I can't see any difference but maybe cause I never really made a deep check.
Wha is your experience?

Quote from tomylee :

I can't see any difference but maybe cause I never really made a deep check.
Wha is your experience?

I am enough bad driver to not find difference, but there is weight difference with fuel in game already.

Quote from JTbo :

I am enough bad driver to not find difference, but there is weight difference with fuel in game already.

you can see it on your time?

Quote from tomylee :

you can see it on your time?

No way, I'm not enough good driver for that, my times jumps more up and down because my lack of skill than what fuel adds, but it sure changes handling of car, specially with softer setups.

Try to make real soft setup and then drive with 5ltr and with full tank, there is difference.

There is a difference and i kind of notice it. On set up testing in SP mode where i have started with 100% fuel my times are slower than normal and as the fuel goes down i get faster but not usually that much.

i did a test few months ago. drag with RB4 with almost empty and almost full tank (dont remember the exact values), but with full tank the time was about 0.35s slower.

Quote from Don :

i did a test few months ago. drag with RB4 with almost empty and almost full tank (dont remember the exact values), but with full tank the time was about 0.35s slower.

Thats not much. When you look at F1 I think it does make a much bigger difference, 1-2 sec.

illepall of course there's a difference!
It's the same way the trainer makes those greyhounds have a dump before each race
Every little helps....

Quote from tomylee :

Thats not much. When you look at F1 I think it does make a much bigger difference, 1-2 sec.

You can't compare difference of 0-400 acceleration time to lap time of F1 car directly you know

also f1 car is VERY light, so each kg makes difference. RB4 is quite heavy, so ~80kg wont make THAT much difference

I actually had to modify my setups for longer races in the FOX.
The FOX consumed fuel and thus changed it's weight balance. On such a light car that was noticable and I had to change the setup to work best at half the amount of fuel I needed for the races.
Of course additionally there was the normal acceleration improvement of roughly half a second for 40% fuel.

Vain

Quote from Vain :

I actually had to modify my setups for longer races in the FOX.
The FOX consumed fuel and thus changed it's weight balance. On such a light car that was noticable and I had to change the setup to work best at half the amount of fuel I needed for the races.
Of course additionally there was the normal acceleration improvement of roughly half a second for 40% fuel.

Vain

I often alter brake balance during longer races, but I have always been thinking that it is because of tire wear, maybe also because of fuel load then. Sometimes I alter it when having close battle and if I try to overtake, sometimes need better turn in while braking.
Of course not possible in all cars.

There's a very noticable difference in the lighter cars. I can tell the difference between 10% full and 2% full in cars like the XFGTi and LX4.

Quote from sinbad :

There's a very noticable difference in the lighter cars. I can tell the difference between 10% full and 2% full in cars like the XFGTi and LX4.

you can? damn you must be a bit off then, because the lowest you can have is 5% full

The effects of fuel depends on the % of weight of a car that is fuel weight, the greater the % the greater the effect and vice-versa.

Honestly I don't see what this thread has to do with the improvement of anything. This should be in the general/race discussion area, not the improvement suggestons area.

Quote from Jakg :

you can? damn you must be a bit off then, because the lowest you can have is 5% full

So if you fill an XFG to 5%, drive 2 laps of BL1 the fuel in the car is still 5%?

I can't tell the difference between 10% and 5% in the XFG. As long as the tyres are warmed up I can go as fast with 10 as 5%, but that's probably because I'm not very fast to begin with

Quote from Jamexing :

The effects of fuel depends on the % of weight of a car that is fuel weight, the greater the % the greater the effect and vice-versa.

Honestly I don't see what this thread has to do with the improvement of anything. This should be in the general/race discussion area, not the improvement suggestons area.

Because I'm not sure if we need an improvement in this area.
When you go over longer distance the most people will take the max. fuel needed for this race but when you look in reality thats not how it works.
I drive mostly the FXR and FZR and I can say that there is not much difference of lap time. Maybe it is not like this with the BF1, I dont know. So we have to check it out cause otherwise the whole pit stop stuff in LFS is for nothing.....

