Race Car vs. Street Performance Car

When released back in 2008, the Audi R8 was unquestionably the most hyped and popular supercar on sale. With space ship looks, magazine reviews promoting amazing driving dynamics and superb mid-engine balance, just about every enthusiast was pining for an R8 experience.

It’s easy to forget nowadays since nearly every car has them, but the R8 was the car that kicked off the artsy daytime running light fad (what Jeremy Clarkson from British Top Gear dubbed “LED fairy lamps”).

I could hardly believe my luck when I caught a glimpse of those unmistakable lights rolling into the paddock for a track day just over a decade ago. After some discussion and no doubt sensing (feeling pity for) my enthusiasm, the driver invited me for a ride along session.

The enjoyment of the experience and my imagined track session dominance was unceremoniously interrupted right amid hot laps at full tilt.

Driver: “This Neon is all over my a##!”

Me: “Neon…huh?

Sure enough, a glimpse in the side mirror revealed a stripped out, fully race-prepped, Mad Max style Dodge Neon SRT-4 magnetized to our rear bumper. After buzzing by, the wicked Neon quickly faded off into the distance just after the next couple of corners, much to my astonishment.

An important lesson was learned that day: No matter how “supercar,” no matter how hyped, race car pace is on another level. Race tracks flip common automotive performance perception upside down, and regularly make supercars eat crow.

It’s a lesson that continues to this day, even though supercar performance technology has rapidly advanced over the past decade, and vehicle manufacturers are releasing more track-focused cars than ever.

The McLaren Senna is the brand’s most track-focused release to date, which in the world of McLaren supercars and hypercars is saying something. When the Senna was released in 2017, McLaren even hinted at race car rivaling pace.

Top Gear’s Chris Harris decided to put McLaren’s suggestion to the test with a lap time shootout between the Senna and a McLaren 650S GT3.

Spoiler alert: Despite hypercar performance credentials and futuristic looks that make the old R8 look like a Ford Escort, the Senna got whooped to the tune of about 6.5 seconds around Silverstone.

Harris’s running commentary from behind the wheel in the video below details the reasons why true race car pace is almost impossible to achieve for anything with number plates:

Tires

The Senna wears Pirelli P Zero Trofeo R tires, which are at the very extreme end of what can be reasonably fitted to a street legal car, but even the Trofeo R lacks grip as compared to a full Pirelli racing slick.

The persistent understeer reported by Harris is a result of the Senna’s relatively modest 245 mm section front tires. Whereas race cars maximize tire width (contact patch) according to chassis and/or race series limitations, performance street cars have to balance tire width with other considerations like suspension geometry and clearance factors, as well street drivability. Extra wide front tires tramline, often to a hazardous extent. (Tramlining is the unsettling phenomenon of the car “following” the road imperfections and contours absent of steering inputs. In some cases, it feels like the car jumps entire lanes.)

To accommodate substantially wider rubber, the 650S GT3 utilizes massive 12.5-inch wide front wheels and 13-nch wide rear.

The Senna has just 8-inch wide front wheels, and 10-inch wide rear.

Widened track

Without considerations like (pesky) lane width restrictions, race cars can maximize not only the tire and wheel width but the width of the axles.

This engineering concept focuses and centralizes the bulk of the vehicle weight well inside of the tires and wheels, and optimizes cornering traction.

Brakes

The Senna’s huge carbon ceramic brakes appear to be a close match size for size with the GT3 racer’s, but what isn’t immediately apparent is the compound of the brake pads.

Here again, the Senna has to balance street and track performance. The most aggressive available brake pad compound would have driver and passenger plunging forward with even a modest application on-road.

Racing brake pads respond with the absolute immediacy that is a match for higher speeds and threshold (last moment) braking points.

Weight

At just over 3,000 lbs. the Senna is no heavyweight, but even with the cage and safety hardware, the 650S GT3 is about 100 lbs. lighter.

Oh, one more thing to keep in mind – the 650S GT3 is down the better part of 300 horsepower to the Senna.

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