At first glance, IndyCar and Formula 1 cars might look broadly similar. But while both series use open-wheel race cars, the contrast between them are many and varied. With that in mind, we thought we’d take a look at some of the key differences between two of the biggest and best-known single-seater championships in the world.
The IndyCar Series has been running since 1996, but it’s the latest incarnation of the official USA open-wheel national championship that dates all the way back to 1905. In contrast, the Formula 1 World Championship started in 1950, using rules standardised in 1946. Its roots can be traced back to various Grand Prix championships of the 1920s and 1930s.
For a while, the two worlds met; from 1950 to 1960, the Indy 500 – now the highlight of the IndyCar season – was part of the F1 World Driver’s Championship, which meant many of the top American drivers of the day appear in the annals of F1 history, even though most didn’t race in other Grands Prix.
The Formula 1 World Championship has been running uninterrupted since 1950.
For the 2023 season, 20 drivers from 10 teams lined up for 22 scheduled races at tracks around the world. Most F1 tracks are purpose-built road courses, although there are also a handful of street tracks thrown in to spice things up.
The number of races per season has been creeping up in recent years; 2023 was originally going to feature 25 events, but the Russian Grand Prix was cancelled due to the invasion of Ukraine, the Chinese GP was axed due to Covid worries and the Emilia Romagna GP was called off because of flooding. A new race in Las Vegas means there are three scheduled Grands Prix in the USA and four in North America.
Formula 1 rules generally have a big overhaul every few years to keep technology up-to-date and relevant. Since 2014 all F1 cars have used 1.6-litre V6 turbo units attached to a hybrid electrical system. Combined, the powertrain makes around 1000bhp. But in 2022 the latest big rule change focused on a radical revision of aerodynamics to promote closer racing and more overtaking.
F1 cars have very advanced and complex aero features on and below the car. This allows them to develop huge amounts of downforce and corner at tremendous speeds., but it can also create a lot of aerodynamic wash, or dirty air, behind them. In recent years, this has made it difficult for F1 cars to follow one another closely at high speed, often leading to criticism from fans.
In 2021, cars lost around 35 per cent of their downforce when within three car lengths of the car in front. The 2022 plans aimed to reduce this to well under 10 per cent, and demanded that teams reduce the complexity of the car’s aero. Rather than complex aero elements on top of the car, they were to focus more on ‘ground effect’, using tunnels under the car’s floor to create areas of low pressure and pulling the car down to create massive high-speed grip – a concept made popular during the 70s and 80s in F1.
Overhauled and simplified front and rear wings were mandated to avoid sending the airflow outwards from the car, but to narrow it instead. Wheel and tyre size has also dramatically increased from 13- to 18-inches, to more closely reflect road car tech.
F1’s Drag Reduction System (DRS), first introduced in 2011, has been retained. When a driver is within one second of the car in front, they can press a button that opens a slot in the rear wing, allowing it to travel faster in a straight line and making it easier to overtake.
The hope was that the 2022 rules would allow less reliance on DRS, but while the changes have made it possible for cars to follow each other more closely, the impact hasn’t been as dramatic as fans had hoped for, so DRS is still a key element in on-track overtakes.
The F1 engines run on E10 fuel, which uses 10 per cent ethanol. New engine regulations arrive in 2026 and will require 100 per cent sustainable fuel in an effort to reduce the sport’s environmental impact.
The cars’ hybrid systems recover energy in two main ways, using two key elements – the MGU-K, and the MGU-H. The ‘K’ part stands for ‘kinetic’ and recovers energy that would otherwise be lost through braking, while the MGU-H (heat) draws thermal energy from the exhaust system. Along with the energy store (ES) and control electronics (CE), these make up the Energy Recovery System (ERS); add in the internal combustion engine (ICE) and the turbocharger (TC) and you have a complete F1 power unit. Theoretically, they’re allowed to rev as high as 15,000rpm, but restrictions on fuel flow, reliability concessions, and the general power curve of the unit mean that drivers usually change gear below 12k.
