Why We Chose the Turbo Diesel
People often ask which engine we recommend. We have a very strong preference for the turbo diesel.
I get asked about horsepower and torque quite often, and I’ve learned that most people aren’t really asking about numbers. What they’re actually asking is: Can I comfortably drive it on the highway? Can I merge into traffic confidently? Can I pass when necessary? Can I climb through the mountains? And does it have enough power to keep pace with modern traffic?
With our turbo diesel, the answer to all of those questions is yes.
The Numbers
Our highest specification Turbo Diesel SV produces approximately 520 lb-ft of torque near 1,800 rpm and is quite comfortable cruising at approximately 85 mph. That’s cruising capability, not its maximum speed. Depending upon specification and driving conditions, we’ve also seen approximately 28–32 mpg.
But those numbers aren’t actually the reason we choose the diesel.
Built for Exploration
The reason is that we believe the engine should complement what a classic Defender was engineered to do rather than attempt to turn it into something it was never intended to be.
A Defender is fundamentally an exploration machine. It needs to be equally comfortable driving across the country as it is climbing a snowy road to a ski lodge, crossing sand in Utah, navigating a wet mountain road in Scotland or slowly working its way across difficult terrain.
In those environments, usable torque and the way that torque is delivered matter considerably more to me than peak horsepower.
Our turbo diesel develops tremendous torque low in the rev range. That gives the driver progressive, controllable power rather than requiring high engine speeds to access it.
In snow, that means being able to feed power into the tires without unnecessarily overwhelming the available traction. In sand, controlling wheelspin can mean the difference between continuing forward and digging yourself in. On a wet road or a twisting mountain pass, progressive power delivery gives the driver greater ability to manage the Defender through the throttle.
Range Means Freedom
Then there is range.
Our turbo diesel can deliver approximately 28–32 mpg. A gasoline V8 Defender consumes substantially more fuel. That isn’t simply an issue when you’re off-road. It changes how frequently you have to stop for fuel and how far you can explore between those stops.
When we’re driving through the Ozarks, across Utah, through Scotland or in Iceland, range isn’t an abstract specification. It means freedom.
That’s part of what a Defender is supposed to provide.
Where Horsepower Stops Helping
There is another part of the horsepower discussion that I think is frequently overlooked.
A classic Defender was never designed to be a high-speed automobile.
Look at one from the side or the front and the reason becomes fairly obvious. The windscreen is nearly upright. The body is tall and square. The sides are essentially vertical. Its shape was engineered around utility, visibility and capability, not aerodynamics.
Installing a 400-, 500- or 600-horsepower gasoline engine doesn’t change any of that.
It can certainly make a Defender accelerate harder and achieve greater speeds. But as speed increases, you’re forcing considerably more air against an inherently unaerodynamic body. Eventually horsepower isn’t the limitation. The architecture of the Defender is.
At Helderburg we’ve gone to extraordinary lengths to address that.
We developed our own cabin-encapsulation process, extensive acoustic treatment and proprietary thicker Helderburg glass. Through that engineering, we have measured cabin sound levels approximately 6–8 decibels lower than other custom Defenders we’ve evaluated.
That makes an enormous difference in how refined the Defender feels at normal road and highway speeds.
Knowing Where to Stop
But engineering also means understanding where to stop.
Once you’re approaching approximately 85 mph, even with everything we’ve done, the fundamental aerodynamics of a classic Defender begin to take over. Air hitting that upright windscreen and moving around the side glass creates wind noise that simply cannot be engineered completely away without changing the fundamental shape of the Defender.
That’s why when I say a Helderburg will comfortably cruise at approximately 85 mph, I’m not suggesting that 85 mph is its maximum speed. I’m explaining that it has more than enough performance for modern interstate travel, merging, passing and keeping pace with traffic.
Could we put an engine into it that makes it considerably faster?
Of course.
But why?
If sustained high-speed driving is the objective, there are much better automobiles for that purpose. They’re called modern sports cars.
We didn’t engineer the Defender to become a sports car. We engineered it to become an exceptionally good Defender.
Heat and the Whole Machine
Heat is another reason we’ve chosen the path we have.
A large-displacement gasoline V8 creates an entirely different heat-management challenge when packaged into the comparatively compact engine compartment of a classic Defender. The issue isn’t whether GM makes a good engine. They do. Those engines were simply engineered for very different applications with very different packaging, cooling and airflow considerations.
When an engine is transplanted into a classic Defender, you’re not just changing an engine. You’re asking the cooling system, transmission, transfer case, differentials, axles, exhaust system, brakes, suspension and the rest of the machine to work with it.
That distinction is very important to me.
Putting a more powerful engine into a Defender is modification. Making the entire Defender work better together is engineering.
That’s how we approach a Helderburg.
The engine isn’t an isolated component selected because its horsepower number looks impressive on a website. It has to work as part of the entire machine.
That’s why we’ve engineered the powertrain together with the transmission, transfer case, differentials, suspension, steering geometry, our Aegis braking system, wheels, tires, cooling system, exhaust and everything else that determines how the Defender actually behaves.
Who Stands Behind It
There is also the question of service and long-term responsibility.
A GM crate engine can be an excellent piece of equipment, but installing a GM engine into a classic Defender doesn’t suddenly make the entire Defender a GM-supported automobile. The engine and certain associated components may carry their respective manufacturer’s warranty, but the complete custom installation and everything surrounding that powertrain is another matter.
With Helderburg, we take responsibility for the complete commission through our seven-year unlimited-mileage concierge program.
That’s an important distinction.
The Question That Guides Us
So if the question is simply whether a gasoline V8 can produce more peak horsepower, absolutely. It can.
If the question is whether that additional horsepower makes a better classic Defender, our engineering philosophy says something very different.
I want enormous usable torque low in the rev range. I want controllable power in snow, rain and sand. I want range. I want manageable heat. I want reliability. I want comfortable highway capability. And I want the character and purpose that made the Defender extraordinary in the first place.
That’s why we chose the turbo diesel.
We didn’t begin by asking, “How much horsepower can we put into a Defender?”
We asked a different question:
“How good can we make a Defender at being a Defender?”
That’s the question that has guided nearly everything we’ve engineered at Helderburg.
If you’d like to talk about engines, or anything else about a commission, you’re always welcome to call us.
Paul
Let’s talk about your Defender
Every Helderburg begins with a conversation about how you’ll actually drive it.