this is just me thinking out loud, so please, feel free to correct if you feel i'm on the wrong path.

i know in dry qualifying, running a heavy fuel load is pointless in Q2, because you'd want to keep the car light enough to make it into Q3, and you don't have to carry a race fuel load.

but in wet qualifying, like we saw today, would it be possible that there would be a benefit to running heavy? given the low downforce packages the teams were running at monza, would a heavy fuel load possibly help in terms of aiding traction? that would be beneficial because in the conditions we saw, it wasn't so much an issue of sheer pace, so much as who could find the most grip to use whatever power they could.

any thoughts?...

I got the impression that they had trouble getting up to tyre temp and brake temp in these conditions (on top of having to deal with the track conditions and aquaplaning risk at Ascari where there was standing water deep enough that the tyre grooves couldn't channel them out fast enough).

So running heavy not only affects rear weight bias traction but also allows them to run longer laps per stint to get those temps up before banking in a decent laptime.

BTW for the race, if the conditions remain the same as qualies, running a longer first stint into the 20-21 laps region rather than 17-18 laps or a 1 stopper in the ballpark of 25-31 laps in the first stint wouldn't be so bad in that you could cover for whatever your rival filled up to and also cover for a SC.

Marshall,

Running heavy on fuel does not aid traction per se. It affects the balance of the car. Grip comes from friction between the tire and the pavement. It is true that more weight equals more grip. But grip is generated as counter to centrifugal force and centrifugal force is directly proportional to the weight of the car. In other words, the extra fuel weight that would generate more grip is cancelled out by a bigger centrifugal force resulting from heavier weight.

basque - 14 September 2008 01:23 AM

Marshall,

Running heavy on fuel does not aid traction per se. It affects the balance of the car. Grip comes from friction between the tire and the pavement. It is true that more weight equals more grip. But grip is generated as counter to centrifugal force and centrifugal force is directly proportional to the weight of the car. In other words, the extra fuel weight that would generate more grip is cancelled out by a bigger centrifugal force resulting from heavier weight.

Basque,
In the rain due to the lack of G force generated not only in cornering but also in acceleration and braking, weight transfer and as much of it to corners of the car that need it, as fast as possilbe, is the only way to get grip in the rain. As none of the cars can put down all of their power and don't get close to the high top speed they have in the dry, the added weight makes little difference and can actually help lower the possiblity of hydroplaning. Lighter cars are more prone to it. It is on a damp track or drying track, not a wet one, that the weight would start to show the difference
A full on rain setup would have soft springs, the dampers all but disconnected, sway bars (if they have them) disconnected and as much downforce as is humanly possible. Brake bias towards the rear. The ride height would set up higher, to prevent the bottom of the car acting like a surf board or a keel of a sailboat.

So as you can see, everything is done to allow the weight to move and as much of it as possible. So the added fuel weight could actually help the car.

speedsense - 14 September 2008 02:09 AM

basque - 14 September 2008 01:23 AM

Marshall,

Running heavy on fuel does not aid traction per se. It affects the balance of the car. Grip comes from friction between the tire and the pavement. It is true that more weight equals more grip. But grip is generated as counter to centrifugal force and centrifugal force is directly proportional to the weight of the car. In other words, the extra fuel weight that would generate more grip is cancelled out by a bigger centrifugal force resulting from heavier weight.

Basque,
In the rain due to the lack of G force generated not only in cornering but also in acceleration and braking, weight transfer and as much of it to corners of the car that need it, as fast as possilbe, is the only way to get grip in the rain. As none of the cars can put down all of their power and don't get close to the high top speed they have in the dry, the added weight makes little difference and can actually help lower the possiblity of hydroplaning. Lighter cars are more prone to it. It is on a damp track or drying track, not a wet one, that the weight would start to show the difference or degrade the handling.
A full on rain setup would have soft springs, the dampers all but disconnected, sway bars (if they have them) disconnected and as much downforce as is humanly possible. Brake bias towards the rear. The ride height would set up higher, to prevent the bottom of the car acting like a surf board or a keel of a sailboat.

So as you can see, everything is done to allow the weight to move and as much of it as possible. So the added fuel weight could actually help the car.

speedsense - 14 September 2008 02:09 AM

The ride height would set up higher, to prevent the bottom of the car acting like a surf board or a keel of a sailboat.

