Automakers are finally figuring out how to make turbos work in mainstream vehicles. Here’s why they are making horsepower and other old guidelines obsolete.
Back in the old days of carburetors and distributor caps, horsepower became a benchmark for shoppers. Automakers advertised the peak horsepower their cars had, and for the most part, that correlated to a level of driving pleasure drivers understood. Those days have been gone a while, and new engine designs focusing on torque are changing the feel of cars and crossovers for the better.
One of the main problems with using “horsepower” as a guide when considering a new vehicle is that the number you read is misleading. The Max or peak horsepower an engine produces is almost meaningless in a mainstream vehicle. The reason is drivers almost never tap that power in normal or even spirited driving. Peak and max horsepower numbers are achieved when the engine is spinning its fastest, close to the engine’s redline. Yet, your automatic transmission is designed and programmed to do everything it can to keep your engine from getting near that redline. Most of the time while you are driving along, even under brisk acceleration, you are only using about 1/4 to 1/2 of the engine’s power capability. However, torque is another matter altogether.
Torque is defined as a twisting force that causes rotation. In terms of your normal driving, torque can be called that pleasant sensation you feel when you press the power pedal and the car accelerates. That is what you really enjoy and what you really want. A car with high torque low in its RPM band offers the most pleasant sensations. Cars equipped with turbochargers and cars with electric drivetrains offer exactly that.
The earliest successful application of turbochargers in mainstream, non-performance cars came on diesel engines. Diesel engines offer significant benefits, but brisk acceleration isn’t one of them, especially in the 1960s and 1970s. Diesel powered cars without a turbocharger were horrible to drive. The real magic in “diesels” was that they generated ample torque at low RPM ranges and it was mainly the turbocharging that enabled that.
Modern gasoline engines can now do this, and do it better. Diesels are going away because they are too dirty and too expensive for automakers to offer in everyday cars and crossovers. New modern turbocharged gas engines have taken their place. The curve above shows how GM’s new 2.7-liter turbocharged gas engine generates its maximum twisting force at just about idle, around 1,200 RPM. That means that when you start off from a stop all of the engines turning force is immediately available to you. We have marked the torque with red arrows above and the hp with blue arrows. Note that in the normal RPM ranges you use in your vehicle, from about 1,200 RPM to about 2,500 RPM, the engine is only using about 50 to 150 hp of its available 310 hp maximum. So why in world would we care about the max hp in a daily driver type of vehicle when shopping? We never use it. On the contrary, we can use the maximum torque at every stop sign and every time we accelerate.
All automakers are moving to turbocharged engines now for mainstream models. Leaders in the race include Volkswagen, Hyundai/Kia, and Honda. Honda is notable because it came from the opposite culture. Its cars’ engines were historically high power generators with very little low-end torque. Honda fans knew this and would rev their manual-transmission-equipped Hondas high into the RPM ranges to enjoy the power. However, times change and Honda wanted to appeal to a broader audience with its Civic, CR-V, and Accord, all of which now use turbocharged engines and primarily continuously variable transmissions. Honda’s engines are more enjoyable than ever and now they pull harder from a stop and work better with automatic transmissions.
In the not too distant past, turbos were tricky. Many automakers had trouble making a turbocharged car that had a linear feel. “Turbo lag” was a real problem. The cars would not have strong pull at low RPMs and would then surge with power as the turbo “spooled up.” All the major automakers have not only eliminated that problem, but they have actually done a 180-degree turn and turbocharged engines now feel stronger at low RPMs than non-turbo cars.
It wasn’t easy. Honda added dozens of new technologies to its turbocharged engines to offset the weaknesses of the past. Rather than offer you a textbook proving this, let us offer one simple sentence from Honda: “With direct injection, low-inertia Mono scroll turbo system with electrical waste-gate and dual Variable Valve Timing Control (VTC), the turbocharged Civic powerplant develops the horsepower and torque of a much larger engine, and is anticipated to help the Civic receive excellent EPA estimated fuel economy ratings.” The best part of this technobabble is that it’s true. We have tested all of the new Civics and they all feel great. And we at BestRide are Civic fans and owners from way, way back.
But can these new turbocharged engines be trusted? Consumer Reports (CR) offers some insight on this. CR did a study looking at the average number of problems with non-turbo engines and then they looked at cars with turbo engines from every automaker. According to owner reports of problems, and CR has literally hundreds of thousands of owner reports to mine data from, cars from Honda, Lexus, Porsche, BMW, Subaru, Audi, Mazda, Mercedes-Benz, and Infiniti with turbo engines have fewer problems than the average non-turbo engine does. For other automakers, it is a mixed bag with MINI being one of the only companies with more problems overall. But is MINI really a “mainstream” car company? Arguably not.
Electric vehicles epitomize the benefits of torque vs. high horsepower. All it takes is a short drive to get the vibe. These motors are ideal for around-town driving and also a blast on back roads. They pull much harder and much more linearly than do gas engines of the past.
The next time you shop for a new vehicle try to look past horsepower and drive the vehicle. See how it feels to you during the type of driving you plan to do most. We are willing to bet dollars to donuts you are going to love the way new boosted and electric drivetrains feel.