“I think this car will always have a special place in our collection…” Mercedes F1 team principal Toto Wolff mentioned to Autosport just last week “…very far back.”
Such has been the success of Toto’s team over the last eight seasons, a car that takes seventeen podiums, one win, one pole and finishes third in the constructors championship is considered a failure.
The nascency of the “Mercedes-AMG W13 E Performance”, or just “W13” if you don’t mind, began with what turned out to be a rather radical approach to the new era of Formula 1. 2022 introduced one of the most significant changes to the F1 ruleset seen in some time, perhaps ever, in which cars were forced into a design that favoured underbody aerodynamics to create downforce using ground effect technology. Ground effect in F1 was originally invented in the late 1970’s and outlawed.
The premise of these changes was led by a desire within the sporting governance to provide better racing by allowing cars to run closer together. With these new 2022 cars, barge boards were banned, changing the way teams had to deal with the turbulent aero wake from the front wheels, favouring intakes on the front of the sidepod floor area that feed air into underfloor venturis. This went hand in hand with a mandated rear wing design to push the car’s wake upwards and reduce “dirty air” for the following car.
There were many other changes but this, along with a move to 18 inch wheels, was the most significant change from a design perspective that sent all of the F1 team designers back to the drawing board after five years of relative rule stability.
At the second test of the year, on the 10th March 2022, Mercedes unveiled the W13’s full aerodynamic package to gasps up and down the pitlane. Where most of the cars had opted for a wider body around the sidepods, Mercedes’ sidepods were “slimline”, pulling in tight to the rear of the car, with a wing mounted upon the homologated crash structure at the leading edge of the sidepod managing airflow from the wake of the front wheels over the top of the rear floor component and onto the rear wing. Where barge boards behind the front wheels had been used in previous eras to manage this wake, this wing mounting appeared to be managing this airflow, this design looked to be a potential work of genius.
Rival teams raised eyebrows, but when the car took to the track any concerns they had about this radical design approach’s potential seemed to ebb away.
Once running it was clear that the car was suffering with almost terrifying amounts of aerodynamic porpoising, as well as bouncing in the suspension, two phenomena brought on by ground effect’s general requirement for running the car as low to the ground as possible to gain performance. The Brackley based team were in crisis.
This of course makes it fascinating that the W13 was already slated to be coming to iRacing as a virtual steed long before all of this came to pass. With the 2021 constructor’s championship winning W12 already in the service, Mercedes had struck a deal with the US based sim developer we all know and love to bring their 2022 challenger into our virtual garages long before they knew how their season would go; giving us the chance to enshrine another genuine F1 curio within the virtual world.
Taking to the track in the iRacing W13, one of the first things to strike me is how stiff the vehicle platform is when compared to its predecessor. The provided setups for each of iRacing’s F1 aligned tracks are designed to provide a gentle learning experience, in as much as is possible with such a complex, rapid machine. The car is stable with a bias towards understeer that becomes more pronounced as the driver’s confidence grows.
The tyres provided, noted as Soft, Medium, and Hard in keeping with F1 nomenclature, simulate Pirelli’s C4, C3 and C2 grades of tyre softness. For my first foray, I take to the Barcelona circuit with a set of hards (The 2022 Spanish Grand Prix utilised the C3, C2 and C1 compounds, so the iRacing Hards are equivalent to the Mediums used in reality) and a full tank of fuel to get a feel for things.
Stiffness is crucial to create a stable aero platform to optimise the airflow field into the diffuser from the front of the floor; if the floor is considered a “wing” then the more consistently this wing is presented to the flow field the more consistent the aerodynamic downforce created will be. Also, running the car lower will effectively constrict this flow and thus speed it up and create downforce in greater numbers.
Whilst my initial impressions involved adapting to the stiffness of the platform, I am ever mindful that the default setups provided are configured with considerably more compliance than will undoubtedly be required to extract maximum pace from the W13, so we have a long way to go.
Handling wise, it is a little cold in Catalunya today and the hards are struggling for temperature without some amendment to pressures. In fast corners the W13 is producing a staggering amount of downforce; the rear sticks and sticks with the rearward centre of pressure showing its hand. Conversely, the fronts start to scrub when leaning on it through turns three, four and nine.
