The “Ferguson Formula” Triumph 2500PI Estate

This is believed to be the only Triumph 2500PI Estate 4×4 in the world, it was developed as a prototype by the engineers at Ferguson Research using their earlier work designing four-wheel drive systems for automobiles.

This Triumph is said to have been created for a Swiss doctor, who wanted a comfortable road car that would be capable of traveling anywhere he needed to go in oftentimes mountainous regions. The car proved perfectly suited to the role, and he kept it for over 10 years before selling it on.

Fast Facts – The Triumph 2500PI Estate 4×4 Prototype

  • This car was developed by the team at Harry Ferguson Research Limited, commonly referred to as Ferguson Research, and it uses the groundbreaking “Ferguson Formula” four-wheel drive system.
  • Ferguson Research was founded by Irish engineering genius Harry Ferguson. He was the first many to design, build, and fly a plane in Ireland, he oversaw the development the first 4×4 Formula 1 car, and he’s credited with being “the father of the modern farm tractor.”
  • The most famous 4×4 car developed by Ferguson Research was likely the Jensen FF (FF standing for Ferguson Formula), a modified version of the Jensen Interceptor with a four-wheel drive system – 320 were produced between 1966 and 1971.
  • The Triumph 2500PI Estate you see here was developed by Ferguson Research as a fully functional prototype for a Swiss doctor. It’s the only one that was ever made, it was restored in 2003, and it’s now being offered for sale by The Market by Bonhams.

The Triumph 2500 Mk2

The Triumph 2500 Mk2 was introduced in 1969 and sold until 1977. It featured considerably updated styling when compared to the Mk 1 car, with both designed by Italian automotive legend Giovanni Michelotti.

Triumph 2.5 PI Mk 2

Image DescriptionThe Mk2 generation featured significantly updated styling courtesy of Michelotti that closely resembled the then-new Triumph Stag sports car.

By the standards of the 1960s the Triumph 2500 Mk2 and its related models were relatively advanced, with unibody engineering, independent front and rear suspension, and engine options that included fuel injection.

The front end of the Mk 2 cars had been redesigned to more closely resemble the new Triumph Stag, and it could be ordered with either 2.0 or 2.5 liter straight-six engine options, with either automatic or manual transmissions, in your choice of four-door sedan or four-door estate (station wagon) body styles.

The Famous Ferguson Formula

The “Ferguson Formula” was a four-wheel drive system with a viscous center differential that had been developed by the team at Ferguson Research, originally headed up by Irish engineer Harry Ferguson.

Ferguson had been the first person to design, build, and fly his own aircraft in Ireland, with the first successful flight taking place in 1909.

He would later become a pioneering tractor designer, patenting the three point linkage system which is still widely in use today, which led to him being called “the father of the modern farm tractor.”

Ferguson Formula Triumph 2500PI Estate 8

Image DescriptionSitting inside this car there’s nothing that immediately gives away the fact that it’s got a four-wheel drive system. The viscous center coupling makes its operation all fairly automatic.

After WWII Ferguson became interested in the burgeoning world of four-wheel drive systems for civilian automobiles, largely due to the influence from racing driver Freddie Dixon who was convinced, well ahead of his time, that four-wheel drive racing cars could offer a major advantage in some forms of motorsport.

Dixon was working with former army officer and racing driver Tony Rolt on his ideas, and Ferguson came onboard as an investor and an experienced engineer to help further the project. Harry Ferguson Research Ltd was formed in 1950, the original plan was to develop a 4×4 family car and sell it to a major manufacturer.

The plan for the company never panned out, but this didn’t stop them, by the end of the 1960s they would have built the first four-wheel drive Formula 1 car in history, the first four-wheel drive Indy car, a British Hillclimb Championship winning sports car, the first 4×4 production car (the Jensen FF), and a slew of prototypes for various manufacturers including Ford, for whom they developed multiple four-wheel drive versions of the Mustang.

Ultimately the company would be closed down in the early 1970s due to the amount of money that was being spent on research and development with relatively little income to show for it.

Ferguson Formula Triumph 2500PI Estate 6

Image DescriptionFrom the outside you can see that the suspension has been lifted slightly to offer better ground clearance.

At the end of the day the men were just ahead of their time, Audi engineers would realize the promise of all-wheel drive by the late 1970s and create the Audi Ur-Quattro, which would be followed by a number of dominant quattro cars in the years that followed.

The Prototype Triumph 2500PI Estate 4×4 Shown Here

As noted in the introduction, this car was built as a prototype and the only one of its kind by the team at Ferguson Research. It’s not stated whether or not the car was ever shown to Triumph, although it seems likely that it would have been.

The person who ordered it, a Swiss doctor who needed a comfortable all-terrain vehicle, kept it for 11 years before selling it on. A future owner in 2003 had the car completely restored, and it’s now being offered in good overall condition by The Market by Bonhams.

They do note they they have not driven the car and can’t provide any assurances as to its operational status, so any bidders will need to do their own due diligence – but this is best practice anyway. If you’d like to read more about this car or register to bid you can visit the listing here.

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Images courtesy of The Market by Bonhams

Ferguson Formula Triumph 2500PI Estate

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