glance, and that was my strong intention. Looking at the side profile, it's exactly the ideal proportions we wanted. Although the designers brought the idea, the engineers improved the technology to make this happen, and all the members got together to realise this design. So that's the one thing I'm most proud of, that we were able to help produce this beautiful design.

BPMuch has been said about the switch from a 5-lug to a 4-lug nut design for the axles. Can you comment on that?

Yamamoto — The NA and NB used a 4 nut design, while the NC was 5 nut. For the ND we wanted to get the weight as low as the NA, that is the reason why we are able to use just 4 nuts. Compared to NC, we were able to reduce the weight by 100kg, that is the reason we were able to use the 4 nuts instead of 5 nuts.

BPThe MX-5 is a very small, lightweight, nimble car, and rotary engines are also very small and light. Do you feel that a rotary engine fits the character of the car?

Yamamoto — I think the expectations between this vehicle and the rotary engine are very different. An MX-5 has to create a very friendly relationship with the customer, and we want it to be like a lifetime partner. If we equipped the MX-5 with a rotary engine, it would probably be too edgy. We receive some questions from customers why we don't have a rotary engine in this vehicle, but if I asked a group of them if they preferred to have a rotary engine to please raise their hands, only the person who asked the question would do so. So most people don’t really believe we need a rotary engine in this car — MX-5 isn't just about horsepower. But in my personal opinion, I do think the MX-5 is well matched to a rotary engine.

BPSo just to carry on from there, which engine option do you think is better for the ND, the 1.5 or 2.0 litre?

Yamamoto — The reason we have the two versions, first of all, is that we have to go back to the basics, and enhance the fun of driving the ND. It has to be compact and has to be light. So a small engine can allow people to enjoy the driving experience more, so the solution was to provide the 1.5-litre engine. But we have to provide this vehicle to markets all over the world, and all their needs are different. Like travelling at 200km/h on the autobahn in Germany, or in the States they have to accelerate quickly between big trucks. So thinking about those driving scenarios, the character of the car has to be relevant to each market. Based on that, in the US we provide only the 2.0-litre, in Japan we have the 1.5-litre alone, while in Europe we have both. So it's not so much about which is better, but it has to be relevant to the market it's in. In Japan, we believe the 1.5 is the best, so that’s why we only have that, but in Europe there is a great variety of customers, so that’s the reason we provide both engines.

BPDown the line, will we see a more powerful MX-5 from the factory?

Yamamoto — Increasing the power, to me, is a bit pointless. This vehicle doesn't need to run fast, it's ok to drive slowly, and we want to give the customer time to drive; that's the value we want to deliver to them. So simply increasing the power is not in line with that kind of concept. Increasing the power means you need to improve the suspension, tyres and brakes, so everything gets bigger and heavier. In the past few years cars were getting heavier, so if we did that we would just be repeating the same things we did before. Rather than increase engine power, we hope we can enhance the MX-5 in other ways, especially by reducing weight. Of course we can easily reduce the weight by using more exotic materials, but the MX-5 will become more expensive, so I don’t think it's something the customer will expect. But in future if carbonfibre becomes cheaper to make and we can get aluminium at a cheaper price, I think we have a bright future for this vehicle.

BPIf there was one location anywhere on Earth you could drive this car, the perfect road for this car, where would it be?

Yamamoto — In Japan we have four seasons; in spring we have the cherry blossoms, in summer there is lots of sunshine so you can drive the car along the coast or beach, in autumn you can enjoy the leaves changing colour in the mountains, and in winter there is snow, and you can wrap up in a scarf and enjoy the scenery. So I believe you can enjoy the drive no matter when or where. I'm sure that no matter where you live, you can find a perfect place, so I'd like for you to find the best for yourself in your own country!