2017 tyre testing cars

[cooken]

but wouldn't the lesser loss of speed also signify you dont 'need' to regain that speed lost, which costs more fuel in comparison, or am i way off here?

Only if you'd stay at the same speed as if you did not have the extra grip (you'd leverage that extra speed for lift and coast). If not, you'd be earlier on the throttle, longer on the throttle and longer in the higher, more fuel consuming range of rpm.

I don't understand what you mean by stay at the same speed as if you did not have extra grip. Can you elaborate?

Aside from that, you can't just look at the difference in average fuel flow rate. The cars will be going ~5 seconds a lap quicker or whatever it works out to be, meaning that they will be consuming fuel faster for less time. Whether that ends up being less fuel mass consumed over a lap or race distance would be down to many other variables.

In your example if the faster car gets to the next corner 1s quicker it would actually burn less fuel despite the higher consumption rate (if I scribbled the math right).

Edit: D'oh, I missed a full page of people going over this. Forgot to refresh browser

[turbof1]

but wouldn't the lesser loss of speed also signify you dont 'need' to regain that speed lost, which costs more fuel in comparison, or am i way off here?

Only if you'd stay at the same speed as if you did not have the extra grip (you'd leverage that extra speed for lift and coast). If not, you'd be earlier on the throttle, longer on the throttle and longer in the higher, more fuel consuming range of rpm.

I don't understand what you mean by stay at the same speed as if you did not have extra grip. Can you elaborate?

Aside from that, you can't just look at the difference in average fuel flow rate. The cars will be going ~5 seconds a lap quicker or whatever it works out to be, meaning that they will be consuming fuel faster for less time. Whether that ends up being less fuel mass consumed over a lap or race distance would be down to many other variables.

In your example if the faster car gets to the next corner 1s quicker it would actually burn less fuel despite the higher consumption rate (if I scribbled the math right).

Edit: D'oh, I missed a full page of people going over this. Forgot to refresh browser

I meant same laptime. Having a faster car (let's assume same drag level, higher downforce) drive the same laptime as the slower car, leads to a better fuel efficiency then the slower car has.

Again, I do want to apology for the rather crude model I made. I indeed omitted speed, which I probably should not have. Fuel flow rate goes up, let's agree on that.

[mrluke]

I fail to see how total fuel requirements is irrelevant to a discussion on whether the drivers will run out of fuel.

Even over the last 3 years we have seen fuel usage drop dramatically despite lap times decreasing.

This years Mexican grand prix was around 2.5 minutes shorter than last year meaning the cars were on average around 2s per lap faster. Was fuel saving "through the roof"?

This whole fixed fuel rate formula requires you to think about it a little differently to the traditional fixed air flow formulas.

[cooken]

I meant same laptime. Having a faster car (let's assume same drag level, higher downforce) drive the same laptime as the slower car, leads to a better fuel efficiency then the slower car has.

Ah ok that makes sense now, thanks.

Again, I do want to apology for the rather crude model I made. I indeed omitted speed, which I probably should not have. Fuel flow rate goes up, let's agree on that.

Don't apologize - we all need crude models to grasp things and it served to illustrate the higher rate.

I don't think anyone can categorically state the cars will use more or less fuel. Too many variables and it will depend on the track. Regardless, the cars should be more exciting to watch.

[henry]

I fail to see how total fuel requirements is irrelevant to a discussion on whether the drivers will run out of fuel.

Even over the last 3 years we have seen fuel usage drop dramatically despite lap times decreasing.

This years Mexican grand prix was around 2.5 minutes shorter than last year meaning the cars were on average around 2s per lap faster. Was fuel saving "through the roof"?

This whole fixed fuel rate formula requires you to think about it a little differently to the traditional fixed air flow formulas.

I think your method is very useful. However I think it needs some refinement.

The drivers are not on the throttle for the whole lap. They spend time on the brakes and some cornering is done off throttle.

I timed the amount of time off throttle from this year's qualifying lap. It was 24 seconds. So race time on throttle goes down from 1h40 to 1h12 and average fuel rate becomes 83kg/hr. If the cars take 5.5 mins less next year the average fuel rate goes to 90kg/hr. a rise of 8%.

it might be possible to refine this by including other off throttle periods, such as braking into the pits, and making allowance for less aggressive driving in the race as opposed to qualifying but they would be guesses as is the estimate of lap time improvement.

[mrluke]

I think your method is very useful. However I think it needs some refinement.

The drivers are not on the throttle for the whole lap. They spend time on the brakes and some cornering is done off throttle.

I timed the amount of time off throttle from this year's qualifying lap. It was 24 seconds. So race time on throttle goes down from 1h40 to 1h12 and average fuel rate becomes 83kg/hr. If the cars take 5.5 mins less next year the average fuel rate goes to 90kg/hr. a rise of 8%.

it might be possible to refine this by including other off throttle periods, such as braking into the pits, and making allowance for less aggressive driving in the race as opposed to qualifying but they would be guesses as is the estimate of lap time improvement.

Agree with your thoughts.

You could probably consider the entire time spent in the pits from braking to the limiter all the way up to exiting the pitlane which is typically 20-25s.

Then you have the safety car / virtual safety car periods to take into account.

[henry]

I think your method is very useful. However I think it needs some refinement.

The drivers are not on the throttle for the whole lap. They spend time on the brakes and some cornering is done off throttle.

I timed the amount of time off throttle from this year's qualifying lap. It was 24 seconds. So race time on throttle goes down from 1h40 to 1h12 and average fuel rate becomes 83kg/hr. If the cars take 5.5 mins less next year the average fuel rate goes to 90kg/hr. a rise of 8%.

it might be possible to refine this by including other off throttle periods, such as braking into the pits, and making allowance for less aggressive driving in the race as opposed to qualifying but they would be guesses as is the estimate of lap time improvement.

