Shinichi Sakaguchi explains the processThe Suzuki development programme continues to move forward in anticipation of its full-season World Rally Championship entry in 2008.
The team's Chief of Chassis Design, Shinichi Sakaguchi, explained how his department has been
going through the development stages.
"The SX4 WRC prototype we unveiled at the 2006 Geneva Motor Show was still very much a work in progress," he began.
"After that, in terms of aerodynamics, we tried adding many shapes and forms of wings, undercowl and overfenders to the production car and performed thousands of tests. We increased the downforce while constantly checking the front-to-rear downforce balance: first the rear downforce, then the front, again rear, front, and so on, until we reached the shape we have now," Sakaguchi continued.
Transforming a production model into a rally machine has its own basic challenges. To that must be added the hurdles created by the original styling department's work when it was thinking of mass-market attraction.
"The SX4 is basically a hatchback design, which made the design of the rear-wing section particularly difficult. Downforce is generated by flowing air to the rear wing to create negative pressure. What's important is how the air coming from the roof flows away from the back of the rear wing.
The SX4 is quite tall and the rear section drops down suddenly, which makes it difficult to obtain the desired air flow into the back of the wing."
A countless amount of testing then went into defining the right aerodynamic shape for each piece added to the car's chassis: "For some parts we would use clay models, trying out different shapes, scraping off or adding on clay. We kept records of each test; we now have a huge accumulated data of rally car aerodynamics in many thick files."
Things are also being worked on under the hood, with physical space and regulation constraints being an important part of the equation, as Sakaguchi cited an example.
"We can get a good picture of the vehicle's characteristics by looking at data from wind-tunnel tests and test drives, but the layout of the cooling system has its own set of difficulties," he said. "The big differences in temperature between rally events complicate matters."
Next comes the car's structural integrity and strength, which involves using several different types of material and steel for the right overall effect. "WRC is an extremely tough, competitive category involving long driving distances, so durability, the strength to complete the run, is the absolute precondition. The question is how to keep the car lightweight while leaving intact its strength," Sakaguchi related.
"It's invisible from the outside, but we have made much progress in the study of material strength, that is, we are learning to use materials with quality and characteristics that are clearly a step ahead of what we've used in the past."
The Suzuki SX4 will be going out on a real-world testing run in October, a date that is approaching quickly for Shinichi Sakaguchi: "We are fully aware of how hard it's going to be for us in our first year of entry. We went through the same process with the Super 1600, but we understand this is going to be much tougher, in light of what we've gone through so far."
"If we take the necessary measures one by one, just as we've done in the past, I am confident we could put on quite a performance and get some exciting results."
Source Suzuki WRC Challenge
