fuel, does it add to the cars total weight?

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dustwave

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Well, I've been wondering and reading around especially about this in the F1 cup.. I've driven the cup myself.. the problem is, is it a difference in a car in GT4 that has nearly empty petrol-tank or full petrol tank?

I hardly notice any difference, at the moment I'm driving the Le Sarthe II 24h endurance race and I can achieve the same lap times with full petroltank and nearly empty petrol tank, both "test" laps ended at 2.57.8xx

The petroltank in GT4 is at 80 litres (SI-units), the density of fuel is approx. 0,737 kg/l (I don't know the value for racing-petrol).. but a tank full of fuel would then weight approx: 80 l * 0,737 kg/l = 58,96 kg

that means that weight of the a full tank is 58,96 kg. If we take a F1 car, it's hp/weight ratio is 0,608, and the weight of it is 550 kg.. when the tank is nearly empty, will the weight of the car be (total weight) - (how much petrol used) = (current weight)? if so, the F1 car would have a lower hp:weight ratio and should then be driving faster, accelerating faster... I can't notice this.. anyone else who have some thoughts about this problem?

my 2 cents
 
I was also dissapointed by this, I would have thought if pd made the effort to have a fuel tank that you can decide how much goes in on a pit, then there should be a reason for this, like conserving weight. I can't feel a difference, but I still try and keep it as low as possible during long races.
 
Firstly there is no indication what the size of the tank is in units. It's certainly 80 something and the consumption data would indicate that it's close to a litre but it's not explicitly stated.

Secondly, no it doesn't. I thought it might after I'd done the Roadster Endurance, but now I'm sure it doesn't.
 
One another thing I've noticed is that pitting is entirely based on tyre-strategy.. in real world races much of the strategy is how much petrol you have in the tank, like in F1 where a full tank and a half full tank can make a huge difference in both lap times and pit strategy.. pitting is not just about tires
 
Famine
Firstly there is no indication what the size of the tank is in units. It's certainly 80 something and the consumption data would indicate that it's close to a litre but it's not explicitly stated.
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if you look at the units the game use in the specifications of the cars, I would surely say they have the SI-units in mind while designing the game, therefore 80L and it makes more sense if you bother doing some calculations:

fill with "standard" petrol at 0,737 kg/l (1 galon = 3,785 litres)

80 litres = 80 l * 0,737 kg/l = 58,96 kg
80 galons = (80 * 3,785) l * 0,737 kg/l = 223,16 kg
80 dekalitres = (80 * 10) l * 0,737 kg/l = 589,6 kg

and so on... it's logical that they use SI-units in the game... but you're right about that it's not explicitly stated
 
dustwave
(1 galon = 3,785 litres)
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Oh no!

1 Gallon (US) = 3.785 litres.
1 Gallon (Imp) = 4.546 litres.

:D

I think that, although the data suggests litres and the fuel consumption data suggests litres, since it's never explicitly stated (and the fact that getting 80 litres of petrol into Daihatsu Midget (or a Daimler trike for that matter) is impossible) we settled on a new name for the fuel unit in GT4. If I recall, it was the "fuelin"... :D
 
I think I can answer this one - yes it does make a difference... but not if you're driving A-spec it seems (I suspect the reason for that, is humans - being humans - don't drive with robotic consistancy). However in B-spec, it's a different story...

Let's say we use the F1 car on sayyyy... New York. Over a long race (60 laps, for example) He pits in after say, 8 laps, having used 35 units of fuel.

At this point I do a bit of quick math. 80 (full tank) -35 (fuel used) = 45 units I don't need for this race. Add say 10% as a safety margin (5 units) and I can let the car run happily on say... 40 units. So first time in, I don't refuel him. (PLEASE NOTE THESE ARE EXAMPLE FIGURES AND NOT MEANT TO BE ACCURATE!)

Second pit in, he's almost out of fuel. I fill it to about 40 units, and watch closely.

Two things tend to happen. (this is assuming that he stays at a set speed, say 3, which I usually keep him at)

1. His tyres tend to last longer. In some cases, an entire lap longer. Which means he pits in less often.

2. His lap times tend to get even faster on green tyres... as he's got perfect grip and minimal fuel weight, he can now get max performance out of the car... sometimes doing some extremely quick laps compared to the rest. I'm estimating at least a second per lap faster in some cars/courses.

So for B-spec at least, dumping fuel is a good idea. :)

BTW I'm running the PAL version. Hope this helps!
 
