Most sports cars and supercars throughout history have followed similar formulas. Sports cars are light, small, and nimble while supercars pile on gobs of power and shocking speeds. Neither formula tends to involve the use of ridiculous heavy low-revving diesel pickup truck engines, but one automaker attempted to do just that. The Trident Iceni tried to be the supercar that did it all by using a GM Duramax 6.6-liter V8 turbodiesel truck engine that got up to a claimed 660 HP and with long legs stretching 2,000 miles between fill-ups.
The Trident Iceni popped up on my radar thanks to CarBuzz. However, that story doesn’t really capture how absurd this whole idea really was. The Trident Iceni wasn’t just built to compete against the supercar establishment, it also wanted to carve out its own niche. Trident Sports Cars saw this bizarre diesel car being the choice of vehicle for the wealthy car enthusiast who was also really concerned about the environment.
The 2000s were a different time in the automotive landscape. Back in those days, diesel was still seen as the green fuel of the future, especially in Europe. As Vox reports, in 1990, only 10 percent of new vehicle registrations in Europe were for diesel vehicles. However, by 2011, a whopping 60 percent of all of the new cars sold in Europe had one underhood. Some individual nations in the union, including France, had such staggeringly high diesel adoption rates that 80 percent of new vehicles were diesel-powered.
While diesel cars never caught on to that degree here in America, diesel did make meaningful gains in the 2000s. There was a time in the mid-2000s when Americans had access to all sorts of diesels from compact cars to SUVs. America also experienced a diesel surge in the early 2010s like Europe did, with about a quarter of Volkswagen of America’s sales going to diesel-powered sleds.
It might seem a bit wild to enthusiasts in America, but this means that there are plenty of cases in which the gasoline engine option of a car is rarer than the diesel. The obsession with diesel power also went further than just the type of engine. Biodiesel– that’s diesel with components from plant matter, discarded food oils, and more–was seen as a greener way to travel.
Yet, most of this diesel fever was applied to economy cars, trucks, and everyday passenger vehicles. Diesel engines were used for heavy hauling or incredible fuel economy, two things that most sports car buyers aren’t really looking for. Diesels also don’t rev particularly high and don’t really have the kind of soundtrack you’d associate with something like a Ferrari.
That’s what makes the Trident Iceni such an oddball. Even when you frame this car in the context of Europe’s previous diesel obsession it still doesn’t make sense. Yet, the automaker behind it spent over a decade trying to sell you one.
Rise And Fall
As with many stories that involve British cars, the chronicle of the Trident’s life starts with financial strife. As British car history resource AROnline writes, in 1964, TVR brass decided they wanted to reel in the type of buyer who might enjoy an Aston Martin or Jaguar E-Type.
TVR and Italian coachbuilder Carrozzeria Fissore would come up with the luxurious metal-bodied Trident, but as was the case with so many British sports car stories, TVR was declared bankrupt only a year later. TVR distributor Martin Lilley picked up most of the marque’s scraps, leaving the Trident still on the table. TVR dealer William Last acquired the Trident’s design and molds, founding Trident Cars Limited to produce the vehicle. Last’s version of the Trident wore a fiberglass body and a chassis from the Austin-Healey 3000, but still had the Ford V8 firepower of the AC Cobra.
It didn’t take long for Trident Cars to experience the same tragedies the rest of the British automotive industry went through. Trident Cars experienced a restructuring, changes in majority control, plant closures, difficulties in maintaining quality, and the weakened economies of the 1970s. The company managed to limp its way to 1977 and the Trident Car Club believes that perhaps only 85 cars were ever built during that decade of time.
Really, that little bit of history doesn’t really matter too much because the modern incarnation of Trident Sports Cars Ltd. is related to the old one in name only.
In 1998, designer Phil Bevan showcased his new idea. Bevan wanted to show the world his idea for a successor to the Trident of the ’70s. The prototype was displayed at the 1998 Birmingham Motor Show, where the sports car public fell in love. A year later, Bevan formed Trident Sportscars to push these cars into reality. Joining Bevan on the project was Eric Broadley, famous for his engineering prowess and for Lola Cars.
