by Ian Kuah
When I drove the new BMW M5 (F90) at Estoril last November it left a very strong impression that BMW had not only recovered from its stumble with its lackluster predecessor but also now had the right stuff to give the mighty E63 S AMG a bloody nose.
The previous F10 M5 was fast in a straight line but felt heavy and unwieldy, which was no surprise since it was around 200 lb heavier than the charismatic, normally aspirated V10 M5 it replaced. The powerful, torque-rich twin-turbo V8 motor also felt on the verge of overwhelming the rear wheel drive chassis. It thus came as no surprise that BMW M not only put their 2018 M5 on a diet but also boosted its power and installed the xDrive all-wheel-drive system to maximize grip in all weather conditions.
Uprated in M5 Competition guise, the revised BMW engine now makes 625hp at 6,000rpm, underpinned by 553 lb-ft of torque between 1,800 and 5,800rpm. That is a useful increase over the standard M5's 600hp, even if the maximum twist on tap is no greater.
With maximum grip assured by the M xDrive all-wheel-drive system, the M5 Competition catapults to 62mph in just 3.3 seconds, which is going some for a car weighing a whopping 4,111 lbs (DIN) or 4,277 lbs (EU). The sprint to 124mph takes 10.8 seconds and top speed is electronically limited to 155mph, although many owners will no doubt specify the M Driver's Package option, which opens this out to 190mph.
"We had the Competition version in mind right from the beginning of the M5 programme," said Project Manager Axel Schramm. "For example, we knew that it would have 625hp."
"The work on the uprated chassis began in early 2017 and this was the time that the suspension settings for the base car had already been set for production," he explained. "The simple fact was that we had to develop the M5 chassis to the end before we could use it as the jumping off point for the Competition version that would be aimed at enhanced performance on track."
"The one area we did not know about at the start of the M2 and M5 Competition development programs was the final specification for the EU6D emissions regulations," he continued. "These were announced fairly late in our programs and at first we thought they were going to pose a serious problem."
In the event the extra restriction in the exhaust caused by the particulates filter was easily overcome more or less with a mild increase in turbo boost. As the V8 engine has 4.4 liters it is inherently powerful and all that was required was for maximum boost to be dialed up from 2.7 to 2.8 bar.
A more engaging exhaust note was another item on the development team's bucket list, and the M5 Competition has a new rear exhaust silencer design that does indeed create a more wholesome soundtrack. We certainly noticed it from the pit lane when the cars were on track at Ascari, but it is quite subtle from inside the car unless you drop a window.
The M5 suspension revisions to Competition spec are based around a 7.0mm reduction in ride height combined with a 10% increase in spring rate. The active dampers were then recalibrated to suit. The rear anti-roll bar is 5% larger to move the handling balance further towards a neutral state, while the two center bushes of the front-anti-roll bar have been uprated.
"More negative camber is dialed into the front suspension to improve turn-in response," explained Christian Flessa, the engineer responsible for driving dynamics. "This is always a balancing act in a road car that goes in a straight line more than it turns, so to avoid excessive tire wear the Competition has 1° 30' of negative camber compared to 50' for the standard M5," he said. To achieve this with minimal cost the top suspension link is modified using rubber bushes with slightly offset metal inserts. Last but not least the software governing the DSC and xDrive were recalibrated to maximize the gains made by the revised suspension hardware.
To minimize weight transfer of the heavy engine under acceleration, braking and cornering the engine mounts have been made 30% stiffer. This is a fine balancing act that skirts the potential problem of over-stiff mounts introducing unacceptable levels of drivetrain NVH.
Thanks to various weight-saving measures such as the forged alloy wheels that shave 6.6 lb from each corner and lower that critical unsprung mass, the M5 Competition ends up no heavier than the standard car.
Despite its massive 20-inch wheels and tires the well-judged steel springs and active dampers of the BMW M5 create a near-perfect balance of ride and handling without the added cost and complexity of air springs.
Dialing things up by around 10-percent for the Competition version has not spoilt that balance, and just puts a slight edge on the ride that is compensated for by using the Comfort mode more in normal driving. On the other hand, Sport mode is still just fine as there is enough latitude in its ride comfort while its superior rebound control still makes it the setting of choice for most situations. Ultimately the choice is down to your mood on the day.
The revised suspension calibration sharpens up the feedback you experience through the steering and seat of your pants when you turn into a bend at speed. The Competition feels a bit tighter, a bit more agile, even more of a super sedan.
It is on track, however, where you can really extend the car to its limits and beyond that the M5 Competition really comes alive. If the truth be told the extra 25hp is barely noticeable, with the real gains coming from the revised chassis settings.
The BMW M xDrive system never allows too much power to be shifted to the front and is very consistent in maintaining the desirable rear-wheel-drive biased high-performance car feel.
Meanwhile, the front axle exerts its mild stabilizing influence to help drag the car out of a bend with maximum possible overall traction. And as with the normal M5, you can switch to rear-wheel-drive only should you wish to showboat and immolate the rear tires with drifts or doughnuts.
I am a big fan of the MDM2 setting, which is accessed by two pushes on the right-hand red lever on the steering wheel. The second push confirms your conscious decision to ask the electronic nanny to step aside and maximizes the potential of the clever M Differential in the rear axle.
Ascari is my home circuit so I was able to use the M5 Competition's full potential from the word 'go' without wondering which way the next bend or the one after goes.
The Competition's slightly stiffer chassis set up imbues an extra measure of body control over the cars not inconsiderable weight, making it feel a touch more incisive on turn-in thanks to a slower roll moment.
Once you reach the apex of a bend and start to apply power the effect of the solid bushes on the rear toe links can be felt peeling away a layer of the vagueness inherent in the normal M5's more comfort-biased rubber bushes. The overall difference is actually quite subtle rather than night and day, and you have to be familiar with the standard M5's behavior on road and track in order to make this judgment.
With that in mind, the changes to the chassis are certainly worthwhile and the car now feels like it could easily handle another 25 or even 50hp, although the latter figure would likely begin to tax the excellent optional carbon-ceramic brakes.
It is also noteworthy that the 4WD chassis is very stable under extreme braking from high speeds, such as on the back straight at Ascari where 90mph has to be shed from 150mph terminal speeds before entering the third gear Piff-Paff sequence at the end. The M5 is such a good overall package out of the box that the debate raged over whether Audi or AMG would be the first to dethrone it as king of the super sedans. But it looks like BMW's own M5 Competition has arrived there first.