At slow speed, the understeer is more pronounced and I start working with the various tools within the car to try to help get the car into corners. In-car brake balance configuration features brake migration, to manage the balance dynamically as speed bleeds off (as has been seen in many other sim-virtualised modern F1 cars), and the obligatory amendments to entry, mid-corner and exit differential locking are available. Nevertheless, with a heavy fuel load and tyres outside of their optimum range, the car is cumbersome at low speed, with so much low end torque delivered by the Mercedes M13 V6 hybrid power unit it can be rather too easy to spin up the rear wheels in the lower gears and find oneself pointing the wrong way. Luckily, this happens to me only once: exiting turn ten after almost twenty-five laps with no one in the empty stands able to bear witness.
As the opening Grand Prix of the season dawned in Bahrain, Mercedes were still quite some way from understanding the problems that they were having with the W13, and were fortunate to score a three-four finish behind the Ferraris as a result of reliability trouble in the Red Bull camp. Saudi Arabia was worse, with the cars lining up sixth and fifteenth and scraping through to fifth and tenth in the race. The Melbourne circuit in Australia did not appear to see the car suffering so much with porpoising, perhaps due to the nature of the circuit requiring a higher ride height, and they were once again fortunate with attrition to score a three-four.
Dire as it may have appeared relative to previous seasons, most of the teams were suffering with getting their all-new cars to work effectively. Mercedes were remaining a clear third best outfit, but the porpoising had to be solved.
In a porpoising scenario, the car ends up with a phase shift between its front and rear aerodynamics, instigating pitch in the aero platform. The phenomenon was first talked about in F1 circles in 1979 when Lotus introduced their Type 80, which aimed to push the ground effect concepts of the Type 79 further. In many ways it did: it did generate more downforce. But with it came porpoising, which made the Type 80 borderline undrivable.
Porpoising tends to occur when there is instability in the underfloor airflow field. When this instability occurs, the diffuser can stall the airflow, resulting in the rear suspension going into heave, raising the rear ride height and moving the aerodynamic centre of pressure forwards as a result of the pitch condition. The flow field then re-attaches to the diffuser, reversing the situation, and pulling the centre of pressure rearward once more and putting the front suspension into heave, resulting in a reversal of the pitch. This happens repeatedly, and very quickly depending on speed, creating a violent pitch oscillation which is not only very uncomfortable for the driver, but makes for an unstable aero platform and very unpredictable handling.
For the Emilia-Romagna Grand Prix in Imola, Mercedes brought changes to their diffuser, sidepod inlets and lower rear deflector endplates in an attempt to tackle their porpoising woes. With qualifying taking place on a drying track after morning rain, the Mercedes pair did not make Q3. Lining up eleventh and fourteenth on the grid, and with the car looking skittish, barely controllable and slower than it had been all year, they still walked away with a fourth place finish. Miami saw only one car make it through to Q3, but a strong fifth and sixth in the race kept the points flowing in.
At the Spanish Grand Prix, Mercedes introduced a much larger upgrade, with an all new floor featuring revised edge detail, a lower deflector endplate on the rear corner in advance of the rear wheel, and a bib vane added to the floor body. These changes were aimed at improving flow conditioning into the diffuser to reduce instability, as well as increasing load. There was also an amendment to the front wing endplate to aid airflow to the rear of the car. Immediately, the W13 looked far more comfortable on track, with the smoother surface of the Circuit de Catalunya allowing the car to run as low as it needed to without suffering porpoising. Mercedes ended Friday just two tenths off the pace. This margin increased somewhat on single lap pace, lining up fourth and sixth on the grid, but they came home third and fifth in the race. Most encouragingly, the W13’s fastest race lap was just a tenth away from the fastest time set by a Red Bull. Smiles started to appear in the garage.
Whilst it appeared that Mercedes had made good progress ironing out its issues regarding underfloor flow field instability that led to porpoising, the W13 continued to suffer from ‘bouncing’ – a heave motion response caused by the underfloor aerodynamic instability – at the next two races. Monaco and Azerbaijan, both bumpy street tracks, would put frowns back on faces in the Mercedes camp.
