Audi LMP1 Discussion

[Artur]

Hey, thanks very much for this. It would be great if GG could talk more about this but I think it's pretty bad that teams can't change their mind about it. This makes it a silly gamble, imho.

Are teams restricted to only 2 different types of slick tyres per weekend? If so, then's it's pretty lame and F1-like.

Are this operational temps related to ambient or track ones? I would assume the later but just to be sure..... It seems it was too hot even during QLF and Toyota might have benefitted even there.

[TF110]

Originally Posted by Artur

Hey, thanks very much for this. It would be great if GG could talk more about this but I think it's pretty bad that teams can't change their mind about it. This makes it a silly gamble, imho.

Are teams restricted to only 2 different types of slick tyres per weekend? If so, then's it's pretty lame and F1-like.

Are this operational temps related to ambient or track ones? I would assume the later but just to be sure..... It seems it was too hot even during QLF and Toyota might have benefitted even there.

It would make sense, but the #6 outqualified the #5. And it was the #5 who had the hot+ tires on. So the #6 was on regular "hot" tires? Then qualifying wasn't that big of an issue for the tire choice. You saw at the beginning of the stint the Porsche's were fine but later into the stint they lost pace.

[bobec]

I still feel this was to some extent a preparation test for Le Mans. When has a full LD package made sense for Spa? The sprint package wouldn't be very well suited either, but I think an inter package is the answer, not LD.

[Victor_RO]

Originally Posted by Artur

Hey, thanks very much for this. It would be great if GG could talk more about this but I think it's pretty bad that teams can't change their mind about it. This makes it a silly gamble, imho.

Are teams restricted to only 2 different types of slick tyres per weekend? If so, then's it's pretty lame and F1-like.

Are this operational temps related to ambient or track ones? I would assume the later but just to be sure..... It seems it was too hot even during QLF and Toyota might have benefitted even there.

1 and 2 - tires have manufacturing/transport lead times, and with a limited number of sets available they need to notify the manufacturer weeks in advance of their choices, so that the manufacturer can produce and deliver the correct tires in time for the race. Racing tires have a limited shelf lifespan, and those that go unused after a race weekend are generally cut up and recycled (if not just destroyed). With a limited amount of tires, teams are more likely to go with less variation of compounds just to get consistent setup data and car behaviour if the conditions stay consistent. If you have 6 sets for quali+a 6hr race, and the conditions stay the same during these sessions, it's rather idiotic to go with 6 different compounds, don't you think?

3 - track temps.

[carbon_titanium]

Originally Posted by tomazy

But Audi did deploy its hybrid system from 310 to 329 kmh, and when it stoped deploying, the speed started to fall down.

https://youtu.be/cUOJZgf2Oxw?t=3973

well... this solves almost all doubts about toyota and audi gearboxes...

[chernaudi]

Does this mean that Audi and Toyota are overgearing their cars, since Porsche use all 7 gears in their transmission, or are Audi and Toyota running a LM-spec gearbox with LM transmission/diff. ratios?

[MyNameIsNigel]

Originally Posted by chernaudi

Does this mean that Audi and Toyota are overgearing their cars, since Porsche use all 7 gears in their transmission, or are Audi and Toyota running a LM-spec gearbox with LM transmission/diff. ratios?

Questions:

1. Do we have evidence that Porsche were using all seven gears ?

2. Audi and Toyota are supposed to be using six-gear and seven-gear gearboxes, but the video shows that the highest gear used by Audi and Toyota at the end of the Kemmel straight was 5th and 6th gear respectively. Is the reverse gear being accounted for as one of the relevant gears ?

[chernaudi]

There's an onboard video on You Tube of one of the Porsche using all 7 gears during a lap, and it was from the steering wheel display.

[sssssssss]

looking at the onboard telemetry from spa 2015, audi is in 6th gear from 260 km/h up and they seem to stay in 6th up to top speed. they did use 7 gears at le mans though and the change from 5th to 6th happened still around 260 km/h. 6th to 7th happened well after 300 km/h. so it's most probable they're doing the same now, with one less gear: 5th for their max speed in spa, 6th for le mans only (and the change from 5th to 6th only happening around 330 km/h??).

[TF110]

Longer gearing can save fuel can it not?

[GasperG]

If that was true, then they would switch to top gear at 300+ kph, maybe they didn't because they where in a fight mode and we don't have telemetry from "normal" drive on that straight.

[carbon_titanium]

I'm more surprised about audi gear box settings than toyota one, and now explain why. Last year TS040 used 7 gears, but was powered by 3.7 NA engine that surely was developing less than 450Nm in the whole rpm range. This year TS050 is powered by a twin turbo engine that even if running close to 8000rpm, surely developes much more torque + the torque released by the rear KERS, I bet that rear differentials of TS050 must to manage an insane amount of torque!!!
that's maybe is the main reason of a 6 speeds gb; it's a clever way to prevent issues at the transmission and its components.