Famine
Firstly there is no indication what the size of the tank is in units. It's certainly 80 something and the consumption data would indicate that it's close to a litre but it's not explicitly stated.
Click to expand...
I assumed it was just like a percentage value, only with 80 divisions instead of 100, because they're silly.
If all the cars had the same size tank, wouldn't the Stingray race car need to pit every lap, and the Prius not ever need to gas up?
 
Famine
Firstly there is no indication what the size of the tank is in units. It's certainly 80 something and the consumption data would indicate that it's close to a litre but it's not explicitly stated.

Secondly, no it doesn't. I thought it might after I'd done the Roadster Endurance, but now I'm sure it doesn't.
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I'd say that it's more than likely "liters". Taken from:

http://www.audi.com/audi/com/en1/experience/motorsport/customer_sport_r80/audi_r8.html


Technical data Audi R8 (2005)Engine type FSI-twin-turbomotor
Wheels magnesium, front 13,5 x 18 inches, rear 14,5 x 18 inches
Tyres Michelin, front 33/65-18, rear 37/71-18
Monocoque carbon fibre
Length 4650 mm
Width 2000 mm
Height 1080 mm
Minimum weight 950 kgs (Le Mans/LMES),
900 kgs (ALMS)
Fuel capacity 80 litres (Le Mans/LMES),
90 litres (ALMS)

...and these are pretty easy to throw in the back of any "modern-day roadgoing car"...80 liters would only be about 21 galons.

page10f.jpg


Considering that we can pretty much tune most cars in every aspect in GT4, in It's not unrealistic to believe that PD would fit a typical road car, which in the game will only see track time, with a fuel cell...even though it is a bit of a stretch. They probably use "80" as a standard, just to make all things being equal.

Do we really want to be picking cars based on different size "tanks" because of the varying "re-fueling times" and "milage" for endurance races? Though that would be cool, I'm sure it would have been a royal pain for the developers with 700 odd cars, and their various tuning levels, to deal with.

Back on topic, while I wondered if fuel levels, and subsequent changes in weight would affect lap times, I vote that in the game, it doesn't.
 
Great thread as I was just thinking about this the other day.

I don't think fuel level does effect the performance of the car. It has in other games though, the Formula One titles spring to mind. It was always good to qualify with 5 laps of fuel on to get a really fast time.

It would be great if it did influence car performance, but I don't think it does. If it did, then they could introduce adjustable brake bias and all the other cool things that go with it, but alas... :)
 
It might just be me but I always seem to go a second or two faster with low fuel. Especially in 700BHP+ cars. It also seems to effect B spec Bob especially in the F1 races. After a few pit stopswhen you can run with ~30 and the other cars have a full load Bob seems to gain much more of an advantage.
I do agree though that they should have implemented somesort of initial fuel load in the setup screen
 
If someone would like the test the theory (different milage for different cars) i'll give them some help right now. I'm doing the 24 hour Sarthe I enduro right now in the CLK GTR, stock. I pit every 8 laps and I always have 8 units of fuel left. So why doesnt someone take a prius or something hybrid and do 8 laps around sarthe I and see how much fuel it will have left. Then we can see if every car has the same fuel economy.
 
VVENOM800TT
If someone would like the test the theory (different milage for different cars) i'll give them some help right now. I'm doing the 24 hour Sarthe I enduro right now in the CLK GTR, stock. I pit every 8 laps and I always have 8 units of fuel left. So why doesnt someone take a prius or something hybrid and do 8 laps around sarthe I and see how much fuel it will have left. Then we can see if every car has the same fuel economy.
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My ~880hp Pescarolo (stage 3 turbo) did 8 laps @ Sarthe 1, topped out at ~235-240mph, and only had 2 liters left after every pit...on an average of 3:25 lap times. I'm sure if I lenghthened the gears, to keep the RPMs low, and kept the speed down, I'd have more fuel left.

....o.k., now I need to go see if I'm right. Too darn curious now.

:)
 
colnago
My ~880hp Pescarolo (stage 3 turbo) did 8 laps @ Sarthe 1, topped out at ~235-240mph, and only had 2 liters left after every pit...on an average of 3:25 lap times. I'm sure if I lenghthened the gears, to keep the RPMs low, and kept the speed down, I'd have more fuel left.

....o.k., now I need to go see if I'm right. Too darn curious now.

