Audi LMP1 Discussion

[templer]

Originally Posted by MyNameIsNigel

Based on the pictures released at the time of the launch of the 2011-spec R18, and comparing those to comparable shots released by Sauber, it is pretty evident that the original R18 wind tunnel model was not a full-scale model:

(source: Mulsanne's Corner)

(source: Sauber F1 website)

(source: F1Technical forum)

Now, have Audi gone as far as testing a full-scale model in Sauber's wind tunnel ? That would be interesting to know.

I don't think so. Full-scale testing is possible at the Sauber tunnel but I don't think that Audi got beyond 60% models. Full-scale wind tunnel tests are run at the Audi tunnel with the real car, not with a model

[MyNameIsNigel]

Originally Posted by templer

I don't think so. Full-scale testing is possible at the Sauber tunnel but I don't think that Audi got beyond 60% models.

It indeed seems that only reduced-scale models have been used at Sauber's facilities.

Originally Posted by templer

Full-scale wind tunnel tests are run at the Audi tunnel with the real car, not with a model

I am not very familiar with the wind tunnel facilities that Audi have at Ingolstadt, but these seem to be less advanced than Sauber's facilities (or TMG's as the case may be). Unless I am mistaken, Audi's wind tunnel facilities in particular appear to be lacking any rolling band enabling simulation of the relative motion between car and road, meaning that complex aerodynamic interactions (such as rotation of the wheels and the resulting impact on the car's overall aerodynamic efficiency) cannot be simulated.

[ger80]

Maybe Sauber also builds the scale model for Audi? That could explain the high price tag. The 2Mil/months seems to high if you consider that Sauber likely wants to use the tunnel as well... F1 teams can run maximum 30 hours "wind on" time a week, so that maybe leaves another 20 hours if you also run weekends

[templer]

Originally Posted by MyNameIsNigel

It indeed seems that only reduced-scale models have been used at Sauber's facilities.



I am not very familiar with the wind tunnel facilities that Audi have at Ingolstadt, but these seem to be less advanced than Sauber's facilities (or TMG's as the case may be). Unless I am mistaken, Audi's wind tunnel facilities in particular appear to be lacking any rolling band enabling simulation of the relative motion between car and road, meaning that complex aerodynamic interactions (such as rotation of the wheels and the resulting impact on the car's overall aerodynamic efficiency) cannot be simulated.

Audi has three of most modern wind tunnel facilities for manufacturers. They are for acoustic, climatic and thermo-dynamic measurements with air speeds up to 300kph and at least one of them is fitted with a rolling road floor.

Full-scale model testing is quite unusually in motorsports. Lancia did it with the LC2 and Alfa with the stillborn SE048SP. Full-scale testing with the real car was common at Porsche and Sauber-Mercedes during the Group C. These tests had quite different targets like the model wind tunnel runs. It was not the aim to improve details or examine the airflow in the wheel arches. The target was to compare the overall downforce and drag figures with the model tests, the airflow over and under the car via smoke walls and pressure measurements at important points like cooling inlet and outlet ducts. It was a kind of control instrument for the real car in comparison to the model. Similar to aero tests done one airfields or straight lines.

[alless]

Originally Posted by templer

I don't think so. Full-scale testing is possible at the Sauber tunnel but I don't think that Audi got beyond 60% models. Full-scale wind tunnel tests are run at the Audi tunnel with the real car, not with a model

Actually they did, all real models are beeing tested at audi wind tunnel at the end. While the first and tweaks are done in lower scale.

[chernaudi]

Audi do have state of the art wind tunnels that they do test both road and race cars in, though most of the initial work is done at Sauber now.

And a Le Mans note: Xtrac confirmed that Audi continue to use XTrac manufactured gearbox internals in the 7 speed gearbox used in the R18.

[chernaudi]

Another thing I found: Doesn't the diff arreangement on this XTrac transverse front engined/FWD touring car gear box look a bit similar to something on the front of the Audi R18?

XTrac FWD touring car transaxle assembly:

http://www.xtrac.com/sectors/motorsp...car/product/84

2014 Audi R18 MGU/front differential for the e-tron quattro system:

https://fbcdn-sphotos-h-a.akamaihd.n...77769058_n.jpg

https://fbcdn-sphotos-e-a.akamaihd.n...33c3a0df8d61df

[aneesh99]

Well, the endurance committee has just cut the R18's diesel energy by 0.3%, but have increased the maximum flow by 1% as well as making a minute change in fuel tank capacity (0.1L)

[Articus]

I'm curious to know on what grounds did the ACO decide to make these changes.
They presumably had all the data from Le Mans so what did they not like in it all?

