Fiat 131 Group 4 New build rally car track test

2019 Michael Ward and Drive-My EN/UK

Fiat 131 Group 4 New build rally car track test Changing of the Guard Ford Escorts have been the mainstay of historic rallying for a long time, now the establishment has a serious challenger. Story by Sean Carson. Photography by Michael Ward.


Sensational new build Group 4 Fiat 131 track test

I’ll ignore the modern VW van and the Brian James Race Shuttle it’s towing, but as Rallysport Development’s Fiat 131 Abarth Group 4 historic competition car rolls off the back of the trailer and onto the hard standing at Blyton Park we could have rewound to the late ’70s.

Fiat 131 Group 4 New build rally car track test

Fiat 131 Group 4 New build rally car track test

Kevin Theaker of RSD – the mastermind behind this project – flicks the battery master switch and ignition on, primes the fuel pumps and prods the starter button; a call for the Fiat twin-cam motor to bark into life with a blap-blap-blap as the narrow diameter twin tailpipes act as a conduit for the waste gas.

It’s a gentle, staccato rasp this side, but walk round to the front and you can hear the throttle bodies swallowing gulps of air from under the bonnet even at idle. What’s it going to sound like beyond 8000rpm? I’ll get to find out soon enough, but first the coldblooded 131 needs to warm through its vital fluids. I decide to abandon my Dictaphone while chatting to Kev and his colleague Chris as it’s fighting a losing battle against the Abarth’s chorus, but what a soundtrack to chat to, hey?


RSD has a short but distinguished history in Group 4 historic rallying, after Kevin Theaker founded the company in 2007 to build Mk1 and Mk2 Ford Escorts, but this new project is something of a departure from its norm. Theaker takes up the story: “As much as I love the Escort, we thought that Group 4 had become a bit stale, so we wanted to give ourselves a new challenge and build something that would give a bit more diversity to the field.”

A Lancia Stratos would have been evocative but a difficult and expensive project to develop – not to mention a highly-strung choice for competitors and gentleman drivers. The natural choice, then, was another Italian car that took a hat-trick of World Rally titles around the same period: the Fiat 131 Abarth. To build a ballistic rival to the Escort, RSD’s development process has been incredibly involved.

“We wanted to future-proof the car and give it plenty of headroom for development. We’re on the limit of what we can do with the Escort, but with the 131 we’ve got lots of potential to explore. “We didn’t want to compromise on the build; we wanted to recreate an iconic car. The attention to detail is amazing – even all the switches on the dashboard have been rebuilt,” says Theaker. The lengths RSD has gone to in developing the 131 run far deeper than that, however.

Apart from the shell, only the crankshaft and engine block are from the original car. Think about that for a second, take in how many thousands of components there must be on this car and marvel at the fact that all, bar a handful, are new, some reverse engineered from the originals.

Suspension components, uprights, subframes, cams, valves, collets, springs – even the bracket for the distributor is fabricated by RSD. It’s built the ignition system, too, and all the gears for the ’box and differential have been stress tested to ensure the same or increased hardness over original components. The chassis needs to be original and with a logbook for homologation purposes and, unlike the Escort, shells are abundant, says Kev’s colleague Chris, who has also worked extensively on the development and build – “They’re not hard to get. Spain, Italy, anywhere that’s warm and dry you can find a chassis.”

Every last component has been built to original designs, so the 131 (registered as a Fiat) flew through its homologation test. This in effect, then, is a brand new 35-year-old car with a spec sheet as mouthwatering as its perfectly retro paintjob.


A 2.0-litre twin-cam sits under the plastic bonnet, nestled in between the fibreglass front wings, as per the original Bertone-built 131 Stradale homologation road cars. According to Kevin, the cam tuning is actually quite conservative at the moment and it’s already pushing out 240bhp at 6200rpm – 20bhp more than a BDA engine in RSD’s Escort from 5000rpm to the rev limiter, which is set somewhere north of eight. There’s a useful 10lb ft more than the BDA, too, holding its torque curve longer than the Ford and kicking out maximum twisting force at 5000rpm. That ballistic engine is mated to a CIMA five-speed manual dog ’box as it would have been in period, transferring its drive to the rear wheels through a limited-slip differential. And it’s at the rear end where the 131 really trumps the Escort.

Whereas the Ford uses a live axle, the Fiat is independently sprung, featuring Bilstein dampers valved to the original settings. At 950kg it’s light, but not as light as an Escort. Despite this it runs softer springs than the Ford – together it gives much more control, composure and ultimately, speed.

“On the tests we’ve done we found that whereas you’d be dabbing the brakes and lifting off over jumps in the Escort, in the Fiat you can be flat out on the rev limiter in top gear,” says Theaker.

“The Ford lands and rebounds one way then the other at the rear – it takes a bit of time to settle. In the Fiat it seems to be more four square and calmer when it touches down.”

That could be helped by the larger 15-inch wheels and tyres compared to the 13s on the Ford, too, but that switch is something that’s not been straightforward for RSD. It’s a learning curve, but one he’s obviously getting to grips with. On just its second outing the 131 was on the pace of the Escort. “You must be delighted with that?” I ask.

“You’re joking, aren’t you?” says Kev. “We were annoyed it wasn’t on the pace of the Escort in the first test!” Given its performance straight out of the box, the 131’s potential is patently obvious. RSD hasn’t touched the setup since it was built, but for one tweak to lengthen the final drive after its last outing.

