The Ultimate Diesel Pre-Runner: Carlos Calderon’s Baja-Built Cummins

CARLOS CALDERON’S CUMMINS PRE-RUNNER

“THE FACTORY FRAME WAS CUT OFF DIRECTLY BEHIND THE CAB TO MAKE WAY FOR AN ALL-NEW BOXED BACK HALF”

Growing up around his family’s tire store, Carlos Calderon of Santa Maria, California, began growing his love of everything automotive at a very young age. Spending all his time around the shop, learning the ins and outs of the cars and trucks his dad was working on all day, created a bit of a truck-centric attitude within him right from the start. Since he was still in his teens at the time this build started, this 2nd Gen Dodge Cummins became almost an extension of Calderon’s body. With time and with the help of a few friends and nearby shops, turning this truck into one of the first true front-beamed and rear-linked diesel Pre-Runners in existence became his true obsession in life.

DIESEL PRE-RUNNER

The true vision of the project involved converting the 24V, 5.9L Cummins into a fully capable Baja truck while maintaining some of the daily driver characteristics that would allow him to drive it to and from work whenever he wanted. The truck has been sitting in its current form for almost four years, but took nearly seven years, endless hours, and too many broken parts and improvements to count. To become a true Baja truck, it first needed the suspension and steering system improved drastically. The gnarly off-road abuse it would be subjected to necessitated more suspension travel, better shocks, and a drive train to support it all.

THE CHASSIS

Starting with frame modifications and roll cage, Calderon turned to Steve Fike of Dirt Designs for his team’s fabrication skills and assistance. A complete chassis cage was built using 2-inch DOM tubing; it was assembled to be race legal for BITD and SCORE sanctioned races. The factory frame was cut off directly behind the cab to make way for a new boxed-back half section to support the fully custom linked rear suspension. The rear trailing arms measure 65 inches in length and use massive JMX16T Heim joints with a 1.25-inch Uniball for durability. The shocks used here are massive 3.0 King coilovers with King 4.5 Tube Race bypasses and 2.5 bump stops. A Detroit locker was installed to strengthen the rear differential, along with forged Yukon axles and a 4.56 Richmond ring and pinion gear set. To make sure everything survives the off-road beating, the hardware used is all safety wired 12-point nuts and bolts.

“500 HP AND 800 LB-FT OF TORQUE”.

SOLID AXLE DELETE

For the first few years the front suspension used a solid axle design, but after breaking it for the third time Calderon decided to dive headfirst into the J-beam conversion that’s now used under the front end. This full-custom front was built to support a swing-steer setup outfitted with a ported steering box and ram from Bench Works Steering. The power steering pump was upgraded with a PSC unit to keep steering input precise and responsive. With a full 21 inches of front suspension travel, the J-Beam system works flawlessly off-road. As with the back end, the truck softens dirt moguls with 3.0 King coilovers and 4.0 six tube race bypasses. The front and rear brakes were upgraded with StopTech drilled and slotted rotors and EBC Yellowstuff pads. The brake lines were also upgraded with stainless braided bits from Crown Performance. The truck rolls on 39×13.50 Toyo M/T Open Countries mounted on 17×9 Ultra bead lock wheels.

BODY WORK

The body was modified and painted by Premier Auto Body of Santa Maria, Calif., and endows the truck with true Pre-runner style using Hannamen front fiberglass fenders and Trailer Products rear fenders. The stock headlights were replaced with blacked-out lamps from Anzo Lighting. A Fuel Safe 50-gallon fuel cell resides directly behind the cab along with Optima Yellow Top batteries. The back end was also modified to make room for mounting two full-size spare tires for quick and easy swaps on the trail. State-of-the-art GPS systems were also needed for the build, so a Lawrence GPS 5 Baja and Lawrence GPS 7 system were installed in the cab along with a Rugged radio intercom and PCI race radio kit. The stock seats were replaced with 5-point Beard Ultra T1 seats and Crowe harnesses.

24V CUMMINS

Since the factory 24V Cummins under the hood wasn’t going to have quite enough grunt to keep those massive tires rolling and make the truck competitive out on the race course, some mild upgrades were required. The fuel system was upgraded with a BD Diesel X-Flow lift pump kit and 150hp Industrial Injection injectors. To improve airflow, a Banks Ram Air intake elbow, BD Diesel intercooler, and BD Diesel Killer B Special turbocharger set at 40 psi boost were installed. A fully custom intake system was built using a high-flow R2C air filter to keep dirt and debris out. The exhaust was upgraded with a full 4-inch piping kit, and a Smarty tuner was used to massage the computer programming for optimum performance. Inside the cab, Calderon monitors engine vitals by using an Edge Attitude gauge kit.

