There’s a gulf between reducing weight and making a true lightweight, says Jethro
‘The benefits only really hit home when you go back to basics’
WE ARE ALL VERY HUNG UP ON WEIGHT. Perhaps to a fault. Every new performance car variant released is ‘too heavy’, according to those sage folks on social media. It’s the cause du jour amongst enthusiasts. I have to admit it’s something that tends to leap to the front of my mind when yet another new car is launched, too. Very often in flashing bold type with klaxons blaring in the background. The latest car to fall victim to this is the BMW M4 CSL.
You see, the new Coupé Sport isn’t so Leichtbau. Even stripped to the tune of 100kg thanks to carbon-ceramic brakes, carbonfibre seats, bonnet, roof and bootlid, deleted rear seats and a titanium exhaust, the M4 CSL weighs 1625kg. Even the giant kidney grille is lightened. It doesn’t stop the creep. The E46 M3 CSL weighed around 1425kg to the same DIN standard as that M4 figure, i.e. with a 90 per cent full fuel tank, and the E92 M3 GTS was a full 95kg lighter than the new CSL at 1530kg.
This isn’t a trend unique to BMW. In fact, perhaps everybody has been a little unfair about the latest extreme M-car. I suppose sticking ‘Lightweight’ in the name is pretty provocative. However, let’s look at the new Lotus Emira. You know Lotus. Chapman. Add lightness. Just saying the name gives people like us Tourette’s and this stuff comes spewing out. Anyway, the Emira in its ‘lightest form’ is 1405kg DIN. I guess that’s the four-cylinder car. According to our scales the Emira fitted with the supercharged V6 weighs 1486kg with a full tank. More than a GT4 or GT3. And even taking out 10 per cent of the fuel load, it’s only around 150kg lighter than the big 4-series based coupe. This is just where we are in 2022.
Is this depressing? It seems that maybe it is. Except that in the last 12 months I’ve driven so many cars that weigh well over 1500kg and drive brilliantly. We’ve already written ad nauseam about the BMW M5 CS, so I won’t repeat yet again how superb it is despite weighing in at a hefty 1825kg. But what about the lasthurrah GT-R? Despite hilariously comprehensive weight saving measures – like new wheels that are 25 grams lighter per corner – the GT-R Nismo can’t escape its big bones.
At 1703kg the square-shouldered coupe should feel cumbersome at times and a little lazy, yet it just loves to turn and has an almost manic responsiveness. You’d scarcely believe any car could change direction with such unwavering speed and precision. Maybe all those years ago when Kazutoshi Mizuno told a group of journalists, myself amongst them, that the GT-R’S weight was an advantage not a hindrance, he was right. The speech itself deserves a column all of its own, but the crux of it was that a contemporary F1 car weighed around 600kg and produced 1300kg of downforce. Adding up to… almost a GT-R with a driver and fuel. It then meandered in all sorts of directions. At one point we thought he was talking about lasers. Anyway, Mizuno argued, passionately, that weight should no longer be demonised. Perhaps we all need to reassess our own prejudices.
The inconvenient truth hits, ironically, like a ton of bricks. The Caterham 420 Cup has taken me out of the pits, along a very short straight and around one hairpin bend. As I grab an upshift just as the wheels rumble over the exit kerbing, foot slammed into the bulkhead, confidence already sky-high and whooping for joy into the thick padding of an Arai helmet, the lesson is as clear as day: Weight is the enemy. Of course it’s the enemy! How could I have ever thought differently? This tiny, fierce, frantic and outrageously capable machine seems like the very best idea in the world.
It’s not a new idea, of course, but it’s one that feels long forgotten. Even if you pay lip service to weight reduction and strive to save 25 grams per wheel, the benefits only really hit home when you go back to basics. Back to a car that is absolutely defined by its lack of mass. Rediscovering this virtuous circle is a joy. And an education. I long for every other manufacturer to own a Seven and for their engineers and development drivers to test it every three months. To feel the benefits of low mass, to reconnect with driving excitement in such a pure expression of engineering simplicity. To remember just how much fun driving can be.
A dozen laps later the evidence for the benefits of lightweight construction is so compelling that it’s irrefutable. Not only am I absolutely enthralled by the 420 Cup for what it can do, I’m also desperately looking for ways that I can improve to try to match the finesse and capability of the car. In reality, I’m too tired and too wired to think. However, the car doesn’t show a bead of sweat. No brake fade. No tyre wear. It waits patiently in the pitlane. Ready to go whilst the supercars nearby have new boots fitted. Again.
The Seven still has much to teach us. Many years ago, we decided to no longer take Caterhams to ecoty. In an era where a CSL weighs 1625kg it’s time to reverse that decision. The campaign starts here.