PDA

View Full Version : Air temperature or density?



tclancey
14-10-2015, 20:53
When is the air temperature monitored during sessions?

Obviously if you start a session early on a cold morning when the air is denser you will go faster than if you start at 3 in the afternoon when it's warmer and thinner. However I have a suspicion this is only calculated when leaving the pits. I run long races with pit stops and find the car can behave dramatically differently after a pit stop when the time of day has changed.

My last example is Le Mans 24 hours, midday lap time 04:02. Early morning 03:54. I think the effect is slightly exaggerated, but I can't say that for sure.

But the problem is the air density isn't re-calculated at the start of each lap, therefore you can be running a long stint through the night on day time settings, or the other way around, meaning there is great disparity of car power if pit stops of cars diverge. Obviously I'm using accelerated time here. And no, I don't want to use static time.

Could SMS please confirm? If I'm right can we please add this to the fix list.

Thank you.

tclancey
15-10-2015, 21:14
Has no one got any feedback on this?

Roger Prynne
15-10-2015, 21:39
Interesting one... I'll put the question to the Devs.

Casey Ringley
16-10-2015, 01:55
It is all figured in real time according to your time acceleration settings and position on the track. Neither temperature nor pressure are locked in when you leave the pits.

tclancey
16-10-2015, 11:24
Thanks for the feedback, I think I've worked out the reason for the anomaly which isn't connected to air pressure at all, I'll open another topic for that.

However, great that this is indeed taken into consideration, the more I learn the more I'm astounded with the depth of this simulation. (Big smiley face)

Roger Prynne
16-10-2015, 11:37
Thanks Casey.

MrBlacky
16-10-2015, 14:48
So what exactly does that mean?

That you have more power whens the air is cold?

Bealdor
16-10-2015, 14:51
Yes, just like IRL.

Schnizz58
16-10-2015, 15:25
More power for NA engines, not so much for turbos, correct? Also more downforce.

Shinzah
16-10-2015, 15:36
Tire grip potential is higher, and tires should also wear slower, assuming soft tires. But also do not heat up as quickly so in order to keep the grip potential one must balance them correctly to keep them in the temperature envelope.

Bealdor
16-10-2015, 15:39
More power for NA engines, not so much for turbos, correct? Also more downforce.

Yes on the engines part but I don't know if even DF is affected by it ingame.

Casey Ringley
16-10-2015, 15:50
Aero and engine cooling aren't affected yet. That stuff is around here somewhere on an 'easy wins' list. Shinz is correct on the tire performance impact, too. You'll turn your best times at Le Mans in the dark of night when the track is coolest. Means you can torture them through all of the Porsche curves without performance falling off as much as in bright sun.

Correct also on turbo engines compensating. They just spin the compressor a bit faster to get back to target. A bit more lag, but no power loss.

Schnizz58
16-10-2015, 16:11
Good info Casey.

havocc
16-10-2015, 17:03
Just to let you know that F1 teams are subject to minimum fuel temperature, if they find that fuel temp in the car tank is too low you are penalized because colder fuel = higher performance

Fre.Mo
16-10-2015, 21:17
When is the air temperature monitored during sessions?

Obviously if you start a session early on a cold morning when the air is denser you will go faster than if you start at 3 in the afternoon when it's warmer and thinner. However I have a suspicion this is only calculated when leaving the pits. I run long races with pit stops and find the car can behave dramatically differently after a pit stop when the time of day has changed.

My last example is Le Mans 24 hours, midday lap time 04:02. Early morning 03:54. I think the effect is slightly exaggerated, but I can't say that for sure.

But the problem is the air density isn't re-calculated at the start of each lap, therefore you can be running a long stint through the night on day time settings, or the other way around, meaning there is great disparity of car power if pit stops of cars diverge. Obviously I'm using accelerated time here. And no, I don't want to use static time.

Could SMS please confirm? If I'm right can we please add this to the fix list.

Thank you.

Ok with cold air the engine works better, but
Physically, I don t understand why with colder air and thus driving against/through a higher density fluid you will be faster: there must be more drag forces so you should be slower from an aerodynamic point of view?

Casey Ringley
16-10-2015, 21:58
Your theory is sound, but ignores the aerodynamic efficiency of some cars being much greater than 1:1. Take an extreme case like the R18 e-tron which has an efficiency of over 5:1. Say the weather conditions mean a 2% increase in downforce and drag over your reference point. That might equal an extra 10lb of drag, hardy affecting top speed at all, but an extra 50lb of downforce, which might give enough extra cornering power to make a difference. This is a big factor at place like Indianapolis. The weather can change favorably so that you can pull wing off the car, still meet your downforce requirement, and be running less drag overall.

Stephen Viljoen
23-10-2015, 08:13
A further bit of info on this - the temperature that you see displayed in the UI is the track surface temperature, not the air temperature. If you take a street car with a temperature indicator on the dash (Audi R8 for example) and drive it around, you'll see there's a difference in the value displayed for temperature on the UI versus on the car's dash. The reason is that, as in real life, the street car's temperature readout shows the air temperature, and we model both. :)

N0body Of The Goat
23-10-2015, 08:50
Just to let you know that F1 teams are subject to minimum fuel temperature, if they find that fuel temp in the car tank is too low you are penalized because colder fuel = higher performance

Unless it is the 2007 Brazil F1 GP. ;)

If the rules had been properly applied, Lewis would have won that championship, despite blunders such as the pitting incident at China that opened the door for Kimi.

flymar
23-10-2015, 09:22
A further bit of info on this - the temperature that you see displayed in the UI is the track surface temperature, not the air temperature. If you take a street car with a temperature indicator on the dash (Audi R8 for example) and drive it around, you'll see there's a difference in the value displayed for temperature on the UI versus on the car's dash. The reason is that, as in real life, the street car's temperature readout shows the air temperature, and we model both. :)
Interesting. We should have 2 icons in the GUI. I know it's just the flavor but it would be nice:)

rotorrian
23-10-2015, 09:24
Really? because in the real world its the opposite ?

The more cooler and dense the air is the gain is alot more for a turbo car than N/A.


More power for NA engines, not so much for turbos, correct? Also more downforce.

MrBlacky
23-10-2015, 09:35
That temperature shown in de car displays (BMW 1M) is always the same if I'm not mistaken.

flymar
23-10-2015, 09:43
That temperature shown in de car displays (BMW 1M) is always the same if I'm not mistaken.

Because temp doesn't fluctuate during one weather slot. But when weather changes, temp changes also.

N0body Of The Goat
23-10-2015, 09:54
That temperature shown in de car displays (BMW 1M) is always the same if I'm not mistaken.

Ambient air temp changes according to the date, time and weather. Set time progression to x60 and watch the temp change, even in "fixed weather" conditions. ;)

Currently, pCARS1 is limited to a minimum air temp of 12 Celcius and a minimum track temp of 16 Celcius.

Schnizz58
23-10-2015, 14:53
Really? because in the real world its the opposite ?

The more cooler and dense the air is the gain is a lot more for a turbo car than N/A.
NA cars are subject to the ambient air density while turbos are not. However if the car has an intercooler it will be more efficient in the cool air.

miagi
23-10-2015, 15:25
I think there might be a point where it's possible that a non-df car is faster in thin air than in dense air. At least some track cycling records are set with the help of thin air because the tracks in Aguascalientes and La Paz are well above sea level. So maybe a low power, not so aero dynamical car on a high speed track would benefit from low air density...