NASCAR Tech: It's A Lot More Than You Think

I’ve heard a lot of derisive comments about NASCAR lately on this site, many of them from people — my fellow racers and fast-road drivers — who should know better. While it’s true that the common template is a disgrace, the idea that NASCAR is a low-tech ghetto compared to the oh-so-modern sports-car series like the ALMS is, to put it mildly, false. There’s a reason that the abortive USF1 team wanted to locate near the NASCAR guys. It’s where the tech is. Click the jump to find out why racing NASCAR takes more brainpower than any Touring Car or prototype series out there…

Let’s start with engines. NASCAR just runs old small-block Chevys with carbs, right? Not so simple. Let’s compare F1 engines to NASCAR engines using Brake Mean Effective Pressure (BMEP) and Mean Piston Speed (MPS). These are measurements of how hard and fast an engine runs. Surely the F1 engine runs at pressures and piston speeds that are FAR beyond those of NASCAR, right?

According to Race Engine Technology, The BMEP of the Formula One engine at peak torque (table line 13) is 15.17 bar while the Cup engine produces a peak torque BMEP of 15.12 bar (0.3 % less). At peak power, the Formula One BMEP value (table line 22) is 14.6 bar while the Cup figure is 14.0 bar (4.1% less). As far as piston speed,

Even more revealing, at peak power RPM (table line 19) the Formula One engine MPS is 25.5 m/s (5025 ft/min), while that of the Cup engine is less than 3% lower at 24.8 m/s (4875 ft/min). At redline, the Formula One MPS is 26.5 m/sec, while the Cup MPS is a stunning 27.5 m/sec. To put those numbers in perspective, Professor Gordon Blair wrote (Race Engine Technology, issue 27) that 26.5 m/sec was the highest he had seen.

How’d those stupid hicks get their pistons to move faster than the mighty engine builders of Formula One? Note that some street cars reach into the same piston-speed zone, but they are incapable of operating under those BMEPs for very long. F1 engines run with much greater friction to create those piston speeds because their crankshafts run faster… but NASCAR engines have a much longer stroke, thus imposing a much greater acceleration load on the parts.

Now let’s talk aero. With millions of dollars at stake, aerodynamic improvements are critical. ALMS designers can draw almost anything they want, because the rules are loose. F1 presents a much stronger challenge, which is why Nick Wirth’s CFD approach was so dominating with the LC75-based Acura ARX but has struggled to keep Virgin Racing from the bottom of the field. The limits to what you can “draw” in F1 are considerable, and any bright ideas don’t last too long, as was shown with the F-duct and flexible front wing that arrived this year and were promptly written out of next year’s rulebook.

NASCAR teams have an even tougher job. They are limited to a common template, so they can’t change the aero at all. Right? If that’s the case, then why is the Holy Grail of aerodynamic testing — the “coastdown tunnel” — rumored to exist right now, in the hands of Chip Ganassi? The answer is that NASCAR teams work at a level of aerodynamics unknown outside the world of military aviation: surface composition aero. A NASCAR Car of Tomorrow is a matrix of multiple surfaces, some smooth, some rough, all designed to manage the airflow at the near-molecular level. Jimmie Johnson’s remarkable pace last year? All the product of rough-surface aero development.

We could go on and talk about the massive effort put into the “little things” of racing — from the kind of brake compounds required to slow a NASCAR-sized sedan from 195+mph to the astoundingly complex calculations of shock absorber valving required to keep a car that big from becoming murderously loose on a bumpy superspeedway — but I hope I’ve encouraged at least some of you to go take a look at what actually happens in NASCAR. It may not be Formula One, but it’s not ALMS P2 either.