eli5: why is the NASCAR Camaro so good at Le Mans compared to LMGTE?
In: 285
This weekend I heard the NASCAR in question being described aerodynamically as “A clenched fist with wheels”
They have a barn door of a rear wing and a ton of drag, but they make up for it with a stupid amount of horsepower and torque.
The car runs a typical Chevy NASCAR engine, a 5.86L V8.
They were joking prior to the race that this is the only race where they get to remove the restricter plates on the engine so it can generate its maximum power. Upwards of 750HP which is possibly upwards of 150 more than the GTE cars depending on who you are talking about.
The Garage 56 NASCAR is also around 400 lb lighter than a typical stock NASCAR, achieved mostly by removing extra safety parts and structure not needed unless you’re bump drafting or on an oval. This is just an educated guess, but since a typical NASCAR weight around 3,300 pounds, removing 400lb would put it on par with the minimum weight of the GTE class (maybe upwards of 150lb heavier which is not nothing in racing but pretty close considering) .
Jenson Button was describing how everyone thought they would be a bullet on the straights and awful in the corners, but the opposite was true. The GTE cars were faster than them in the straights, but the NASCAR could break hard because of the mechanical grip and downforce (and the special carbon ceramic breaks they were using) and accelerate fast because of all the torque.
But mostly it’s because it’s purpose made race car, not a modified GT car.
NASCAR has the benefit of all the teams working on similar cars for decades and they know all the tricks to make them go fast.
It ran without any rules, against no-one, and blew its transmission after 20 hours.
It also had an unrestricted budget on par with a Team LMP1 entry, not a GTE car.
Next question.
That’s right, folks. The NASCAR Camaro is like a clenched fist with wheels…and a really, really big engine.
Fundamentally, it is because all modern sportscar racing classes are tightly regulated, and the regulations allowed the NASCAR Camaro to be faster. But let’s break this down a bit.
First, we’re talking about sportscar racing. Sportscar racing are series like FIA WEC, IMSA WTSCC, SRO GT World Challenge, etc. These series race a type of race car called sportscars. This type of race car covers a broad range from GT cars that look like road cars all the way up to dedicated racing prototypes that look like spaceships with wheels. Sportscars are distinguished from open wheel race cars like they race in F1, IndyCar, and the various “Formula” feeder series.
In the early days of motorsports, regulations were very light. Teams & manufacturers had the ability to “run what you brung” on race day. As technology & engineering advanced, speeds climbed and incidents became more serious. In 1955, there was a crash at Le Mans that changed motorsports forever. From that point, sanctioning bodies began adopting regulations that focused on safety, which often resulted in restricting just how fast/powerful the race cars could be.
All of the top sportscar racing series in the modern era use a regulatory framework that restricts cars in a way that they are all relatively competitive. The two key elements are:
* **Performance envelope.** This is, essentially, a mathematical representation of a car’s ability to accelerate, brake, and turn. The performance envelope is calculated from things like engine power, aerodynamic performance, braking capacity, and tire grip. During the design of a race car, computer modeling is used to ensure that the cars stay within the performance envelope. If a car doesn’t fit within the performance envelope, the sanctioning body won’t allow them to race.
* **Balance of performance.** Once the cars are built, they are tested on track and the sanctioning body makes adjustments to ensure the cars remain competitive.
So in the case of the NASCAR Camaro, it finished 39th overall. So it’s kind of difficult to characterize it as “so good”, but I have a feeling you might be reacting to some of the footage of it blasting by traffic. That can be explained by the fact that the car has a lot of horsepower (for strong acceleration) and a lot of aero (for downforce), which made it perform very well on some sections of the circuit, but not as well on others. For example, they were getting passed on Mulsanne pretty easily.
Jenson Button and Jimmy Johnson (the drivers) themselves, said, “we are comparing ourselves against GTE AM class”. That said, it means they did not finish all that well, but through “most” of the race, they hovered around 10th-ish, in comparison to GTE AM.
Back when they had IROC races between the superstars of several racing “leagues” if you will they interviewed several drivers. One question asked was how they liked driving the IROC Camaros. The NASCAR drivers agreed, if they could use the IROCs against the sedans on any track they could win every race. They also agreed it was all aerodynamics.
It’s setup for cornering, it’s not a run of the mill NASCAR with the proper safety equipment just thrown on a circuit. Suspension setup isn’t a secret recipe either. Squeezing a few hundredths of a second out of a lap type of fine tuning is wizardry, but general alignment, shock valving, weight balance & other metrics are known by shops/teams & initial setup isn’t difficult.
GTE have well known (10+ years) rules to make all the different cars as similar and fair as possible. The Garage 56 car has had a set of rules to get the Nascar to suit the lemans track, but not to make it similar/fair to the GTE cars.
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It is also interesting to note that they beat all the GTE cars and ranked 5th overall across all classes. They used a manual floor jack instead of the air jacks that all other cars used. Their pit stop crew was recruited from Nascar teams. They changed 4 tires in a little over 10 seconds. Here’s a link to the challenge video:
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