That car was called the Trident Iceni, and the Independent explains the name:
Well, if you know your regional history, you’ll know that the Iceni were Boudicca’s gang who hung out in the Norfolk hood back in 60AD. Also Trident Cars was a manufacturer of sports cars in Suffolk. So, unsurprisingly, Trident Iceni R is being handbuilt on an industrial estate just off the A47 in Norfolk by Trident Performance Vehicles.
Trident Sportscars produced a handful of Iceni prototypes before Bevan left the project in 2002. Now under Broadley control, the company changed its name to Broadley Performance Vehicles that year. The Iceni’s name was also changed to the Broadley 1-37. The original Iceni/1-37 wasn’t incredibly ambitious. It featured a 3.0-liter V6 of GM origin that made a respectable 240 HP. A proposed optional engine would have been a 375 HP V8.
Once again, Broadley Performance Vehicles built more prototypes but never reached production. Bevan entered back into the picture in 2004 and this time he had an even bigger plan. Forget plain V-engines, Bevan wanted to produce the most unique grand touring car the world had ever seen. The Trident was back again for the third time in less than a decade, and this time Bevan was swinging for the fences with an idea for an all-electric model and a diesel supercar.
The Diesel Supercar
In 2005, that diesel supercar finally took form. Gone was the gasoline engine. In its place was a General Motors Duramax 6.6-liter turbodiesel V8. Trident never noted the specific engine code of its Duramax engines, but said they were snatched from GM’s heavy duty pickup trucks. Based on the timelines given, the Iceni diesel likely had a Duramax LLY or a Duramax LBZ, engines so fabled for their power and durability that people are paying absolutely insane prices for trucks with them today.
If the Iceni diesel prototypes had any LBZ Duramax engines in them, they were getting something truly special, from my retrospective:
See, while the LB7 and LLY Duramax engines are good, diesel resource websites note that they had a few issues that keep them from being truly great engines. The LLY has a list of common issues from overheating and water pump failures to glow plug issues and bent rods. The latter is noted to be an uncommon problem with stock trucks, but happens more often with tuned rigs. Another notable issue is a blown head gasket and reportedly, it’s not just because of overheating, but because of the engine’s apparently inadequate cooling system.
Mechanically, the LBZ is similar to the LLY, but with a thicker engine block casting, beefy forged-steel connecting rods, and the common-rail fuel system was turned up even higher with a Bosch CP3 fuel pump. That fuel pump is so powerful that it’s capable of moving 200 liters of fuel per hour. Other upgrades include more webbing in the main bearings, taller main bearing caps, and the bores for those cap bolts dig 4mm deeper before. In other words, GM went through the faults of its previous Duramax powerplants and hardened them.
But GM didn’t stop with making a more reliable engine, as engineers found more power in the Duramax 6.6-liter V8. The previous engine had a bottleneck on the compressor side of the turbo. GM fixed that with a larger turbo inlet manifold. As a result, the turbo also lost lag. Additional changes come from injector pressure increased from 23,000 psi to 26,000 psi, a larger EGR cooler, and new seven-hole Bosch solenoid-style injectors. The engines also utilized oil-spray cooling at the bottom of the piston bowl to help keep the engine cooler. Out of the other end of the changes, buyers got 360 HP and 650 lb-ft, power that’s still more than healthy enough for current-day duty. Oh, and it stomped its Ford and Dodge contemporaries.
Sadly, while there is video out there showing the early Iceni Duramax prototype on the move and complete with GM information readouts, the video doesn’t let us hear the music of that engine:
Trident gave the Duramax mild upgrades inside of the Iceni supercar. This resulted in an output of 395 HP and 700 lb-ft of torque. These power figures aren’t that impressive in the world of diesel tuning. There are trucks making multiples of what their engines made when stock. Again, what was silly was just the fact that this big lumpy diesel truck engine was fitted to a supercar.
