Published on: Jan 18, 2016 @ 23:55 Originally Published in: 2015 (old website) (C) Jay Auger - website owner & author Notice: Any form of duplication methods (including but not limited to copy/paste of text and screen capture) of the website's content is strictly forbidden.
In 1985, the FISA (former ruling committee of the FIA) announced a possible replacement class to Group B that was referred to as “Group S”. The new regulations would require only 10 cars for homologation and was essentially a “prototype” class for rallying. The class was originally scheduled to make its debut on January 1st 1988, then as a heavily revised replacement to Group B for 1987, but both were ultimately cancelled. To learn much more about the history of Group S, please CLICK HERE!
QUICK BROWSE CONTENT
- SE040 “Lancia Delta S4 E2”
- SE041 “ECV”
- SE042 “Group S Proposal”
- ECV 2 Study
SE040 / LANCIA DELTA S4 “E2” – The Prelude to the ECV
In early 1986, before Group B’s official ban, Abarth was already working diligently on a second evolution “E2” version of the Delta S4 (code-named project SE040) which would have brought further improvements to the already very competitive rally car. The main goals were; better engine and gearbox reliability and performance, new front suspension design, better aerodynamic efficiency (which was not the S4’s strong suit), and better handling specifically by shifting more weight towards the centre of gravity.
To achieve this, new ideas were put forward towards the car’s aerodynamics; it would be improved with use of side skirts, (or “miniskirts”), fins added to the rear spoiler’s sides, and a rear extractor (diffuser). Furthermore, a flexible Teflon flap fitted underneath the front of the car would aerodynamically deform depending on vehicle speed and help with providing more or less downforce. The intercoolers (heat exchangers) were considered to be moved from the rear to a top mounted position (fed by a larger roof scoop), with the side air scoops (ears) now used only to achieve engine bay venting (which could allow them to be made smaller and more aerodynamic). Finally, the twin headlights setup would be replaced by a dual function single unit per side. All of these improvements were actually tested in Fiat’s wind tunnel between March and April 1986.
On the engine and drivetrain side, the twin-charged engine was meant to be improved with the possible use of a new toothed belt-driven supercharger or the unit replaced altogether with a new sequential twin-turbo setup made possible due to recent advances in electronic controls. These new electronics would also have permitted use of a new electronically controlled limited-slip differentials. A F1-derived continued-variation “CVT” type transmission, developed by Dante Giacosa, was actually tested but was found to be inadequate due to the massive torque surges of the engine.
Sadly, the SE040 “E2” project was cancelled alongside Group B’s untimely ban. However, for possible use in the Group S replacement formula, most of the SE040’s technical advancements carried intact on to the new “SE041” project: the ECV (Experimental Composite Vehicle). The resulting car was displayed at the 1986 Bologna Motor Show.
SE041 / ECV
With its mere 10 units required for homologation, Group S would bring many possibilities for manufacturers to incorporate very expensive technologies. To this end, the 1986 ECV had something entirely new to the Delta S4; an experimental chassis made out of a combination of carbon fibre and an aluminium honeycomb monocoque – it had actually previously been developed and produced at Abarth as a design study in 1984.
The new bodywork also incorporated carbon/Kevlar, thermoplastics, and fibreglass body panels. Even the wheels were experimental Speedline composite units weighing only 6 kg (13 lbs) each. The chassis itself was claimed to be 20% lighter with equal torsional stiffness than the standard steel space-frame unit of the Delta S4 and was one of the first to use computer assisted design (CAD) in its conception. Such technology and materials were normally reserved for Formula 1 before the advent of Group B. The Abarth engineers claimed that a theoretical target of 40% improvement in lightness would have been possible if further development of the chassis had continued.
Another distinctive difference from the Delta S4 was the use of a “TriFlux” engine: brainchild of engineer Claudio Lombardi. While the basic 1759 cc engine block remained the same, the head was totally redesigned in conjunction with a new sequential twin-turbo setup. The new design had one exhaust and one inlet valve on each side of the cylinder head, with the resulting twin exhaust manifolds each feeding one turbocharger. At low engine speeds one side of the exhaust was shut-off, forcing all of the exhaust gases through only one turbocharger and thus providing good low-rev performance.
As engine speed rose the second turbocharger was gradually introduced until high-revs where both turbochargers would run in parallel. The more homogeneous heat dissipation meant less chance of the head buckling under high loads as well as being far easier to cool through the standard liquid cooling system. The TriFlux was claimed to provide up to 600 BHP with less turbo lag than the twin-charged (supercharger / turbo) setup found in the works rally cars. A total of five prototype TriFlux engines are said to have been built.
The aerodynamic features originally planned for the Delta S4 “E2” (SE040) were implemented in the ECV such as the single headlights, side skirts, rear diffuser, finned roof spoiler, smoother side scoops, and a new front air dam. The intercoolers planned to be moved to the roof scoop were however retained in the side scoops.
This new setup, paired with the new enclosed rear undercarriage, necessitated the rear screen to be replaced with louvres to aid in engine bay venting. However, this turned out to be less efficient at dissipating heat than the normal setup which was greatly aided by a natural low pressure zone under the rear edge of the car.
The ECV embodied the exact vision that the FISA had for the original draft of Group S back in 1985; new ground-breaking innovations in lightweight chassis design, exotic materials, aerodynamics, and advanced electronics. In theory, would Group B not have been banned, the ECV (minus its carbon tub) would most likely have first seen action as the Lancia Delta S4 E2 in 1987.
SE042 / Group S Prototype
With the much stricter and revised Group S rules set to forcibly replace Group B in 1987, using the ECV for the category now seemed too much of a compromise for Abarth since it no longer would maximise the new regulations. The engineering team thus begun drafting ideas of developing a smaller Lancia Delta S4 variant: project SE042.