Each car may use a maximum of two energy stores or control electronics, and three each of the ICE, TC, MGU-K, or MGU-H elements. Any more than this and drivers will have to take grid penalties.
At the moment the 10 F1 teams are supplied by four different power unit manufacturers: Mercedes, Renault, Ferrari and Red Bull Powertrains. Red Bull took over the project after Honda left at the end of the 2021 season (although Honda – perennial ditherers when it comes to F1 involvement – has announced another return with Aston Martin from 2026). Development of the power units is being frozen in 2022 ahead of a new formula for 2026. So far, we know that the 2026 engines will have similar performance using high-revving V6 engines, but increase electrical power to 50 per cent and use 100 per cent sustainable fuel.
The gearbox comprises eight forward gears (with a fixed ratio across the whole season) and a mandatory reverse. They are of course semi-automatic and seamless shift, and must last for six consecutive events - if any are changed before that then yup, you’ve guessed it, grid penalty.
In an effort to level the playing field and prevent money from being the key factor in on-track success, F1 uses a cost cap system, which in 2023 is set at $135 million, although certain things such as driver salaries and marketing aren’t subject to the restrictions. There are also other development restrictions – the higher a team finishes in the championship, the less time they’re allowed to spend testing aerodynamics in the wind tunnel or through CFD simulations. This is all part of efforts to narrow the gap in performance between teams.
The total weight of the cars is mandated to be a minimum of 798kg (including the driver), a hefty increase from the 605kg cars of little more than a decade ago. Part of this is down to the increased mass of the larger new wheels, hybrid systems, but also improvements in safety, such as the Halo device, which extends over the cockpit and protects the driver’s head in a crash.
The steering wheels are very complicated with a considerable number of buttons, dials, thumb wheels, paddles and combinations that are used to adjust things like brake balance, differential settings, and engine modes, as well as a screen display for viewing information and data. Carbonfibre composite brake discs squeezed by conventional hydraulic calipers are used with the rear braking assisted by the ERS.
Tyres are supplied by Pirelli, with five dry-weather compounds available across the season. Three are available to use at any given race, depending on the circuit characteristics; Pirelli uses data from all the teams to decide which compounds to use where. There’s also an intermediate tyre for when the track surface gets a bit wet, and a wet-weather compound in case it’s really chucking it down.
Pit stops are mandatory during races and each driver needs to use at least two different dry compounds of tyre in a race. There’s no mid-race refuelling and as a result the pit stops have become blink-and-you’ll-miss-it fast – during the 2019 Brazilian GP, Red Bull managed to change all four tyres on Max Verstappen’s car in just 1.82 seconds.
Unlike F1, the IndyCar grid runs the same chassis and aerodynamic kit, with power coming from one of two engine manufacturers - Honda or Chevrolet. In 2023, IndyCar is running 17 races in the USA, with a double-headers event in Iowa featuring two races over one weekend. Grid sizes are a bit more fluid than in F1, with most races featuring 27 or 28 drivers, ballooning up to a field of 34 for the blue riband Indianapolis 500. Teams run anything from one to six cars and teammates don’t usually share the same livery. Some drivers even have a different colour scheme for each race.
The carbonfibre Dallara DW12 chassis is used by the entire field and has been since 2012. The cars run 2.2-litre twin-turbocharged V6 engines from Honda and Chevrolet and produce between 550bhp-700bhp depending on the amount of boost used and the type of circuit being raced on (generally speaking there’s a lower power figure on ovals for reasons of durability and safety). In 2024 the cars will run hybrid powertrains, with hybrid systems added to the existing 2.2-litre engines. The series had planned to introduce new 2.4-litre engines alongside the hybrid tech, but those plans were dropped at the end of 2022.
