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10 Apr 2014, 14:08 (Ref:3390785)
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#3466
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Veteran
Join Date: Sep 2010
Posts: 943
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10 Apr 2014, 17:46 (Ref:3390828)
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#3467
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Veteran
Join Date: Nov 2013
Posts: 734
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So not only does diesel car has smaller fuel tanks but also smaller refueling systems to balance their pitstop times I believe. But should it? The advantage of shorter refueling time cannot even compensate the deficit in stint distances. This really annoys me.
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__________________
Eat, sleep, race, repeat.
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10 Apr 2014, 18:31 (Ref:3390837)
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#3468
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Veteran
Join Date: Sep 2010
Posts: 14,297
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Will they have shorter stints? I'm not so sure.
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11 Apr 2014, 04:06 (Ref:3390952)
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#3469
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Veteran
Join Date: Nov 2013
Posts: 734
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Quote:
Originally Posted by TF110
Will they have shorter stints? I'm not so sure.
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Numbers speak louder than wild guessing.
Quote:
Originally Posted by JoestForEver
Ok, a bit more computing here, hopefully not too scary.
Based on @MyNameIsNigel 's figure, we have
FTFave=1.074
FTFMax=1.088
KTF=0.987
Penergy(allocation)=139.5 MJ/lap
Pflow=89.5 kg/h
Ptank=68.3L
Denergy=138.7 MJ/lap
Dflow=80.2 kg/h
Dtank=54.3L
As published lately, ACO/FIA decides the fuel type should be E20/B10 diesel(base bio 10%). Source: http://www.fia.com/sites/default/fil..._2014_fuel.pdf
For convenience and data availability, we refer to B20 diesel for energy density per kg.
http://www.rms.nsw.gov.au/heavyvehic...-biodiesel.pdf shows B20 is 2% down on energy comparing with petroleum diesel at 38.6MJ/L
http://www.biodiesel.org/docs/ffs-ba...5.pdf?sfvrsn=6 shows the density of B20 is 0.856
http://psrcentre.org/images/extraimages/212181.pdf reveals the energy density of E20 at 15 degrees Celsius is 32.43 MJ/L with 0.7541 kg/L.
As a result, the ED(petrol) and ED(diesel) in the formula of FTF should be 43MJ/kg and 44.19 MJ/kg respectively, which allows us to compute the ratio of BSFC(petrol) and BSFC(diesel) average. And the answer is 1.103, bigger than 1.090 previously. As for BSFCmax(petrol)/BSFCmax(diesel), it is 1.12 now. Diesel is still superior at peak power economy.
In terms of E(additional) (a.k.a, additional allocated diesel energy due to technology differences.), we can know easily compute it by maneuvering the formula of KTF. And the result is 1.71 MJ comparing with 2.24 MJ in the past.
So now what? We can compare stint lengths of petrol and diesel class based on BSFC fuel consumption and fuel tank volume. The ratio of petrol and diesel is 1.14 against 1.12 in the past.
However, the final number actually means nothing other than its relative relationship as it is not the fuel consumption per lap or per minute. It only means that although Audi is making progress in fuel economy, it still needs more pitstop than Toyota and Porsche. Thanks to the reduction in fuel tank volume, the more economic diesel engine is forcing Audi to refuel more! Ridiculous I'd say. Unless Audi's pace is better than Toyota and the gap is greater than 2013. There's no way it is going to win anything.
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__________________
Eat, sleep, race, repeat.
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11 Apr 2014, 08:56 (Ref:3390993)
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#3470
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Veteran
Join Date: Sep 2010
Posts: 14,297
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I will wait until Silverstone to see who goes how far.
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11 Apr 2014, 10:10 (Ref:3391008)
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#3471
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Veteran
Join Date: Feb 2013
Posts: 2,132
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Quote:
Originally Posted by JoestForEver
Numbers speak louder than wild guessing. 
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With these figures, the minimum fuel autonomy for Porsche and Toyota at LM would increase to more than 15 laps (assuming that all the fuel energy allocation is consumed at each lap):
(32.43 MJ/l * 68.3 l) / 139.5 MJ/lap = 15.88 laps
They could potentially stretch the stints to 16 laps at LM.
As for Audi, the minimum fuel autonomy would increase to more than 14 laps:
(27.83 MJ/l * 54.3 l) / 138.7 MJ/lap = 14.81 laps
That is still one lap less than Porsche and Toyota, but Audi could likewise try to stretch the stints to 15 laps at LM.
It is however far from being an ideal situation for Rebellion Racing (and Lotus, if they ever make it to the race track...) which would end up with a minimum fuel autonomy of slightly more than 14 laps at LM:
(32.43 MJ/l * 68.3 l) / 157.2 MJ/lap = 14.09 laps
In that respect, I am a bit surprised that the Endurance Committee did not increase the fuel tank capacity in the LMP1-L class.
