Hot Car Spotlight:

This is a spotlight of a track/race car that we love. We’ll examine some of the details that make these cars so cool, from examples of cutting edge aerodynamics and engineering to historically awesome cars that influenced today’s race car design.

Written by: Ryan Passey

Say hello to the Under Suzuki Nissan S15 (240sx)

The thing I like so much about the story of this car is the dedicated and grassroots approach that the owner has taken, building the car himself and learning the skills necessary to make new parts as he goes. By day Suzuki-San works at his parent’s pharmacy. By night, he makes his own carbon fiber body panels.

Now is a great time to take a look at this car as it will be competing at the World Time Attack Challenge in Australia next month!

This S15 is developed for the Unlimited/Pro class of Time Attack where there are very few regulations to restrict what can be done to the car. As a result, we can often gain even more valuable insight into the most effective strategies regarding the aero and chassis than from looking at cars from most professional race series.

A very exciting bit of news is that American aero guru Andrew Brilliant – who I am a big fan of – is now a part of the effort this year. This has brought the car’s aero up to a new level with lots of focus on increasing front downforce. In fact they recently changed to a custom rear wing designed by Andrew in order to keep the car balanced with all the front grip they created.

The car still uses a Nissan SR20 motor and produces 800 hp, with intense focus on weight distribution in the car; the turbo is mounted very low, with a titanium exhaust and the dry sump sits in the passenger footwell of the car.

Already, there are some impressive achievements under its belt. In Dec. 2012 Suzuki-San set a new track record at Tsukuba Raceway for a production car on street legal semi-slick tires, dethroning the HKS C230 Evo by a full second. Incredible particularly considering that it is rear-wheel drive.

There are many fine details to be noticed; The front splitter is not flat – much of it slopes upwards to create a diffuser effect. The splitter has endplates which encourage air pressure to build on the top surface of the splitter. The canards have a gradual curve to them, avoiding flow separation of the air that passes along the underside, and they are cambered towards the center of the car to build pressure on the top portion.

Then there is the rear of the fender – notice a similarity between this and last week’s Car of the Week feature? Venting the pressure out of the wheel well is beneficial in most cases, but it becomes absolutely crucial when you are also introducing additional pressure into this area with diffusers in the splitter. Something to note is the addition of large louvers on the top of the fender this year (seen in the first picture), which hadn’t yet made their appearance in the picture above (circa 2013).

The above photo is from the day Suzuki-San set the Tsukuba record in 2012. Hard to imagine that this is the smaller rear wing, which has since been replaced! Notice the low-angle spoiler which extends off the back of the trunk – this keeps airflow horizontal and smooth as it passes under the wing.

An amazing note to make is that until 2014, this car did not have a flat bottom, making the 2012 lap record even more impressive. Flat bottoms can produce serious results – I am testing one which I designed for my own time attack car – but they can be difficult to tune, so Suzuki-San left that for last. With the help of Andrew at AMB Aero however, this and many other elements have been added.

Less than a month to go before World Time Attack and we see whether Suzuki-San and his personal build can match the best that the big shops bring to the fight.