Know It All with Jason Cammisa

EVs are the quickest cars on the road, and it's not just in drag races. They're especially fast in the real world, and it's because of how they respond. It's not actually the instant torque of the motors that provides the advantage, it's the lack of multiple gears in their transmissions and the shape of an electric motor's power curve. Automotive journalist Jason Cammisa explains the science behind why even non-performance EVs can beat the quickest cars through traffic.

Sound is an important part of the internal-combustion-engine experience, and many engine configurations have their own distinctive sound. There are many reasons why, but one of the most important factors in an engine's sound is how evenly the exhaust pulses reach the tailpipes. Evenly spaced exhaust pulses tend to result in higher-pitched, smoother sound. Unevenly spaced pulses in deeper, more complex, and angrier noise. In this episode, nerdy automotive journalist Jason Cammisa gives an oversimplified overview of the science behind this, explaining how the regularity can be determined by the crankshaft or the exhaust — and giving examples of each. He covers 4-cylinders (the Honda S2000's equal-length headers compared to the Subaru WRX STI's burble), V6 engines (the Nissan VQ versus Ford EcoBoost), V8 (the Ferrari flat-plane crank V-8 versus an American cross-plane V8), V10 engines (the Lamborghini Gallardo even-fire V10 versus the LP560's odd-fire, which sounds like two 5-cylinder

We all love to go bench-racing, but using car magazine 0-to-60 tests won't tell you what happens in the real world. The zero-to-60 test isn't actually measuring from a stop, at least not by U.S.-based car magazines. They use a term called "rollout," which comes from the drag-racing world. Basically, when car magazines record testing numbers, they omit the first foot of travel (or "rollout"), resulting in a time that's more than 0.2 seconds too short. Sometimes as much as a half-second. Additionally, the techniques that car magazines use to launch cars is brutal, abusive, and sometimes even fatal to the car. All is fair in love, war, and instrumented testing: nobody seems to mind if we blow up a car during testing, so long as we got great numbers in the process. The bigger issue is that 0-60 is such an important yardstick that it feeds back into the engineering of cars. Manufacturers sometimes make decisions to improve instrumented-testing numbers that come at the expense of real-w

All AWD systems will help with additional traction, but the layouts have dramatic effects on handling. Most AWD systems induce understeer, but some can actually help a car handle even better. Marketing departments often fib about the capabilities of their company's AWD system. In most cases, no, your car can't send all of its power to just one axle — unless the other axle is in the air. Manufacturers often leave that little detail out. To understand what your car's AWD system can and can't do, you need to understand its base layout - if it's a FWD-based car, like a VW Golf R, that happens to have AWD, it can never decouple its front wheels — only add power to the back. It can send 100% of its power to the front wheels, but never more than half to the rears. If it's a RWD car like a BMW 3-Series, it can never decouple the rear wheels, only send some power to the fronts. It can send 100% to the rear, just not to the front. Then, there are fixed-AWD systems like Subaru's "Symmetrical"

Ever wondered why your engine sounds the best first thing after a cold start? It's angry, it's aggressive... and then it just calms down into a regular idle? This is the Cold Start Cycle, and it's your engine management doing everything it can to waste fuel so that it can warm up more quickly. Cold-start emissions are a major challenge for automakers, so they program engines to run as inefficiently as possible so that they can light off the catalytic converters more quickly. This is because cats don't operate properly until they've reached operating temperature. Wasting fuel by changing ignition and valve timing and injecting a rich mixture sends unburned fuel and extra heat down the exhaust, which can then be burned by the catalytic converter, heating it up more quickly. The result is an angry, awesome-sounding idle — that sadly lasts only a few seconds.

Many cars come with two different horsepower ratings, and that's because there are two measures of horsepower: Imperial Horsepower (hp or bhp) and Metric Horsepower (PS, CV, PK, etc.) Power is a measure of how quickly work can be done, and horsepower is no different. Imperial (US/SAE) horsepower is defined as 550 ft-lbf/s, where Metric (European/DIN) horsepower is defined as 75 kgf-m/s. They're similar, but it turns out European horses are only 0.986 times as strong as American ones. Of course, horsepower is an outdated unit, replaced by watts. 1 hp = 745.7 watts; 1 PS = 735.5 watt - and of course all electric motors are already rated in thousands of watts, or kW. But that's far less sexy, isn't it? Watts may move a car, but horsepower sells it.

