2012 Abu Dhabi GP - Yas Marina

[CHT]

There is no such thing as underfuel at start because underfuel will mean you will run out of fuel before the end of the race. However FIA do set the minimum weight of car + driver after the race, this is to ensure that no car is running under weight.

However it is possible that RBR do have more fuel efficient renault engine as compared to Ferrari and Mclaren, and this will translate to them carrying lesser fuel at the start.

more than less cars on the grid are actually underfueled at the start of the race, because having less fuel on board nets out as a gain overall, even if for a while you have to turn down the engine a bit and shortshift, add a pretty much mandatory tire conservation to this, and you get a race that we have nowdays, where leader is coasting at a safe distance (10-20sec) for long periods of time, even when he could theoretically go 0,5 or more seconds faster a lap

and everyone has to do this to a certain degree, except SV in this last race

every team on the grid will always try their best at fueling their cars to the minimum fuel level required to finish the race, so there is no such thing as underfuel for the race, because when you underfuel that means you have less then enough fuel on board in the tank to finish a normal race.

Honestly why could any race engineers want to take such a big risk to compromise driver's race with insufficient fuel. Plus the opportunity for driver turning down the fuel mix in the race is not something that can be planned ahead of the race.

[jz11]

when people say "underfueled", they mean that the car fill not be able to finish the race at maximum performance acceleration wise, you can underfuel so you have to coast for 10% of the race, or 5%, or 25% (those numbers are imaginary, just to illustrate the idea), and it will wary with the track, track condition, weather, tires, everything, that is what is understood by "underfueling a car" and that is tied together with the drivers race strategy!

so yes, there is such a thing as an underfueled car, and we can only estimate and guess by how much...

[Cam]

@jz11 & @CHT - you're both saying the same thing. Yes, the teams limit the fuel, but perhaps not the same as every other team. Maybe some teams want to run full revs for the entire race, we don't know. I think you're both getting bogged down on the word 'underfuel' - whereas you both actually mean - fuel the car, for the strategy chosen, not more, not less.

[CHT]

@jz11 & @CHT - you're both saying the same thing. Yes, the teams limit the fuel, but perhaps not the same as every other team. Maybe some teams want to run full revs for the entire race, we don't know. I think you're both getting bogged down on the word 'underfuel' - whereas you both actually mean - fuel the car, for the strategy chosen, not more, not less.

I have never heard of the term underfuel being used to describe a race strategy, the word "under" mean insufficient, which is abnormal and not optimal.

Also in a race where teams are fighting for championship points, why would any engineers want to compromise the driver's race or the full potential of their machinery by giving pre-race instructions that the driver will need to spend 10 or 25% of the race cruising to conserve fuel? Honestly which engineers will be able to predict how the race will progress and when they need to attack or defend?

[raymondu999]

Actually - it's not about compromising their race speed.

Lotus for example said a while back that for their car, their engine, their fuel consumption - the optimal race distance time was gained not from running the engine at "standard" for the entire distance. They would start out at a slightly higher fuel mode, then taper it down to a fuel saving mode.

[CHT]

when people say "underfueled", they mean that the car fill not be able to finish the race at maximum performance acceleration wise, you can underfuel so you have to coast for 10% of the race, or 5%, or 25% (those numbers are imaginary, just to illustrate the idea), and it will wary with the track, track condition, weather, tires, everything, that is what is understood by "underfueling a car" and that is tied together with the drivers race strategy!

so yes, there is such a thing as an underfueled car, and we can only estimate and guess by how much...

I have not heard of anyone using the term underfuel to describe a race strategy for a race because when you underfuel the car, that means you are not giving the driver a machinery capable of going on full attack. And to be honest, I have never heard of any team or driver going into a F1 race not expected to go on 100% attacked. And btw, going on 100% attack doesnt mean that accelerator is at 100% throughout the race.