Everything that he said except that last one. The keel of a sailboat has very little to do with keeping it afloat, and more to do with keeping it upright and act as a resistance force against which the wind can push the craft.
But we all knew that you meant 'hull' and 'powerboat'.

speedsense - 14 September 2008 02:09 AM

basque - 14 September 2008 01:23 AM

Marshall,

Running heavy on fuel does not aid traction per se. It affects the balance of the car. Grip comes from friction between the tire and the pavement. It is true that more weight equals more grip. But grip is generated as counter to centrifugal force and centrifugal force is directly proportional to the weight of the car. In other words, the extra fuel weight that would generate more grip is cancelled out by a bigger centrifugal force resulting from heavier weight.

Basque,
In the rain due to the lack of G force generated not only in cornering but also in acceleration and braking, weight transfer and as much of it to corners of the car that need it, as fast as possilbe, is the only way to get grip in the rain. As none of the cars can put down all of their power and don't get close to the high top speed they have in the dry, the added weight makes little difference and can actually help lower the possiblity of hydroplaning. Lighter cars are more prone to it. It is on a damp track or drying track, not a wet one, that the weight would start to show the difference
A full on rain setup would have soft springs, the dampers all but disconnected, sway bars (if they have them) disconnected and as much downforce as is humanly possible. Brake bias towards the rear. The ride height would set up higher, to prevent the bottom of the car acting like a surf board or a keel of a sailboat.

So as you can see, everything is done to allow the weight to move and as much of it as possible. So the added fuel weight could actually help the car.

Hydroplaning occurs when the tires cannot evacuate enough water through the thread and a film of water develops between the pavement and the tire. Weight of the car has very little to do with it. Width and characteristics of the tire and the speed of the car are more relevant. The question was about grip. When turning, accelerating or breaking, in normal circumstances where the tire is touching the pavement, extra weight generates more grip, but you have a heavier car accelerating, turning or breaking (more stress on the tyre). In fact, you could increase centrifugal force indefinitely by adding weight, but the grip will have a limit based on your tire characteristics. Grip is generated as a reaction to centrifugal or breaking force. There is nothing preventing F1 teams from adding kilos of lead when driving in the rain. Nobody does it.

basque - 14 September 2008 02:35 AM

speedsense - 14 September 2008 02:09 AM

basque - 14 September 2008 01:23 AM

Marshall,

Running heavy on fuel does not aid traction per se. It affects the balance of the car. Grip comes from friction between the tire and the pavement. It is true that more weight equals more grip. But grip is generated as counter to centrifugal force and centrifugal force is directly proportional to the weight of the car. In other words, the extra fuel weight that would generate more grip is cancelled out by a bigger centrifugal force resulting from heavier weight.

Basque,
In the rain due to the lack of G force generated not only in cornering but also in acceleration and braking, weight transfer and as much of it to corners of the car that need it, as fast as possilbe, is the only way to get grip in the rain. As none of the cars can put down all of their power and don't get close to the high top speed they have in the dry, the added weight makes little difference and can actually help lower the possiblity of hydroplaning. Lighter cars are more prone to it. It is on a damp track or drying track, not a wet one, that the weight would start to show the difference
A full on rain setup would have soft springs, the dampers all but disconnected, sway bars (if they have them) disconnected and as much downforce as is humanly possible. Brake bias towards the rear. The ride height would set up higher, to prevent the bottom of the car acting like a surf board or a keel of a sailboat.

So as you can see, everything is done to allow the weight to move and as much of it as possible. So the added fuel weight could actually help the car.

Hydroplaning occurs when the tires cannot evacuate enough water through the thread and a film of water develops between the pavement and the tire. Weight of the car has very little to do with it. Width and characteristics of the tire and the speed of the car are more relevant. The question was about grip. When turning, accelerating or breaking, in normal circumstances in where the tire is touching the pavement, extra weight generates more grip, but you have a heavier car accelerating, turning or breaking (more stress on the tyre). Grip is generated as a reaction to centrifugal or breaking force. There is nothing preventing F1 teams from adding kilos of lead when driving in the rain. Nobody does it.