:)
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I top out at about 225mph and my lap times are about 3'16-3'18. As I said before, the fuel is always at 8 when I pit, and i'm on lap 271 right now and about 15 hours and 45min into it. It's getting boring, no, no, wait, scratch that, it's been boring for the last 10 hours. I'm only in the lead by 7 laps.
 
colnago
My ~880hp Pescarolo (stage 3 turbo) did 8 laps @ Sarthe 1, topped out at ~235-240mph, and only had 2 liters left after every pit...on an average of 3:25 lap times. I'm sure if I lenghthened the gears, to keep the RPMs low, and kept the speed down, I'd have more fuel left.

....o.k., now I need to go see if I'm right. Too darn curious now.

:)
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O.k., it looks like there is some sort of "dynamic milage" at work. As stated before, in my last Sarth 1 24hrs testing, last week, I was running the Pescarolo Judd, w/ stg.3 turbo @ about 880hp, 235mph on the straights, and "HAD" to pit after 8 laps as I the "in-car" view fuel gauge was "blank". In the pit, I only had 2 "liters" of fuel left, once refueling started.

I ran the same car/track setup just now, but set "gearing" to have a top speed of about 260mph. I "short-shifted" at a max of 6k RPM, and kept speed at or near 200mph on the straight, which put me at about 5750 RPM. Lap times were in the mid 3:40s. I pit after 4 laps (too tired to do a full stint), and had 53 "liters" of fuel left. If I extrapolate that out to 8 laps, I'd have about 26 "liters" of fuel left.

The slower pace/gearing netted me a big fuel savings. I knew there was a reason I setup taller gears for all the endurance racing. 💡
 
colnago
Do we really want to be picking cars based on different size "tanks" because of the varying "re-fueling times" and "milage" for endurance races? Though that would be cool, I'm sure it would have been a royal pain for the developers with 700 odd cars, and their various tuning levels, to deal with.
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They're already collecting information much more esoteric then MPG figures and tank size. It seems that information would be relatively trivial to find and include.
 
so gear ratios and a consistent pace that does not push the engine to work hard increases fuel economy, hmmm? we might be on to something here.
 
VVENOM800TT
so gear ratios and a consistent pace that does not push the engine to work hard increases fuel economy, hmmm? we might be on to something here.
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You've got that right - but it seems weird to me that they would go to the trouble of implementing differing fuel usage, then not have the fuel weight effect the cars performance. I would have thought it would have been easier to do the latter, rather than the former, so why use a complex feature, then not back it up with a basic one?
Maybe they do. Maybe the fuel amount just adds to the cars total weight, the weight they would have used to determine handling characteristics, but because the weight changes are so small in comparison to the cars weight, we cannot perceive the effectss on the handling? Now there's something to think about... :)
 
AS previously stated the formula one cars only weigh 550 or so kilo's.. surely we would realise if a further 60 kilo was missing.....
 
~Sp33~
AS previously stated the formula one cars only weigh 550 or so kilo's.. surely we would realise if a further 60 kilo was missing.....
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I suppose - there is a noticable difference if you add 60 units (anyone know what these units are) of ballast weight, so I guess you're right. No effect on handling or perfomance then... :)
 
let's put it in this perspective... the fuel tank weight about 1/10th of the F1 cars weight... would you notice it if 1/10th of you were missing? =)
 
dustwave
if you look at the units the game use in the specifications of the cars, I would surely say they have the SI-units in mind while designing the game, therefore 80L and it makes more sense if you bother doing some calculations:

fill with "standard" petrol at 0,737 kg/l (1 galon = 3,785 litres)

80 litres = 80 l * 0,737 kg/l = 58,96 kg
80 galons = (80 * 3,785) l * 0,737 kg/l = 223,16 kg
80 dekalitres = (80 * 10) l * 0,737 kg/l = 589,6 kg

and so on... it's logical that they use SI-units in the game... but you're right about that it's not explicitly stated
Click to expand...
Not many road cars have 80L petrol tanks and most racing cars, especially the Le Mans cars have 120L tanks. I think its just 80 units but 1 unit varies from car to car.
 
ferrari_chris
You've got that right - but it seems weird to me that they would go to the trouble of implementing differing fuel usage, then not have the fuel weight effect the cars performance. I would have thought it would have been easier to do the latter, rather than the former, so why use a complex feature, then not back it up with a basic one?
Maybe they do. Maybe the fuel amount just adds to the cars total weight, the weight they would have used to determine handling characteristics, but because the weight changes are so small in comparison to the cars weight, we cannot perceive the effectss on the handling? Now there's something to think about... :)
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No, fuel should definately effect the cars handling particularly on racing cars and especially if the tank were mounted toward the front or rear of the car.
 

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