Quote :

There's a very noticable difference in the lighter cars. I can tell the difference between 10% full and 2% full in cars like the XFGTi and LX4.

handling i do agree but lap time?

I would say that majority is not enough good drivers to gain much from putting less fuel at start. I usually race with 50% no matter how long race and I loose at acceleration, but I'm more constant with more fuel, that is just odd, but that is how it goes

I don't find there is much difference in terms of outright grip, but the fuel does change the weight distribution of the car alot, which can turn subtle understeer into major oversteer. For example I need an extra 2 degrees of rear wing on the XRR to keep the rear in place with a full tank over an empty tank.

if you cant see it in your times, surely you notice the difference in your top speed? if you are running heavy on fuel, the car will not have as good acceleration in the higher gears. say... you would normally be able to reach 171mph on aston's 1st straight (with xrr). with a heavier tank, you may struggle to hit 169.

it seems like the difference is more noticeable in the lighter cars like fox and f08, but maybe i am wrong.

Quote from Bob Smith :

I don't find there is much difference in terms of outright grip, but the fuel does change the weight distribution of the car alot, which can turn subtle understeer into major oversteer. For example I need an extra 2 degrees of rear wing on the XRR to keep the rear in place with a full tank over an empty tank.

but it should slow down the car as well otherwise we would see no pit stop in F1 cause they have just to change the wings about 2°

Well, erm, eh?

Pitstops in F1 (last time I watched it anyway, has been a while now) is to change the worn tyres (I know that's changed recently) and put more fuel in, which they have to do regardless since they don't have enough fuel for the whole race. Unlike most other cars (in LFS) the BF1 has a large fuel tank as well as low weight, so the effect is going to be most pronounced in that car (e.g. an extra 10% is added to the vehicles total mass wityh a full tank compared to 3 to 4% for a road car). Finally, the fuel is kept very close to the CoG so wing adjustments aren't needed (unlike XRR, most static mass at the front, tank behind the rear axle).

Btw I just realised you had two threads on this matter, one was indeed an improvement suggestion but this sounds more like a general question, so I moved it to general discussion for you.

Stop using F1 as an example. They are amazing drivers in amazing machines right on the limit. For you, who I suspect isn't close to an F1 WR in LFS, it isn't entirely applicable. And we've not got entirely realistic F1 tyre compounds/graining/blistering either.

And if you watch F1 you'll see they do change the aero balance of the car depending on fuel load - a longer stint will generally have a little less front wing, and you can see this plainly when they change strategies. It's slightly muddled by drivers trying to cure a chassis setup problem with aero tweaks, but still noticable.

I find the FOX slower on fuller tanks, but not so much on the GTR cars where the weight and CoG effects are less.

Quote from tomylee :

handling i do agree but lap time?

Yes, it's often just tenths but I can tell.
If you gave me an LX4 with 5% fuel and an LX4 with 15% fuel, I'd be faster with the 5% filled car.

PS: Thanks to NAI for responding to Jakg's brainfart post for me

Quote from tristancliffe :

I find the FOX slower on fuller tanks, but not so much on the GTR cars where the weight and CoG effects are less.

Which I find rather odd, since the maths would point to the exact opposite of that happening.

A full tank in the FOX increases weight by ~5% and shifts the weight distribution by just 0.25%. Taking the FZR as another example, a full tank increases weight by ~6% (not too dissimilar) but weight distribution by ~4.5%, - or 18 times more than in the FOX. Alternatively ~4% for FXR or ~3.5% for XRR.

So I would expect the GTRs handling to change a lot more than the FOX. I would expect you are noticing the difference more for a couple of reasons:

a) the FOX can be used with a full tank and the tyres will last the duration, whereas the GTRs burn the tyres out before using up all the fuel (usually)
b) the FOX needs very little understeer, you probably have a very neutrally balanced set that will show up even very subtle changes, the GTRs are not so set up so precisely so larger changes can happen without throwing the handling off.