EXCLUSIVE! On track in the McLaren Senna
Nobody outside of McLaren has sampled its latest creation, the high-downforce, high-drama Senna – until now. By Ben Barry
THE MCLAREN SENNA is billed as ‘the ultimate road-legal track car’. A dry weight of 1198kg and 789bhp combine for a 659bhp-per-tonne power-to-weight ratio, and mind-bending acceleration: 2.8sec to 62mph, 6.8sec to 124mph, a 9.9sec demolition of the quarter mile and a 211mph top end.
We’ve come to the Goodwood Members’ Meeting to get a world exclusive passenger ride in a final verification prototype. Vehicle line director Andy Palmer (the other Andy Palmer is on p108) will be driving, and heroically navigated the £750k Senna from Woking through snow at 5.30am.
This prototype is tasked with signing off the Senna’s dynamics, levels of refinement and electrics. Palmer says he was pondering some small tweaks to the steering on the drive down – minor alterations to the suspension geometry and steering-pump map, perhaps – and chats me through the incredible spec. The Senna is built around an evolution of the McLaren 720S’s MonoCage III carbon tub, but with a new rear crash structure, which means it shouldn’t require a rollcage should it race (which it probably will). The body is entirely carbon – the front wings weigh just 0.66kg, and even the doors are under 10kg, half that of a 720S door.
Select Race and the hydraulically interconnected suspension drops 30mm at the front, 22mm at the rear, opening the door to ground-effect aerodynamics. But it’s perhaps the Senna’s active aerodynamics that are most astonishing: the rear wing weighs
just 5kg but can generate up to 500kg of downforce alone as it adjusts through 45°. The front splitter is 150mm longer than a P1’s but the red aero blades under the front lights automatically adjust to balance out the rear wing’s movement. The result is up to 800kg of downforce at 155mph – 40 per cent more than a P1.
I lower myself into the laid-back, embryonic embrace of a carbon seat that weighs just 3.5kg. Palmer fires up the twinturbo V8 and immediately you feel one key difference versus the mechanically similar 720S: there’s a much stronger fizz of vibration through the seats, like you’re sitting on a lightly struck tuning fork. Solid engine mounts are responsible, and they promise to contribute to the Senna’s sharper dynamics. You hear more of that engine too, because the carbon doors and bare floor let more noise in, so already the Senna feels alive with mechanical energy.
The digital dash flashes up a ‘ caution frost’ warning, and puts tyre temperatures at 0°C. ‘I don’t know if we actually have a minus reading,’ jokes Palmer. As we ponder the wisdom of 789bhp on a slippery track, I ask if the P1 wasn’t already far beyond the capabilities of most drivers, and if the Senna is only further out of reach – its lap times, after all, are said to be comparable to the track-only, slick-shod P1 GTR. ‘ The Senna is easier to drive,’ replies Palmer. ‘We’ve worked hard on our control systems, tyre technology has improved, and the active aerodynamics make a big difference too.’
As we head out onto the track in a flurry of wheelspin, tarmac blurs through the Gorilla Glass in the lower doors, and I’m struck by how unintimidating the Senna feels. But there’s no doubt it’s scarily quick, and even moderate throttle punts it down the straights like it’s been kicked up the backside. No consideration was given to adding a P1-style hybrid powertrain, but power and torque are up 79bhp and 22lb ft on the similar 720S engine, and the 4.0-litre gets lighter cams and pistons, plus a recalibrated ECU. Throttle response is sharper too, and there’s more aural drama as air is dragged through the roof snorkel and into the induction system (as it was to such great effect on the F1-apeing 650S LM), more turbo whoosh when Palmer releases the throttle, and a louder roar from the iconel and titanium exhaust when he flattens it. But this remains the domestic appliance of supercar soundtracks.
As Palmer carries good speed up to the chicane, though, it’s the authority of the way in which the Senna changes direction, how it snaps down through the faster gearchanges and, above all, how it stops thanks to 390mm carbon ceramic discs and six-piston monobloc calipers that really shock. We go out in the Sport chassis and Track Powertrain setting first, switching to max-attack Race mode later and feeling the dramatic increase in suspension stiffness, but the conditions mean we get only a glimpse of the Senna’s staggering performance for now.
The Senna will be limited to 500 examples, plus prototypes like this, which have a cult following that dates back to the McLaren F1 XP prototypes. This car’s story isn’t over yet. With the Senna soon going into production, it’s likely to be converted into GTR spec, a track-only evolution with more power, more downforce and slick tyres. For now, let’s just hope for better weather when we drive a prototype Senna at Silverstone for the June issue of CAR.
Inside the Goodwood Members’ Meeting, p92