Trident then claimed that their car could hit 60 mph in 3.7 seconds, reach a top speed of 200 mph, and get 60 mpg. But Bevan didn’t stop there, of course. He said he’d sell you an Iceni Duramax tuned to 430 HP or tuned to 660 HP. Bevan said his Iceni Duramax supercar would hit 60 mph in as little as 2.9 seconds and produce 1,050 lb-ft of torque.
In a press release, Bevan explained that his grand tourer wasn’t just about speed either, but about being green:
“Just as everyone thinks there’s no substitute for cubic inches in the engine,” explains Trident’s Phil Bevan, “they also obsess over crankshaft horsepower. What they fail to realize is that if you’re running a car at 8,000-9,000 rpm, you’re going through fuel at a rapid clip. We’ve taken a different approach and change gears at 3,000 rpm. By cutting engine revs by more than 50%, we also halve fuel use and emissions. People overlook the value of torque.” Phil observes that the low horsepower/high torque that defines Trident vehicles can be both a blessing and curse because it yields a … different driving experience. No potential customer of a Trident Iceni can buy a car without a test drive or two.
Another unique aspect of all Trident’s vehicles is that they feature multi-fuel engines that will run on any oil-based fuel, from conventional diesels or bio-diesel to mineral oil, paraffin, kerosene and central-heating oil. When fueled by annually renewable, carbon-fixing, plant-based bio-diesel (e.g., from new or used cooking oil), the vehicles offer another unique benefit: Plants from which cooking oils are derived absorb carbon and nitrogen (greenhouse gases) during their growing cycle. When they are harvested, and ultimately used to make a bio-fuel, they represent a credit — a net carbon offset. When bio-diesel is burned in the Trident vehicle, the owner, in theory, cashes in on the carbon credit from the plant’s work during its lifecycle, especially if the fuel is made from used cooking oil. Then the vehicle technically operates at a zero (net) carbon footprint.
Onboard diagnostics and computer-controlled systems will sense fuel changes from tank to tank and automatically adjust various combustion conditions and other ratios to maximize efficiency. To reduce emissions further, a new feature, hydrogen injection, will kick in and burn any unburned fuel and particulates when the engine isn’t operating at maximum efficiency.
Trident said that those ordering an Iceni would get a choice of either a six-speed automatic transmission or a manual, both of Trident design. Somehow, the bold claims didn’t stop with the powertrain.
Trident said the car got good enough fuel economy and use from its 35-gallon tank to permit a range of 2,000 miles and that the body had a trick convertible top that allowed for the roof to be opened only for one occupant of the vehicle at a time. For those of you doing the math, that means that Trident claimed 57 mpg at 70 mph. I say “claimed” because while Trident did lend the car out to be driven, I have seen no confirmation of the vehicle’s actual fuel economy. But let’s say it got a nice and even 30 mpg. That’s still over 1,000 miles of driving range!
Don’t think I’m done with the wild claims, either. Composites World explains the vehicle’s chassis:
Trident Sports Cars Ltd.’s Iceni chassis is formed from 4003 low-chrome/low-carbon stainless steel, supplied by Columbus Stainless (Pty.) Ltd. (Middelburg, South Africa). It isn’t pretty (see top photo at left), says Trident’s Phil Bevan, but it won’t rust (the frame is warranted for a century), and more importantly, it’s very resilient (won’t workharden), making it perfect, he says, for chassis construction. That means the Iceni has the highest torsional rigidity of any sports car not using a carbon fiber composite chassis, which, in turn, reportedly means that in a head-on crash at 161 kmh, the engine won’t land in the driver’s lap. Because it won’t workharden, damaged stainless steel can be reworked nearly endlessly without losing its properties and becoming brittle, yet it’s fully recyclable.
The Iceni convertible’s chassis includes a central, longitudinal spine/rollover bar, and strategically positioned folds and shapes (further benefits of an origami vs. tubular frame) that enable the vehicle to form a strong passenger cell. This cage not only provides excellent occupant crash protection, but also is designed to prevent anything from penetrating the bulkhead. The mid-front-mounted engine is designed to drop down and become wedged in the tunnel during a crash, and even the crankshaft pulley stays around the car’s wheelbase.