This new Group S rally car would be directly based on the Delta S4’s tubular chassis with mostly identical mechanical and transmission systems. The biggest change would come in the use of a smaller 1430 cc turbocharged engine that would have complied with the revised displacement and 300 BHP limits set by the new regulations. (the 1200 cc limit is often misinterpreted – see HERE for details)
The new smaller engine, since it would have produced less heat due to its lesser power output, provided for unique opportunities to improve on the Delta S4’s basic design; the front-mounted radiator could be made smaller, which in turn could be used to improve the car’s frontal aerodynamics and allow room to fit the dual shock absorbers setup that the engineers had unsuccessfully tried to implement in the S4 back in 1985.
Use of a single (instead of two) rear mounted air/air intercooler (originally fed by the side scoops – one each), would have allowed the roof mounted oil cooler to be relocated to one of the former intercooler’s position. This in turn would have eliminated the need for the roof scoop entirely and help make the car more compact, hence improving aerodynamics once again.
No actual prototype has been built and the car only existed in theory since Group S was ultimately cancelled a very short time after its confirmation as Group B’s replacement in late 1986. However, while the SE042 project was stillborn, Lancia did not stop the development of the ECV and would give Abarth the task to improve the design even further.
ECV 2 STUDY
In 1988, as design study, Lancia unveiled an even more radical version of the ECV; simply dubbed the “ECV 2”, it featured the same carbon / aluminium monocoque chassis and TriFlux engine as the ECV, but it made way with the Delta S4’s traditional appearance in favour of a more compact and better flowing aerodynamic design strongly inspired by the defunct SE042 Group S project.
The front and rear of the ECV2 were made as short and low-slung as the chassis and mechanical elements allowed: resulting in a 100 mm reduction in length over the ECV. This necessitated moving some of the engine’s ancillaries to the front of the car which in turn had helped improve weight distribution. The twin intercoolers still resided in the rear section but had to be made smaller hence allowing them to also be moved lower for a better centre of gravity. However, since airflow was now very limited the intercoolers featured water cooling.
It is worth to mention that the ECV2 literally used the very same chassis and TriFlux engine as the ECV, which means that the latter was completely dismantled for the fabrication of the ECV2. As such, the original ECV prototype does not exist any more. However in 2010, Giuseppe Volta, with the help of many former Abarth team members, rebuilt a replica by using a standard tubular Delta S4 Stradale (road car) as its base and by using original ECV body parts left over. To complete the work, a brand new TriFlux engine was painstakingly recreated with the help of the unit’s original designer: engineer Claudio Lombardi. The ECV recreation was first publicly displayed at the 2010 Rally Legend event in San Marino.
At the time of their production, both ECV cars were deemed as “impossible to drive” by Abarth’s test drivers due to the TriFlux’s very small torque figures at low RPMs and the huge blast of power when the turbos reached unison. To try and fix this problem on the ECV2 the turbos were reduced in size but with increased boost levels which resulted in slightly better drivability for the exact same amount of horsepower.
However, all insiders agree that the potential of the engine and the cars themselves would have been greater if enough development had been put in. Sadly, since Group S was annulled this never happened. So, even though the ECV and ECV2 would never race, the exercise was nonetheless a favourable showcase of technology for Fiat / Lancia / Abarth, pioneering many technologies 20 years before their actual debut in production cars, and providing an all important glimpse of the Delta S4’s would-be future if Group B / S had not been banned.
It is worth to mention that the very last bit of official engineering done to the Delta S4 platform by Abarth was the testing of a four wheel steering system that was fitted on a Stradale (road car) version in 1988. At the end of these tests the car was returned to factory form and sold, thus closing the final chapter of the Lancia Delta S4’s development.
ECV 1/2 SPECIFICATIONS
|Group/class||S – never raced|
|Type||Abarth 233 ATR 18S “TriFlux”, I-4, DOHC 16v, gas||located middle longitudinal|
|Capacity||1759 cc||WRC: x 1.4 = 2463 cc|
|Output power – torque||600 HP @ 8000 rpm||398 lb-ft @ 5000 rpm|
|Materials||block: aluminium alloy||cylinder head: aluminium alloy|
|Ignition||firing order 1-3-4-2|
|Lubrication system||dry sump|
|Type||four wheel drive||Hewland 5 speed gearbox with magnesium housing and straight cut gears (dogbox)|
|Differential ratio||N/A||central Ferguson FF epicyclic differential with 30% – 70% F/R distribution and automatic viscous coupling. Front: free. Rear: locked 25%|
|Clutch||dry – double plate|
|Type||Load-bearing structure made of carbon fibre & aluminum honeycomb with steel tube screen front structure. Bodywork mostly made of carbon and Kevlar resins, thermoplastics, and fiberglass.|
|Front suspension||double unequal wishbones, coil springs over Bilstein hydraulic shock absorbers, anti-roll bar|
|Rear suspension||double unequal wishbones, coil springs, twin Bilstein hydraulic shock absorbers, anti-roll bar|
|Steering system||rack and pinion||2.5 turns|
|Brakes||front and rear ventilated disks 300 mm diameter, 4 piston calipers all around||hydraulic pumps in parallel with manual balance adjustment|
|wheelbase: 2440 mm (96.1 in)||front track: 1500 mm (59.0 in)||rear track: 1520 mm (59.1 in)|
|Rims – tires||Composite Speedline Experimental
|Fuel tank||25 litres|
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(C) Article by Jay Auger – website owner & author
- Images & videos are the property of their original owners
- Eifel Rallye Festival pictures used under permission – McKlein Publishing
- DISCLAIMER / LEGAL NOTICES
- Giuseppe Volta – for making this article possible before his untimely passing…