Dodge Dakota Platform

 

The Project Sidewinder turbo diesel sport truck was evaluated on the diesel chassis dyno to determine the diesel power requirement.

The Banks Sidewinder Project Dakota was run on the chassis dyno at Banks Engineering in stock trim.

 


The Dodge Dakota platform provides a smaller, lower-drag aerodynamic package for top speed runs. With less frontal area and a slightly smaller coefficient of drag, the Dakota requires less power to reach 210 miles per hour than the larger Dodge Ram package. Since the Project Sidewinder is a street vehicle, power goals must take into account the tractability, efficiency and reliability needed on the highway. The smaller aero package needs less power to reach the 210+ mile per hour speed goal.

In order to determine the power needed to reach the speed goal of 210 miles per hour at Bonneville, the power at the rear wheels, top speed and aerodynamic and parasitic drag had to be determined for the stock truck. Initial chassis dyno testing was needed to determine horsepower and torque at the rear wheels for the stock truck. Our Dakota was fitted with a four cylinder engine from the factory. The stock power output was 98 horsepower at the rear wheels. This power figure was used along with top speed (terminal velocity) and coastdown test data to determine the actual total drag of the stock truck. Then the power needed to reach higher speeds was calculated, as shown on the accompanying graph. The stock truck was then taken to Mrs. Orcutt's driveway, a 5-mile long stretch of perfectly flat road in California's Mojave Desert, for top speed runs and coastdown testing. The Banks Dynafact, a complete on-board computerized testing rig, was used to gather data for calculating aerodynamic and parasitic drag. From those numbers, the Banks team was able to calculate the amount of horsepower required to reach 210 miles per hour in the Dakota. Well over 800 horsepower would be required with the Dakota in stock trim at stock ride height. Since the Cummins Turbo diesel engine in race trim was projected to produce 600 horsepower (on straight diesel fuel), considerable drag reduction was needed to reach the desired speed of 210 MPH at Bonneville. Lowering the truck reduced frontal area and an air dam and other allowable aerodynamic modifications reduced the drag coefficient.

Reducing Frontal Area and Drag Coefficient

After chassis dyno testing at Banks Engineering and coastdown testing, the Banks engineering staff determined that over 800 horsepower would be required to reach the desired speed of 210 miles per hour with the stock Dakota frontal area and coefficient of drag. But by lowering the truck to race configuration and cleaning up the aero profile with a front air dam and other allowed modifications, both the frontal area and drag coefficient were reduced enough to lower horsepower requirements to a projected 600 BHP to hit the target speed of 210 mile per hour.
 
   
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Banks engineers recorded data from the chassis dyno and matched it against the Dakota aerodynamics to determine high-speed power needs.
Determining the horsepower and torque curves of the stock engine was necessary for the engineering staff to determine power needs of the turbo compression ignition engine for the assault on the Bonneville record book.
Determining the necessary power requirements was essential before modification of the Cummins turbo diesel began.
Combined with top speed and coastdown data, power figures were determined.
On the road coastdown testing on Project Sidewinder revealed the need for Dakota aerodynamic improvements.
 Testing at Mrs. Orcutt's driveway with the Banks DynaFact onboard data acquisition system gave the engineering team the information needed to calculate power requirements for Project Sidewinder.
Project Sidewinder Dakota is the worldïs first diesel sport truck exhibiting both aerodynamic improvements and diesel performance. Power requirements go up with the square of the speed.

This graph shows the horsepower needed to move the stock Dakota at various speeds.
The stock configuration and ride height of the Dakota pickup are not aerodynamically clean.
 The Dakota pickup in stock form. The goal of reducing aerodynamic drag to a minimum requires lowering of the truck as much as possible to reduce frontal area and to clean up air flow wherever possible to reduce parasitic drag. Banks’ wind tunnel experience on the GMC Syclone project will be drawn upon heavily in this development.
Modified and lowered, Project Sidewinder becomes more aero dynamically clean for the Bonneville Salt Flats.

The Dakota pickup in modified form. A front air dam is used to reduce airflow under the truck as much as possible. Aerodynamic downforce is also needed at the rear, so a slight rake of about one degree (nose lower) is used to get some downforce on the rear tires at high speeds. This also improves straight line stability. Many aerodynamic details are left unspoken in this explanation as they fall into the realm of “Speed Secrets.”