The last time Mclaren was short of fuel, they call it a MISTAKE in calculation, not a wrong fuel strategy.
http://www.autosport.com/news/report.php/id/98176

[Cam]

@jz11 & @CHT - you're both saying the same thing. Yes, the teams limit the fuel, but perhaps not the same as every other team. Maybe some teams want to run full revs for the entire race, we don't know. I think you're both getting bogged down on the word 'underfuel' - whereas you both actually mean - fuel the car, for the strategy chosen, not more, not less.

I have never heard of the term underfuel being used to describe a race strategy, the word "under" mean insufficient, which is abnormal and not optimal.

Also in a race where teams are fighting for championship points, why would any engineers want to compromise the driver's race or the full potential of their machinery by giving pre-race instructions that the driver will need to spend 10 or 25% of the race cruising to conserve fuel? Honestly which engineers will be able to predict how the race will progress and when they need to attack or defend?

Like most words, they rarely mean the same thing when used in a different context. What you are saying is right, no-one would 'under' or short fill a car on fuel, you will run out or have to have a 'splash & dash'. However in racing, I have heard these terms 'short fill' 'under fuel' etc many times, but they actually mean to put less fuel in the car so the driver must drive economically to conserve fuel so he can make full distance. If a driver heard 'underfuel' or 'short fuelled' he would understand that he'll be driving carefully and not too push too hard. That is the context.

In this context, you are both saying the same thing.

[CHT]

@jz11 & @CHT - you're both saying the same thing. Yes, the teams limit the fuel, but perhaps not the same as every other team. Maybe some teams want to run full revs for the entire race, we don't know. I think you're both getting bogged down on the word 'underfuel' - whereas you both actually mean - fuel the car, for the strategy chosen, not more, not less.

I have never heard of the term underfuel being used to describe a race strategy, the word "under" mean insufficient, which is abnormal and not optimal.

Also in a race where teams are fighting for championship points, why would any engineers want to compromise the driver's race or the full potential of their machinery by giving pre-race instructions that the driver will need to spend 10 or 25% of the race cruising to conserve fuel? Honestly which engineers will be able to predict how the race will progress and when they need to attack or defend?

Like most words, they rarely mean the same thing when used in a different context. What you are saying is right, no-one would 'under' or short fill a car on fuel, you will run out or have to have a 'splash & dash'. However in racing, I have heard these terms 'short fill' 'under fuel' etc many times, but they actually mean to put less fuel in the car so the driver must drive economically to conserve fuel so he can make full distance. If a driver heard 'underfuel' or 'short fuelled' he would understand that he'll be driving carefully and not too push too hard. That is the context.

In this context, you are both saying the same thing.

In F1, I have hear of engine engineers saying going aggressive on fuel load, which mean they are filling the car with just enough fuel to finish the race based on theoretical calculation using track parameters, not more.

Btw, under what sort of circumstance will you short-fuel a car? perhaps if you are running a 1 stop strategy?

[Cam]

Btw, under what sort of circumstance will you short-fuel a car? perhaps if you are running a 1 stop strategy?

I'm not in an F1 team, so I couldn't say. I can however guess.

Strategy 1: Normal
25 laps - run rich go hard
15 laps - run lean, conserve
10 laps - run rich to end

Strategy 2: Heavy
50 laps - run rich

Strategy 3: Light
50 laps - run lean

"You could under fuel the car and go with strategy 3, as you'd be a lot lighter, as opposed to a normal strategy 1 or 2 scenario fuel load, where you'd be heavier" - That's how I would discuss it and how I would use that term.

We're getting stuck on semantics and I guess you simply can't see my point of view. Is okay.

[raymondu999]

I'd like to take this time to draw attention back to my post a while back

Lotus for example said a while back that for their car, their engine, their fuel consumption - the optimal race distance time was gained not from running the engine at "standard" for the entire distance. They would start out at a slightly higher fuel mode, then taper it down to a fuel saving mode.