The gearboxes are Xtrac six-speed, semi-automatic paddle shifts with a reverse gear. Tyres are supplied by Firestone and, like F1, feature different dry-weather compounds. There are also wet tyres available for road and street courses, with no wet running at all allowed on oval circuits. For the first time in 2023, each driver must use two tyre compounds in every race, including ovals; previously this had only applied to road and street courses. Also new for the 2023 tyre racks is a new compound made with a lower carbon footprint. It’s made from guayule rubber, which is manufactured from a plant grown in the US rather than trees grown in Asia, and will be the ‘alternate’ tyre at all the 2023 street course races.
All cars have used PFC brake components since 2018; prior to that, some cars used Brembo setups. PFC discs, pads and disc bells are all made by PFC, although teams can choose Brembo or Alcon master cylinders.
Just because the cars all have the same chassis and aero kits it doesn’t mean the cars are all identical. Teams are allowed to build and develop their own parts such as the brake ducts and certain suspension components, with the dampers being a particularly key area of potential improvement.
This is critical when you see the type of circuits that IndyCar races on a wide range of circuits, with drivers having to master undulating road courses, bumpy rough-and-ready street courses, and high-speed ovals across the course of a season. For each of these, the specification of car is different - so the amount of power, the brakes, the aero kits and weight all change, as will suspension setups and ride height. This is to react to the unique characteristics and demands placed on the cars.
Like F1, IndyCar has an overtaking aid - the push-to-pass system (again, only on road and street courses), where drivers can press a button on the steering wheel to get around 60bhp of extra power. However, unlike F1, its usage is much less restricted. Drivers can use it to attack or defend, on any part of the circuit they want to, and for as little or as long as they want to (up to a maximum of 15 or 20 seconds in one push, depending on the track). The only limitation is the number of seconds they’re allowed to use it in a race, which changes from circuit to circuit but is normally around the 200 mark.
Drivers also have to be wary of how much fuel they’re using because refuelling is a key strategy element in IndyCar. Drivers will usually have to make two or three stops for fuel during a race and, depending on the frequency and timing of a caution period, fuel-saving is a key weapon in the driver’s armoury. Because of the need to refuel and a limit on the number of people allowed to be involved in a stop, a normal pit stop in IndyCar can range anywhere from six to 10 seconds.
As in F1, IndyCar also recently introduced cockpit safety measures, although the American series decided against the halo and instead introduced the Red Bull-developed aeroscreen in 2020. This fighter jet-style screen, made from polycarbonate and titanium, is designed to deflect debris away from the driver’s head at speed. The design has been slightly tweaked since its introduction, with 2023 upgrades including adjustments to improve visibility in the wet and reduce misting inside the screen.
Although an IndyCar is around 40cm shorter than an F1 car and significantly lighter, the simpler aero means they’re much slower around a typical track. For comparison, at the Circuit of the Americas in Texas, the quickest IndyCar lap in 2019 (the last time the series visited) was a 1:46.018. In 2022, the F1 United States Grand Prix at the same track saw Carlos Sainz hit a pole position time of 1:34.356. F1 cars top speeds are limited by the circuits and draggy aero, meaning the highest speed you’ll see in a season these days is generally around 220mph with the assistance of slipstream and DRS, while an IndyCar in superspeedway setup will nudge 240mph in clean air, despite just having a smidge over half the horsepower.
Another key difference between the two is that F1 cars have power steering, whereas IndyCar’s don’t, making for a more physical driving experience – something that former F1 drivers making the switch to IndyCar have been quick to comment on.
Although they may look similar, IndyCars and F1 cars are very different beasts, designed with differing priorities in mind. IndyCar races on a wider range of tracks and the cars can change significantly depending on the circuit. F1 is much more standardised race-by-race, but the innovation and development of the cars create more diversity among the teams and, around a typical race track, makes them the fastest racing cars in the world. Both series produce phenomenal racing and at the end of the day, that’s what matters the most.