The Fan Car: The Roadster's Suction System Is a 1970 Idea That Got Banned Twice

The thrusters got the headlines. The fans may be the product. MKBHD, in his reaction video, called the flip a party trick and the fan system the real handling technology. This page is the fan system’s family tree — because Tesla did not invent it, and the two cars that proved it were both legislated out of their sports.

The system as Tesla describes it is on the package page.

What the fans do

Underbody fans pull air from beneath the car and hold it to the surface: up to 2 g of suction, per Tesla’s claims, working at zero speed — which no wing can do. During the October 15 demo, a live gauge showed about 4,700 kg of downforce while the car hung upside down on the ramp.

Label: Tesla’s figures, from Tesla’s film and copy. No independent measurement exists in the record. The patent the engineering explainers cite for the fan system is Tesla’s US 12,377,920 B1 — a document, which is a stronger grade of evidence than a stage claim and weaker than a test.

The ancestors

• Chaparral 2J (1970). Jim Hall’s Can-Am car carried two fans driven by a separate engine, sucking the car to the track behind Lexan skirts. It was fast enough to be banned after one season. The 2J is the proof of concept and the warning label in one car: the suction worked, and the rulebook answered it.
• Brabham BT46B (1978). Gordon Murray’s Formula 1 “fan car” put one large fan at the rear, officially for cooling. It won its only race — the 1978 Swedish Grand Prix, Niki Lauda driving — and was withdrawn before the authorities had to ban it a second time.

Both cars are the reason “fan car” is a known phrase in engineering and a closed chapter in racing. The Roadster reopens it on the road, where the regulator is not a racing federation but the DOT and the state traffic code — the wall the legality page is about.

Why the lineage matters to the claims

A wing needs speed. A fan does not. Suction at zero speed is what lets a car hang upside down at a standstill, corner beyond its tires, and — combined with the thrusters — leave the ground in a controlled hop rather than a launch. It is also what makes the Performance trim (fans only, no thrusters) a coherent product: under 1.6 seconds to 60, road-ready, no tanks. The trims are compared on the trims page.

None of that makes the ancestors’ fate irrelevant. Both fan cars were ended by rule-makers, not by physics. The physics on this page is 56 years old and undisputed. The open question was never whether suction works. It is whether it will be allowed to.