I thought contemporary motorsport had long given up on supercharging engines to increase performance. I figured this to be anachronistic engineering from the pre-war era of ‘Blower’ Bentleys and such. But the latest development in Phil Abbott’s futuristic revolution in affordable sports-prototype racing harks back to this bygone age.
It’s been a long time since I first drove the Revolution, during its earliest pre-pandemic development. The car was clearly well-built and decently quick. The lower-cost design approach using CFD programming that until recently was only really applied in Formula 1 and for Le Mans was also very interesting. But the lack of power steering wore me out after only a handful of laps around the Algarve Circuit near Portimao – and it did feel as though the car was a bit heavy for an engine output still shy of 400bhp.
I had a second go – in the wet – at Donington Park in February 2020, just before the pandemic shut everything down. In those conditions, I didn’t notice the lack of grunt from the Ford V6 so much – and the absence of power steering (a first system was in transit to Donington on the day of my test) didn’t matter given lower speeds. I enjoyed myself so much I slid the car into the Coppice gravel…
The Revolution has come on quite considerably in the two years since. James Bailey’s PitBox91 organisation promotes the Sports Prototype Cup (administered by the British Automobile Racing Club) as a destination for these cars, and Revolutions have been racing at grand prix venues such as Monza, Portimao and Spa as part of that category for two seasons and counting. This year’s calendar features five events – a mix of mini-enduro (45-60 minutes) and sprint (20mins) races – at five F1 venues: Zandvoort, Silverstone, Spa, Barcelona and Paul Ricard.
Olympic cycling champion turned sportscar racing driver Chris Hoy is one such who’s found a new home in Abbott’s growing Revolution. He has raced the first two seasons so has seen the full progression first-hand.
“It feels like a really polished product now,” Hoy tells Autosport. “I enjoyed the non-supercharged version of it, but it feels like it’s been calling out for that bit more power. It brings the chassis to life I think – and makes it far more exciting. It feels like a serious bit of kit now.
“At Portimao we were only about a second off LMP3 pole time from last year. That was without the [current version of the] supercharger with the bigger intercoolers and everything turned up to 10.
“I feel for an amateur driver such as myself, I can attack rather than sort of being intimidated and scared by it. And that’s on a day like today where the weather has been pretty bad.
“It’s a fun car. That test we did in Portugal, everybody who drove it came out with a massive smile on their face.”
As we chat, at the back of a Donington garage, Hoy excitedly shows me pictures on his phone from last season’s race at Monza – where he finished on the podium. The buzz of racing on classic F1 circuits is a massive part of the Revolution’s appeal. And the cars even sound like classic F1 machines now they’re supercharged.
“I’ve raced Caterhams, Radicals, LMP3, LMP2, GT3, GT4, classics, and to me this feels like a sweet spot – it suits me perfectly,” Hoy continues. “You can have two or three bites of the apple; there’s a bit more movement happening, but it’s hard braking, use the downforce, carry the momentum through the corners – but it’s got that much more grunt now that you can almost barrel it into the slow stuff, stop it, turn it and go.
“It feels like a really polished product now. I enjoyed the non-supercharged version of it, but it feels like it’s been calling out for that bit more power. It brings the chassis to life" Chris Hoy
“It’s [now] about 25mph quicker than the non-supercharged one – at Portimao at the end of the straight you’ve got to recalibrate your braking points and everything. Craners here… you’ve got to be thinking ahead, looking ahead. More than ever, you’ve got to be disciplined.
“And the cars go to the next level when racing side by side – and they’re quite robust. Honestly, it’s the best car I’ve driven on the track for a number of years, and I’ve done quite a few in the last few years. It’s fast enough to be scary, but not so scary that it makes you…”
Want to do something else? “Exactly!”
Commercially speaking, the Abbotts’ pursuit of power is all about chasing that lucrative American market – somewhere Radical is heavily focusing its new SR10, and where the Revolution is disrupting.
By increasing compression and developing a new six-body intake system with Mike Jenvey, the Abbotts managed to get their original engine (“bulletproof to 10,000km” says Abbott) up to 427bhp. But supercharging – which has also required enlarging the engine bay and rear bodywork – has taken output from the original 385bhp to comfortably past 500bhp, hence the new 500SC designation.