Cutting the total energy by 0.3% won't change the stint lengths at Le Mans. Neither is will 100mL of fuel. That's not even enough fuel to offset the extra amount of fuel they can burn per stint.

What were they massaging?

[MyNameIsNigel]

I am curious to see the full Appendix B table as last revised by the Endurance Committee. The changes reported by Sportscar365.com seem pretty much of minor nature.

[chernaudi]

Seems that the changes are intended to give Audi more engine power, something that they've had an issue with since before the WEC Prologue test, where Audi claimed that the EOT changes made back then gave Porsche and Toyota a 20-30bhp edge.

It's been noted elsewhere that the EOT update gives Audi about a 10bhp power increase on the engine side. The minor hybrid system power output change and .1 liter fuel capacity increase seems to be to be sure that Audi don't gain that much in overall power, but are yet helped on the area where they said that the EOT short chained them, which is engine power.

[Articus]

It's not the hybrid system power output that got changed. It's still 2MJ. It's the total MJ of diesel fuel they can use per lap at Le Mans. They have to complete the lap with a little tiny amount less fuel.

I don't think it's a problem because I'm sure Audi will keep upping the compression ratio and playing with injectors year after year which means they can increase fuel efficiency. The higher flow rate is most interesting but I didn't think it was 10bhp!


On another note, the Audi's weren't smoking this year were they .

[chernaudi]

The curious thing is that Audi supposedly gets .3% less overall energy, but are allowed 1% more flow and also are allowed .1 of a liter more fuel capacity. You do the math between energy vs flow, it seems that Audi gain about .7% more power and come out ahead by that much.

You ask me, this seems to be about giving Audi more ability to crank up the engine power without having a longer stint length. We know that between EOT and how much more downforce they've carried all year that if there's been one area that Audi has struggled in it's been top speed. Even at Le Mans it was noticeable.

The R18s could accelerate with Toyota and Porsche out of corners, and were significantly better in terms of cornering and braking, but above a certain speed, the lack of engine power showed. The same thing often hampered Audi against Peugeot as well, and we know that Peugeot had a power advantage over Audi that Audi often had trouble completely defeating by compensating in other areas.

I see this as the ACO and FIA giving Audi a BHP break while trying to keep overall energy figures similar to what they were earlier in this season.

Calculations would seem that Audi may gain nearly 10 bhp and that would've made them .35 seconds a lap faster at Le Mans. With the additional coasting/energy harvesting that Audi would have to do to compensate for the increased fuel flow, Audi would still come out ahead by nearly .3 of a second per lap on average at LM. Of course, this is an assumption based on numbers then and now. The actual gains could be somewhat more or less.

[chernaudi]

Also, any theories on what the black button/switch like object is that protrudes out of the right side access hatch? Could it be an actual button or switch, or is it some type of sensor? In either case, I see wiring attached to it for some purpose.

You can see it from the front here:

http://fourtitude.com/emAlbum/albums...-Days-2659.jpg

And from the side:

http://fourtitude.com/emAlbum/albums...nesday-288.jpg

[MyNameIsNigel]

Originally Posted by chernaudi

Also, any theories on what the black button/switch like object is that protrudes out of the right side access hatch? Could it be an actual button or switch, or is it some type of sensor? In either case, I see wiring attached to it for some purpose.

You can see it from the front here:

http://fourtitude.com/emAlbum/albums...-Days-2659.jpg

And from the side:

http://fourtitude.com/emAlbum/albums...nesday-288.jpg

My best guess is that this may be a temperature sensor used to measure ambient temperature and which may be of relevance with respect to the provision imposing a maximum temperature inside the cockpit.

[MyNameIsNigel]

Audi set to stick with single ERS according to Autosport.com.

It is almost certain that Audi will move up to the 4 MJ ERS category. Dr. Ullrich's comments do not however exclude the possibility of running the ERS-H next year IMHO. Even though reliability concerns were apparently the main motivation not to run the ERS-H, one may wonder if Audi will not give it a try considering that they actually had reliability issues with their "usual" VTGs this year.

[deltawing]

Why would they move to 4MJ and lose fuel, when they are doing so well with more fuel and 2 MJ? I know majority here will never agree, but I will repeat myself again - we have not yet seen the limits of that diesel! The have developed an engine that makes a lot more out of fuel and the scary part is, they never had to push it to its limit (yet), so we don't even know what this engine can do if pushed to the max. I strongly suspect they are going to talk about 4 MJ as it is great talking point for the fans, but just before the 2015 season starts they are going to come out and say "We tried, but it really does not work for us, we are going to stay with 2 MJ".....

