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11 Jun 2015

Lift and Coast and fuel saving have come to the fore since the Canadian GP, however, as is always the case, most seem to have their nose pressed firmly against the glass, so instead lets stand back and try to look at the entire view....

Lift & Coast

It's something that all of us do, whether you're dropping your kids off at school or commuting to work.  It's that moment before a corner that you lift out of the throttle before applying the brakes, something I've been doing for years with the express intention of saving fuel.

But we aren't talking about me in my hatchback, we're talking about racing drivers and so in qualifying trim a driver will choose his braking point based on the maximum amount of apex speed he can carry, whilst the penalty of carrying additional fuel on laptime during a race ("fuel effect") means that the engineers will calculate how much fuel a driver can get away with using by doing some "lift and coast" throughout the race. 

You can chuck this calculation out of the window for Montreal, as the Circuit Gilles Villeneuve is a power hungry circuit, with 100kg's of fuel loaded into the cars before they set off on the formation lap (although the regulations specify 100kg's for the race distance, the teams will try not to exceed this amount including the formation and in-lap, if possible).
For those of you that nodded off during the race and missed the graphic on Hamilton's in-lap:
Yes that's right Hamilton, you know the guy who's won the race by only 2.2 seconds from his teammate but 40 seconds from the next nearest driver (Bottas), had his engineer telling him he needed to lift and coast. Hamilton much like most of the top 10 had used nearly all of their 100kg fuel limit and certainly in the case of the top 5 another lap would have seen the drivers run out of fuel, meaning the engineer was actually vindicated in his decision to ask for fuel saving.

During the race another graphic showed the current and average fuel per lap of the two Mercedes drivers:
The average of both drivers: 1.42kg's per lap over 70 laps brings them to 99.4kg's for the race, which with a formation lap and in-lap added at low speed, coasting and maximum cylinder deactivation,  it makes it all extremely marginal on fuel.

During the V8 era there was no upper limit on fuel weight and teams generally ran somewhere between 120-150kg's of fuel depending on the circuit, but remember those engines were much hungrier, often consuming a little more than 2kg's per lap, so with more fuel the drivers still needed to manage their fuel to make a race distance.

The fuel weight factor

Whilst the starting weight of the current cars broadly aligns with that of its predecessors, as the fuel burns off the current cars are at a distinct disadvantage.

2010-2013 Montreal - Dry weight - 642kg's + *150kg's fuel = 792kg's
2015 Montreal - Dry weight - 702kg's + 100kg's fuel = 802kg's

*Fuel weight confirmed by MercedesAMGF1 with an offset of +/- 5% between 2010-2013, based on prevailing blown diffuser trends

That means that the cars are dragging around an additional 10kg's of fuel at the start of a GP, with 10kg normally good for around 3 tenths in lap time.  Get to the end of the race and the cars will be edging toward 60kg's heavier, which should make them around 2 seconds a lap slower than their predecessors.  

Thankfully all things aren't equal and the FIA/teams realised early on that to achieve their objectives they would have to make the cars more efficient.  Some of this was realised through regulation, with the reduction in nose height, loss of 150mm of the front wing span, the loss of the beam wing etc reducing downforce and drag. Although other design concessions have had to come into play to make up the rest, with designers sacrificing downforce in favour of efficiency, a bitter pill to swallow for the Adrian Newey's of this world...

In other words we are comparing apples and oranges, with the downforce and drag created by the pre 2014 cars made inline with their objectives and trends.  Cramming a 2014/5 powerunit into the back of a 2010-2013 car would therefore make laptimes even slower and at a circuit like Montreal mean everyone runs out of fuel before crossing the finishing line.

Energy recovery

The other thing to consider is ERS, we now have two systems onboard, the MGU-H which either harvests or supplies energy to the Turbo or the MGU-K which supplies or harvests energy through the crankshaft.  Previously KERS (MGU-K) could harvest 400kj's per lap, now it harvests 5 times that (2mj), that can be stored in the ES with more passed directly to the MGU-H for immediate use.  This has a direct correlation to fuel economy as nothing comes for free, with the MGU-K significantly affecting braking distance depending on the harvest setting selected by the driver on the steering wheel rotary.  Toward the maximum end of the setting spectrum lifting out of the throttle would feel like driving with a parachute attached to the rear of the car, resulting in the mechanical braking system (rear discs and pads) doing less work.  This slowing of the car by the MGU-K results in more energy being harvested but at the consequence of fuel efficiency (think of the engine braking difference you have relative to the gear you are in, ie the ratio).


Gear ratios, now there is another topic worth some consideration, lest we forget  that 8 forward gears came in for 2014, superseding the 7 gears previously utilized. The additional gear was added to balance the MGU-K demand, smoothing the transition and making life easier for the MGU-K to harvest energy during the downshifts.

In 2014 the teams could play a joker, should they have incorrectly calculated the ratios or made sufficient aerodynamic improvements gains to warrant it. Under the V8's, teams were free to make changes to the ratios from GP to GP, which is clearly more of a an issue when you're dealing with an N/A engine, owing to the narrow power band, but much the same for a turbocharged car when you are dealing with the difference between Monaco and Montreal.