Because of this, Trident also advertised a 100-year guarantee on the chassis. You were supposed to get all of this for the seemingly sweetheart deal of a price of £96,000 or $161,578 in 2014 money, or $219,431 today. The Iceni was also advertised in three models: a coupe, convertible, and shooting brake. All of them had fiberglass bodies on top of the stainless steel chassis.
Trident’s marketing plan involved taking one racing and taking another on a fuel economy challenge. Once again, I can’t find the results of these tests, if they even happened.
Of all of these claims, the idea of a company making a diesel supercar is actually the least crazy. Audi’s R10 TDI racer proved that diesel power is not just competitive on the track, but could even dominate a field at Le Mans. So, it’s not entirely crazy to think you could do the same with a road vehicle.
You Still Can’t Buy One
The amazing thing about all of this is that Trident did build working prototypes. The company website is even still around today and is still promising the Iceni diesel supercar. However, these promises have been unfulfilled. Trident made press releases in 2014 that talked up global launches, including here in the United States. Trident also bragged about how its modded Duramax engines exceeded emissions standards years before specific regulations went into effect. Sadly, as of today, there hasn’t been a single production example built.
As Top Gear reported in 2017, the reason comes down to money. Trident did not take in any loans from banks and instead tried to self-fund the entire effort. Of course, putting a car into production means putting up some serious capital. At the very least, it’s nice that Trident didn’t take the typical startup route of having consumers invest thousands of dollars in reservations for a vehicle that may never reach reality.
Sadly, it’s unclear if the Iceni will ever be more than a slew of running prototypes. In 2018, Bevan moved onto his next thing. Ironically, that latest project, a car company named Iceni Motor Company, went back to the modern Trident’s roots. The Iceni Enigma is powered by a gasoline V6, just like the Trident rebirth did back in 1998. As of publishing, the Enigma has also yet to enter into production.
Even though Bevan failed to get his dream diesel supercar off of the ground, he managed to create the craziest sports car/supercar thing ever built. He really did look at something like a Silverado HD and think that its powertrain was a great option to make the world’s most efficient supercar. There’s no telling if there was even a market for such an absurd vehicle. I mean, what’s the venn diagram of the people who want to go 200 mph in a supercar but also the people who want to save the planet with a big truck engine? Still, it’s a shame. I would have loved to drive one of these just for the laughs.
Top graphic images: Trident Performance Vehicles Ltd.; GM; Mazola/ABF
Shame the cowards at Audi never put that V12 diesel R8 into production.
Also wow, baby Johnny. His presenting has come on a long way since then.
Volkswagen did offer a W12 TDI Touareg for the rest of the world.
“Hey you should buy that Audi W12 diesel R8 supercar”
-something you tell your worst enemy
I wish there were more diesel sports cars. Although a tdi just before dieselgate was alot more like a GTI then anyone with a GTI would like to admit. Too bad thats done. Isuzu always made a decent engine. Kinda sad the answer to go fast now is always Tesla swap.
As the owner of a Jetta wagon with GTI levels of power, they are not the same. GTI has a powerband that seems to go forever. TDI pushes hard without any downshifting, but only winds out to 4500 rpm. The former is great of autocrosses and drag racing. The latter excels on two-lane roads where you want no-drama passing maneuvers and effortless climbing up grades.
My point exactly jeez. I said no gti owner would ever admit it. I had an 03 GTI and I would never admit it. Then I had a 13 TDI yeah it only revs to 4500 because it’s a diesel but the torque will throw you back. Drive one they are tighter and quicker then you realize. But still nothing like a Tesla instant torque
Ah, diesels and Europe. My first trips to Europe happened to be during the wetter parts of the year. To this day, the aroma of cool, moist diesel exhaust puts me right back in London or Paris.
2000 miles? That would take me like 6 months. I work from home. Does diesel keep that long in a tank? And then add on that this is a toy car, how long would the diesel actually be sitting in the car?!