The Abbotts even ran CFD on the internals to make their supercharging process more efficient. The airbox, for example, is now three times the size it was, but creates no extra drag – because of the accuracy of their CFD modelling.
“The American market – the words were ‘as long as it’s more than 400 it’ll be fine’,” recounts Phil Abbott, as we chat in Donington’s trackside restaurant. “Then we launched in the States [at country clubs in Chicago and California in July 2021] and they liked it – but generally, they wanted more grunt in the mid-range… more horsepower. And I thought, ‘Well, I’m not going to go through another round of development on pistons and valves – we’ll put pressure charge on it’. And then we’ve got a screw and we’ll turn it up when we want to!”
Abbott was inspired by reading a book about Stanley Hooker – “one of the greatest jet engine experts” – who worked for Rolls-Royce during the Second World War. This mathematician “designed in long-hand with a pencil, the supercharger for the Merlin [Spitfire] engine. He took it from 1000 horsepower on the ground to 1000 horsepower at 20,000 feet by supercharging”.
The Revolution uses a centrifugal supercharger, which is gear and engine driven, with a compressor wheel that looks “very similar to running a turbocharger” but maxes out at 90,000rpm (a turbo would probably run to 180,000rpm). Turbos use exhaust gases and tend to create problems with pre-ignition and ‘knock’ because of the pressure changes created inside the engine when a driver comes off the throttle.
Supercharged engines are more straightforward to manage, in that you know the volume of air coming in is directly related to the engine’s speed. Abbott says the other attraction is that, from a user perspective, the engine behaves like a normally aspirated motor – you don’t get lag and torque spikes and the like. Modern engine management technology mitigates unreliability.
“I kinda liked the supercharging idea,” says Abbott. “But I didn’t really grasp it. For me to do anything, I’ll have to really understand it at a molecular level. So reading that book about Hooker – a jet engine is just like a big supercharger.
“My tech teacher used to say the only way you get more power out of something, as regards a piston engine, is you have to put more air and fuel in it. Supercharging just kind of fits really. It gives you the nice normally aspirated power curve, but just more of it.
“I couldn’t see [originally] why we needed 500 horsepower – that’s an LMP2 car – but, when you drive it, you know.”
Certainly, this power increase – now up to 553bhp on the dyno, according to Abbott – transforms the Revolution into a bit of a beast, particularly through the Craner Curves, which just feel insanely fast and impossible to navigate properly in these tricky conditions. Honestly, throughout my time in the car I feel it’s driving me through here – and almost all of the quick bits between Redgate and the back straight. It’s humbling, but also exciting, because there is always opportunity to be found in the unknown.
By the third run, confident enough to turn the engine up and better able to manage the weight of the car under braking for the slower corners, I work down to a 1m29.72s best on Donington’s Grand Prix loop.
“My tech teacher used to say the only way you get more power out of something, as regards a piston engine, is you have to put more air and fuel in it. Supercharging just kind of fits really" Phil Abbott
The car has an oversteer tendency on exit that’s holding me back a bit, and I’m not surprised to learn from James Abbott’s data analysis that my lack of confidence in the high-speed sections is costing me the best part of my 1.72 seconds to his own reference lap (set in a mule car with less power than the one I’m driving). I gain a bit back by being 10km/h (6mph) faster through the Melbourne loop – which is a boon for me because slow-speed is often the weaker aspect of my driving.
The power steering system is working well – I no longer feel the need to have a lie-down after half a dozen laps of dry weather driving. The Revolution has now also upgraded its dampers, using products developed by R53 – which has also worked on Gordon Murray’s latest supercar project. Abbott says this alone made the car 1.5s faster around bumpy Blyton – though he concedes the effect is less obvious at somewhere smooth like Donington.
In any case, it’s the sheer acceleration of this car that now hits home more than anything: 142mph before I wimp out through the Craners; almost 150mph before we hit the brakes for the chicane (and I’m braking too early here as well!). This is now one seriously fast piece of kit, for a revolution that is rapidly gaining pace.