Weight has to do with how long the car hydroplanes and how much, a lighter car will stay hydroplaning longer and more frequently. Just like more downforce creates least hydroplaning, weight also effects it. (think about a boat in water, where do the light ones ride given the same speed?)
In terms of grip in the wet, you are talking about a lot less movement (in the car) than is generated in the dry. None of the parameters of the traction circle are unaffected. The braking is the only part of it that is even remotely close to the grip level in the dry,given a fresh set of rains and not worn ones.
No one is going to add unneeded weight. The point is the full load can only make a difference if you have a reasonable amount of weight transfer. In heavy wet conditions, you have so little weight transfer and acceleration ability that the fuel weight wouldn't make a lot of difference. The added weight of the fuel load may actually help acceleration and not hinder it. It all depends on the track surface and the grip level availiable, amount of puddles, etc.
Now at the end of the straightaway, different story, the weight will show it's difference as none of the traction circle is being used and the downforce comes on. This is a double edged sword. Trade acceleration and potiental top speed for less acceleration (due to less weight transfer) and the effects at the end of the straightaway. IMHO, it's too close to determine if 100 lbs of will make any difference.
Given that a few of the cars are on a dry setup, it may be the added weight of fuel could help the car get off a corner better by adding some weight transfer with a less than optimum rain setup.

speedsense - 14 September 2008 02:52 AM

basque - 14 September 2008 02:35 AM

speedsense - 14 September 2008 02:09 AM

basque - 14 September 2008 01:23 AM

Marshall,

Running heavy on fuel does not aid traction per se. It affects the balance of the car. Grip comes from friction between the tire and the pavement. It is true that more weight equals more grip. But grip is generated as counter to centrifugal force and centrifugal force is directly proportional to the weight of the car. In other words, the extra fuel weight that would generate more grip is cancelled out by a bigger centrifugal force resulting from heavier weight.

Basque,
In the rain due to the lack of G force generated not only in cornering but also in acceleration and braking, weight transfer and as much of it to corners of the car that need it, as fast as possilbe, is the only way to get grip in the rain. As none of the cars can put down all of their power and don't get close to the high top speed they have in the dry, the added weight makes little difference and can actually help lower the possiblity of hydroplaning. Lighter cars are more prone to it. It is on a damp track or drying track, not a wet one, that the weight would start to show the difference
A full on rain setup would have soft springs, the dampers all but disconnected, sway bars (if they have them) disconnected and as much downforce as is humanly possible. Brake bias towards the rear. The ride height would set up higher, to prevent the bottom of the car acting like a surf board or a keel of a sailboat.

So as you can see, everything is done to allow the weight to move and as much of it as possible. So the added fuel weight could actually help the car.

Hydroplaning occurs when the tires cannot evacuate enough water through the thread and a film of water develops between the pavement and the tire. Weight of the car has very little to do with it. Width and characteristics of the tire and the speed of the car are more relevant. The question was about grip. When turning, accelerating or breaking, in normal circumstances in where the tire is touching the pavement, extra weight generates more grip, but you have a heavier car accelerating, turning or breaking (more stress on the tyre). Grip is generated as a reaction to centrifugal or breaking force. There is nothing preventing F1 teams from adding kilos of lead when driving in the rain. Nobody does it.

Weight has to do with how long the car hydroplanes and how much, a lighter car will stay hydroplaning longer and more frequently. Just like more downforce creates least hydroplaning, weight also effects it. (think about a boat in water, where do the light ones ride given the same speed?)
In terms of grip in the wet, you are talking about a lot less movement (in the car) than is generated in the dry. None of the parameters of the traction circle are unaffected. The braking is the only part of it that is even remotely close to the grip level in the dry,given a fresh set of rains and not worn ones.
No one is going to add unneeded weight. The point is the full load can only make a difference if you have a reasonable amount of weight transfer. In heavy wet conditions, you have so little weight transfer and acceleration ability that the fuel weight wouldn't make a lot of difference. The added weight of the fuel load may actually help acceleration and not hinder it. It all depends on the track surface and the grip level availiable, amount of puddles, etc.
Now at the end of the straightaway, different story, the weight will show it's difference as none of the traction circle is being used and the downforce comes on. This is a double edged sword. Trade acceleration and potiental top speed for less acceleration (due to less weight transfer) and the effects at the end of the straightaway. IMHO, it's too close to determine if 100 lbs of will make any difference.
Given that a few of the cars are on a dry setup, it may be the added weight of fuel could help the car get off a corner better by adding some weight transfer with a less than optimum rain setup.