For the afternoon session, I bring the fuel load down to one-third race distance and switch to the Mediums, the C3s. I Bring up the tyre pressures all-round, particularly on the underused right-side, and lower the ride height front and rear at speed to as low as I can get away with. iRacing’s “setup calculator” allows the “ride height at speed” setting to be assigned directly, rather than via packer adjustments and judicious telemetry study.
Right away the car is more alive on the lower fuel load and the rear is even more nailed to the ground; so much so as to create something of an imbalance and I am soon back in to put more front wing flap on to better balance out the high speed behaviour.
The grip is intoxicating through the first sweeps of turns one and two, and I seem to be able to brake deeper and deeper every lap. Turn three is flat-chat full throttle and I feel like I am lifting purely for my own confidence to tuck the nose in on entry to turn fournine.
At the lower speed turn five it is still hard to get down to the apex, but the benefits I am reaping in the high speed sections are making laptimes tumble. As I am pushing harder, just as I think the rear has seemingly unbreakable grip, I get a snap on the exit of turn four, then the rears give out under traction on the kerb out of turn six; I am getting closer to the limit.
Bouncing… This catchily named term is noted when you see a car literally, well, bouncing on all four corners. Mercedes Technical Director Mike Elliott talked with RaceCar Engineering magazine in their December issue about it and had the following to say: “Bouncing issues are complex. The aerodynamics put energy in the vertical motion of the car due to a phase shift between the aerodynamic load and the car’s ride height position that gives a net energy input more than the dampers can deal with. The fact we have to run these cars so low to the ground, with so much downforce on them to be performant, means they must run really stiff , and that’s a huge contributor to these significant consequences.”
F1’s move to eighteen inch rims with lower profile Pirelli tyres have an impact here, Elliott goes on:
“The new tyres want slightly different things to get them into the window that works when compared to the previous thirteen inch ones. Though this isn’t the way to solve the challenges we’ve been facing with car behaviour. You have to put it in perspective. The tyre is not particularly stiff , and then you’ve got stiff suspension springs and, in parallel with the suspension springs, you have stiff dampers. In reality, these cars are inflexible, so it’s hard to dampen the motions and take a lot of energy out of the car’s movement.”
While the pain felt in the pair of street races was lessened somewhat by both cars scoring points in both, it remained the case that the Mercedes occupied a no-mans-land in performance terms; comfortably ahead of McLaren and Alpine behind, but significantly behind the faster Red Bulls and Ferraris ahead.
The Canadian Grand Prix appeared a far more competitive outing as, after qualifying fourth and eighth, the two Mercedes finished third and fourth once more; this time only seven and twelve seconds behind the leader, respectively.
At Silverstone they were on the podium again, suffering the first DNF of the year with the other car due to a gruesome startline shunt. Another notable update was brought to the car for the British round, modifying the front suspension design as well as modifications to the sidepod inlet to aid flow conditioning under the floor. Changes to the floor body added downforce load and aided flow conditioning, and a re-profiling of the rear wing tips would reduce drag on Silverstone’s long straights. Hamilton’s Mercedes appeared to be in the mix for the win, ultimately finishing third just six seconds back.
In Austria, promising practice pace was somewhat squandered by both drivers binning it in Q3, but competitive drives once again secured a three-four finish. At the mid-point of the season, the best result for the W13 was third place and the constructors’ championship looked well out of reach.
The W13 struggled with bouncing in Paul Ricard, despite a revised nose, but managed a double podium with a season best second and third place finish. The same result was repeated in Hungary, where a first pole position of the season had offered the hope of a win.
Belgium’s fast sweepers saw another downturn after this strong run, with the vagaries of the Spa-Francorchamps circuit forcing a compromise on ride height through Eau Rouge. In qualifying, the W13 was further away from pole than it had been all year. Another DNF struck after a first lap incident, with the remaining car coming home fourth, albeit almost thirty seconds back. Pace was strong in Zandvoort however, proving that the track layout was causing quite large swings in relative performance. They took the flag second and fourth, but then once again in Monza the pace dropped off. It appeared at this stage that to take a win with this car was going to require a dose of good fortune.