[MyNameIsNigel]

Originally Posted by deltawing

Why would they move to 4MJ and lose fuel, when they are doing so well with more fuel and 2 MJ? I know majority here will never agree, but I will repeat myself again - we have not yet seen the limits of that diesel! The have developed an engine that makes a lot more out of fuel and the scary part is, they never had to push it to its limit (yet), so we don't even know what this engine can do if pushed to the max. I strongly suspect they are going to talk about 4 MJ as it is great talking point for the fans, but just before the 2015 season starts they are going to come out and say "We tried, but it really does not work for us, we are going to stay with 2 MJ".....

You may be right but with the ERS incentive in place there is now a more evident motivation to go for the 4 MJ ERS option as it ensures a greater overall energy allocation compared to the 2 MJ ERS option which is supposedly equivalent to a benefit of 1 sec/lap @ LM.

This being said, with the new EoT in place and valid up to an including LM 2015, Audi could now definitely work on further improving the efficieny of their diesel engine. The same would apply for Porsche and Toyota BTW. If I am not mistaken, the "dissuasive penalty" was only contemplated for this year's LM race and nothing would prevent Audi or any of the other manufacturers from working on beating the fuel efficiency targets that now form the basis of the new EoT.

[deltawing]

Let's don't forget that MJ increase comes with big weight penalty! Moving from 2 MJ to 4 MJ is not free....

[TF110]

Dont believe thats the case deltawing. They are free to harvest and release whenever they want. 4mj at Le Mans is only 500kj more than 2013. There is a serious flaw in their hybrid powertrain if they struggle to do that! They just want more fuel because its easier and the diesel is more efficient than people believe. I think 43% thermal efficiency is not out of belief.

[deltawing]

Originally Posted by TF110

...They are free to harvest and release whenever they want.....

No one is questioning that..... but if you meant "whatever", that is a different story. They are free to harvest whatever they want, but they are not free to release whatever they want.

Let's talk in April, or hopefully they will announce their MJ entry earlier than that...

[TF110]

No. I meant whenever. There are no "hybrid zones" any longer. Anytime they brake they can harvest. So if theyre struggling making or harvesting a significant enough of energy, they can use more than one braking area to harvest more and release that energy when desired. Its all computer controlled anyway. The biggest issue would be having enough storage space. But imo, that shouldnt be much of an issue with what we know.

[chernaudi]

TF110's right with the current rules.

Teams can harvest energy in every brake zone basically and are free to use that captured energy whenever they want. Audi and Toyota use it out of corners, while it's believed that Porsche use it on top end to gain straight line speed and top end surge.

Even with less hybrid energy than last year, Audi have said that the new hybrid system is a huge improvement over it's predcessor just because they have no 120km/h limit and the hybrid boost can now be used at the drivers' discretion instantaneously upon harvesting.

Just imagine how much more boost that Audi would have if they had a 4MJ system this year. And this is the car that's set fastest lap at Silverstone and Le Mans and ended up being the fastest car over a long stint at LM when they had nothing to lose but run down the #20 Porsche after that turbocharger issue.

[deltawing]

Originally Posted by TF110

No. I meant whenever....

No one was questioning the "when" of anything. I just don't understand what this has to do with the conversation about moving from 2 MJ to 4 MJ? The reason Audi chose to go with 2 MJ is they need fuel more than anything else. They can do with fuel more than what others can do with fuel + hybrid systems. As long as ACO lets them burn this much fuel per lap (as currently allocated), they have no business in the 4 MJ class.

[TF110]

Originally Posted by deltawing

No one was questioning the "when" of anything. I just don't understand what this has to do with the conversation about moving from 2 MJ to 4 MJ? The reason Audi chose to go with 2 MJ is they need fuel more than anything else. They can do with fuel more than what others can do with fuel + hybrid systems. As long as ACO lets them burn this much fuel per lap (as currently allocated), they have no business in the 4 MJ class.

You didnt get it, Im sorry. Ill explain it more.

The problem with the previous R18 was harvesting enough energy. That was their words. The point is the ers incentive exists in wording, so bigger hybrids = faster laps! Not sure how that isnt relevant to moving up to 4mj We know they like their higher fuel usage, but its clear that more hybrid power is the best choice. The 'harvesting and releasing whenever' is relevant because they have more opportunity to make that energy recovery.