The Audi Sport Quattro was one of the defining cars of the Group B era, a time which, for many, represents the absolute pinnacle of rallying.
The cars were ludicrously fast, and the sport incredibly dangerous. Manufacturers were going to lengths almost unimaginable in today’s comparatively vanilla industry to outdo one another on the rally stages by building faster, lighter, more agile and more extreme machines. The racing was exciting, and although the danger-factor played a part in that, records were being broken and boundaries were being pushed.
Before the introduction of Group B, Audi was enjoying a certain dominance in the sport. It had introduced the world to the Audi Quattro 80, also referred to as the UrQuattro, which had brought the concept of a highly competitive four-wheel drive rally car to fruition. Other manufacturers followed suite and before long Audi was fighting a losing battle – Peugeot developed the lighter and more nimble 205 T16. The Quattro had to evolve to survive.
The Sport Quattro’s biggest downfalls were its weight and length, which gave the car unwieldy handling characteristics. Rather than opt to take the same route as the likes of Peugeot with the T16, or Lancia with their 037, and develop an all-new ground-up space frame rally car, Audi didn’t want to damage the UrQuattro’s reputation by dropping it from competition. It was keen to persevere with the Quattro model, albeit with some substantial improvements.
The answer? Audi’s engineers opted to shorten the chassis by removing some 320mm from behind the doors. The shortened wheelbase, it was calculated, would help reduce understeer, improve initial turn-in grip, and decrease the car’s overall weight, whilst leaving it somewhat resembling a road-going Quattro still.
The engineers frugally used this exercise to address another problem with the Sport Quattro too: the heavy rake of the windscreen was causing the rally drivers serious glare issues. The solution? As they were essentially chopping the car in half anyway, they replaced the front half of the car with the front end from an Audi 80 Typ 81, which had a steeper screen – job done. The result was the Audi Quattro S1.
With continued development, the S1 was later improved, widened, bulked up and fed a healthy dose of extra power to become the instantly-recognisable S1E2 in 1985. At the time, with over 550bhp, it was the most powerful rally car ever. The S1E2 enjoyed a very limited lifespan in Group B as the class was banned in 1986, but its legacy wasn’t over.
Audi took the car to the world famous Pikes Peak International Hill Climb in Colorado and, in 1987, German driver Walter Röhrl became the first person to complete the gruelling 14.42-mile sprint in under 11 minutes in a specially-prepared 590bhp Quattro S1. His time was a blisteringly quick 10:47.85.
Now, exactly 30 years after the sound of Röhrl’s five-cylinder Quattro reverberated around Pikes Peak, Australian-born, UK-based David Rowe is bringing the turbocharged five-cylinder back to the mountain in his modernised EPS Motorsport Quattro S1E2.
This is his story.Returning To The Peak
Lofty ambitions you might think, and you’d be right in a sense. But this isn’t Dave’s first rodeo.
This isn’t even the first Quattro that Dave has to his name. A few years ago, he built a V8-powered S1, appropriately named Walter (after Walter Röhrl), which graced these very pages.
Nor is it the first time Dave has taken on the Peak. In 2013, with the support of his father and brother Jason who made the long journey over from Australia for the trip, Dave built and raced a 750bhp Mitsubishi Lancer Evo IX RS up to the clouds.
The initial climb was a great success, but unfortunately Dave didn’t have the funds to return and race again the following year like he had hoped. However, he was called upon by a French race team to fly out to Colorado and help maintain their Porsche during the event.
On the morning of his first day on the mountain in Colorado, Dave received a phone call from his family with the sad news that his brother had suddenly, and unexpectedly, passed away at the age of 41.
Jason’s legacy, their shared love for the Quattro S1, and the poignancy of Pikes Peak all play a part in the car that you see before you today.
The new car is named Ray, after Jason’s middle name, Raymond. With motorsport running through the family blood, I can’t think of a more fitting tribute.
Having already built the first S1, Dave already had a good idea on where he wanted to go with this second project. The concept was to build a car that was true to the Quattro’s retro roots and heritage, but upgraded with modern technology and equipped with the power and ability to put in a respectable time on the mountain.
The project began, as Audi’s did back in the ‘80s, with two cars – the front end of an Audi 80 and the back of an Audi Coupe Quattro. The two halves were brought together over a full custom T45 cage and the chassis was seam-welded front to back.
Dave wanted to stay true to the Group B legend’s aesthetics, up to a point. Opting for the full Group B bodykit, weight was saved by having it constructed in carbon-Kevlar wherever possible. The windows are all polycarbonate items too, complete with WRC-style sliding openings. Quick-release door hinges allow the Quattro’s openings to be accessed easier for maintenance too.
Dave foolishly trusted me to try them for myself, but surprisingly the doors are light enough to lift off and carry with one arm. I managed the feat without breaking or damaging anything, which is saying something.