Diesel does last about 6 months exactly, straight from the pump – a full year if you add stabilizer, so about twice as long as ethanol blended gasoline.
Either way, that’s about a month for me, but I am in traveling sales and do split mileage across 4 cars. None of which are diesel, because its like 2019 or something now.
In warm climates, diesel is very susceptible to algal growth. In the winter, my ritual is to make sure that all of our diesels have used up their summer blend and run #1 diesel. Most moderate climates run a blend of #1 and #2 diesel. When you get near the Arctic, it needs to be #1, which has a gel point of -70F. #1 has far less lubricity for your fuel pump and has less energy density (so less power and less fuel economy).
Honestly, if you drive 4000 miles/year, you should be driving gasoline or electric vehicles. Diesels are better suited for people that drive 20,000 – 120,000 miles / year. That kind of driving keeps the modern emissions systems happy.
Reminds me of a few forum threads of a fella putting a 6.5 Detroit in a c4 corvette and supposedly pulling down high 40s mpg. Great formula except for added weight to the front end.
Wow, yeah it’s really too bad that none of these were ever put into production! Great history, design etc
So they designed and built their own transmissions (both manual and automatic) AND powertrain ECUs. Is there anything they can’t do? Elio needs to hire these guys to get them into production mode!
Ha! I haven’t thought of Elio in years. Now I gotta see if they are even a thing anymore.
I have to wonder about how the weight of the LLY/LBZ affects the handling, as both of them weigh close to 900lbs. I enjoyed my LLY 2500HD back in the 2000s, but I never really thought “This should be in a sports car!”, as it just doesn’t have the demeanor. Still kind of neat though, even if it turned out to be vaporware.
When you consider that a modern Miata weighs 2200# and a Duramax 6.6 weighs 830# without a transmission, you can imagine how is works in a sports car. That said, Audi won 24 hours of Lemans several years in a row with a lighter diesel.
I personally buy the hype. Done right diesel has more capability than gasoline. This would’ve been an amazing car.
I still am very sad. We never got the rumored diesel Lancer Evolution 11.
Owned a BMW 335d for a few years. That car with 425+ ft.lbs .of torque was a bit of a hoot to drive. Waaay different feel from a gas-powred sports sedan, but still fun in its own way.
But will it smell like a doughnut shop?
This whole thing is such a stereotypically British sports car history, the country seems to specialize in tiny operations run out of a rented shed, putting fiberglass bodies around American engines, that go broke after making 2 cars, but experience multiple zombie rebirths and deaths over decades, reusing the same name regardless of whether anyone really remembers it from the last time
Isn’t this basically the Toecutter special?
Na, he would want more aero and much more affordable. He seems to hate how expensive supercars are. He likes affordable streamlined fuel efficient high performance cars. And I can’t argue with his logic.
I assume the only way to make a 400 ci turbo diesel get anywhere near the claimed mpg is to be pretty aero optimized
Weight has a huge effect. My Peterbilt 389, with a van trailer and aero worse than a brick, gets 5mpg loaded at 80k lbs. Empty, it weighs 30k and gets 9mpg. Now since that Sports car is very aerodynamic and much lighter compared to a pickup truck, it gets much better fuel economy. But Toecutter likes super efficient aero, the kind you see on land speed record cars. He has a recumbent bike with a super aero shell, and it is the kind of aero he likes.
That’s the kind of aero that could yield 4-digit MPG in a lightweight, one-seater vehicle.
The Nissan deltawing proved you could make a narrow streamlined car that could corner and get excellent fuel economy. Imagine a diesel engine in a deltawing style body.
If it’s CdA value is comparable to the average new “subcompact” car, that alone would be enough to get that sort of MPG with that engine when carefully driven. If it were a dedicated streamliner, it could probably do double that claimed efficiency.
I agree the concept is a looker. I am always fascinated by the fringes of the auto industry. I was always curious how Gerald Wiegert was still promoting some new concept until the end of his life. He apparently still drove his Vector as a testament to his vision. Throw in the late John Delorean and a litany of others trying their hand at this.