When you see and hear the phenomenal speeds and volumes at which NASCAR vehicles fly around the circuit, it would be hard not to assume that the powertrains must be augmented with all kinds of amazing turbocharging gear. How else would they achieve all of that horsepower?
NASCAR regulations, unlike IndyCar, Rally and F1, do not allow for turbocharged engines. NASCAR stock cars can produce up to 900 Horsepower without turbochargers, and the speeds they are capable of are approaching the safety limits of the tracks. There is not a requirement for more power, but potentially less.
It is in some ways surprising to know that that your typical NASCAR vehicle, while being very heavy on the horsepower — often up to 750-hp — achieves its amazing power and speed without the use of turbochargers, superchargers or any other kinds of special turbo-delivering equipment.
A turbocharger, sometimes just called a turbo, is a special device that can be fitted to a car’s engine to boost overall performance. It comprises 2 main housings joined together by a central shaft. It takes in exhaust gas to spin a turbine that in turn connects to a second turbine sucking in air and compressing it to the engine. That’s where the extra power is coming from, with more air flowing rapidly into the combustion chamber.
When compared to its sibling component, the supercharger, the main advantage of the turbocharger is not needing the vehicle’s engine to power or drive it. It’s also unaffected by altitude, unlike naturally aspirated engines which don’t do well at higher elevation where oxygen is thinner.
So if these devices are so great and bring so many advantages to cars, why don’t NASCAR use them? We’ll get more into pros and cons further below, but first of all what are the reasons NASCAR shuns these?
The first and primary reason for not making use of turbochargers is that the cars simply don’t need them. The NASCAR stock engine specification is more than capable of generating all the horsepower and speed that the drivers need, sometimes more than they can handle!
Read on a little further below to see in more detail how NASCARs generate all that power.
Let’s also not forget that for many years in the world of NASCAR already we have seen the use of restrictor plates. In other words, NASCAR is trying, if anything, to get the cars in their races to slow down a bit. With that in mind, it wouldn’t make a lot of sense for them to start advocating or encouraging the installation of turbochargers.
If you look at some of the historic records, too, you notice curious things like racers back in 2004 completing the Talladega circuit in record times at 228-mph, but supposedly more restricted cars in 2019 finishing the Michigan Speedway up to 13-mph faster in qualifying than previously seen in 2004.
What it shows is that there’s really no future in modifying NASCAR vehicles for additional horsepower. It’s safe to say at least for now that they are at their speed apex.
- First and foremost, they have big, and we mean huge engines. That’s a good starting point. The typical NASCAR has an engine displacement of 358 cubic inches, or 5.87L. Any engine that big is easily capable of generating 300+ horsepower.
- They also have a much more radical cam profile compared to regular street cars. The intake valves open far earlier and stay open, unlike street cars. With air packing into the cylinders at that rate, it’s like having a turbo built in anyway.
- Furthermore, the NASCAR engine has a finely tuned intake and exhaust system that will deliver strategic boosts at just the right speeds. The high-performance tuning is easy when you also factor in the lack of any muffler or catalytic converter.
- Finally, the specially designed racing carburetors and programmable ignition systems ensure the engine always has enough air and fuel flow, as well as impeccable spark timing to deliver all possible power.
In sum, the typical NASCAR vehicle is one that is built for the conditions in which racers use them. Every single component is tougher, made to endure harsher, hotter and more extreme conditions, and made to deliver every scrap of power that it can without relying on further aftermarket devices.
Not all motorsports share the apparent indifference to turbochargers that NASCAR vehicles do, it would seem. Formula 1, international rally, and IndyCar vehicles all contain turbochargers.
Since 2014, the standard F1 engine has been the 1.6L V6 unit, and it is turbocharged. Formula 1 decided to lift a long-standing ban on turbochargers that had been in place since 1989. The idea wasn’t instituted just in the interests of power or racing dynamics, but also in efficiency.
Turbocharging is a good way to improve fuel efficiency, and it’s working well on F1 cars that now have an average improvement of 29 percent compared to previous models.
Rally cars have been using turbochargers for a fairly long time, at least 2 decades in fact. A World Rally Championship car turbo has turbines that spin at up to 150,000-rpm.
Rally cars benefit from being turbocharged because some courses — e.g. Rally Mexico — are demanding in their high-altitude conditions. The turbocharger ensures that there’s always enough air flowing through the engine to allow the car to keep on flying.
IndyCar has used turbocharging even longer than Formula 1, but not as long as the rallying world. From 2012 to 2020, the IndyCar series had been making use of the 2.2L turbocharged V6 engine formula. The turbo specification was augmented to a twin-turbo setup in 2014.
The 2021 year welcomed a new specification to the mix, namely the 2.4L twin-turbocharged V6 engine which is planned to be in use through the 2026 year.
After extensive testing in 2020, the engine was put into use and was projected to offer at least 100 additional horsepower compared with the previous long-standing 2.2L option.
We are unlikely to see a change in the NASCAR regulations surrounding turbo or supercharging in the near future. Although we could have said the same about hybrid or electric engines as well and at least in the case of hybrids they make be something in the pipeline.
Although these are stock cars, and most modern cars are able or already have turbos as options, NASCAR is a Unique racing sport that while keeping an eye on the future also places great importance in its heritage and roots in the past.
If it it ain’t broke don’t fix it!