For my final session of the day, I start to experiment with stiffening up the heave and roll rates to try to solidify the underfloor aero platform and hopefully pull more performance out of the car. Once again I see immediate gains in rear downforce that require balancing out with front flap adjustments. We’re maintaining a thirty kilogram fuel load as I pop in and out of the pits; iRacing’s cost-capless environment granting me a fresh set of tyres each time.
When looking at configuration of the hybrid systems in the W13, it is once again clear that iRacing have dumbed things down from the real-world car. As they did with the W12, and with revisions to the McLaren-Honda MP4-30 in the service, they present basic options for the ERS recovery and deployment such as “build/balanced/attack.” Most of my running is on the “balanced” setting to allow me not to give it much thought. With a limited amount of changes allowed even in private practice, based on competition regulation, it can be painful to experiment with these settings. On the whole I am not in favour of these simplifications; a simulator should aim to replicate the controls and systems of the real world vehicle as accurately as possible, and this has historically been an area where iRacing have excelled. I can understand the need to attract players to online races, which in complex cars can be tough given the learning curve, but it would be nice to have greater verisimilitude as an option in offline or hosted sessions at least.
Nonetheless, running in “balanced” mode did not present much trouble. With the system potentially changing the deploy mode on the fly, there can be a danger that you could enter a braking area at speed without a solid idea of the retardation available to you; something I had suffered in the aforementioned McLaren. Yet, in over ninety laps of Barcelona, and seventy laps of Imola, I had no such problems with the W13.
I did start to have trouble, however, with my push for stiffness making the car become more and more edgy. When the tyres were fresh and up to temperature they would hold on, but as the rears began to wear they started to cry “enough”, and after a few “brown trouser events” through turn four and turn six, I head back to the garage to loosen things up.
A chaotic, wet Singapore Grand Prix masked how close the W13 was to the leader’s pace; they were in the hunt for pole and set fastest lap in the race. Rain also fell in Suzuka, where the car’s aero deficiency saw their pace drop away from the top teams in the drier sessions.
In Austin, for the United States Grand Prix, Mercedes fitted what was planned to be the final upgrade to the car: a new front wing, floor fences to once again aid flow conditioning, and revisions to the floor edge and rear wing endplates to increase overall load. These were met with strong performances; Russell taking fifth and Hamilton almost stealing a fortuitous win on the way to coming in second.
Mexico saw the W13’s second and third on the grid, but fall back somewhat on race pace to finish in second and fourth. Strong results, and outpacing the Ferraris, but not quite there. Through the season one thing had been clear: even if the W13’s pace was inconsistent track to track, it was able to look after its tyres better than most of the other cars. Perhaps this would be the advantage it needed in the final stretch.
The samba beats from the crowds rang out at Interlagos for the Brazilian Grand Prix, which featured a sprint event on Saturday. This meant limited practice running and, right away, it was clear that the Red Bulls were not happy with their front end. Everyone was struggling with tyre wear, and there was only one practice session before qualifying to do anything about it.
Then the rain came for that qualifying session, and a shock standout performance for Kevin Magnussen put him on pole for Haas. The Mercedes lined up third and eighth for the sprint; George Russell would win that event, with Hamilton fighting up to third. This would be where they would start on race day and the smart money said that this one was theirs to lose. The sprint had demonstrated that the Red Bulls were struggling and had dropped behind both the Mercedes and Ferrari on pace due to the nature of the circuit. There was an air of calm confidence emanating from the garage of the Silver Arrows, which proved to be justified as Russell dominated from pole to take the win, with Hamilton close behind in second – the team’s first one-two since Imola 2020.
The season ended at Abu Dhabi where a grid lined up two-by-two and a representation of the season looked to bear up; the W13s firmly fifth and sixth. Russell would end the season with a solid fifth place, while Hamilton would suffer the W13’s first, and only, mechanical failure of the season and DNF.
