Mohd Azad Jasmi

By: Azad Jasmi

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Friday, 4-Jul-2008 07:58 Email | Share | Bookmark
Suzuki WRC - Interview with Najima

The WRC is the pinnacle of production-car-based motorsports. There are lots of closed-circuit competitions like the Formula-1, but they’re all for dedicated racing vehicles specially prepared for the purpose from top to bottom. In the WRC, our challenge, champions are those who can get their machines, based on cars with over 25,000 units in production and with only limited modifications allowed, to run, compete, survive and win in all kinds of natural settings, every type of tough conditions from icy roads in Monte Carlo, snow-covered minus 30 Celsius climates in Sweden to hot 30-to-40-degree conditions in Greece where temperatures inside the vehicles can reach 60 degrees. It doesn’t come easy, but I’m ready to give it my best, around the clock and all through the calendar.

We accepted the challenge, and we’re determined to win no matter what it takes. Easier said than done, naturally. Hopefully, with all our hard-working staff and with the precious support of our fans around the world, we’ll be moving ahead toward reaching our goal.

The SX4, firstly, has excellent body rigidity; I think it’s an outstandingly tough body in its class. Another good thing is, because it already has large-size tires in production form for stable driving performance, the wheelstroke is quite long to begin with. We have lots of room for tire movement up and down, and that’s a big advantage in developing it for the WRC, in terms of providing better traction after big jumps, and driving performance over depressions on rough courses.
I’d like to mention one technical detail. The front pillars on this car are deeply inclined, and by fitting the roll cage in a way that it runs down along these pillars, it reaches the front suspension top mounts in a straight line, and as a result, the loading inputs to the front suspension can be delivered from the top mounts through the roll cage to the entire chassis in a well-dispersed manner, by which they are more effectively absorbed, This allowed us to come up with a very good roll-cage design. This is just an example of how the original SX4 body is wonderfully suited as a basis for manufacturing a World Rally Car.

Compared to its rivals, the SX4’s big advantage is its compactness. Looking at all 16 WRC rounds, maybe in the really high-speed courses, the big-body machines might have an edge in handling stability and so they might have some advantage over us. However it is more common for rally events to be decided by how well you do at average speeds of around 100 km/h. At that speed range, the main factor is cornering performance. Under WRC regulations, the SX4, due to its short body length, has a 30mm-narrower tread compared to its rivals. We can make use of the SX4’s compactness to clock better times through corners, which should make us fully competitive against our rivals in overall time, too.

The regulations specify a minimum weight limit of 320 kilograms for the body shell (body in white) with safety features added. Our car has large reinforcing sections in its production version, so we have a lot of weight to cut to get it down near the minimum weight figure. Regulations don’t allow much in the way of changing materials and reducing thickness, so we look for parts we can remove, like unnecessary brackets, etc. Then we take the remaining, definitely necessary sections and build the body shell, welding and assembling the component pipes in a manner prescribed by safety, strength and rigidity concerns.

Our body-shell construction starts with the roll cage, as it is mostly pipes and plays a major factor in maintaining safety and rigidity and keeping our machine as close as possible to the minimum weight limit.

The SX4 engine is naturally aspirated with 4 cylinders and 2-liter displacement in its production form. We add a regulation turbocharger, change bore and stroke, and tune the engine to deliver lots of torque from the lowest rpm and maintain a flat torque curve through high rpm. The turbocharger naturally takes in more air as its rotating speed increases; however, the air-intake volume is restricted by regulations, so when it exceeds a certain rotating speed, negative pressure sets in and cuts down the intake air flow. The most important requirement for a World Rally Car engine is to bring out as much torque as possible before the onset of negative pressure.

World Rally Cars can also be converted to 4-wheel-drive. Specifically, the regulations allow us to make cut-outs on the floor panel to make room for a 4WD gear box, cut-outs on the partitioning wall between the engine and chassis, and tunneling cuts-outs on the floor for the propeller shaft. The regulations also permit big changes in space layouts to make room for 4WD differential arrangements which is different from a conventional front-wheel-drive layout. Also because of the rear differential, the regulations permit extensive modifications related to the allowed use of strut-type rear suspension.
In short, the SX4 WRC is based on a front-engine, four-wheel-drive vehicle and fitted with specially prepared gear box, propeller shaft and differential systems incorporating modifications allowed under WRC regulations

Every maker and team is working busy at their wind-tunnel testing facilities to streamline their vehicles’ aerodynamic performance. Demand for aerodynamic-performance upgrades come in various forms. Not often mentioned, however, is the cooling aspect. The objective is to boost cooling performance efficiently, that is, you need to improve cooling performance while also making sure the design generates good downforce, that is, preparing front and rear aerodynamic devices to create air flow that keeps the vehicle pushed down and well-connected to the ground as much as possible. The requirements for cooling, downforce, front/rear balance, all have to be satisfied while also keeping a low drag as possible. Since aerodynamic designing involves all such demands, we spend lots of time at wind-tunnel-testing facilities in our search for the most effective machine shape and aerodynamic devices.

With competition machines, the first step, determining basic specifications such as vehicle layout and performance potential, is of extreme importance. Make errors at this stage and we get bogged down with problems later on. And so we specified for the highest possible, ideal performance figures within the modifications allowed under WRC regulations. We are at the stage of considering whether our car can really function properly at such specifications, looking for possible errors in our performance estimates. As soon as we have those cleared, we’re on to the next phase, checking the car’s durability, whether it can withstand the rigors of competitions intact. That plus maintenance issues, serviceability in actual rally conditions. WRC events comprise three days of tough running across huge distances that have to be run with only little allotted servicing time. If anything breaks, it is of paramount importance that it can be properly replaced, maintained or repaired in short time. This needs to be checked very carefully, and we are also working on that right now. It’s still the early stages of development, so all our work is still done in Japan. We’ll continue testing in Japan, much of it at Suzuki test courses, until we feel that it’s shaped up to be ready to be tried out by European drivers.
We hope to be ready to go to Europe sometime before the end of year or the start of next year, and begin in earnest the job of tuning the car to winning specs. Until then, we’ll be busy in Japan looking for any potential problems, taking care of them.
We also have a surprise announcement – though it will probably be officially announced by the time this interview is uploaded. Michel Nandan, as technical manager, and Nino Frison, as chief designer, have joined our team.
We regard Michel-san as the European engineer most qualified to help us in moving forward with our WRC project. He has had lots of success in various teams including Toyota and Peugeot, and we are certain his rich rally experience will greatly add to our team performance. There is simply no one more fit for the task than him. He and I have good chemistry; he’s a great character, a person driven to winning, someone who has much experience and lots of fresh ideas. And since we have many suppliers in France, we are also counting on him to represent us and improve our communication in Europe. We also look forward to his help in communicating with FIA, as the FIA headquarters is also located in France, in Paris.
Nino-san also has rich experience, in a whole range of top competition categories including WRC, F1 and DTM. We are particularly impressed with his machine-building expertise. I remember there was a time when we used to think of working skills like welding and processing techniques to be a strongpoint of us Japanese. Together with his construction expertise, we will surely be valuing his advice in selecting methods for getting the best results within FIA regulations, as he has an intricate understanding of WRC. We asked Nino-san to join because we believe his experience and expertise will be indispensable in making our new World Rally Car construction a success.
With the team capability now greatly boosted with the joining of Michel-san and Nino-san, we are keen to develop the SX4 WRC into the world’s best WRC machine in the near future. With our experience coupled with their experience, I have no doubt we will be able to make our car the most competitive on the field. Towards that goal, we’d like them to join us in working hard, and in keeping our spirits and fitness high to endure such hard work.

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