Agree with your thoughts.

You could probably consider the entire time spent in the pits from braking to the limiter all the way up to exiting the pitlane which is typically 20-25s.

Then you have the safety car / virtual safety car periods to take into account.

Yes I had thought that is how pit stops might be accounted. I hadn't considered safety cars.

It might be a useful exercise to look at the part throttle usage, taking off full throttle as well as no throttle. That is probably the thing that will change most in 2017. The full throttle will be extended by earlier traction and later braking, the former will extend the "part throttle" the latter reduce the non throttle time.

I have been playing with some numbers just_a_fan posted in the W07 thread that might give a hint at the effect from the change in grip we might look forward to next year. It might give a feel for how tight, or otherwise, the 105 kg might be. So far I've done it as a respite from counting sheep. I'll see if I can turn it into something useful.

[mrluke]

later braking maybe, but given the cars will exit corners at a higher speed and with more traction available, will their time on the straight also be shorter?

Personally there are too many variables at play for me to get a gut feel on where the right answer lies which makes me suspect that overall its going to end up being pretty similar to today.

[Henk]

I think your method is very useful. However I think it needs some refinement.

The drivers are not on the throttle for the whole lap. They spend time on the brakes and some cornering is done off throttle.

I timed the amount of time off throttle from this year's qualifying lap. It was 24 seconds. So race time on throttle goes down from 1h40 to 1h12 and average fuel rate becomes 83kg/hr. If the cars take 5.5 mins less next year the average fuel rate goes to 90kg/hr. a rise of 8%.

it might be possible to refine this by including other off throttle periods, such as braking into the pits, and making allowance for less aggressive driving in the race as opposed to qualifying but they would be guesses as is the estimate of lap time improvement.

Agree with your thoughts.

You could probably consider the entire time spent in the pits from braking to the limiter all the way up to exiting the pitlane which is typically 20-25s.

Then you have the safety car / virtual safety car periods to take into account.

Yes I had thought that is how pit stops might be accounted. I hadn't considered safety cars.

It might be a useful exercise to look at the part throttle usage, taking off full throttle as well as no throttle. That is probably the thing that will change most in 2017. The full throttle will be extended by earlier traction and later braking, the former will extend the "part throttle" the latter reduce the non throttle time.

I have been playing with some numbers just_a_fan posted in the W07 thread that might give a hint at the effect from the change in grip we might look forward to next year. It might give a feel for how tight, or otherwise, the 105 kg might be. So far I've done it as a respite from counting sheep. I'll see if I can turn it into something useful.

I also think a qualifying lap is not representative of an early race lap. They'll be later on the power earlier on the brakes. I think there should be some fuel there.

[henry]

Agree with your thoughts.

You could probably consider the entire time spent in the pits from braking to the limiter all the way up to exiting the pitlane which is typically 20-25s.

Then you have the safety car / virtual safety car periods to take into account.

Yes I had thought that is how pit stops might be accounted. I hadn't considered safety cars.

It might be a useful exercise to look at the part throttle usage, taking off full throttle as well as no throttle. That is probably the thing that will change most in 2017. The full throttle will be extended by earlier traction and later braking, the former will extend the "part throttle" the latter reduce the non throttle time.

I have been playing with some numbers just_a_fan posted in the W07 thread that might give a hint at the effect from the change in grip we might look forward to next year. It might give a feel for how tight, or otherwise, the 105 kg might be. So far I've done it as a respite from counting sheep. I'll see if I can turn it into something useful.

I also think a qualifying lap is not representative of an early race lap. They'll be later on the power earlier on the brakes. I think there should be some fuel there.

Of course that is true.

What we are trying to get at is a feel for whether the increase in fuel allowance from 100 to 105 kg/hr is likely to increase or decrease the need to fuel save. Any difference between qualifying laps and race laps is potentially going to be similar between this year and next year, so the absolute numbers might change but the ratios should be similar.

I don't think we have a useful answer yet but I think mrluke's approach points at a way forward.

[hollus]

One must account for the increase in drag reducing maximum speeds.
In a small stright, what was the full throttle section in 2016 will still be full throttle in 2017 but it will likely have a higher average speed due to higher corner exit speeds, hence last less, hence need less fuel.
In a long straight where cars approach terminal speeds, the 2017 car will need more time to cover the same section of road due to lower top speeds, and it will need more fuel for that section.
This needs a proper model, intution is hard to apply.

[f1316]

There's also a question of whether saving brakes will necessitate lifting and coasting and hence, if it's happening anyway, you might as well factor that into your fuel usage.

We heard from Mercedes in Singapore that it was entirely intentional to have to save their brakes throughout the Grand Prix - it's quicker to design the ducts for optimal one lap performance and save them in the race, given you can't push the tyres in the race anyway, than create enough brake tolerance to survive being pushed throughout the Grand Prix.

Again, the extent to which the tyres will hold up during the race completely dictates this and hence is all important for a number of different parameters.

[godlameroso]

Next year where cars would routinely hit ~330kph they'll be more likely to hit 322ish. Drag will only be an issue in long straights.

[Restomaniac]

It would seem that in today's testing Hamilton has turned up unexpected by Pirell.
It's now Kimi for Ferarri.
Wehrlein and Hamilton for Merc.
Ricciardo and Verstappen for Red Bull.

[ThumbsUp]

Quick question: Are they now allowed to test the new tires with the current car with some modifications for more downforce?