Obviously, the above is only based on revised assumptions concerning the relevant fuel specifications. Aren't Shell going to make those specifications public BTW ?
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__________________
In order to finish first, first you have to finish
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20 Apr 2014, 10:14 (Ref:3395430)
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#3472
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Veteran
Join Date: Jun 2010
Posts: 9,868
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So I was wondering, if there's a situation at LM where P1 team has exceeded BSFC by more than 2% and refuses to take the in-race penalty as said below:
"If the competitor refuses the penalty, the final classification will be published subject to further investigations, with possible exclusion following the race, further to detailed analysis between the FIA and the competitor: “dissuasive penalty”. The detailed post race analysis could involve tests and inspections with the competitor or elsewhere (calibration sensor check), and will include an analysis of the other data at the disposal of the FIA (reverse engineering)"
but then goes to win the race - do we really think that FIA and ACO would later disqualify the winner of the largest motor race in the world? It would be one of the biggest farces in decades, whichever stand they take (whether they disqualify the team in question OR not). Just utterly terrible PR.
Why did they leave the door open for teams not to accept the in-race penalties (stop and gos)? What exactly was the thought process in this...
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20 Apr 2014, 10:42 (Ref:3395448)
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#3473
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Veteran
Join Date: Feb 2013
Posts: 2,132
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Quote:
Originally Posted by Chiana
So I was wondering, if there's a situation at LM where P1 team has exceeded BSFC by more than 2% and refuses to take the in-race penalty as said below:
"If the competitor refuses the penalty, the final classification will be published subject to further investigations, with possible exclusion following the race, further to detailed analysis between the FIA and the competitor: “dissuasive penalty”. The detailed post race analysis could involve tests and inspections with the competitor or elsewhere (calibration sensor check), and will include an analysis of the other data at the disposal of the FIA (reverse engineering)"
but then goes to win the race - do we really think that FIA and ACO would later disqualify the winner of the largest motor race in the world? It would be one of the biggest farces in decades, whichever stand they take (whether they disqualify the team in question OR not). Just utterly terrible PR.
Why did they leave the door open for teams not to accept the in-race penalties (stop and gos)? What exactly was the thought process in this...
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Disqualification may indeed be the likely outcome, but this at least leaves a chance to appeal the decision if the relevant manufacturer believes that this is not justified. You cannot appeal a stop-and-go penalty, nor any other penalty imposed during the race.
I am keeping my fingers crossed and hope that we shall not experience such a mess.
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__________________
In order to finish first, first you have to finish
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20 Apr 2014, 16:07 (Ref:3395725)
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#3475
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Veteran
Join Date: Jan 2010
Posts: 6,229
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Quote:
Originally Posted by Chiana
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Different fuel specification for Le Mans? Or different refuelling pump supplier?
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__________________
When in doubt? C4.
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20 Apr 2014, 16:09 (Ref:3395726)
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#3476
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Veteran
Join Date: Jun 2010
Posts: 9,868
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24h-lemans says
"Note that height of the fuel reserves (in the pits) is 2.60 m at Le Mans and 2 m at the other circuits."
? Has that anything to do with that. No? Wouldn't explain diesel staying same
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20 Apr 2014, 16:32 (Ref:3395744)
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#3477
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Veteran
Join Date: Jan 2010
Posts: 6,229
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Quote:
Originally Posted by Chiana
24h-lemans says
"Note that height of the fuel reserves (in the pits) is 2.60 m at Le Mans and 2 m at the other circuits."
? Has that anything to do with that. No? Wouldn't explain diesel staying same
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Diesel and petrol do flow differently, different chemical compounds, density and viscosity, so I suspect that's what they took into account. And the fuelling systems are gravity-fed, not pressurised.
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__________________
When in doubt? C4.
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21 Apr 2014, 16:11 (Ref:3396245)
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#3478
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Subscriber
Veteran
Join Date: Sep 2009
Posts: 2,817
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Any mention of F1/Red Bull style problems with the homologated FIA fuel sensors this past weekend?
Richard
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21 Apr 2014, 16:13 (Ref:3396246)
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#3479
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Veteran
Join Date: Feb 2013
Posts: 2,132
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Quote:
Originally Posted by Richard Casto
Any mention of F1/Red Bull style problems with the homologated FIA fuel sensors this past weekend?
Richard
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None that have been reported, which is a good sign, isn't it ?
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__________________
In order to finish first, first you have to finish
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21 Apr 2014, 19:47 (Ref:3396333)
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#3480
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Veteran
Join Date: Mar 2008
Posts: 889
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Quote:
Originally Posted by JoestForEver
Ok, a bit more computing here, hopefully not too scary.