By-wire throttle seems like a silly idea, replacing a simple cable with a potentiometer and an electric motor to accomplish the same thing. But there are many benefits, some of which are explored here. We have many names for the right pedal — gas, throttle, accelerator — but none of those are accurate. Today's cars use them as "throttle request pedals," since they're connected to nothing but a computer. Then, it's up to the computer to decide how to make the torque you've requested at the drive wheels, with a combination of dozens of variables including, finally, throttle opening. Giving a computer full control over everything actually simplifies functions like cruise control, idle speed control, and traction control. But it also helps your car get better fuel economy, and cruise more quietly. Oh, and it can help avoid a crash.

The actual definition of the term "homologation" isn't how car enthusiasts use the term. We use 'homologation' as shorthand for a "homologation car" or "homologation special" — which is a car that was produced solely to comply with regulations in order to go racing. Many of the coolest cars of all time are homologation specials — and no surprise. They're exactly the type of car that enthusiasts love, and rarely make financial sense to produce. But in order go racing, a manufacturer has to produce them, and that benefits us all. And whatever you do, don't ask Merriam Webster what she thinks.

Adding extra weight to your car will slow acceleration, but won't reduce its top speed. In determining a car's top speed, its engine battles two main forces: rolling resistance and aerodynamic drag. At very high speeds, air resistance makes up the vast majority of the overall drag on your car. So much so that an increase in rolling resistance from extra weight is likely negligible. Adding weight may increase your car's rolling resistance, but it's also usually offset by a decrease in wind resistance because the weight compresses the suspension, which in turn decreases the car's frontal area and, typically, its drag coefficient too. So in some cases, your car may be even faster when fully loaded — at least on level ground. The extra weight will increase top speed going downhill, but decrease it going uphill. But be careful of things that seem like they'd be related. Like, don't believe someone when they say the only sure way to make it rain is to wash your car. Because no matter ho

Wonder why you can't get a diesel-powered, manual-transmission wagon? Or a Hellcat-powered minivan? Or even the Golf GTI's plaid cloth seats in the mechanically identical VW Jetta GLI? It's all because the cost of homologation is so high relative to the number of people who'd buy it that it doesn't make financial sense. It's uncool, but that's why we can't have nice things. It costs an obscene amount of money to get a car certified for sale in the U.S. — and if there isn't a huge market for a car, that means the per-car certification process can be prohibitively expensive. The Lotus Elise is a perfect example. Roughly 20 percent of the Elise's original MSRP covered the $50 million it cost to engineer and prepare the mid-engined sports car for sale in America. And the Elise, by the way, received side-impact and smart-airbag exemptions from the U.S. government. And it still cost $50 million to certify. Ouch.

These days, automatic-equipped cars can accelerate more quickly than their manual-transmission counterparts. One of the reasons is that many automatics can shift quickly and with little or no interruption in power. But that was always the case. Something else has changed — and that "something" is gearing. It's the same reason why the 992-chassis Porsche 911 GT3 Touring didn't initially pass drive-by noise regulations with the PDK automatic versus the manual — when both cars used the same engine and exhaust. In fact, the majority of the discrepancy between the transmissions' acceleration isn't due the shift-times, it's due to gearing. Watch and learn why.

Drag coefficient describes a car's shape — not its size. Think of it as a coupon code that reduces or increases a car's effective frontal area, the measure of how big the air sees it. A low Cd can make a huge difference in a vehicle's overall aerodynamic drag. A Tesla Model X has 1.6 times the frontal area of a Lotus Elise SC, and yet its overall drag is lower. Meaning: to the air, the tiny Lotus is actually the bigger car. Watch for more colorful, humorous insights on the definition of coefficient of drag.