Formula One races are often won and lost not by the driver but by the decisions made by the team, be it on the prat perch or back at the factory, as telemetry from the car is beamed around the world.  Strategy plays a huge role in shaping each drivers race even if they are in the lead and seemingly have everything in hand.  I often here from broadcasters, fans and ex racers alike that driving a modern Formula One car is easy, which may be true from a physical standpoint but don't underestimate the mental dexterity that is required...

So let's imagine you're leading the race and you've managed your fuel, tyres and brakes to the best of your ability and are now in the 'pit window' (an imaginary window of opportunity that the engineers have pre carved out as the best time to make the pit stop), problem is those cars behind you will mean you encounter traffic as you re-emerge from the pit lane.  Now the strategy plays out, as the drivers and engineers have to take decisions on whether they start pushing and use up the remaining tyre life or back off and fall further back into the pit window, hoping those behind have to pit first.  These decisions are based on simulations and calculations made by the engineers at the circuit and at base, based on not only the information collated from their own car but observations and analysis of other drivers relative pace.

Dropping your driver back into traffic is the least efficient way of managing the next stint as it then means the tyres degrade more quickly as their life is used to affect the pass.  Finding a pit stop window is therefore paramount to giving a driver the cleanest possible race.

The marmite of F1, tyres are a contributing factor in how the teams go racing and how that translates as a spectacle.  I like to see it like the Goldilocks Paradox, with Pirelli in the unfortunate position of never being able to get it quite right for everyone.  Love them or loath them Pirelli have supplied the sport with a range of thermally degrading tyres that encourage more overtaking and differing strategy windows, which is essentially what the FIA asked for.  However, the events that surrounded Silverstone in 2013, have since prompted Pirelli to be much more conservative in the design of their tyres.

As many of you know that regularly read my blog I firmly believe the tyre that was in use prior to Silverstone 2013 was actually the best the sport has seen for some time.  It caused the teams no shortage of headaches, as they leveraged more mechanical grip and disturbed the aerodynamic consistency of the car.  The problem came when the teams pushed the limits of the regulations to their advantage, swapping the orientation of the tyres and going beyond the recommended camber and pressure settings issued by Pirelli.  As these did not form part of the regulatory process at the time, teams didn't have to accept the advice, so when they didn't and things started to go wrong the blame was laid at Pirelli's door.

A less limp wristed or omnipresent FIA president may have seen through what the teams had done and retained the rubber, issuing instructions that the recommended Pirelli settings be adhered to.  Instead we returned to the rubber used in 2012 and issued directives at each race with settings from Pirelli that needed to be followed, swinging the championship back in Red Bull's direction and robbing the fans of some better racing.

Fast forwarding back to Montreal and the tyres can once again be seen as an issue, Goldilocks suggesting that even the Super Soft & Soft compound combination didn't degrade quickly enough around Circuit Gilles Villeneuve as the teams managed their stint lengths.  The Canadian GP should be a 2 stopper, especially as the time to pit is extremely short when compared to other races, but with the teams marginal on fuel they didn't exert enough force on the tyres to warrant the switch.  Furthermore a larger time differential normally exists between the compounds but owing to the maturity of the teams knowledge of the construction and compounds, allied to climatic conditions, meant stint length could be eeked out.

Following this line of thought I have to refer to those out there who want a 'concrete' or 'bulletproof' tyre, like we saw Bridgestone produce in 2009, suggesting it will give a return to flat out racing.  What we saw in Montreal is effectively that, now do you think it produces better racing?  A 'concrete' tyre with the current regulatory construct will simply give the teams one less strategic headache to worry about, making the racing even more metronomic not improve the racing.

What did Montreal teach us and where do we go from here?

Montreal is a fuel limited track, which without a safety car period exacerbated the fuel usage issues.  This was highlighted by the numerous radio transmissions, broadcast by FOM, as they tried to instill a sense of drama between the silver arrows.  Montreal the scene of many great races in modern times was dulled to a metronomic display of fuel, brakes and tyre management, but, it isn't the first and certainly won't be the last race that's failed to stir the senses.  How these issues are addressed is of paramount importance, requiring a measured approach rather than a kneejerk reaction.

Time must be spent analysing how best to frame the regulations for the future, so that if we increase the amount of fuel that can be carried it outweighs the strategical advantages of fuel saving, encouraging faster lap times.  The most obvious solution to me is at high consumption tracks like Montreal a 5 lap reduction in race length is made, taking us from 70 to 65 laps which with the current 1.42kg Mercedes usage model would allow for another 7.1kg's of fuel to average out over the 65 laps.  This may not seem like a lot but would mean running at a 1.52kg average....

Meanwhile, as a method of improving the racing at other circuits, mandate the 100kg fuel weight, changing the strategic model and forcing teams to use a high fuel flow model to burn off the fuel.  Currently teams are under fuelling their cars depending on the circuit at hand, knowing at some point they'll have to run lean, so as not to run out of fuel.  For example, some teams will have used as little as 80kg's at Monaco, as they offset maximum lap time against the fuel adjusted lap times.  This tye of fuel adjustement has been a part of F1 for decades but most haven't noted it, the teams simply calculate the slowest way they can win the race, minimising the strategic calls they'll need to make throughout.

