Pro Racer’s Take: McLaren Senna
Redefining “Street Legal”
Ayrton Senna claimed the first of his 41 F1 wins at the Autódromo do Estoril racetrack in Portugal on April 21, 1985. Thinking of that while walking down the track's pit lane hammered home the point that the McLaren Senna is a special car—especially if you're a fan of the man and F1. I've heard people say it's ugly, but to my eyes it has a striking presence and exudes unapologetic functionality. I think it looks impressive.
McLaren provided a 720S for our first laps of Estoril. Yes, to find our way around a circuit most of us had never seen before, we warmed up in the massively fast 720S. Imagine it as a 710-hp rent-a-car type of thing. Worth noting: The 720S is rather well balanced, but it doesn't have much in the way of aerodynamic downforce to help you, especially compared to other 700-plus-horsepower cars now available (see our November issue). To get a fast lap in a 720S, you have to slide it around a lot, including through high-speed turns. Thankfully, the car's balance is so amenable and communicative that slipping and sliding all day at complete nutter speeds is twitch-free and enjoyable.
After a few laps in the 720S learner car, it was time to jump into the Senna. I was excited and tried to take as much out of every minute as I could. Estoril, apart from one horrible "slow them down" chicane, is exactly as Senna found it when he won his first F1 race. But thank goodness we didn't have the horrendous rain the F1 field did on that particular April day.
If you have almost 800 hp, you'd better have plenty of stopping capability. The Senna can pull 2.1 g in deceleration, a number that's serious race car good. The brake feel is excellent and easy to modulate; I could just tickle the ABS or modulate deceleration to rotate the car on corner entry. You enter the brake zone for the 50-mph first turn at more than 180 mph, so you need amazing stoppers. The car passed that test with zero trouble.
"The stiffer suspension setup makes any steering input an almost instantaneous instruction to the tire patch, so it's up to the driver to control this."
The steering is quick but not too quick. Although the Senna comes with Pirelli P Zero Trofeo R tires, they're still street tires. To get the most from them, they need a slower steering rate than race tires, especially after they heat up. Once I slowed my hands down, I could manage the plentiful front grip much better. Slowing my hands gave my steering input more time to speak to the tire patch through the suspension. The Senna is sprung on the stiff side to handle the almost 1,800 pounds of total downforce it can generate at 155 mph. The stiffer suspension setup makes any steering input an almost instantaneous instruction to the tire patch, so it's up to the driver to control this.
That downforce figure is just amazing. To help save the tires, the active aero limits downforce to an 1,800-pound maximum, but the downforce level could in theory be even greater. For comparison, a Corvette ZR1 or Porsche GT2 RS will produce about 450 pounds of downforce at 155 mph and a maximum of around 1,000 pounds at their top speed of roughly 212 mph. That's not really any comparison to the Senna. In terms of cornering speeds, those cars are like GT3 racers whereas the Senna is like a prototype racer.
The suspension setup is impressive for its overall front-to-rear chassis balance. As stiff as it is, once I got my steering wheel rate figured out on corner entry, I could use the steering and a slight throttle lift or slight left-foot braking to move the car and control rotation. This was very useful entering the midspeed kinks. Downforce helped to make the Turn 5 kink easy to take flat out at more than 130 mph. The ability to rotate the car on corner entry to midcorner takes away the need for the front tires to do all the work, allowing me to carry more speed and making the car a joy to drive. I could also use these same techniques for post-apex/corner-exit power-down situations. It worked particularly well for putting the power down early in the Interior Parabolica Turn 6 and the really quick and long Ayrton Senna Parabolica Turn 13. This car is so much fun to drive at full rip; I tip my hat to McLaren's engineers and test drivers for its development.
I often find acceleration to be the least impressive part of a high-performance road car, especially when you get it on a track where everything around you goes equally as quick. However, the Senna is something else. The 720S has roughly 4.6 pounds per horsepower when you include fuel and a driver. You might be surprised to find a modern-day GT3 race car would be around 6 pounds per horsepower. The Senna is 3.7 pounds per horsepower, including fuel and a driver. It really does feel like a prototype race car on acceleration, especially up to 100 mph, when the downforce is lower—and the car still pulled strongly to more than 180 mph on Estoril's front straight.
"A modern-day GT3 race car would be around 6 pounds per horsepower. The Senna is 3.7 pounds per horsepower, including fuel and a driver."
For lap time, this is certainly the quickest street car I've ever driven on a racetrack. I imagine McLaren felt a fair amount of pressure when it began this project to create a car worthy of carrying the Senna name, but it can rest easy knowing it succeeded.