Based on @MyNameIsNigel 's figure, we have
FTFave=1.074
FTFMax=1.088
KTF=0.987
Penergy(allocation)=139.5 MJ/lap
Pflow=89.5 kg/h
Ptank=68.3L
Denergy=138.7 MJ/lap
Dflow=80.2 kg/h
Dtank=54.3L
As published lately, ACO/FIA decides the fuel type should be E20/B10 diesel(base bio 10%). Source: http://www.fia.com/sites/default/fil..._2014_fuel.pdf
For convenience and data availability, we refer to B20 diesel for energy density per kg.
http://www.rms.nsw.gov.au/heavyvehic...-biodiesel.pdf shows B20 is 2% down on energy comparing with petroleum diesel at 38.6MJ/L
http://www.biodiesel.org/docs/ffs-ba...5.pdf?sfvrsn=6 shows the density of B20 is 0.856
http://psrcentre.org/images/extraimages/212181.pdf reveals the energy density of E20 at 15 degrees Celsius is 32.43 MJ/L with 0.7541 kg/L.
As a result, the ED(petrol) and ED(diesel) in the formula of FTF should be 43MJ/kg and 44.19 MJ/kg respectively, which allows us to compute the ratio of BSFC(petrol) and BSFC(diesel) average. And the answer is 1.103, bigger than 1.090 previously. As for BSFCmax(petrol)/BSFCmax(diesel), it is 1.12 now. Diesel is still superior at peak power economy.
In terms of E(additional) (a.k.a, additional allocated diesel energy due to technology differences.), we can know easily compute it by maneuvering the formula of KTF. And the result is 1.71 MJ comparing with 2.24 MJ in the past.
So now what? We can compare stint lengths of petrol and diesel class based on BSFC fuel consumption and fuel tank volume. The ratio of petrol and diesel is 1.14 against 1.12 in the past.
However, the final number actually means nothing other than its relative relationship as it is not the fuel consumption per lap or per minute. It only means that although Audi is making progress in fuel economy, it still needs more pitstop than Toyota and Porsche. Thanks to the reduction in fuel tank volume, the more economic diesel engine is forcing Audi to refuel more! Ridiculous I'd say. Unless Audi's pace is better than Toyota and the gap is greater than 2013. There's no way it is going to win anything.
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Quote:
Originally Posted by JoestForEver
Quote:
Will they have shorter stints? I'm not so sure.
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Numbers speak louder than wild guessing. 
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An understatement lol
But lets play it fairly.
* Gravimetric energy density
Its the base to calculate the fuel flows, and its ok to me, since *its supposed* FIA/ACO controls tightly the quality of fuels... no *additives* are allowed and this is "inspected" !... (IS IT ? -> a Ferrari took fire at Silverstone while re-fueling, dangerous stupid stuff, seems not like regular E20 gasoline at all -> so if it isn't "inspected" this fuels (surprise samples taken on pit garages of every team), even a very small addition of alpha or beta pirenes, or turpentines, on any of those petrol or diesel fuels, can alter the numbers radically in terms of energy densities -> yes a "race petrol" could have more energy density than a regular diesel with only a small amount of additives... even more difference if the other way around)
Fuel flows in the rules are in Kg/hour... http://www.fia.com/sites/default/fil...2013-FINAL.pdf annexe/appendix B
So in light of the new biofuel revelations
Petrol = 43MJ/Kg
Diesel = 44.19 MJ/Kg
Difference is 2.767 % in favor of diesel, so diesel should have 2.767% less fuel flow.... which is not the case at all, since in the rules if you calculate from appendix B, is around 7% difference, that is, ~2.5 to 3 x percent *less* diesel fuel flow than it should be, and this even attending the different hybrid release categories.
* Volumetric energy density
Its the base ( or should be) to calculate the fuel tank capacity... which in the rules are in liters
Petrol = 32.43MJ/L
Diesel = ( -1% of 38.6 MJ/L for B10) = 38.21 MJ/L
Difference is 17.82% in favor of diesel ... makes sense since the diesel substance in itself is more dense, and so more heavy... and so if a petrol tank is 66.9 Liters, a diesel tank should be 56.8 Liters, 4.2% more tank capacity than now.
And the worst is not that, why not give more lean way with it, why not 70 Liters petrol and 59.4 Liters diesel. And why that ? ... because you can even regulate the flows of the refueling hoses, but is a side issue, you could opt for more laps and or less laps per stint and so the refueling time can vary a lot to, independent of the hoses or fuels used.
Those are the REAL numbers, the technology factors and the energy spend per lap "A RUSE, SMOKE & MIRRORS"... if you go real slow you can beat the more conservative estimations by a large margin, it depends NOT on the fuel "per se", it depends NOT on how much efficient your engine is, it depends most above all on the pace you adopt. The present rules have no flexibility and or options at all, fuel tanks are too small, specially diesel, even if 2 or 3 liters more, perhaps would not be enough for an additional lap... an on purpose clumsy way to try to make things slower, when the best option above all would had been "more weight" that is independent of number of laps ... instead of less weight... but that would benefit the engines with much more torque... yeah! a rejected no brainer!, and why did they rejected a no brainer!?...
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