[CHT]

Btw, under what sort of circumstance will you short-fuel a car? perhaps if you are running a 1 stop strategy?

I'm not in an F1 team, so I couldn't say. I can however guess.

Strategy 1: Normal
25 laps - run rich go hard
15 laps - run lean, conserve
10 laps - run rich to end

Strategy 2: Heavy
50 laps - run rich

Strategy 3: Light
50 laps - run lean

"You could under fuel the car and go with strategy 3, as you'd be a lot lighter, as opposed to a normal strategy 1 or 2 scenario fuel load, where you'd be heavier" - That's how I would discuss it and how I would use that term.

We're getting stuck on semantics and I guess you simply can't see my point of view. Is okay.

I believe fuel consumption calculation from the engine department should include many different variables such as weather, fuel blend, track characteristic, temperature and tyre strategy etc. So there is really no such thing as a fixed normal fuel benchmark to follow. If you are running a one stop strategy, then the NORMAL fuel load will be lower than the norm for a 2 or 3 stopper and vice versa.

Having said that, I do believe that fuel load is not a strategy in itself, it is more of a variable used to maximize the team tyre strategy.

Honestly how do you expect any team to pre-determine how many laps the driver should run rich lean or normal?

[CHT]

I'd like to take this time to draw attention back to my post a while back

Lotus for example said a while back that for their car, their engine, their fuel consumption - the optimal race distance time was gained not from running the engine at "standard" for the entire distance. They would start out at a slightly higher fuel mode, then taper it down to a fuel saving mode.

I remember Lotus did mention something about taking a risk to go aggressive on fuel load as they are no very sure about the actual fuel consumption of that particular race.

Btw, does fuel blend also play a big part in fuel load?
http://www.shell.com/home/content/motor ... alculator/

[jz11]

that is the fun part, it is a gamble, on more than one occasion there were team messages on the radio telling the driver to conserve fuel near the end of the race, or the opposite, he can go flat out, and there is no fuel check after the race I believe, so those cases were not about having enough for that sample or not, it was whether they will have enough fuel to actually get to the finish line, and the payoff from underfueling is directly related to tire wear as well

we would have much more clarity about this if we knew actual numbers about how much fuel they started with (because I believe that at the finish line they had more or less the same) from the last race for lets say Kimis car, Alonsos car, Marks and Sebastians, this would be a secret before the race, since it's a tell tell sign about what sort of strategy they are planning, I would expect first 3 to begin the race with similar amounts of fuel and SV having a bit more, that is why there was all the talk about him even attempting the 1stop, because with all the "extra" fuel and max attack mode, the tires wouldn't last for 1stop anyway, that is why I also believe that they were shooting for somewhere between 6th - 10th place at the finish, which was confirmed by Horner

also that extra fuel "costs" a lot more at the beginning of the race rather than at the end, because large portion of it is sitting way high in the car, that is another reason to not have a tiny bit more than really needed

[raymondu999]

The quote I mentioned in particular was not a vague "let's try to go aggressive" quote - it was James Allison, in an interview with either Sky or the BBC.

During the 2012 Belgisan GP Kimi said "so give me full power!" On the team radio. James Allison was asked afterwards whether there were any issues. He said no, and just said (in no unclear words) that standard procedure for Lotus completing a dry race was to start the early laps on full power and taper off gradually along the race distance until they finish the race in a fuel-saving mode, because it was the quickest way for the Lotus E20 to complete the race distance.

In 2010 Ross Brawn also said (after Turkey 2010, IIRC) that the quickest way to complete a race distance was to end off on fuel conservation mode, because the earlier laps on a lighter fuel load would pay you more than you paid with the lower power at the end. It would also, let's not forget, lighten the duty of the tyres and help them last longer

[1158]

I would assume the nature of the circuit comes in to play as well. For instance at Singapore the SC is almost guaranteed to be deployed. I'm sure the teams take that into account and figure several laps being run with much lower fuel consumption.