Formula One season 1.
Anyone would say taking the next step was a natural one but putting things back in perspective, this was a giant step to take. Renault had revolutionized the Formula One world, from being nicknamed the “yellow teapot” to having all major manufacturers switch to turbo technology in just a few years’ time. The main difference was that for Hart there wasn’t a manufacturer behind and that was all a privately funded effort.
The 415T for inline-4 1500cc turbocharged would be a spin-off from the previous BD 420R and the funding would come from Hawkridge through Toleman as had been the case previously with the Formula Two effort. 1981 saw the team join the Formula One grid from the 4th round and San Marino Grand Prix with effectively what was an adapted 420R converted engine rather than the real and to be introduced 415T unit. The development would go on publicly to satisfy the sponsors and governing body, a crazy endeavor, if you considered the team, car, engine, and tires through Pirelli, were all new to the category.
The season served to build the foundation and an agreement was made between Hawkridge and Hart to fund a three-year effort initially. The learning curve was steep, managing and working the Formula One politics and embargo on existing supply and use that the reigning manufacturers had established to suit their needs. Hart evaluated various bore and compression ratios along with his turbo arrangement to achieve the best engine response. The first tests were conducted at Goodwood using a prototype car at Goodwood in December 1980 and the initial response was that there would be a lot to work on from driver Henton.
From initial tests to the real world that Byrne had worked out chassis side, Hart’s engine switched from a twin turbos setup to a single one. The architecture of the car which showed a top transaxle-mounted turbo unit at Imola where it did not qualify for its first race changed rapidly to the top of the engine. This was to implement air-to-water aftercooling and improve the air stream generally speaking but it proved a complex and overweight car altogether. The issues were large and charge air temperature remained the issue in situ rather than on the dyno so the car didn’t fare as well as expected, just like it affected reliability.
By Hockenheim and well into the second half of the season, the car proved faster than the naturally aspirated ones on the straights, by Monza, the first iteration of the 415T engine came into play. It featured a monobloc construction in terms of head and block, to achieve maximum head sealing if considering the inferior structural rigidity of aluminium if compared to iron blocks. A challenge it was if considering the CNC capabilities back then as all machining work had to go through the bore and with the block upside down but the engine builders at Hart proved extensively skilled to complete the task. With all that said, the 415T now featured an 88mm bore and twin injectors for each cylinder if you consider all the above already.
That end-of-the-year formula permitted, along with particular Pirelli tyres for the Italian occasion Henton to qualify for the first time as 23rd on the grid and to achieve a 10th place finish in Monza. Teammate Warwick would make it onto the grid for the penultimate round of the season even if he would not finish at Las Vegas. A striking effort for a private effort but a sign of things to come, time and perseverance were the way, the only way.
Season 2, transition, and more development.
Building on the experience of the previous year, Hart went on to develop the engine, reviewing the turbo and going smaller for improved response, increasing the compression ratio, and modifying the camshafts profile for driveability, the unit was now running 580 bhp for a 2.3 bar plenum pressure. In terms of architecture, the intercooler was now on top of the engine, turbo aside and the charge air flow flowed over the top of the engine into the inlet system on the other side.
Swiss driver Marc Surer conducted a test with the car and having had the chance to sample the BMW turbo unit which had become a very effective engine in the fast-evolving turbo world as well as the good old Cosworth DFV V8 he noted that driveability was one of the main force of the Hart unit. Ultimately it would be Italian Teo Fabi who replaced Henton alongside Warwick and the cars proved much more reliable and performed that season making it onto the grid 11 times out of 15 Grand Prix that year.
The development train was also on a different timetable as the team produced 3 different versions of the car proving that even though the road remained long, things were getting more straightforward. The TG183, still penned by Rory Byrne was the first carbon monocoque by Toleman and the first to make way from the Ralt-inspired rear end to a more standard and straightforward A-frames design. The most competitive design to date for the team, yet it came too late with only Warwick benefitting from the design for the Italian Grand Prix in Monza and the Las Vegas race to close the season.
Season 3, flat bottom, it’s time for a change.
1983 saw a radical change of design philosophy, the flat-bottom stipulation came into effect and forced a redesign of the chassis but also made way for better packaging. The engine and packaging had proven complicated in the two previous seasons and in relation to the location of the turbo or water-cooled intercooler was also responsible for the car being overweight.
With the change, the engine went to an air-to-air cooler which was the fruit of the possibility to locate it in one of the sidepods. Altogether, the car would prove on the minimum weight for the first time and it looked promising with Warwick and Giacomelli qualifying in the top 10 early in the season. But the engine which now sported a twin-plug setup proved unreliable and it took 10 races for the team to score a finish that year.
On the engine development, the whole twin-plug ignition was aimed at better ignition of the pump fuel the team was running on which proved slow and uneven, the design retained the original plug location while adding a second one down where the head gasket would normally have sat on this unordinary unitary block and head design. It did upset the the form of the chamber but made up in an area prone to detonation and Hart reckoned the system was actually worth at least a second a lap.
The second part was the ability of Toleman and Hart to secure a good and strong supply for the turbo and that came through Holset who was the Penske supplier for USAC Championship Car over the pond with their Inconel units. From race 11 in Zandvoort, Warwick, and the Toleman team took their first World Championship points and took another four top-six finishes by the end of the season and 15th round. By then, the engine was reliable and with a 6:7:1 compression ratio and race boost of up to 2.9 bar absolute for 630 bhp at 10000rpm.
Season 4, results, electronics, and wisdom.
1984 would prove to be the final year for Toleman as an entity in Formula One as the team would continue under the Benetton’s ownership the year after.
That season, the results, and the driver’s line-up is probably the one the team is best remembered for with Ayrton Senna and Johnny Cecotto coming on board. There was also the near-miss Monaco story but altogether the challenge to produce a competitive Formula One car and engine combination had happened and that was down to the relentless work done by Brian Hart.
Back to the story, the biggest development in engine technology that year was the introduction of an Electronic Management System (EMS) by Hart. Something that had been pioneered by the likes of Renault and, Ferrari while BMW had been using an electro-mechanical system already with its engine but a solution that couldn’t be achieved due to some mechanical differences between the Hart and BMW units in terms of fuel injection metering unit.
The EMS was essentially the way to balance the 220 liters of fuel allocated per race and ensure the best delivery, ignition, burn, and power over the distance, a key element as the Formula One circus continued along the turbocharged trend.
The system that Hart developed was engineered by Electronic Racing Aids and Bill Gibson, an ex-Lucas employee, the first time the system was used was effectively at Monaco where Ayrton Senna claimed his famous second-place finish in the rain but only during practice.
The mapping was developed on the test bench directly, using 250 rpm and 0.25 bar intervals and it took time to set up but in the end, it allowed for a more progressive power through a wider band, better driveability and it showed a significant step forward. Senna would debut the electronic system in Detroit and scored a third-place finish at the British Grand Prix and Portuguese Grand Prix that year.
That year coming from a mechanical to an electronic version of the engine, the engine was rated for 640bhp for 3.0 bar boost at the beginning when by the end of the season, the ERA system allowed for the engine to be raced at 700bhp with 3.1-3.2 bar and made way for 800bhp at 4.0 bar in qualifying trim.
Not a bad story for a two-dozen-person team and operation and a story that continued well beyond the 415T engine, all the way into the later and return of naturally aspirated engines and the 3.5 era. The Hart story is cool because all the way and until the Formula Operation stopped, he showed the way on small budgets, yet he always delivered.
Historic Motor Sport Central. 