As I continue to pound around the sun starts to drop low in the sky over Montmelo and, with it, the track temperature starts to fall. At the track’s peak I record a time that was around seven tenths away from the time set by George Russell in FP2 during the Spanish Grand Prix, and feel happy enough with this pace. As the temperature drops, I never manage to match that pace again, whilst continuing to pop in and out of the pits to further experiment with setup. The colder track surface makes it harder and harder to maintain temperature in the tyres and the fronts increasingly scrabble to hold their line where previously it had been solid. I revert to the setup that yielded the peak laptime and head out for a final run, despite my shoulders and arms advising me that they’ve had enough of wrestling this direct drive wheel.
The next day I take the car to Imola, a circuit that the Mercedes team struggled with in real life, to see how the car compares. Right away the track surface is more tricky to deal with, and the car becomes more skittish over bumps as we lower and stiffen it. As a circuit Imola requires one to use the kerbs to extract decent lap times and on almost every turn I wince at the sound of the car smashing into the ground as we land. Setup provides options to adjust heave and roll rates but we simply cannot get away with roll rates as stiff here as we enjoyed in Barcelona.
As we saw in Catalunya, getting a good high speed feeling involves continual adjustment of these spring rates, while the front flap and rear gurney fine tune the balance; but where the smooth sweeps of Barcelona made the process relatively straightforward, Imola is a trickier customer. Every change gives us a different feeling, it may feel better in Rivazza but terrible in Piratella, try to fix that and we lose precision in direction change and every Variante is a nightmare. Ultimately laptime is all, as over two hours I fail to get the car feeling comfortable around this circuit; sooner or later you’ve just got what you’ve got! After sixty-five laps of Imola I finally have my first crash, after asking too much on the turn one kerb, I am spat into the wall that the Ayrton Senna monument looks down upon. Time to pack up.
The W13 is demanding to drive, especially on the limit, but like many F1 cars its sheer speed can really pull you in to keep running it more and more. Nothing quite compares in simracing to pitching a modern F1 car into a high speed corner and finding yourself exclaiming at how much sheer grip the machine has.
At Barcelona I could not get myself into a position whereby I had the car porpoising or bouncing, however I did experience what appeared to be some bouncing at Imola on the main straight, but it was not severe.
It is unclear to me what specification the W13 model in iRacing is representative of, and I was unable to obtain an answer to the question at the time of writing, but as we’ve seen, the car was upgraded notably throughout the season. The 3D model, particularly around the exposed rear floor area, seems to suggest an early season specification, but the aerodynamic stability seems to suggest that the physics implementation may be more apposite to the late season aero package.
After six or so hours in the car I feel like I have only scratched the surface of the depth on offer; setup options are not as extensive as some other offerings, aero adjustments are limited to high, medium and low downforce packages with no finer control of what these entail. Once a package is selected one is left to adjust the ride heights and heave and roll stiffness to manage the floor optimisation, with the rear gurney and front wing flap adjustment the only options for overbody aero, iRacing in general do not bother with cooling so there are no adjustments there that might present a drag trade-off. When it comes to suspension we can adjust static ride height offsets, cambers and toes, alongside the aforementioned front and rear roll and heave spring rates. There are no configuration options for dampers or anti-roll bars, the W13 of course has both of these components so omitting them from the setup options seems strange, especially when dampers can be so critical in managing the underbody aero platform stability. In the garage the differential and brake-by-wire configurations offer the same electronic controls as are available in the cockpit, again, it seems surprising that the engineers would not have more options at their disposal. iRacing have typically been very good in providing a thorough series of available setup options in their other complex cars, so I am somewhat surprised to see the W13 appearing so simplified.
That said, the sensitivity of the car to setup changes and the varying demands of different track layouts leaves us replete with experimentation potential. The demands of the W13 will present fascinating challenges for a while yet.
This is the first F1 car from the modern ground effect era to be officially implemented into a racing sim and I must commend the hard work iRacing have clearly put into it, and also thank the Mercedes team for granting the licence and letting us get a taste of such modern machinery. All too often these unique cars fall away from our consciousness as the season ends, but now the W13 is with us in virtual form for years to come.
Back to Toto: “…I think that hopefully the next few years will do her justice, because the learning curve with that car was enormous. Our fundamental understanding of aerodynamic, vehicle dynamics correlation, has gone through a step change of learning.”
The W13 may not be remembered as the most successful Mercedes Formula One car, but it certainly won’t be forgotten.