Theaker says, “We had it geared too short – coming out of the corners it was just revving too much and not really translating into much drive, we were spending more time changing gears than going forward. But lengthening the final drive should mean there’s a bit more progression.”


We haven’t got a gravel forest stage to test the 131’s true rally performance, so the slippery Blyton track is going to have to do. I’ve already clocked the forest tyres, so I’m expecting it to feel a bit vague at the front end and for the chilly October air and damp surface to conspire against grip even further.

With a brake bias setup pushed towards the rear for the loose, it should actually help today.

However, I’m not looking to Scandinavian flick it into anywhere, as this is a £120,000 car – excluding the VAT. And it’s already sold.

Threading my way through the roll cage, dropping down into the bucket seat and affixing myself to the Fiat with the six-point harness, it’s the interior that first makes you beam with awe, giving yet another screaming indicator as to the thoroughness of the project.

Each switch has been remade and the toggles and push buttons are all labelled in Italian for the authentic affect. Markku Alen and Walter Rohrl – who both won world drivers’ titles in the 131 – have seen the car and commented on its time warp nature, with everything being identical to the original.

Theaker knocked the car off once it had gained a bit of temperature, so as I flick the battery master switch myself, prime the fuel pumps – announced by a buzzing whir – and coax the twin-cam back into life, it catches with a solid thud. A prod of throttle gives a zip of revs. Despite the longer final drive, first is still short.

Theaker comments that I might not need it, but I hook the lever across and back to select the dogleg first anyway with a schunk from the straight-cut CIMA five-speeder. A paddle clutch transmits the power so it doesn’t like to be slipped too much. It’s therefore better to be a bit more forceful when pulling away. As I let the clutch out with a flare of revs, the 131 rolls forward to a buzzing vibration from the effervescent motor and a slight judder from the drivetrain. This is cool. This is what proper competition-bred rally cars are all about.

Kev is right. First is short, so I immediately grab second. The gearbox oil is cold, but it’s still easy to snick a new gear. As we tool around for the first few laps, waiting for the oil temperature to come up to operating levels as the dry sump system pumps the Fiat’s blood around its circulatory system, Kev’s imposed 5000rpm rev ceiling is actually enlightening. It shows just how tractable the motor is, pulling hard with a garble from under the bonnet even in fifth gear. It’s only just starting to come on the cam there, so when I get a chance to fully extend the engine beyond 8000, the way the induction note from the snorting throttle bodies morphs from a bassy snarl into a hard-edged, cacophonous cry is a tonic, overlaid by the screeching whine from the straight-cut transmission. The noise replicates the engine’s characteristics, delivering solid tractable torque and screaming top-end power. If this doesn’t make you smile, you’re not a petrolhead.

The Kugelfischer mechanical fuel injection is so crisp and the throttle response so accurate that getting on the power is addictive. The engine revs like a nutter. Downshifts are never anything but blipped to perfection. I kiss the limiter in second on the exit of Blyton’s back straight chicane, a gentle drift on the way out, and hook third. I’m not even going quickly and it feels so natural and intuitive. The dog ’box means you have to be very positive with your gearshift technique, as I find out to my wincing displeasure by grinding the dogs going up the gears. But once I get used to a lack of synchros again – kick the clutch, forcefully slot home the next ratio and stamp back on the power – the momentary pause in motive force and the engine’s demented bark becomes shorter and shorter. The noise is infectious, and as the speed rises the sensations the Abarth feeds back are communicated so clearly. Even on forest tyres, with their glassy, numb-feeling response to direction changes, it’s a total grin fest.

You need to be forceful and accurate with all your inputs at the weighty controls. Pushing the brakes feels like trying to leg press 100kg with just one lower limb. The pedal is mightily solid and needs a good shove, but there’s lots of stopping power there. Set up for gravel, retardation is biased a little more rearwards than normal, but it’s still so progressive.

In the heavier braking zones you do get the sensation that this thing wants to start rotating from the rear. That you could get the back moving to set the car’s attitude for the corner, holding it with the transition to the throttle and riding out a long ‘three right opens’ with massive oversteer and a hail of bap-bap-bap as the motor headbutts the rev limiter. I wasn’t alive in the 1970s, but if it was like this, I want to go there. Now.


And if this is what the 131 is like without any refinement of the setup, the car has the potential to turn the Group 4 field on its head; the Escort old guard could be about to get a shock.

Currently the car is running higher and softer at the front for a bit more weight transfer and feel, but with spring rate, damper settings, ride height, antiroll bars and just about everything else to tweak to find the perfect setup, the development room the Fiat 131 Abarth has is massive.

As an ‘evocation’ of the original car and an object of motorsport appreciation, the 131 is redolent of an iconic period of rallying. As a competition car, a tool with which to win, it’s on the pace already – the potential for an illustrious second wind in Group 4 rallying is there undoubtedly.

ABOVE: The RSD Fiat 131 project is set to make an exciting change to the UK rallying scene. CENTRE: PAG alloy wheels available from FACING PAGE: Examples of the high quality engineering that has gone into the 131 project.

BELOW: All new engine except the block and crank. An impressive 240bhp straight out of the box. ABOVE: Donor 131 two-door shells are being sourced from Europe, in particular Spain where the climate has preserved the cars.

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Additional Info
  • Year: 1977
  • Engine: Petro 2.0-litre L4
  • Power: 240bhp at 7000rpm
  • Torque: 167lb ft at 5600rpm
  • Speed: 122mph
  • 0-60mph: 7.0sec