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Infiniti Q50S Hybrid

Daniel Wong September 10, 2015 17:46

Its makers tout it as being one of the quickest hybrids around, but its hybrid performance isn’t the only bit that astounds us about the Q50S. 

For an industry that was built on technical innovation it seems that we are deeply entrenched and highly defensive of traditional values. Old technology such as manual transmissions and hydraulic powered steering systems should have gone the way of the Dodo long ago. But enthusiasts are a very traditional lot. We do quite enjoy the raw, mechanical feel in driving even though to the casual observer, those traits come across as being uncomfortable and rather unnecessary.

Enter Infiniti’s new Q50 sedan, which should come across as pure heresy then, as it is the world’s first production car to come with “Steer-by-Wire” technology, a car that does away with that last bastion of mechanical connection between driver and car, the steering wheel.

Instead of a direct mechanical linkage connecting the steering wheel to the steering column, the steering in the Q50 communicates with the front wheels via data streams going through an ECU, instead of the traditional method of a having a physical shaft. There is a conventional steering mechanism built into the Q50, but for the most time it is decoupled from the steering wheel and only activated should there be a malfunction with the ECU. Even when that happens the Q50 packs two additional ECUs as a backup. Why all the needless complication for a system that has been working fine for the better part of the last century you might ask? According to Infiniti, by having no mechanical linkage, you won’t get the steering wheel jinking about as the wheels tramline, nor would you have to feel or input any steering corrections in the event of a crosswind as the wheels would be able to self correct themselves thanks to the information fed from the steering wheel motors.

The system, known as Direct Adaptive Steer (DAS) gets a little spookier when you count in the array of camera systems and sensors that can recognise if you are wandering from your lane or might be on a collision course with a car in your blind spot. The information of your surroundings are constantly being fed into the steering ECU and carries out complicated algorithms to determine if you are really oblivious to the things around you and promptly realigns your steering to avoid any danger without any input from the driver or any change in steering angle. However far from feeling like a giant Sony Playstation controller for Gran Turismo, the steering on the Q50 is surprisingly weighty and very quick in its response. You are given a huge amount of freedom to tailor the steering weight and response to your liking, though I never really saw the need to go for anything less than the heaviest and sharpest response.


Set with those settings, the Q50 has a rather lovely weighty and razor sharp response, any little nudge in the steering angle and the motors in the wheels would immediately response with the appropriate amount of direction change. However there are times when the steering does feel slightly artificial, which is weird to say for something that is already artificial in itself. Not in the sense of feeling over assisted, but moments where I caught the front wheels doing some minor adjustments without any steering inputs. I suppose it was the DAS’ self-correcting functions that Infiniti can only achieve with the steer-by-wire system. But then again it isn’t so much a flaw of the DAS but rather me being too use of having complete steering control and relying on my instincts to read what the movements of the car. Instead the DAS is meant to take away the stresses of dealing with unforeseen situations on the road, but that is only if you would trust the system entirely, and being a traditionalist, I find it hard to trust the ghost in the machine.

The powertrain on the other hand is something that is very familiar and traditional. This being the range-topping Q50S Hybrid, it comes with the powertrain of the M35h (now renamed the Q70 Hybrid), with the exception of a number of mechanical improvement done to the gearbox in order to improve its hybrid nature and potential. The clutch which connects the gearbox-mounted electric motor to the engine now boasts a better response time, whereas modifications to the hydraulic actuators delivers a more seamless power transition, and improvements in the motor has improved the car’s all-electric range. With a light throttle, and probably a downhill start, you can get up to 100kmph on electric power alone. Put together the hybrid system works remarkably well, with barely a shudder to be felt or heard when the massive 3.5-litre V6 engine comes into play. But then again we are talking about one the smoothest engines in the business, and when hard pressed, it delivers a linear powerband overlaid with the growl of a big-displacement V6.

With a power output of 298PS at 6800rpm and 338Nm at 5000rpm, topped with the assistance of a 50kW electric motor delivering 270Nm of torque, the Q50S Hybrid isn’t lacking in power, with 100kmph achievable in 5.1 seconds. Put together the hybrid system delivers 364PS and 546Nm of torque. The surge from the electric motors is satisfying and the urge from the V6 is unending, right up its 7000rpm redline. Unleash the power quickly and it could easily overwhelm its specially developed performance Dunlops tyres. But unlike the fully digital steering the chassis feels rather communicative and predictable. The stability control comes with an additional feature known as Active Trace Control, which applies braking force to individual wheels to improve grip in the corners.

With such power on tap and such mass to keep in check, the Q50S Hybrid is specified with huge 355mm four-piston front disc brakes and 350mm two-piston rears. However, this being a hybrid, while the big brakes delivers big stopping power, its regenerative system still suffers from the familiar trait of being tricky to modulate, particularly in low speed traffic where its engagement is rather jerky.

The Q50S Hybrid performance brings into mind that other Germanic uber-hybrid, the BMW ActiveHybrid 3 which only deals 340PS and a 0 to 100kph of 5.3 seconds. Despite the Q50S claiming top trumps, the BMW comes across as the more engaging and exciting of the two. Then again you get the impression that despite Infiniti’s presence in Formula One, the Q50S Hybrid wasn’t built to be the sort of car for drivers, but as a technological showcase.

Credit where credit is due, the DAS works remarkably well, better than expected, even though it is still at odds with drivers at heart. Furthermore the car just bristles with safety technology with the world’s first Predictive Forward Collision Warning system that is able to detect the speed of the car in front of the car that you are following behind, radar guided cruise control, and even a system that prevents you from reversing out of a parking into oncoming traffic. On that note I have to admit that the Q50S Hybrid is by far, the most technologically advanced car of its class. Pity that it is quite far from being the most thrilling to drive.  

Engine V6, 3498cc, with 50kW electric motor
CO2 144g/km
Power 364PS (combined)@ 6800rpm
Torque 546Nm (combined) @ 5000rpm
Performance 5.1sec (claimed 0-100kph), 250kph (limited)
Weight 1750kg (208PS/tonne)
Price RM398,800

+Technically the most advanced car of its class, that powertrain
-Objective not the most fun car of its class, those brakes 

This article first appeared on our performance oriented-sister publication, Malaysian Evo magazine (October 2014 issue).

2015 Infiniti Q50S Hybrid Gallery

About Daniel Wong

Born with a sizable cranium that is only humbled by Rubens Barrichello's, Daniel doesn't care much for numbers or figures but the immediate sensations and experiences one gets from a drive. To him a measure of a good car is one that does what it was set out to do well. A great car is one that draws a smile on your face with a quality that isn't quantifiable and keeps it there.


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