The Quattro’s sizeable overbite is thanks to the large front wing, providing much-needed downforce and front end grip.
At the rear, the comically big dual-plane rear wings are completely functional, adjustable in angle to control exactly how the air flows over the back of the car, and how the downforce is applied.
Even the roof serves a greater purpose than shielding the occupants from any inclement weather – a large scoop directs air towards the back of the car and down into the Quattro’s rear-mounted, dual-pass radiator and oil cooler setup. Two Kenlow fans pull the hot air out of the rear grille and away from the cooling setup while an ECU-controlled electric water pump also helps keep engine temperatures down.
Just in front of this, through the polycarbonate rear window, the uprated fuelling system can be viewed, comprising of 40-litre fuel cell and surge tank, as well as a Peterson dry sump tank.
The graphics are a clear nod to the design the Quattro bore when Röhrl last ran it up Pikes Peak, with the clear distinction being the signature green and black of Dave’s company, EPS Motorsport.
The EPS Quattro’s large front and rear overhangs give it a deceptive sense of scale, but it’s not until you see the car in profile that you can appreciate just how short the wheelbase is – just 86 inches in fact.
For comparison, that’s shorter than a Ford Ka, new Fiat 500, and Suzuki Jimny. It’s barely much more than a Toyota iQ!
Rather than opt for the period-correct wheels, Dave decided to depart from the old and embrace the new with a set of 18×10.5-inch Rotiform LSRs. It might seem a controversial, or strange decision to run what many consider a relatively large street/show wheel on a race car, but Rotiform offered Dave a custom-specced, lightweight, three-piece forged solution that allowed for a substantial braking setup and suited the car perfectly.
I say they work pretty damn well.
Doing a terrible job of hiding behind the spokes are a gigantic set of Alcon GT calipers and discs, with a 380mm 6-pot setup up front and 355mm 4-pot setup at the back. Coupled with a Bosch Motorsport ABS system, there’s plenty of stopping power considering the car only just tips the scales at 1,000kg!
Road-holding is quite important when you’re doing your best not to fall off a mountain at speed, so KW Suspensions was called upon to provide a set of its 3-way Competition dampers with remote reservoirs.
Heavy-duty Audi Works front strut tops were employed, as per the original S1E2 allowing for quick changing between tarmac and gravel setups, and underneath the car custom Works-style suspension arms keep the alignment in check all around. The EPS Quattro has been built to take some serious abuse.
Step inside the cabin and amidst the zig-zag of T45 sits a lone Recaro Profi SPG seat with Sabelt harness. The interior is sleek, clean and clinical; you don’t need much else with 800bhp on tap and the mountain in front of you.
Slide into the hot-seat and a Tilton 600 pedal box awaits your commands. Your right hand finds the sequential shifter, linked down to a Drag Power Systems 01e sequential gearbox that was built for Dave using custom ratios specifically suited for the climb.
Ignition on and the MoTeC control panel and display lights up – this gives Dave all of the car’s vitals and can be cycled through numerous screens and readouts. When the Quattro barks to life the noise is immense.
Sticking true to the ethos of the project of bringing the S1 bang up to date, it might be a five-cylinder turbocharged powerplant, but that’s not the sound of the original 2.1-litre you hear.The Quattro, Reimagined
The EPS Quattro’s modern heart is a fully built 2.5-litre five cylinder O7K engine from an Audi TT-RS. Internally, the engine has been treated to CP forged pistons, I-beam rods and custom cams and runs a 11.0:1 compression ratio. Dave has retained the variable valve timing on the inlet cam, which brings power in nice and early.
The motor uses +2mm oversized valves on both inlet and exhaust sides, with air being fed in through a custom inlet manifold and an 82mm Bosch drive-by-wire throttle body and exhaust gasses sent packing down a custom ceramic-coated stainless system.
For testing in the UK, the car ran a more restrictive side-pipe setup exiting the car just in front of the passenger’s rear wheel, however just before shipping Ray off to the US, Dave had a un-silenced ‘US-spec’ exhaust fabricated. Pikes Peak will certainly hear him coming.
Plentiful boost is provided by a AET Precision 6466 unit, again ceramic-coated, controlled by a Turbosmart 4-port boost control unit and Turbosmart Hyper-Gate45 wastegate. A large custom intercooler sits at the front of the engine bay and Vibrant clamps keep the boost where it should be.
Dave’s attention to detail is admirable – from the careful labelling of the entire loom throughout the car, to how neat everything is positioned and mounted. Even down to the custom four-rings that he’s had fabricated for the inlet manifold, mimicking the original S1E2’s inlet. Just because it’s fast doesn’t mean it can’t be tidy.
