About this time two years ago, one of our readers posted an analysis of engine design comparing the Japanese and German Luxury/Premium makers to see who really had the technical expertise and finesse to extract the maximum power out of their designs.
Horsepower per liter is the commonly accept formula for gaging the overall efficiency and performance of a motor regardless of displacement. While any manufacture can insert a large power plant into a vehicle and make it go faster, it takes a much higher degree of technological expertise to extract every last horsepower and ft/lb of torque out of any given design. These technological achievements are typically evident across the entire line up, and are not limited to just one or two designs. One can also say these figures may be an indicator of how mature the development of the product lineup is when compared to their peers.
With all of the banter of who is the best, and who really possesses the leading edge. A list was compiled and an analysis of the European Premium Brands and the Big Three Japanese Luxury Brands to see how the figures actually pan out.
The results were surprising to me to say the least. I took all of the current engine specifications for each, and inputted these into a matrix and extrapolated the average horsepower and torque figures per liter for each manufacturer. I included all forms of engines in the overall mix: Turbocharged, Supercharged, and Performance Hybrids and even Diesels, as they are all considered valid technologies.
These results are taken directly from the specification database from Automotive News and the results are computed by the engine capacity and horse power rating listed in the database. The sole exception was the Lexus hybrids power ratings were taken from the web site, since the Automotive News database did not account for the additional electric power capacity.
The calculations were preformed by taking an example of each motor from the database and then adding it to the matrix. If a maker had the same engine but in various tuning states, the average power for the given motor was used rather than have multiple entries for the same motor added needlessly.
Examples:
Acura has two engines a 3.2 liter @ 258 hp and a 3.5 liter @290 hp. The total displacement across the line up averages 3.4 liters and the average horsepower per liter is 81.79 hp per liter.
Infiniti however has two variations of the 3.5 liter (275hp and 306hp) these are averaged together and yield an average of 291hp for the 3.5 liter and that figure is added to the matrix for that particular motor.
And the ranking are:
Power per Liter (hp)
1st 83.86 Mercedes
2nd 83.25 Audi
3rd 82.64 Jaguar
4th 81.79 Acura
5th 80.64 BMW
6th 80.04 Volvo
7th 78.27 Lexus
8th 76.94 Infiniti
Torque per Liter (ft/lb)
1st 88.89 Mercedes
2nd 83.24 Jaguar
3rd 82.35 Volvo
4th 77.05 Audi
5th 76.38 Lexus
6th 75.50 Infiniti
7th 73.20 BMW
8th 72.99 Acura
Average Engine Displacement across the lineup (liters)
1st 4.3 BMW
2nd 4.2 MB
3rd 4.1 Audi
4th 4.0 Infiniti
5th 3.7 Lexus
6th 3.6 Jaguar
7th 3.4 Acura
8th 3.1 Volvo
As you can clearly see those with less effective designs tend to trail in the matrix. But one interesting note is that while BMW has the largest average displacement across the lineup, the designs typically don’t translate into leading examples of horsepower efficiency.
So who really has the edge, the Europeans or the Japanese?
* memo *
The figures are for passenger cars only, no SUV or truck power trains were considered.