Saving Weight

Author
Discussion

MrJingles705

407 posts

79 months

Thursday 6th December
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Gc285 said:
Agreed, I race prototypes and not a lot can be saved without huge expense.

I did however take the wife out at Brands a couple of years ago and managed a time a second quicker with her, than I could manage in qually a month later in the same car.
Weight transfer? screaming encouragement? who knows - I'd try and get the regs changed to include passengers wink

HustleRussell said:
I am really surprised that it's as little as a tenth per 10kg, especially in the example of the Formula Ford where the 10kg added weight is the biggest disadvantage as a percentage when you consider car weight.

I am simultaneously heartened and worried by this as I have a 34kg car weight disadvantage going into next season and as it turns out that may not be the excuse I thought it was.
It'll never hurt, but there is nearly always more time in the driver than the car assuming the car is otherwise competitive. Old tyres, tired engine etc and yes weight have their place, but what you really need is back-to-back data from someone willing to either share it or drive yours if you wanted to rule that out, and that can be tricky to do/get.

Norfolkandchance said:
Generally I would be entirely in agreement with this. However, the low powered cars I often compete in it isn't always true. This is because a better power to weight ratio and better braking / cornering that come with lighter weight were not always needed at high speed as wind resistance becomes more of a limit on acceleration than weight. My first competition car was an MG Midget with 75bhp at the wheels and a bit more that 100bhp per tonne. At fast circuits large sections could be taken flat in top. An extra 10 bhp would have increased top speed and therefore reduced lap time. Since I wasn't braking and accelerating very often, 100kg less wouldn't have made as much difference to lap time, even though I would have been able to brake later and accelerate quicker. It would be possible, therefore, for a light car with a better power to weight ratio to be slower than a heavy car with a lot of power. Would have been the opposite on a low speed / highly twisty venue.
Understood, and what works in a physics model (friction less vacuums, yay!) - but now you are talking about a different issue, vmax and aerodynamics.

Caterhams are a classic case of "could do with more power than even less weight" because they have the aerodynamics of a brick wink Less so with a FF1600 which is pretty slippery.

Norfolkandchance said:
Also, there is the issue of passing people / being passed. In the 80's or 90's A class was created for the 500 GP bikes that was for 400cc twins. The 400s (basically 250's with an enlarged engine) were allowed to be quite a lot lighter than the 500s. As I remember it, the 400s were solid mid table in qualifying lap times but couldn't use their faster cornering and later braking in the race because the 500s were n the way. So they were easy picking to the powerful 500s on the straights and therefore lost places.
Not a bike guy so sadly know bugger all about bike racing but multi-class races in cars get this as well..... circuits have inherent biases depending on straights and corners, but even without that it makes sense it's easier to hold someone up on a corner than a straight. Sounds like they got their BOP completely arse backwards to be frank.

MagicalTrevor

6,242 posts

165 months

Thursday 6th December
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CedricN said:
There is a free simulation software if you want to try out to predict lap time improvements like this, its pretty descent although a bit simple in certain areas.

http://www.optimumg.com/software/optimumlap/

I did several parameter sweeps on my car (1250kg/180hp), removing 10kg was about 0,1s on a 1:20s lap. Try it out for yourself, its a good way to learn how different parameters affects the lap times.
I’ve used this to do parameter sweeps of aero downforce and power improvements. Extremely useful.

Norfolkandchance

1,392 posts

135 months

Friday 7th December
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[/quote]
Sounds like they got their BOP completely arse backwards to be frank.

[/quote]

I'm not sure it was accidental. The 400s were there to bolster the grid, not challenge the creme de la creme 500s.

NJH

2,827 posts

145 months

Friday 7th December
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I did a similar thing using rFactor several years ago, in particular because I had the opportunity to get 30 kg out of my car (944 down from 1150 to 1120 Kg). I found it made about 0.5 secs on a short lap like Combe and more or less a second round Silverstone GP.

Chris Sideways

344 posts

188 months

Friday 7th December
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MrJingles705 said:
I'm in this category myself to be fair wink already lost 2 stone, need to lose a little bit more before the season start.... and then there are the general health benefits etc.

Still, you can do both I suppose.
I lost almost 4 stone between the end of the 2011 season and start of 2012, this caused 2 problems one I needed a new racesuit smile but more importantly when I was harnessed into the car I could no longer reach any of the switches on dash, I must of had a really fat back as I went back so far in the seat smile but boy did I feel great in the car I was like a fit youngster again smile
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Chris Sideways

344 posts

188 months

Friday 7th December
quotequote all
MrJingles705 said:
I'm in this category myself to be fair wink already lost 2 stone, need to lose a little bit more before the season start.... and then there are the general health benefits etc.

Still, you can do both I suppose.
I lost almost 4 stone between the end of the 2011 season and start of 2012, this caused 2 problems one I needed a new racesuit smile but more importantly when I was harnessed into the car I could no longer reach any of the switches on dash, I must of had a really fat back as I went back so far in the seat smile but boy did I feel great in the car I was like a fit youngster again smile

Edited by Chris Sideways on Friday 7th December 21:44

MrJingles705

407 posts

79 months

Saturday
quotequote all
Chris Sideways said:
MrJingles705 said:
I'm in this category myself to be fair wink already lost 2 stone, need to lose a little bit more before the season start.... and then there are the general health benefits etc.

Still, you can do both I suppose.
I lost almost 4 stone between the end of the 2011 season and start of 2012, this caused 2 problems one I needed a new racesuit smile but more importantly when I was harnessed into the car I could no longer reach any of the switches on dash, I must of had a really fat back as I went back so far in the seat smile but boy did I feel great in the car I was like a fit youngster again smile
Yeah, starting to find everything needs a belt - good problem to have wink