Why do we have a fuel allowance and a max fuel flow rate??

[AlexCarey]

As far as I understand, the max fuel flow rate of 100kg/hr was put in place to limit the engine power. For a given fuel flow, you can only extract so much energy, so by imposing a max fuel flow rate you impose a limit on the amount of power that can be generated by the power unit.

I think the intention here was to stop teams spending money on developing power units with crazy qualifying modes - I'm thinking of the rumoured 1500+hp qualifying engines of the 80s.

For PU manufacturers, the fuel flow limit rewards those that have the most efficient PUs, which aligns with their commercial aims. Also by having a fuel flow limit, different engines will converge over time in their maximum power output as they approach the theoretical efficiency limits of hybrid power units (somewhere around 50%).

What I don't understand is why we have the fuel allowance for a race (currently 110kg, up from 105kg last year). Every kg of fuel that a car starts with in the race is a weight penalty. A team will calculate the amount of fuel they will need to give the fastest time to the flag. This may include some lift-and-coast fuel saving on some tracks, depending on the fuel consumption - and we know many teams short-fill their cars based on this calculation.

But my point is that the amount of fuel is self limiting. No team is going to carry more fuel than they calculate is the optimal amount so why mandate a maximum?

[Jolle]

Else teams would give the car a 180 kg of fuel and run the PU 100% all of the time (as in, during braking, mid corner, etc) to charge up the e-systems.

[Big Tea]

Else teams would give the car a 180 kg of fuel and run the PU 100% all of the time (as in, during braking, mid corner, etc) to charge up the e-systems.

Thinking on this, would it be such a bad thing? (literally, just daydreaming)

Exhaust blowing is banned so that would not be used, and an engine must be more efficient and less stressed run at constant RPM than throttle and rev up and down. This could be a good tie up to road car hybrid.

CVT is banned, but I don't know why, so maybe, if engineers are given free rein it is the right time to develop a new hybrid system?

Also, I dont know if the trade off between the extra weight and extra performance would be considered worth it, as both weight and power would come out of the tyres too.

[El Scorchio]

Wasn't there a thing years ago where a team or two had extra fuel tanks, so they put more fuel than was required in, but then dumped it as a way of gaming the minimum weight of the car regs? (or a cheeky way of distributing ballast?) The rule could be because of that? I could be remembering that a bit wrongly, though.

[Jolle]

Wasn't there a thing years ago where a team or two had extra fuel tanks, so they put more fuel than was required in, but then dumped it as a way of gaming the minimum weight of the car regs? (or a cheeky way of distributing ballast?) The rule could be because of that? I could be remembering that a bit wrongly, though.

It was BAR during the refuelling days, where they could run the car effectively under weight up to the last refuelling. Bit like the “water cooling” of brakes and engines back in the early eighties.

[Jolle]

Else teams would give the car a 180 kg of fuel and run the PU 100% all of the time (as in, during braking, mid corner, etc) to charge up the e-systems.

Thinking on this, would it be such a bad thing? (literally, just daydreaming)

Exhaust blowing is banned so that would not be used, and an engine must be more efficient and less stressed run at constant RPM than throttle and rev up and down. This could be a good tie up to road car hybrid.

CVT is banned, but I don't know why, so maybe, if engineers are given free rein it is the right time to develop a new hybrid system?

Also, I dont know if the trade off between the extra weight and extra performance would be considered worth it, as both weight and power would come out of the tyres too.

It wouldn’t be a bad thing per see, but it would be a different formula, not one they envisioned when starting with these regs.

[El Scorchio]

Wasn't there a thing years ago where a team or two had extra fuel tanks, so they put more fuel than was required in, but then dumped it as a way of gaming the minimum weight of the car regs? (or a cheeky way of distributing ballast?) The rule could be because of that? I could be remembering that a bit wrongly, though.

It was BAR during the refuelling days, where they could run the car effectively under weight up to the last refuelling. Bit like the “water cooling” of brakes and engines back in the early eighties.

Ah- there you go! Thanks
Actually I think I had gotten the BAR thing and the water cooling thing muddled up. It was water they dumped rather than fuel- because that would be INSANE....

[Just_a_fan]

What I don't understand is why we have the fuel allowance for a race (currently 110kg, up from 105kg last year). Every kg of fuel that a car starts with in the race is a weight penalty. A team will calculate the amount of fuel they will need to give the fastest time to the flag. This may include some lift-and-coast fuel saving on some tracks, depending on the fuel consumption - and we know many teams short-fill their cars based on this calculation.

But my point is that the amount of fuel is self limiting. No team is going to carry more fuel than they calculate is the optimal amount so why mandate a maximum?

Quite simply it's to drive the improvement of efficiency. The fuel flow limits the maximum theoretical power the ICE can generate on dino-juice alone, the total fuel allowance forces the teams to make the overall PU as efficient as possible - and it also makes them have the electrical bits. The rules are a way to try to make F1 look environmentally responsible and thus make the competing manufacturers look environmentally responsible.