“THE TRUCK HAS MULTIPLE TOP TEN FINISHES IN BAJA”.

DRIVETRAIN MODS

To channel 500 hp and 800 lb-ft of torque, the truck’s drivetrain needed to be beefed up as well, so a fully built 47RE automatic transmission was assembled by Gars Transmission of Paso Robles, Calif. Running all billet shafts, a triple-disc torque converter, BD Diesel billet fl ex plate and Suncoast manual valve body, it’s basically built to handle anything thrown at it. A Mag-Hytec deep transmission pan and Mishimoto aluminum radiator were also installed to help keep fluid temperatures down in the hot desert conditions. A Santa Maria Driveline was used to improve the drivetrain’s strength and durability.

Since being completed, the truck has competed at Baja on two separate occasions, where it placed in the top 10 both times. Which is not bad considering the 70+ truck field it was competing against. Calderon has been very happy with the truck’s multi-purpose uses, and believe it or not he still drives the truck every day to work. To his knowledge, this truck was the first and still one of only a handful of front-beamed, rear-linked, full-size diesel-powered Pre-Runner trucks either on or off the road. He gives thanks to his friends at Dirt Designs and ALLCO for all their hard work and help on the project through the years. He also takes pride in knowing he built something particularly special and different. DW

FREQUENTLY ASKED QUESTIONS.

What are the pros and cons of choosing a diesel engine for a pre-runner truck build?

Pros and Cons of Choosing a Diesel Engine for a Pre-Runner Truck Build

Considering a diesel engine for your pre-runner truck build is an intriguing proposition, but it’s vital to weigh both the advantages and drawbacks before making a commitment.

Pros of Diesel Engines

1. Torque and Power:
   • Diesel engines offer exceptional torque, which is beneficial for towing and pulling heavy loads.
   • Provides a stable power output, particularly beneficial for off-road adventures requiring steady and reliable performance.
2. Fuel Efficiency:
   • Generally, diesel engines are more fuel-efficient compared to their gasoline counterparts, leading to longer distances on a single tank.
   • Some smaller diesel engine combos now offer both torque and improved fuel economy, appealing to those conscious of mileage and costs.
3. Durability and Reliability:
   • Known for longevity, diesel engines can handle harsh conditions and extended use without significant issues.
   • Less frequent maintenance needs due to the robust design geared towards heavy-duty applications.

Cons of Diesel Engines

1. Weight:
   • Diesel engines tend to be heavier than gasoline engines, which can affect the truck’s balance and agility.
   • The additional weight may not suit a pre-runner focused on speed and dexterity across terrains.
2. RPM and Acceleration:
   • Diesel engines often struggle with quick acceleration and high RPMs, which are essential for rapid desert racing conditions.
   • Gasoline engines offer better revving capacities suitable for environments requiring swift power shifts.
3. Availability and Regulations:
   • Limited available small diesel engine options for pre-runner builds can be challenging, particularly with current emissions regulations hindering some modifications.
   • Emission standards in certain regions can limit the feasible use of diesel engines, making it difficult to modify and maintain legality.
4. Cost and Complexity:
   • Building a diesel pre-runner may involve higher upfront and maintenance costs due to specialized parts and tuning.
   • Complexity in installation and potential need for aftermarket modifications may add to the difficulty compared to gas engines.

Conclusion

While diesel engines offer significant power, durability, and efficiency, their weight and less agile performance can be detractors for a pre-runner truck focused on speed and maneuverability. Carefully consider your goals and the terrain you plan to conquer when deciding between diesel and other engine types for your build.

How do different diesel engine models compare in terms of weight, horsepower, and torque?

When comparing different diesel engine models, key factors to consider are weight, horsepower, and torque. Let’s break down some examples:

1. Heavy-Duty Engines:
   • Weight: For instance, certain heavy-duty diesel engines, like a 6-cylinder model, can weigh around 850 pounds.
   • Horsepower and Torque: These typically offer robust performance but may vary widely depending on the specific model and year.
2. High-Performance Diesel Engines:
   • Weight: Some larger models can weigh up to 1,100 pounds.
   • Horsepower and Torque: Known for higher outputs, they usually deliver a powerful combination, ideal for demanding applications.
3. Compact Diesel Engines:
   • Weight: More compact models, such as a 4-cylinder turbocharged option, often weigh approximately 500 pounds.
   • Horsepower and Torque: These may offer around 168 horsepower and impressive torque figures, like 442 lb-ft, while still providing decent fuel efficiency (close to 20 mpg).

