Guide: Group S Death Star - a Historical & Technical Appraisal of the Lancia ECV (Abarth SE 041)
Background
As more and more manufacturers piled into rallying following the introduction of Group B regulations for 1982, the new generation of purpose-built machinery led to an explosion in media interest and fan popularity.
Initially things got off to a great start and, after three years of unprecedented growth, motor sport’s governing body thought supercharging the Group B concept would take the sport to the next level and make it potentially an even bigger draw than Formula 1. By reducing homologation requirements yet further, such a move would also placate those manufacturers who thought the need to build and sell 200 ultra specialised Group B cars was too difficult and expensive.
With this in mind, during early 1985 the FIA announced an even more extreme category for rally cars would come into effect for 1987: Group S.
Unlike Group B, to qualify for Group S manufacturers would only need to build ten cars with ten Evolution variants permitted every twelve months thereafter.
Essentially a prototype class for rallying (or Group B on steroids), Group S cars were scheduled to be allowed into the WRC from 1987, but would not be eligible for championship points until 1988.
With work on the Delta S4 programme at an advanced stage, Lancia commissioned their competition department, Abarth, to begin work on a Group S challenger that would be ready for the ‘87 season. The goal was to create a lighter, more powerful iteration of the Delta S4 by making extensive use of advanced composite materials and innovative engine technology.
What ultimately emerged was dubbed the ECV (Experimental Composite Vehicle) and represented a radical change from the Group B cars that it would have replaced.
Chassis
The ECV was built around a brand new monocoque fashioned from a carbonfibre, Kevlar and aluminium honeycomb. Designed using the latest Computer Aided Design software (CAD), the finished tub came in 20% lighter and 20% stiffer than the S4’s tubular spaceframe.
The engine was supported on an integrated cradle and attached at the front was a steel subframe that could easily be repaired or replaced.
At 2440mm, the ECV’s wheelbase was identical to the Delta S4.
Fully adjustable suspension was via double wishbones with coil sprung Bilstein dampers (two per side at rear) and an anti-roll bar at either end.
The brake system with 300mm vented discs and four-piston calipers was supplied by Brembo.
A hitherto unseen feature of the ECV was its super lightweight wheels that were 40% lighter than the S4’s magnesium rims. The result of a collaboration between Abarth, Enichem and Ingegnere dei Compositi (IdC), the ECV’s wheels were formed from an experimental carbonfibre impregnated with epoxy resin to which an aluminium honeycomb was added for the rim.
Pirelli-shod 9 x 16-inch wheels were used at the front and 11 x 16-inch at the rear (with 230/660 and 290/660 profile tyres respectively).
Steering was via a TRW power-assisted rack.
Located up against the rear bulkhead was a diminutive 25-litre fuel tank.
Engine / Gearbox
Mounted on the ECV’s engine cradle was another party piece: an updated version of Abarth’s all-alloy DOHC Claudio Lombardi-designed Tipo 233 ATR 18S inline four cylinder dry-sump motor now with trick Triflux head and sequential turbos.
Instead of a conventional layout with the inlet valves on one side of the head and the exhaust valves on the other, the Triflux motor ran four valves laid out in a cross pattern with the inlet and exhaust valves alternated on each side. This allowed Lombardi to fit an exhaust manifold (each of which fed one of the turbos) on both sides of the engine with the inlet manifolds entering from the centre, either independently or combined. As the intakes combined into one near the valve, three gas flows were left for each cylinder hence the Triflux moniker.
Advantages of the Triflux system included improved cooling / heat distribution in the cylinder head and better performance at low engine speeds (when one side of the exhaust was shut off and all the exhaust gases were directed to one turbo). The second turbo was brought in at higher revs from which point both units ran in parallel with one another.
The engine block was carried over from the Delta S4 and retained a 1759cc displacement with 88.5mm bore and 71.5mm stroke. This gave a swept volume of 2463cc when the FIA’s 1.4 multiplier for turbo engines was taken into account.
Compression was increased from 7.1:1 on the S4 Evoluzione to 7.5:1.
Instead of the solitary KKK K27 turbo fitted to the S4 Evoluzione, the ECV ran a pair of smaller K26 units (of the type fitted to the single turbo S4 Stradale). Each turbo had its own air-to-air intercooler mounted at an angle above the rear wheels and the electronic boost control was set at between 1.8 and 2.2 bar.
Peak output was 600bhp at 8000rpm and 398lb-ft at 5000rpm.
For comparison, at its peak in WRC trim, the S4 Evoluzione ran with 480bhp at 8400rpm and 362lb-ft at 5000rpm.
As per the S4 Evoluzione, the ECV’s straight-cut gearbox was a five-speed Hewland unit housed in a magnesium casing. Transmission was through an AP Racing twin dry-plate clutch and a Ferguson viscous coupling with centre differential and a self-locking limited-slip differential at either end (ZF front / Hewland rear).
Instead of the titanium and steel driveshafts used front and rear respectively on the S4 Evoluzione, the ECV came with carbonfibre items.
Bodywork
Although the Group S regulations effectively gave manufacturers a clean sheet to create brand new bodywork, the ECV was clearly derived from the Delta S4 and adopted many features of the stillborn Evoluzione 2 (the SE 040) which would have come on stream in late 1986 had the FIA not banned further evolutions from May of that year.
Compared to the S4 Evoluzione, the ECV incorporated a subtly reworked front clamshell that featured a flatter nose profile with single instead of twin headlights per side plus bigger intakes in between and underneath. Lower down was a jutting fully integrated chin spoiler while up top were two new banks of body coloured vents.
Along each flank were deeper, flatter side skirts, more smoothly blended fender flares and longer engine cooling scoops that now obscured over half the rear quarter window surface area.
The ECV’s roof adopted a similar shallow scoop to the S4 Evoluzione, behind which was an enormous multi-plane rear spoiler with dramatically tilted end sections.
At the back was a new slatted rear window treatment and a redesigned bumper that housed a massive diffuser that worked in conjunction with the partially enclosed underbody and active Teflon flap to maximise downforce.
In line with the rest of the ECV’s approach to construction, body panels were a mix of carbonfibe, Kevlar and thermosplastics.
Interior
Inside, the ECV also resembled an updated S4 Evoluzione.
Behind the two-spoke Momo steering wheel was a boxy carbonfibre dash with a small array of analogue gauges, an exposed fuseboard, fresh air vents and a variety of warning lights.
Aside from the leather-rimmed steering wheel, a leather gear gaiter and a pair of fireproof Recaro seats, there was no upholstery to speak of with practically every other surface having been left in exposed composite material.
Weight / Performance
Lancia quoted a 930kg weight for the ECV.
Depending on gearing, top speed was likely in the region of 140mph with a 0-62mph time of comfortably under three seconds.
Subsequent History
Lancia unveiled the ECV at the Bologna Motor Show in December 1986, by which time the FIA had long since abandoned the Group S formula.
Unfortunately, the ECV was subsequently used as the basis for Lancia’s smaller, rounder ECV2 which perhaps better represented the sort of machine Group S would ultimately have spawned.
In 2010, a replica of the ECV built by famed Lancia preparation expert Giusppe Volta emerged based on S4 Evoluzione underpinnings. Volta was able to use the original ECV body panels which Lancia had kept in storage and also sourced a correct Triflux engine.
Text copyright: Supercar Nostalgia
Photo copyright: Lancia - https://www.lancia.com