All I have to say to this is watch today's race. All commentator's were saying that on the first stint, Vettel was lower on fuel and that this would represent an advantage when trying to open a gap to Heikki (track was really wet). We can argue this until the cows come home, but the reality of racing is that nobody adds gas on rainy conditions to increase grip. Case closed.

basque - 14 September 2008 12:25 PM

speedsense - 14 September 2008 02:52 AM

basque - 14 September 2008 02:35 AM

speedsense - 14 September 2008 02:09 AM

basque - 14 September 2008 01:23 AM

Marshall,

Running heavy on fuel does not aid traction per se. It affects the balance of the car. Grip comes from friction between the tire and the pavement. It is true that more weight equals more grip. But grip is generated as counter to centrifugal force and centrifugal force is directly proportional to the weight of the car. In other words, the extra fuel weight that would generate more grip is cancelled out by a bigger centrifugal force resulting from heavier weight.

Basque,
In the rain due to the lack of G force generated not only in cornering but also in acceleration and braking, weight transfer and as much of it to corners of the car that need it, as fast as possilbe, is the only way to get grip in the rain. As none of the cars can put down all of their power and don't get close to the high top speed they have in the dry, the added weight makes little difference and can actually help lower the possiblity of hydroplaning. Lighter cars are more prone to it. It is on a damp track or drying track, not a wet one, that the weight would start to show the difference
A full on rain setup would have soft springs, the dampers all but disconnected, sway bars (if they have them) disconnected and as much downforce as is humanly possible. Brake bias towards the rear. The ride height would set up higher, to prevent the bottom of the car acting like a surf board or a keel of a sailboat.

So as you can see, everything is done to allow the weight to move and as much of it as possible. So the added fuel weight could actually help the car.

Hydroplaning occurs when the tires cannot evacuate enough water through the thread and a film of water develops between the pavement and the tire. Weight of the car has very little to do with it. Width and characteristics of the tire and the speed of the car are more relevant. The question was about grip. When turning, accelerating or breaking, in normal circumstances in where the tire is touching the pavement, extra weight generates more grip, but you have a heavier car accelerating, turning or breaking (more stress on the tyre). Grip is generated as a reaction to centrifugal or breaking force. There is nothing preventing F1 teams from adding kilos of lead when driving in the rain. Nobody does it.

Weight has to do with how long the car hydroplanes and how much, a lighter car will stay hydroplaning longer and more frequently. Just like more downforce creates least hydroplaning, weight also effects it. (think about a boat in water, where do the light ones ride given the same speed?)
In terms of grip in the wet, you are talking about a lot less movement (in the car) than is generated in the dry. None of the parameters of the traction circle are unaffected. The braking is the only part of it that is even remotely close to the grip level in the dry,given a fresh set of rains and not worn ones.
No one is going to add unneeded weight. The point is the full load can only make a difference if you have a reasonable amount of weight transfer. In heavy wet conditions, you have so little weight transfer and acceleration ability that the fuel weight wouldn't make a lot of difference. The added weight of the fuel load may actually help acceleration and not hinder it. It all depends on the track surface and the grip level availiable, amount of puddles, etc.
Now at the end of the straightaway, different story, the weight will show it's difference as none of the traction circle is being used and the downforce comes on. This is a double edged sword. Trade acceleration and potiental top speed for less acceleration (due to less weight transfer) and the effects at the end of the straightaway. IMHO, it's too close to determine if 100 lbs of will make any difference.
Given that a few of the cars are on a dry setup, it may be the added weight of fuel could help the car get off a corner better by adding some weight transfer with a less than optimum rain setup.

All I have to say to this is watch today's race. All commentator's were saying that on the first stint, Vettel was lower on fuel and that this would represent an advantage when trying to open a gap to Heikki (track was really wet). We can argue this until the cows come home, but the reality of racing is that nobody adds gas on rainy conditions to increase grip. Case closed.

I guess Hamilton being the last one to pit (heaviest on fuel) in the first stint and setting the fastest race laptimes during the stint (up to that point), kinda blows a few holes in yours and the commentators theories.

Psyd - 14 September 2008 02:16 AM

speedsense - 14 September 2008 02:09 AM

The ride height would set up higher, to prevent the bottom of the car acting like a surf board or a keel of a sailboat.

Everything that he said except that last one. The keel of a sailboat has very little to do with keeping it afloat, and more to do with keeping it upright and act as a resistance force against which the wind can push the craft.
But we all knew that you meant 'hull' and 'powerboat'.

No, I did mean keel. If the car were to go over a curb and scoop a puddle at the same time, it will pull the car in that direction and will also pull the car down, just like a t-shaped keel would.