hornet

As usual, the Europeans (aka BBC News/Top Gear) don't dumb-down their articles for their readers. A very nice change compared to the mostly drivel we are used to here in the States.



Naturally aspirated vs forced induction - BBC Top Gear

Tibbi

That's mostly related to economy an daily drivers less performance.

The reality is when it comes to raw, unhindered performance NA will be better. But good luck finding a 37 liter motor that will fit into any project car. Turbos and SCs are a simple answer to gaining output from increasingly smaller engines. And as the article pointed out, most daily yawn-machines will see an economical befit to turbo lag. Less air in the motor means less gas, less gas means less cost. It's simple economics really. And with autos becoming increasingly more common globally and growing in gear quantity, cars are operating at decreasing rpms. Meaning, there will be many scenarios where the average drive will never even engage the turbo until truly necessary. Very similar to Toyota's old clutch supercharger from the 4AGZE days, but simpler and cheaper to manufacture. Also, as the article points out, lighter. There's no question that cars today have become bloated and heavy with all kinds of technology. But reducing weight is key to improving economy, an up-shift that is slowly being adopted by manufacturers. Hell, look at Formula 1! Even in the top tier of motorsports has accepted the turbo as a way to improve efficiency. Today modern F1 cars run with 100kg of fuel for a full race duration (volume differs by temperate so today it's weighed to prevent team trickery). The interesting bit to consider with that application though, and something that may come to higher end vehicles in a number of years, is the use of hybrid motors to keep the turbo spooled to around 100k rpms even when exhaust pressure is low. in effect this creates a "best of both worlds" scenario since the turbo now acts like a supercharger at low revs, but still has an extra 50k to play with at higher speeds. I've long dreamed about creating something like this, but it hasn't been until recent that the technology has caught up making that a possibility.







Now if we're talking strictly performance, of course NA is preferred. Who doesn't want raw, instantaneous power? Like I said before, build a 37 liter, high revving cammed, ITB, high compression engine... and then find some place to shoe-horn it. Now good luck driving that without going deaf. Boost is the next best solution, and in reality is pretty much the Holy Grail when it comes to performance mods. Because, lets be realistic here, even that 37 liter monster could make infinitely more power with a good blower. The sacrifices, in the case of turbos lag and supers power leaching, are quickly becoming arguably negligible.

wheel_of_steel

Will 27 litres do?



The ticket for any vehicle is power density. High performance when it's needed, but low pumping/frictional/heat losses when it's not. See, the ford 1.0 ecoboost engine. That's also why hybrids are so fantastic, because you can shut down the petrol motor for long periods. That's also why 'pulse and glide' is a viable technique for hypermiling.