EPS Motorsport’s business is engine management and tuning, so naturally Ray is in good hands. It also means that there’s more electronics, sensors and engine management gadgets in Ray than the original S1’s engineers could ever dream of. The EPS Motorsport loom, crafted by Dave’s fair hands, is a meticulously-prepared example of exemplary organisation. At the centre of the operation is a MoTeC M150 ECU and C127 colour display.
Throughout the car are a plethora of KA Sensors which allow Dave to log every tiny variation in boost, turbo speed, clutch engagement, braking, throttle, and even suspension travel. This all hooks in to a built-in camera system that can overlay this information in real time. Let me tell you it’s an automotive technophile’s dream to see in action.
One particular point of note here is the turbo speed sensor. Keeping an eye on turbo speed and air temperature, it allows Dave to monitor and make allowances for variations in air temperature and density when climbing Pikes Peak, and adjust boost pressure to suit as the altitude increases and air becomes less dense. Trick stuff indeed.
Because too much power is never enough, there’s also a healthy shot of nitrous on hand to provide an extra kick. The numbers you’ll want to know of course: the car was dynoed at VRS Northampton and produced mid 600bhp at low boost of 1.4bar (20.6psi), with 800bhp+ on tap when it’s ready to race.
You might have noticed some continuity changes throughout this feature in terms of the door numbers. Dave had planned to run the number 1, as per Röhrl’s car, but he later discovered that this reserved for last year’s Pikes Peak winner, so he’s been allowed to use the number 0 instead, which the car was wearing when I caught up with Dave just before it was shipped off.
With the annual Pikes Peak pilgrimage taking place in June it’s been a frantic few months for Dave and his team to finish off the build in time to get the car shipped, landed and tested out in the States. Before loading up, a quick visit was made to Blyton Park in Lincolnshire to actually try the car out for the first time.
Part of me finds it amusing that a car that’s been specifically built to climb 4,720ft up a mountain was tested in the flattest part of the UK without even as much as a molehill in sight.
You’ll be glad to hear that Ray absolutely flies, and sounds incredible on full boost. I only got to experience a handful of flybys with a silenced, UK-friendly exhaust on the car too. I can’t begin to imagine the noise this thing will make as it begins its ascent at Pikes Peak.
From the initial idea through to completion, the EPS Quattro is a testament to Dave’s expertise, skill and dedication. It’s also a build worth of its namesake; I’m sure Jason would be incredibly proud of what his brother has achieved so far.
But now the real work beings. Ray’s soon to be sitting at the feet of a giant, and the only way is up.
EPS Motorsport Audi Quattro S1E2 Pikes Peak
Custom S1 chassis with 86-inch wheelbase, T45 roll cage, seam-welded throughout
Audi 2.5-litre O7K five-cylinder, 11.0:1 compression ratio, CP forge pistons, I-beam rods, custom cams, VVT cam control, 2mm+ oversized inlet & exhaust valves, custom intake, Bosch 82mm DBW throttle body, EPS Motorsport dry sump system, AET Turbo Precision 6466 turbocharger, Turbosmart 4-port boost control, Turbosmart Hyper-Gate45 external wastegate, nitrous oxide injection, dual-pass rear-mounted alloy radiator & oil cooler, 2x Kenlow cooling fans, electronic water pump, 40L ATL FIA fuel cell with internal lift pumps, 4L surge tank with ASNU Veyron fuel pump, RacingLines super light hoses, Turbosmart 2000 FPR2000 adjustable fuel pressure regulator, 1100cc ASNU injectors, MoTeC M150 ECU, EPS wiring loom made with DR25 and type 44 wire, KA sensors, Varley Red Top 30 battery with remote cut-off
6-speed Sequential 01e Gearbox with custom ratios from Drag Power Systems, Tilton 7.25 Clutch, EPS lightweight flywheel, AK Motorsport heavy dutydriveshafts
KW 3-way Competition dampers, Audi Works strut tops, custom Audi Works-style suspension arms, T45 cross-members made by Webster Race Engineering, Alcon GT 6-piston calipers, 380mm discs (front), Alcon GT 4-piston calipers, 355mm discs (rear), RacingLines brake hoses, Bosch Motorsport ABS system
Custom Rotiform LSR 18×10.5-inch 3-piece forged
Carbon-Kevlar and E Glass body kit, polycarbonate windows with WRC window sliders, paint and bodywork by Stylehaus Northampton
FIA Spec fire safety system, Recaro Profi SPG FIA seat, Sabelt 6-point FIA harness, Tilton 600 series pedal box, hydraulic handbrake, MoTeC C127 display, MoTeC PDM 30 power distribution module with 15-way keypad
VRS Performance, Racing Lines,MoTeC, Webster Race Engineering, AET Turbos, Turbosmart, ASNU, Rotiform, Alcon, Competition Supplies, StyleHaus