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I need a stats guru – :) (13 posts)

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Karl Fuss said 10 months, 1 week ago:

Hi Guys,
I’m trying to sort out the best way to calculate pitstop loss time using only lap time data.
Currently I use the in lap and out lap times and compare them to average lap times before and after the pitstop.
So:
Pitstop time loss = (in lap time – avg lap time before in lap) + (out lap time – avg lap time after out lap)

But is this the best way to calculate it?

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Girts said 10 months, 1 week ago:

@niblips I’m mostly too lazy to calculate such figures myself so I just search for the data on the web. James Allen includes the approximate pit stop loss time in his pre-race previews, out of which I have made an overview table. These are the figures (in seconds) concerning the 2012 circuits (so far):

Hockenheim 12.8
Silverstone 15
Valencia 16
Montreal 11.2
Monte Carlo 20
Catalunya 19
Sakhir 18.6
Shanghai 17.5
Sepang 16.5
Albert Park 20

Maybe you can try to recalculate the times yourself using your formula to see if it’s correct :)

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mnmracer said 10 months, 1 week ago:

I would not take average lap time into consideration, because there are simply too many variables on that. The further you get away from the pitstop, the bigger the difference in variables, fuel for one.

It depends on what you want to calculate it for. If you want to calculate best strategy, you need to take even more things into account.

But taken just this question I would say:
Pitstop time loss = average (in-lap + out-lap ) – average (3 laps before in-lap)

I would not bother with laps afterwards.

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Karl Fuss said 10 months, 1 week ago:

thanx mnmracer.
The only reason i consider laps after to help calculate it is because the tyre compound can be different…. the driver may change from option to prime and that will effect the outlap time.
I like the 3 lap average idea though, that is good provided the lap times are not compromised by traffic or a driving error. when i calculate the stint averages i try to exclude laps that had traffic or errors.

Grits – i have found those lists before, but i don’t think they are entirely correct. take Shanghai for example and look at Rosberg’s pit times. his pitlane loss time was more like 20-22 seconds. That’s why i want to come up with a way to do it myself.

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bag0 said 10 months, 1 week ago:

@niblips
At least JA is 3-5 seconds off at almost every track.

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Karl Fuss said 10 months, 1 week ago:

@bag0
Maybe JA isn’t counting the pit road to when the limiter starts…..maybe he’s just counting the seconds from enter speed limit line to exit speed limit line

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Keith Collantine said 10 months, 1 week ago:

@niblips If I understand you correctly what you’re looking for is total time lost, those are listed for every pit stop in every race here:

http://www.f1fanatic.co.uk/category/2012-f1-season/2012-f1-race-data/

E.g.:

2012 British GP tyre strategies and pit stops

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Karl Fuss said 10 months, 1 week ago:

@Keith Collantine
That’s what I’m looking for, but do you know how it’s calculated? I would like to do this when I play F1 games as well.

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bag0 said 10 months, 1 week ago:

@niblips

Maybe JA isn’t counting the pit road to when the limiter starts

I tought about that, but I checked, and thats not his method. The pitlane in catalunya is about 305 meters long from line to line, and the limit is 100 kph so the time is about 11 seconds. If you count the time entering and exiting the lane too, you got JAs list, which (imo) does not count the stops just driving throught the lane.

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Girts said 10 months, 1 week ago:

Well, I made some approximate calculations for Silverstone and it seems that JA is absolutely correct, at least on the ‘Loss time for a Pit stop’, which, as I understand, is the time you lose, compared to a normal lap or, in other words, it is the minimum gap to the follower you need if you want to make a pit stop and still come out in front of him.

My calculation formula:

Loss time for a pit stop = In lap time + Out lap time – 2 x normal lap time*

* Normal lap time – I just used the lap time before the in lap

So this is how I calculated the loss time for Vettel’s pit stop on lap 31:
1:35.176 + 1:54.252 – 2*1:37.249 = 14.930

The same with Webber’s pit stop on lap 33:
1:34.629 + 1:53.928 – 2*1:36.938 = 14.681

Which is exactly what JA says – around 15 seconds

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Karl Fuss said 10 months, 1 week ago:

@bag0 – so it appears JA is right some of the time, but some of his quoted pit stop loss times are not correct. or he’s calculating them differently for some reason or another….

@Grits – yes, JA appears to be right with about 15secs for the Silverstone track. His calc for Shanghai is way off though.
the *normal lap time* is the variable that makes the biggest difference as its the lap that you compare the in and out lap to. Deciding what a normal lap time should be is what i’m really looking to peg down.
If you use the average lap time for the whole stint (which i have been doing) you end up with the fuel variable in it and also the tyre wear variable. I think i’ll start using an average of the 3 laps before the in lap as the *normal lap time* (provided there are no errors or traffic involved with those laps)

I like to know this information (pit lane loss time) because when i watch the F1 races live i also watch the live timing to see the gaps btwn the cars and to try and figure out strategies on-the-fly like the teams do.
That info is also helpful when i play F1 2011.

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Karl Fuss said 10 months ago:

@Girts
I have sorted it out. there are two different calculations!!!!
One is “Loss time for a Pit stop” that’s the amount of track time you lose by going into the pits for a stop instead of staying out and completing the lap.

The other is “Total time needed for pit stop” and that’s the amount of time it actually takes to pull into the pits and stop for tyres and pull out again.

JA’s list is the loss time for a pit stop and what i have been talking about is total time needed for a pit stop. Two very different things.

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Enigma said 10 months ago:

@keithcollantine That’s not the total time loss, is it? It takes 25 seconds, for example, to get from the entry to the exit, but you travel a certain distance in that time so you save some time.

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