[LMS] Audi R18 (including Cake Analysis)

[Adam43]

Is the e-tron balanced as well as the ultra? It's dry pace hints that it isn't. Very early days and difficult to tell, but there is a little intrigue for Le Mans. It could be different there.

[CTD]

Originally Posted by Adam43

Is the e-tron balanced as well as the ultra? It's dry pace hints that it isn't. Very early days and difficult to tell, but there is a little intrigue for Le Mans. It could be different there.

There has been hints that the E-tron is currently harder for the drivers to setup properly, as it drives in a different manor than they are used to.
A problem which should not occur at Le Mans as they would have enough laps to create a good setup.

Besides, the Ultra should be able to use previous data from Spa easier than the E-tron, because of the more conventional construction

[Adam43]

Good point, it is difficult to know whether it inherently doesn't handle as well, or if it is just new and they are coming to grips.
Whatever, the blasts of extra hp should be the deciding factor when they can get it close.

[TF110]

So was tire wear a problem on the front mostly? Or was it the rear or both? Maybe it was conditions at Spa that hindered the E-tron. You know the changing weather and all.

[gwyllion]

I have read no complaints about tire wear. The issue for the e-tron quattro was understeer, so a lack of grip at the front.

[TF110]

During the race when the E-tron pit the tires on the front looked bad. Maybe that was a one-off issue, but I remember the commentators saying the tire wear was worse than on the Ultras. Did they just speculate then?

[CTD]

Originally Posted by TF110

During the race when the E-tron pit the tires on the front looked bad. Maybe that was a one-off issue, but I remember the commentators saying the tire wear was worse than on the Ultras. Did they just speculate then?

Could be setup, if there is any tire wear difference between the E-tron and the Ultra.
We know that there was setup difficulties with the Etron

[TF110]

I'm just wondering because I thought I heard that the tire wear was questionable on their E-Tron. I could be hearing things or maybe heard wrong. If it is I doubt they'll have much trouble with it at LeMans.

[gwyllion]

According to McNish in http://www.youtube.com/watch?v=XiH6ttjB9Cs#t=1m13 the tire wear is similar between both cars.

[chernaudi]

McNish has said that in testing, tire wear between the two cars are virtually the same, and the drivers complained about a lack of heat in the front tires until late in the event due to the dryer track.

This seems to hint--intentionally or inadvertently--that the e-trons were set up maybe with a bit too much of a bias towards wet conditions, almost like the front suspension was set up a bit too soft or a bit too compliant. The Ultras may've run a stiffer set up up front, which to a slight extent may explain some of the wet weather pace difference, but why the Ultras picked up the pace as a dry line formed. And considering his wet weather F1 and LMP1 experience, that's probably what encouraged Gene to change on to slicks before everyone else.

As CTD mentioned, the Ultra may share it's tub with the e-tron and about everything else, but lacking the hybrid AWD system, those guys can rely more on the notes from 2011 if they get in a jam compared to the e-tron, which Fassler, Ben, and Allan have mentioned does drive sliglty but noticeably different until you get used to it. Both cars are different than the '11 cars with improved areo, weight distribution, and improved grip and handling, but the e-tron system does make the cars handle slightly differently when it's activated.

[gwyllion]

I am not convinced that the understeer issue has to do with the suspension settings. It could also be a weight or aero balance problem. In the ultra they have a lot of ballast weight that can be moved around freely.

In http://www.lemanslive.com/en/2012/05...llon-flat-out/ Dumas explains that "the new R18 ultra is completely different to the R18 TDI" and that he could do Raidillon flat out for the first time in an Audi prototype. The front suspension and the steering have been changed significantly since last year.

[gwyllion]

Originally Posted by gwyllion

I had a look at the timing information from Spa. The R18 e-tron quattro did 23 lap stints and the R18 ultra 24 lap stints. Last year Audi and Peugeot also did 24 lap stints at Spa.

So Audi does is suffering much less than expected from the fuel tank reduction: in 2011 65 liters and in 2012 60 liters for non-hybrid and 58 liters for hybrid.

In http://www.ten-tenths.com/forum/show...43#post3070743 I calculated the average of 20% fastest race laps for the different LMP1 cars. That avearge lap time was around 2:05 for both versions of the new R18.

Out of curiosity I decided to compute the same metric on the timing data from the 2011 race.

• Audi #1: 2:08.4
• Audi #2: 2:06.8
• Audi #3: 2:07.4
• Peugeot #7: 2:06.9
• Peugeot #8: 2:07.0
• Peugeot #9: 2:06.9
• Oreca Peugeot #10: 2:09.4
• Rebellion #12: 2:10.5
• Rebellion #13: 2:11.5
• Pescarolo #16: 2:11.5

These numbers show that the Audi got quite a bit quicker this year, while still using less fuel during a stint. Of course, the weather conditions were completely different last year: around 25°C (2011) vs 8°C (2012).

[TF110]

Doesn't cooler weather allow for better engine performance? I'd like to know how the difference in temperature affects the power the engines put out. Also tire construction may be better this year? And temperature can have an affect on grip as well. But it seems that even with the smaller tanks and less power, the Audi has gained what they lost and some. I think last year with the fact the R18 was a new concept to them in terms of the car being a coupe compared to this year, they can make better gains with better understanding.

[chernaudi]

I still think based on driver comments that it was probably a set up issue, and some other factors seem to be playing into this, me being as out of the loop as anyone else here. The e-trons were marginally faster than the Ultras in each practice session, but the keyword is marginally--it wasn't like the e-trons were off in another time zone, the times usually being a matter of tenths of a second a lap, and only a few tenths at that.

Also, the e-trons seemed to be faster when the track was warm, as on Friday. I wouldn't put it past Audi that they stuck to a conservative set up and strategy with the suspension settings and tire compound choices on the e-trons as those guys are racing for the drivers' title. The Ultra guys aren't running for points, so why not use them sort of as guinea pigs and let them test a slightly more aggressive set up? McNish's comments post race does seem to suggest that Audi went with the "safe" route on the e-trons as far as set up and tire selection.

But I do think that the Ultra does have a slight advantage over the e-tron right now due to it not having the hybrid system, and that's one less set up variable to deal with. The Ultra chassis wise is as different from the old R18 as the e-tron is, but it's more of an intermediate between the old R18 and the R18 e-tron. And the drivers do say that both cars are a bit different to drive and that some driving style changes are needed to get the best out of either car. So it stands to reason that even though the base setups may be nearly identical, some slight differences are likely because of the individual idiosyncrasies of both cars to optimize them due to those differences.

[MitchZ06]

Originally Posted by TF110

Doesn't cooler weather allow for better engine performance? I'd like to know how the difference in temperature affects the power the engines put out.

Cool air = denser air = more oxygen in the combustion chamber = more power.

That's why dusk is the best time to go drag racing (warm track, cool air) and early morning at Le Mans is called 'happy hour' because the track is well rubbered in, the air is still cool and there's better visibility.