ACO's fuel capacity rules

[neiltbag]

I just went back over an older thread about the ACO reg changes for 2007, looking to see if any discussion had been made of the reduced fuel tank size for diesels. It hadn't, before the thread deteriorated into a lot of finger-pointing on grammar usage.

Anyway, given that diesels will only be allowed an 81-liter tank this year, what impact will that have? Looking at last year, the winning Audi made 27 stops, which makes for about 2700 litres of fuel. That same amount of fuel will require 33 stops with the smaller tank. How long would an additional 6 stops take? 40 seconds for the stop, plus 40 in/out time (just guessing here)? If so, that's an extra 8 minutes, or 2.3 laps, which would turn the winning margin was 4 laps into 1.7. That's pretty damn close, and augers well for a close fight this year.

Feel free to tear my numbers to shreds, by the way..

[chewymonster]

Yes, no more complaining about tank sizes unless someone wants to complain that a diesel is a more fuel efficient engine. I think that the diesels might do the same amount of laps/at most one more per tank. But they would have some left in the tank if they do the same amount of laps. Also the diesels should be lighter as they run as they have less fuel on board.

[Fogelhund]

Originally Posted by neiltbag

I just went back over an older thread about the ACO reg changes for 2007, looking to see if any discussion had been made of the reduced fuel tank size for diesels. It hadn't, before the thread deteriorated into a lot of finger-pointing on grammar usage.

Anyway, given that diesels will only be allowed an 81-liter tank this year, what impact will that have? Looking at last year, the winning Audi made 27 stops, which makes for about 2700 litres of fuel. That same amount of fuel will require 33 stops with the smaller tank. How long would an additional 6 stops take? 40 seconds for the stop, plus 40 in/out time (just guessing here)? If so, that's an extra 8 minutes, or 2.3 laps, which would turn the winning margin was 4 laps into 1.7. That's pretty damn close, and augers well for a close fight this year.

Feel free to tear my numbers to shreds, by the way..

All valid conclusions, if one assumes that the tanks were empty when they came in the pits.

[Hammerdown]

Sounds good to me. I like your thinking. It will certainly be interesting to see how they cope. Turn the power down a bit and gain a bit more economy would seem the obvious solution, and they probably have the capacity to do that.

[gwyllion]

Remember that engine design is a performance/fuel economy tradeoff. Maybe this year Audi will focus a bit more on fuel economy and give up some power (everybody knows they have a power advantage). Bruno Famin, Technical Director of the Peugeot 908 project, literally said so.

Have the changes to the ACO regulations made you late?

No, not really, but it now means that we have to look at the performance /fuel consumption to be more in favour of fuel consumption.

source: http://www.speedarena.com/news/publi...cle_7282.shtml

So diesels could still do more laps with the same tank as petrol car.

[AU N EGL]

Originally Posted by gwyllion

Remember that engine design is a performance/fuel economy tradeoff. Maybe this year Audi will focus a bit more on fuel economy and give up some power (everybody knows they have a power advantage). Bruno Famin, Technical Director of the Peugeot 908 project, literally said so.
source: http://www.speedarena.com/news/publi...cle_7282.shtml

So diesels could still do more laps with the same tank as petrol car.

I think Audi and Peugeot will do what ever it takes to win. If that means forget economy for more power, so be it.

However, I am sure if the fuel econmy was great but they did not win, that companies spin doctors would make the fuel economy issue more important in the eye of the consumer.

[Mal]

Providing the Pug proves competitive it will only be Le Mans this year that we can truly be sure we have seen the full potential of the R10.

Perhaps this is why they have chosen not to enter LMS so the true diesel potential is not seen before.

Assuming this happens and the diesel proves to have a significant advantage after slogging it out at Le Mans this year they hopefully will peg them back as seems to be widely expected for 2008 thus allowing Porsche and Acura to join the party in LMP1.

This of course could be why these two are in LMP2 so that the ACO uses what may be slower gasoline cars as their benchmark and not the speed of a full works effort.

This again could explain why Audi have decided to enter an LMP1 gasoline car - to raise the bar for the gasoline cars so that this is taken into account when the 2008 formula is worked out.

A lot of speculation I know but an interesting train of thought!

[chewymonster]

Yep, we will see what a gasoline P1 can do with the same engine that the R8 had, I think it will do pretty well.

Porsche and Acura can sure make some fast P2s...

[bonedome]

If both R10's or for that matter both Pug's, were on the front row of the grid in June, would one car be set up for out and out power heading off into the distance and building up a strong early lead. And the second car more aligned toward an economy setting. Just so the team covers all the bases?
Idle curiosity on my part.

[Fogelhund]

Originally Posted by bonedome

If both R10's or for that matter both Pug's, were on the front row of the grid in June, would one car be set up for out and out power heading off into the distance and building up a strong early lead. And the second car more aligned toward an economy setting. Just so the team covers all the bases?
Idle curiosity on my part.

You are likely to see three or four Audi's at LM this year. At this point, we are getting a bit ahead of ourselves, as the Pug's haven't turned a wheel competitively, and we don't know how quick they will be. Audi will certainly be able to run some calculations on what pace they will need to run, what the economy will be, and what is the theoretical best pace. If they need to split their strategies, they'll have enough cars to do so.