Friday, June 12, 2015

The Decline of Naturally Aspirated

For several years now, the writing has been getting clearer on the wall. NA engines are becoming niche, and there's little evidence that automakers are running off to design new NA engines from scratch apart from a few modifications year on year.

A casual look at this year's 2015 Ward's 10 Best engines shows that 8 out of the 10 winners are forced induction and 6 are specifically turbocharged engines. (Incidentally, my favorite "sports" car is on this list with its fine 6.2L supercharged V-8... actually this makes it twice in a row as it had won in 2014 as well).

An article in June's Engine Technology International puts some figures to the case for turbos. Apparently, even the worst turbocharged engine will get you an honest mean effective pressure of 15 bar. Put into other words, these low end turbocharged engines already put out a specific power of 100 kW/liter, which is roundabout the same figure the best NA engines muster today.

There's really no competition, or is there ? What can possibly compete?

Electric superchargers are independent of parasitic losses but lose a ton of power in energy conversion. Further, they are only transient devices. Commercial entries to "electric boosters" have been labeled a scam. They don't work.

PHEVs offer promise, since they supply instant torque on startup and eliminate the need for turbo assisted low speed torque. Hybrids also cut back on range anxiety since you can technically always fall back on an IC engine. However, battery costs are looking prohibitive for most people right now. In countries like the U.A.E where I live, the electric infrastructure is only starting to pop up, and in minuscule amounts.

At some point in the next few years, I'll buy a new car and it won't be special to tell others it's turbocharged.  I'll most likely get disgusted looks if I say it's NA.

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Ward's 10 best engines of 2015 (link) :

127-kW Electric Motor (BMW i3 electric vehicle)
6.2L OHV V-8 (Chevrolet Corvette Stingray)
6.2L Supercharged OHV V-8 (Dodge Challenger SRT Hellcat)
1.0L Turbocharged DOHC 3-cyl. (Ford Fiesta)
100-kW Fuel Cell (Hyundai Tucson FCV)
1.5L Turbocharged DOHC 3-cyl. (Mini Cooper)
3.0L Turbodiesel DOHC V-6 (Ram 1500 EcoDiesel)
2.0L Turbocharged DOHC H-4 (Subaru WRX)
1.8L Turbocharged DOHC 4-cyl. (Volkswagen Golf)
2.0L Turbocharged  DOHC 4-cyl. (Volvo S60)


Sean Yeager said...

Sadly, I think we're entering an age where, while buying one won't be a problem, even the cheapest of vehicles will be out of reach for many consumers when it comes to repairs and maintenance. The ECUs that control them and the diagnosis process has gotten terribly complicated (currently fighting a variable timing issue in an '07 BMW). Turbos add a level of complexity, and a serious expense when one goes bad. Hopefully the new turbos are as reliable as the engines!

Ron said...

Thanks Sean, I quite agree with you that cars get more complicated but with the way things are going now it's inevitable. On the bright side, we'll need more qualified technicians to service our cars, and the level of their education will inevitably go up. It creates opportunities, and maybe it won't sound that bad to tell someone you're a car mechanic!