Audi kept the same 4L turbo diesel engine; it was updated indeed, but because of 6MJ jump and more restrictive fuel flow, very likely is less powerfull than last year when R18 had a 7 speeds gb, even if all races but le mans were used only 6 speeds. If engine very likely developes less torque than last year, why step back to a 5 or 6 gb?
I guess is because audi extremized every part inside the 2016 R18, making the transmission as lightest as possible. A lighter transmision can sustain less stress, so better drop the 7th speed and basically run very long ratios of speeds used more frequently (3th and 4th). It makes sense, also because is the same solution used in past for R10 and R15 (that had only 5 speeds)

Like audi, porsche hybrid power is released only to front wheels, and very likely ICE and transmission remained almost untouched from 2015; there was no need to drop anything.

[roderick]

my guess is that, for audi, 6th gear is not on board to save weight in Spa. They will change the gear for Le Mans to gain the extra speed.
Toyota on the other hand, has a higher rev engine so they are unlikely to have 7th gear. (guessing the top speed of 340~350 is their max

[carbon_titanium]

of course is just my interpreration of reality.

[GasperG]

The answer may lay in fuel flow cut from last year.

Lets, say that Audi engine is capable of developing 650 HP at 4,500 rpm (1,014 Nm), but only if you feed it with enough fuel flow (eg. 90 kg/h). On the other hand it may be true that it can develop 500 HP at as low as 3,500 rpm (1,004 Nm), but naturally it can not be feed with same amount of fuel flow, but less (in the 70 kg/h region).

Now what happens when you restrict fuel flow to 71 kg/h? Power curve will be near flat from 3,500 to 4,500 rpm, no need to have extra gears if the engine can produce the same power already between longer gears.

Same thing can be said for petrol engine, especially if it's turbo.

I think this is the answer why they didn't bother with changing gear ratios for eg. Silverstone, top gear will be only used at top speed at LeMans. It may also be that 10MJ fuel flow restriction news came too late, when every one already had gearbox to utilize higher and more narrow engine rpm with higher fuel flow.

But from efficiency stand point, it's hard to say it's worth it to rev higher on same restricted fuel flow if you already have max power in lower rpm with reving higher comes higher friction losses, and engine power with same fuel flow will be droping, not staying the same. But here also turbo comes into play and I have no idea how that affects efficiency.

[bobec]

Originally Posted by carbon_titanium

It makes sense, also because is the same solution used in past for R10 and R15 (that had only 5 speeds)

Didn't the R15+ have 6 gears for Le Mans? Not sure if the 2009 R15 can be used as a positive example, especially the R10 (vs the 908s).

[bobec]

Still intrigued by the high nose aero. The 908 also had a sort-of high nose. The front was open for most Le Mans series races, where you need some downforce, but for Le Mans it was covered in 2009-2011 (mostly covered in 2011).

2010 Spa:




2010 Le Mans:

[ederss7]

Originally Posted by bobec

Didn't the R15+ have 6 gears for Le Mans? Not sure if the 2009 R15 can be used as a positive example, especially the R10 (vs the 908s).

5 gears only for the R10 and R15.

[carbon_titanium]

Originally Posted by bobec

Didn't the R15+ have 6 gears for Le Mans? Not sure if the 2009 R15 can be used as a positive example, especially the R10 (vs the 908s).

R10 and R15 (+ and ++) used 5 gears gb to don't make suffer too much the transmission that had to endure constantly >1200Nm (at least speking of R10 engine). Peugeot 908HDi had 6 gears, but I guess peugeot used a more resistant gearbox, surely heavier than audi one. Infact min. weight of 908HDi was almost always closer to 1000kg than 930.

[bobec]

Wow, I always thought the R15+ had upgraded to a 6-speed, don't remember why. So then the R18 was the first Audi lmp to have a 6-speed. Interesting.

But I also feel 6 gears would be enough for this year.

[sssssssss]

Originally Posted by bobec

So then the R18 was the first Audi lmp to have a 6-speed. Interesting.

well, the r8, as well as the '99 R8C and R8R also had six speed gearboxes.

[MyNameIsNigel]

Originally Posted by MyNameIsNigel

Another series of shots of the Audi R18 front end, nose section removed, have been posted on the motorport.com website. These shots were apparently taken during one of the interventions on the #7 car during the race:



(source: Spa photo gallery / race)

It seems that the last shot above shows the damage sustained by the #7 car which required repairs.

Has anybody a clue as to what the keel-like structure hanging from the underside of the monocoque actually is ?

I was wondering if this structure could be used to house ballast, but it is quite exposed to potential damage.

Could this house some sensor of some sort ?

[seanyb505]

Mass air flow? It looks large for one though. Might have something to do with how sensitive the aero is, a maf sensor would give info as to how much air is actually moving through the aero devices.

[tomazy]

My guess would be that it is a laser ride hight sensor.

[Richard C]

We shall name it the "Uvula"!

It seems large for a sensor. Maybe it houses multiple sensors. Given the size and being so low, I can imagine the gravitation toward the idea of ballast. How about a tuned mass damper of some sort! (I expect those are illegal?)

Richard