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Weight vs time

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Wed Nov 25, 2015 12:19 pm PostPost subject: Weight vs time
nefarious
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Just curious if anyone's done any back-to-back tests on the impact of ballast on lap times?
Ive got about 8-10kg to lose between the car and myself as part of the winter rebuild - some will come easily, some less so (especially the bit on my belly!). Just trying to work out a rough quantification of what benefit I can expect to see.
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Wed Nov 25, 2015 12:57 pm PostPost subject:
AK
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i did some reading of F1 data a while back.... where they had quantified the gains for weight/ or lack of.

Give it a google. I will look again when I get some time.
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Wed Nov 25, 2015 4:35 pm PostPost subject:
foz01
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Look at laptimes st start of race vs end for F1, dunno how much fuel they have and there's all the tyre management, maybe WEC would be more representative?
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Wed Nov 25, 2015 4:46 pm PostPost subject:
nefarious
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I was looking at some BTCC data, but I don't trust it. I suspect the teams are deliberately sandbagging with ballast in order to convince TOCA that the success ballast should be kept to a minimum (just like they do with the power/boost data).
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Wed Nov 25, 2015 5:30 pm PostPost subject:
David Long
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I spent a trackday adding ballast up to 30KG for SLS prep. It didn't make as much of a difference as I expected. Maybe at most a 1/10th second per 10 KG (600kg car). Most noticeable was the 'feel' rather than anything else, but the data suggested braking was the biggest loser.
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Wed Nov 25, 2015 6:19 pm PostPost subject:
nefarious
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David Long wrote:
I spent a trackday adding ballast up to 30KG for SLS prep. It didn't make as much of a difference as I expected. Maybe at most a 1/10th second per 10 KG (600kg car). Most noticeable was the 'feel' rather than anything else, but the data suggested braking was the biggest loser.

Interesting. That's quite a bit less than I would have expected - suggests a 1.7% increase in weight only leads to a 0.18% difference in times.
The relationship surely can't stay at a 10:1 ratio across a range of weights, so I wonder what the critical factor is...
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Wed Nov 25, 2015 8:07 pm PostPost subject:
scottish scrutineer
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nefarious wrote:
<snip> so I wonder what the critical factor is...


Driver ability Wink
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Thu Nov 26, 2015 7:59 am PostPost subject:
nefarious
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scottish scrutineer wrote:
nefarious wrote:
<snip> so I wonder what the critical factor is...


Driver ability Wink


It's all relative Renny - I might be a ham-fisted oaf, but I was hoping I might be marginally faster if I were a less fat ham-fisted oaf!
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Thu Nov 26, 2015 9:31 am PostPost subject:
alistairolsen
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Under acceleration and braking it should be a linear change 1:1, cornering is more complex as you increase the normal force and therefore increase the grip, but not in proportion so you lose out.

The bigger issue eventually is step changes like being unable to pull a particular gear and having to drop one for the hairpin for instance, or a particular gear being suited, but now at a different point on the power curve.

It will affect every car, on every different circuit differently is the real answer which you dont want
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Thu Nov 26, 2015 7:11 pm PostPost subject:
Ciprian
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I noticed a big difference when removing weight from the Alfa. 20kg shaved me 2 sec per lap. There's much more to come off! Wink
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Fri Nov 27, 2015 2:16 pm PostPost subject:
scottish scrutineer
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nefarious wrote:
scottish scrutineer wrote:
nefarious wrote:
<snip> so I wonder what the critical factor is...


Driver ability Wink


It's all relative Renny - I might be a ham-fisted oaf, but I was hoping I might be marginally faster if I were a less fat ham-fisted oaf!

Laughing
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