IF we want Formula One to continue to push the technological boundaries lets adopt a similar petrochemical/electrical energy matrix to WEC (see below)
That way it promotes energy efficiency in every sense, providing those that can generate more electrical energy throughout a lap the means to do so but with the jeopardy of less fuel weight and/or fuel flow.  This should marginalise the weight issue (although we still have the cars weighing 60kg's more at the end of the race).  This'll open the strategic window, making for a more entertaining battle as some teams use more fuel and low electrical energy consumption in one lap (or several) whilst the next (or few after that) they'll use a lower fuel flow and use energy stored.  This would require a rebalancing of the energy flow diagram currently used and an adjustment of the regulations pertaining to the Energy Store, which is an area that I feel should have more developmental scope, promoting the development of new technologies, that will power our EV's of the future.  Furthermore, if an unlimited approach to energy release was adopted, as we see in WEC, it would mean that the MGU-K could provide a more substantial peak boost (currently 120kw).

Furthermore, in the spirit of being aggressive we should scrap the fuel flow and energy recovery model for qualifying, introducing a run what ya brung style, which would lead to the ultimate lap time cars that people crave.  Going one step further you could even remove the parc ferme restriction and have aero and setup changes between qually and the race.  Run that higher downforce setting for max attack in qualifying and then run a different configuration for the race.  IndyCar do it, why can't F1?  Yea, yea tell me about how much extra money it's going to cost and I'll retort with the fact that from a relative standpoint F1 is only as expensive as it has always been.  Those that purport otherwise should look at the bottom line, not the headline grabbing areas of isolation. 

These changes could help the likes of Renault and Honda bridge the gaps they currently have to the other suppliers, with energy recovery and the symbiotic energy relationship between the MGU-K and MGU-H a considerable factor under the current regulatory framework.  At the very least it may save us another diatribe from Christian Horner (I can hardly talk how long this post is going on), who seems to expel more energy than the Renault powerunit at the moment.

The crux of the dull race we encountered in Montreal is that the teams didn't have enough energy margin (be it petrochemical or electrical) or tyres that forced more stops.  It is not something we will see at all the races this season but something that should be used as a way of addressing the more widesweeping issues that Formula One currently endures, especially as most of the proposals the Strategy Group offered simply conflict with one another.  I don't have all the answers but I'm prepared to look at the whole ecology of the problem than just try and identify isolated issues, perhaps those who makes the rules should look at things in the same way, or as I've suggested before have an independent working group that research and develop models that do work.


  1. Some great points. Thanks.

  2. I don't really understand or agree with the notion that a 2013 car with the current PU would be slower than a current car around Montreal. The 2013 cars weren't forced to run the wider front wings or a beam wing so they could have run the same bits and pieces as the current cars. They wouldn't because they could probably generate less draggy downforce i guess. I'm not the expert on this off course.

    I also have to object to the cost aspect of the game. The cost of buying an engine for smaller teams has increased and is pretty much the only thing they can't really influence. Increasing development on the PU would therefore squeeze them even further. For all other areas the cost shmost argument is valid in my opinion.

    I really like your suggestions about a different quali and race trim because the car in front in qualifying might not be the best car for the race. Anything to shut Christian Horner up.

    1. If it were possible, and it isn't, installing a 2014/15 powerunit in a 2010/13 car would result in a heavier car with far too much downforce, increasing the laptime.

      You're doing what everyone else does and looks at the cost in isolation, granted the cost to purchase the PU's is more than the V8's but wind tunnel time and CFD restrictions were curtailed in order to lower the costs. The problem is that the teams are still pushing in other directions and so the cost has been spread out in other directions, so who's really to blame?...

  3. Good piece. I agree with most of your suggestions. The Le Mans Appendix B is too convoluted though, IMO. On the engine side, simply removing the fuel flow restriction, keeping 100 kg fuel, and freeing up engine regulations (ERS storage capacity upper limits, VVTi, and other modern technologies) would result in banzai laps by lower order cars, overtaking better cars, and all sorts of traffic for the top teams later in the race. On the car front, increased mechanical grip through wider tyres and track width to cope with the peak power seem obvious.

    1. Without flow restriction, they would easily reach twice the current power. Every engine formula needs a way to limit power. For turbos flow limit is the best way to do that.

    2. Anon 12 June 1316: The 100 kg fuel limit combined with limited available traction (recall no traction control) would be an effective power limiter.

    3. Another power limiter is, of course, the four engine per season rule.

  4. Can the teams not just be told by the FIA that they need to be fully fueled (100kg) for every race. That way they will have excess fuel on a lot of circuits can could then push harder?

  5. Many thanks for yet another informative article.
    I seem to remember in the 'good old days' that fuel saving meant short-shifting rather than lift and coast, can you clarify why they they don't seem to do it that way any more?


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