Poor old Porsche, eh. You go to the enormous expense of engineering a bespoke flat-four turbo engine for your new
718 Boxster
bloody four-pot
. Pure coincidence then it's chosen now to pull the covers off the previously mysterious V4 at the heart of the Le Mans winning 919 Hybrid to prove we have nothing to fear from the new four-cylinder Boxster and Cayman.
Let's overlook the fact that this 'trend-setting' 2.0-litre V4 turbo has, um, nothing to do with the 2.0-litre flat-four turbo in the 718, and celebrate the fact that we're actually getting to see it. Until now, Porsche kept the 919's engine bay tightly under wraps perhaps wary of promoting 'game changing' technology until it had proven itself and earned some silverware.
Porsche makes no bones about it: this is the most efficient internal combustion it's ever built, full stop. Size matters too, its compactness a major attraction over the V8 in its Toyota rival or V6 in the Audi. You'd have thought it might have chosen a regular in-line four but chose instead to build a 90-degree V4, sticking the turbo in the middle and enjoying the additional load-bearing stiffness of this layout.
Porsche doesn't say how it balanced this. Conventional wisdom states, once you add in firing forces, the 180-degree gap between four cylinder engines is best - i.e. the boxer in the 718. Porsche seemingly discovered this during testing in 2013 when vibrations from the engine caused the suspension to shake itself apart. Enter a redesigned crank to realise the benefits Honda's racing motorcycles have long since enjoyed; compactness, narrowness, fine primary balance.
You'll note in the beautifully detailed images Porsche's released that there's something missing. Er, the turbo. And the hybrid gear. And the clever second turbine in the exhaust gas stream connected to an electric motor rather than to a compressor, permanently recovering energy to store in lithium ion battery packs. This stuff is clearly still secret-squirrel and not ready for public consumption. Best not give away the crown megajoules.
Particularly as, unlike in 2014, system improvements saw Porsche recovering so much energy so efficiently, it was last year able to run in the 8MJ category. It meant a smaller fuel allocation but ability to deploy more recovered energy per lap. The 1,000hp Porsche racer was back.
In 2015, the engine alone produced 500hp, which is a hefty output per cylinder, never mind per litre. It won't be outputting this in 2016 though, as WEC regulations have been revised. Less energy from the fuel itself per lap is allowed, so the fuel flow has been reduced accordingly. By eight per cent, say the regs. Porsche's not saying how much power it now has, only that it "translates into a figure of less than 500hp". No, we don't expect the correlation to be linear, either.
Besides, with a total system output of around 900hp, the 919 Hybrid's still going to be quick. It was quite happy to step up from 6MJ to 8MJ last year; you can bet the additional system improvements it's found for 2016 won't exactly leave it short on power. Makes you wonder why the 718 Boxster S is so relatively inefficient compared to the standard car, really. 300hp from 2.0-litres is better than 350hp from 2.5-litres, after all...
Despite this curio, the 718 Boxster four is literally dripping in the trend-setting technology shared in Weissach canteens with the 919 Hybrid four, insists Porsche. You only have to look at ... well, the space between the cylinders. Er, the short stroke. Direct injection mounted centrally - yes, that too. Yup, virtual bedfellows - indeed race and road engineers worked day and night together on such fundamental, integral areas as ... combustion and fuel mixture. Two peas in a pod, no?
Perhaps it's a question we'll have to ask next week, when we go for a 718 Boxster tech deep-dive with the great and the good of Porsche's powertrain department. In the meantime, here are the 919 Hybrid V4 racer engines in all their glory.
![](data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 4 3"%3E%3C/svg%3E)
![](data:image/svg+xml,%3Csvg xmlns="https://www.w3.org/2000/svg" viewBox="0 0 1 1"%3E%3C/svg%3E)