If you let the teams run whatever fuel amount and fuel flow they wanted, they'd ditch the battery etc., and just run the ICE. More power and a car that gets much lighter as the race goes on.

But the manufacturers wanted to push the "green" aspect and the hybrid aspect in order to get a link with their road cars. So the hybrid stuff and fuel limits were brought in. You want to go quicker? Get more out of the limited fuel and maximise the hybrid stuff too.

And that's why the cars are running at somewhere around 50% thermal efficiency.

[Jolle]

Wasn't there a thing years ago where a team or two had extra fuel tanks, so they put more fuel than was required in, but then dumped it as a way of gaming the minimum weight of the car regs? (or a cheeky way of distributing ballast?) The rule could be because of that? I could be remembering that a bit wrongly, though.

It was BAR during the refuelling days, where they could run the car effectively under weight up to the last refuelling. Bit like the “water cooling” of brakes and engines back in the early eighties.

Ah- there you go! Thanks
Actually I think I had gotten the BAR thing and the water cooling thing muddled up. It was water they dumped rather than fuel- because that would be INSANE....

It was insane. They “allowed” it for the NA teams because there was just no way they could keep up with the (very expensive) turbo’s. Before weighing you were allowed to top up all fluids apart from fuel. But… to make it even more effective, Tyrrell added lead buckshot to the last filling, covering the whole pit with small balls. Because they did this in the “engine cooling” water tank, they got DQF for two seasons for using fuel additives.

[Just_a_fan]

Wasn't there a thing years ago where a team or two had extra fuel tanks, so they put more fuel than was required in, but then dumped it as a way of gaming the minimum weight of the car regs? (or a cheeky way of distributing ballast?) The rule could be because of that? I could be remembering that a bit wrongly, though.

It was BAR during the refuelling days, where they could run the car effectively under weight up to the last refuelling. Bit like the “water cooling” of brakes and engines back in the early eighties.

Ah- there you go! Thanks
Actually I think I had gotten the BAR thing and the water cooling thing muddled up. It was water they dumped rather than fuel- because that would be INSANE....

The water cooling of the brakes was one of F1's darkest episodes. Tyrrell added some lead weights to the refill water before the post-race weigh-in. They were allowed to replace the water but obviously the lead was a cheat. They got caught. Fair enough. And they were excluded from the championship which was very harsh. However, they were excluded not because of the cheat but because they weren't happy with some political moves going on off-track. By excluding the team, Tyrrell couldn't vote on the moves and thus was unable to prevent them.

[OO7]

Else teams would give the car a 180 kg of fuel and run the PU 100% all of the time (as in, during braking, mid corner, etc) to charge up the e-systems.

Thinking on this, would it be such a bad thing? (literally, just daydreaming)

Wouldn't that be a waste though? Rather than having the additional cost of the electrical system (battery, MGUs, cooling etc) and going around the houses converting fuel to ES energy (wasteful), why not just increase fuel flow to give another 160bhp?

[Big Tea]

Else teams would give the car a 180 kg of fuel and run the PU 100% all of the time (as in, during braking, mid corner, etc) to charge up the e-systems.

Thinking on this, would it be such a bad thing? (literally, just daydreaming)

Wouldn't that be a waste though? Rather than having the additional cost of the electrical system (battery, MGUs, cooling etc) and going around the houses converting fuel to ES energy (wasteful), why not just increase fuel flow to give another 160bhp?

That would be the easy and logical way, but as we know F1 does not take that route.
You are right of course, but manufacturers claim they would be attracted to F1 by road relevance, like making lightweight cars etc.

[Jolle]

Else teams would give the car a 180 kg of fuel and run the PU 100% all of the time (as in, during braking, mid corner, etc) to charge up the e-systems.

Thinking on this, would it be such a bad thing? (literally, just daydreaming)

Wouldn't that be a waste though? Rather than having the additional cost of the electrical system (battery, MGUs, cooling etc) and going around the houses converting fuel to ES energy (wasteful), why not just increase fuel flow to give another 160bhp?

I think cost isn’t really impacted with the complexity. If they would go for instance with a relative cheap solution: 4 cilinder inline with a big turbo, Daimler and Ferrari would still put about 1000 engineers on it to extract every last drop of performance out of it.
PU development cost the amount they decide, technical rules have quite limited influence on it. That’s why for the team as a whole (bar PU), the only solution was a financial addendum

[flynfrog]

Wasn't there a thing years ago where a team or two had extra fuel tanks, so they put more fuel than was required in, but then dumped it as a way of gaming the minimum weight of the car regs? (or a cheeky way of distributing ballast?) The rule could be because of that? I could be remembering that a bit wrongly, though.

water tanks for "brake cooling" on the last put stop they dropped a tungsten ball into the tank to get the weight up too

[Stu]

Else teams would give the car a 180 kg of fuel and run the PU 100% all of the time (as in, during braking, mid corner, etc) to charge up the e-systems.

…and the cars would be the size of a London bus…

…as opposed to a mini-bus!!