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(GT-NSX Dissection)
Learn of the Secrets Unseen From the Grandstands

Volume 4 - A Subtle Arsenal

Lecturer: Akie Oku

The last 3 volumes talked about air resistance design, suspension, and engine -- all as it applied to the GT version NSX.  This time, we will speak on other modifications that don't relate directly to on-road performance, but were applied to the GT version NSX.  These are subtle modifications, but all contribute to making a more complete race car.

*Secret Weapon #1 - Plenty of Vent

One of the unique design aspects of the GT version NSX is in its airflow efficiency through the passenger compartment.  It may sound odd that we speak of airflow through the passenger compartment, considering we're talking about a race car meant to go fast -- not for passenger comforts.  

However, with a closed-body (has a roof) racing car, venting the air through the passenger compartment is extremely important.  A race engine makes a lot of heat, and with such basic components as the heat shield removed, the interior is much hotter than a factory car -- as high as 60 degrees Celsius.  (140F)  Under these conditions, a driver will lose stamina very quickly, and while vehicle performance will not be affected, the overall driving performance will surely fall.  It's possible to even burn one's self while operating sizzling-hot pedals and shifters.  Obviously, with such extreme heat, this is not a operable vehicle.

 
Upon designing the GT version NSX, we were committed to making it vent well.  The key point of venting the air is not in getting it in, but getting it out.  Without the air being pushed out, the heat will still build up.  For the NSX, there are 3 points of air intake -- above the radiator, and under the headlight covers.  In order to not affect drag, these holes are extremely small.

Getting air is important, but getting
it out is even more important.

 

 

From here, the air that is delivered to the cockpit flows through the interior and escapes from the side windows.  The side window area is a point of low pressure, so it is ideal position for air to exit.  Not only will it simply flow out, it will get sucked out.

There are 3 types of exhaust ports on the side window.  One port is a cut-out of the window, the second is made of slits to the window, and the last is a flap-type port that can be adjusted.

 

Air collected from the front of the car is 
delivered to the cockpit via ducts.

With these efforts, we have gotten compliments from other drivers that "The vent works so well, it can actually get cold in the Winter."  Ultimately, man has to extract the car's performance, and this is just another obstacle we had to remove.

*Secret Weapon #2 - One-Touch Jacks

The GT version NSX has air jacks on all 4 corners.  An air jack is a device that lifts the car up when external air pressure is applied.
Normally, a lever-type jack is used in the pits.  Once the race car enters the pits, the pit crew slides the lever-type jack underneath the car and lifts it up.  I'm sure you've seen such a sight before.  So, why did we forego using lever-type jacks and install heavy jacks as part of the race car?

When the pit crew inserts air from the rear of the vehicle, 
all 4 jacks are activated, and lift the car up.

Because the GT car is a factory-modified vehicle, the minimum weight requirement is actually pretty high.  Because of that, unlike Formula 1 racing, there isn't much of an advantage of making the car overly lightweight.  Matter of fact, the NSX was too light, and we added additional chassis strengthening reinforcements.  If we are going to have to add even more deadweight, we figured that we can add a mechanism that will make the lives of our pit crew easier.  Not only is this method faster, it is far more reliable.  After all, we are in a race where hundredths of a second matters.  This small consideration can make a big difference.

*Secret Weapon #3 - Sequential Shifter

 
Although it is not commonly known, the GT version NSX's transmission has a sequential shifter. The factory NSX has the standard H-gate pattern where each leg is designated as a gear. However, with the sequential shifter, pulling the shifter toward you will shift up one gear -- pushing the shifter away from you will shift down one gear.
Factory shiftgates require
 you to move in 4 directions
The sequential shifter
 allows for simpler shifting

 

 
While it may seem as though using the sequential shifter is more of a pain than the standard H-gate, when one considers the lower number of missed shifts, speed of changing gears, etc., the sequential shifter wins on all accounts. In addition, it is easier for the driver to shift up when the G-forces are pushing his body back, and shift down, when the braking forces are already pushing him forward. It is a very natural movement. With the H-gate, drivers need to push their arm forward while being pressed back against their seats during hard acceleration. (3rd/5th gear) The opposite applies when shifting down during hard deceleration. (2nd/4th gear) While this may seem like a small issue, the race car driver is already exerting all sorts of bodily forces to support himself -- the sequential shifter helps a lot in this respect.
As can be seen from this picture, the
shifter can only move forward and back.

 

*Secret Weapon #4 - Flip-Up Steering Wheel

The GT version NSX's steering wheel flips up. As you well know, modern-day Formula 1 race cars all have removable steering wheels. The main function of this is to allow the driver to get in/out easier in an already cramped cockpit. Many GT cars also have adopted a similar mechanism in the pursuit of optimal driving position.

The GT version NSX desires the same things. However, we decided to add a different, unique idea. The GT version NSX's steering wheel is made to flip up, without the need to remove the steering wheel itself. This is because the GT race has one aspect that a Formula 1 race does not have -- 'driver changes'.

 
Upon changing drivers, the steering wheel would have to be removed, and installed again in a short time period. This can easily become problematic, as the steering wheel could be placed in different places, or it may simply roll away. The flip-up steering wheel solves all of these problems by getting out of the way of the driver, but not requiring removal/installation.
The steering wheel flips down, the steering 
column rises under normal driving.

 

During a pit stop with a driver swap, the driver would simply flip the steering wheel up and exit. The replacement driver would get seated, lower the steering wheel, and they are ready to go. This flip-up system is extremely popular with our drivers. Tom Cornell (spelling? -editor) has even gone to say that while he cannot take the NSX back to Europe, he would like to at least take the steering wheel home with him.

The fastest car does not guarantee the win. Racing is all about going fast, and being strong. While the main aspects of the race car are vital, all the little things quietly contribute to creating a more potent race car.

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Updated January 15, 2000