Overall, the choice depends on the intended use. Heavy-duty engines suit larger vehicles needing maximum power, while compact options are ideal for lighter trucks, balancing performance and efficiency.

What are some challenges faced when using diesel trucks in desert environments?

“Keeping the truck and driver alive and functioning, plus knowing exactly where you are, is extremely important in off-road racing. The interior of Carlos Calderon’s Ram is designed to do exactly that with multiple GPS systems, engine monitors, race seats with 5-point harnesses and a full cage.”

However, when it comes to choosing the right engine for desert racing, not all options are created equal. Diesel engines, renowned for their capacity to tow and pull with immense torque, often fall short in these high-speed, dynamic environments. The steady RPMs that make diesel engines ideal for tasks requiring consistent power output don’t align with the quick-revving, high RPM demands of desert racing.

Key Challenges of Diesel Engines in Desert Racing:

• High RPM Requirement: Desert racing demands engines that can rapidly rev to high RPMs, a challenge for the traditionally slower-revving diesel engines.
• Quick Acceleration: The need for bursts of speed and agility in desert terrains highlights a diesel engine’s slower acceleration compared to lighter, high-revving motors.

In these challenging environments, the choice of engine can be as critical as the advanced safety and navigation systems fitted inside the vehicle. The combination of cutting-edge interior technology and the right engine type ensures the vehicle not only survives the harsh desert conditions but thrives in them.

How do people feel about using diesel trucks as pre-runners?

To his knowledge, this truck was the first and still one of only a handful of front-beamed, rear-linked, full-size diesel-powered Pre-Runner trucks either on or off the road. He gives thanks to his friends at Dirt Designs and ALLCO for all their hard work and help on the project through the years. He also takes pride in knowing he built something particularly special and different.

While diesel engines are renowned for their torque and efficiency, they’re not always the top choice for pre-runner trucks. Many enthusiasts argue that the weight of diesel engines, such as the Duramax at 850 lbs or the 12-valve Cummins at 1100 lbs, can be a drawback for desert racing, where lighter, quick-revving engines are preferred.

However, not everyone agrees. Some have successfully integrated diesel engines into their pre-runners, citing the reliability and power delivery as significant benefits. For instance, one enthusiast has been running a second-gen 12-valve Cummins in his truck for a decade, tackling both racecourses and highways without a hitch.

Pros of Diesel Pre-Runners:

• Torque and Power: Diesel engines provide substantial torque, ideal for heavy-duty tasks and maneuvering large tires.
• Fuel Efficiency: Many users report reasonable fuel economy, even with larger setups.

Cons of Diesel Pre-Runners:

• Weight: The heft of diesel engines can impact vehicle dynamics in high-speed desert environments.
• RPM Limitations: Diesel engines don’t typically offer the high RPMs needed for quick acceleration.

There is a growing interest in smaller, more efficient diesel options, which might soon change the landscape for diesel pre-runners. Builders are exploring various setups, from the Cummins crate R 2.8 to newer straight-six designs, each offering unique benefits.

Ultimately, while diesel may not be the conventional choice for pre-runners, those who embrace it often find satisfaction in the distinctiveness and robust performance it offers. As the diesel scene evolves, so too might the perception of these powerful engines in the world of pre-running.

What are some considerations regarding the weight of diesel engines for off-road trucks?

“With racing in mind, Calderon filled the bed with spare tires, tools, spare parts, and more. Outside the obvious necessity for on-the-fly repairs, this was also done to help even out the truck’s weight distribution front to rear. After all, that 24-valve Cummins isn’t light.

When considering diesel engines for off-road adventures, weight becomes a pivotal factor. For instance, the 12-valve Cummins engine tips the scales at around 1,100 lbs, while a Duramax engine weighs in at about 850 lbs. This hefty weight can significantly influence performance, from handling to fuel efficiency. Calderon’s setup achieves an average of 14 mpg, proving that strategic weight distribution can mitigate some of the challenges posed by heavier engines.

However, not all diesel engines are created equal in terms of weight. The Cummins R 2.8 4-cylinder turbo, for example, presents a lighter alternative at approximately 500 lbs. With 168 hp and 442 lb-ft of torque, it offers a compelling option for lighter trucks, balancing power and efficiency at around 20 mpg.

Calderon’s experience over a decade shows that a well-maintained 12-valve Cummins can handle the rigors of off-road racing and long highway journeys without issues. His truck, weighing in at 6,000 lbs with a 60/40 weight bias, handles 37-inch tires effortlessly, soon to tackle 40s, underscoring the importance of understanding and managing engine weight in any off-road build.”