- 1,846
- Arizona
- maxpontiac
No, you are just a virtual fisherman in the world-wide-pond.đź‘Ť
Maximum vs. Minimum Downforce
- Thread starter FishHunters
- 73 comments
- 13,624 views
No, you are just a virtual fisherman in the world-wide-pond.đź‘Ť
- 1,973
- Florida - USA
- Flsurffisher
- 1,155
- gtp_iLex
Well... If you prove something people allready "know" (read: suspect) you get flamed for wasting forum space.
If however you found out that downforce was simulated in a very bad way and that fiddling with the downforce could increase your grinding with 746Cr/h, people would have loved you for it.
it's a dirty job mate... thank you for doing it
Intuitivley I suspected this would be the case, and also assumed that PD modeled it correctly. I'm sure for the twisty courses (e.g. Rome), a lot of us tune down the engine (lower top speed, closer gears) and up the downforce for quick response and accurate cornering.
What's a more interesting question is if you can OFFSET the loss in speed on faster courses (e.g. Sarthe I think? With the long straights broken up by chicaines?) with a moderate (not low) downforce so you can still corner well on the top and S-bend area, but up the transmission max speed so that you offset the negative effect of the downforce. Seems like you'd only need one or two ticks to move it faster.
So I guess my question is...
IS Max DF + engine top speed up 2 notches > Max DF (normal transmission) > Normal DF, Normal Transmission? (*note -on races where your speed will peak).
dhandeh
Premium
- 11,390
- England
- dhandes
Any test like this done at nordscheilfe, I normally treat with a grain of salt, its too long to get consistent laps, one after another. Suzuka would be more suitable, low speed and faster corners, straights should provide a more suitable venue, also sector times need to be considered, as you main gain in some areas and lose out on others with one setup and vice versa with the other. Good idea though.
- 1,973
- Florida - USA
- Flsurffisher
I would think La Sarthe is one where less down force is best. Not a whole lot of turns and the S isn't that difficult nor long. Two long runs then chicanes then the Indy straight, followed by the straight before the S, then the start straight. Lots of places to go fast. I'll probably test it though.
- 1,835
- DrKrFfXx_
Just had a quick go on La Sarthe 2009 no chicanes, with an untuned Peugeot 908, with stock power, and the gearbox set to I think 450kmh max speed and hard racing tires with grip reduction on real.
Lowest downforce (30/50): 3:15. Max speed 385 kmh.
Full downforce (65/85): 3:11. Max speed 370 kmh.
As I stated before, there is not a single time where low downforce is more convenient, not even in circuits where speed matters (Monza, Fuji, Sarthe).
The low downforce setting would gain like 1 second on the straight but lose everywhere else. 1 second in a 6km straight is ****, considering it loses 5 everywhere else. There is not a trade of top speed + acceleration vs cornering speed, because cornering it's always better in the game.
Lowest downforce (30/50): 3:15. Max speed 385 kmh.
Full downforce (65/85): 3:11. Max speed 370 kmh.
As I stated before, there is not a single time where low downforce is more convenient, not even in circuits where speed matters (Monza, Fuji, Sarthe).
The low downforce setting would gain like 1 second on the straight but lose everywhere else. 1 second in a 6km straight is ****, considering it loses 5 everywhere else. There is not a trade of top speed + acceleration vs cornering speed, because cornering it's always better in the game.
- 373
- Porto
- Divinusable
In this case 16 is not equal to 8+8Hey you agree with each other. The more downforce the more weight the car as to support with the increase of speed. Of course, ceteris paribus, more downforce means less acelaration => Top Speed and vice versa. However more downforce means more speed at corners where it can be used. Even the veyron with max or min downforce behaves differently. (However it as a system that makes downforce dynamic).
Thank you for testing this đź‘Ť
Lol, you have more option than max or min. Just try to decrease a little bit and see if your lap timer improve in the fast tracks. However im not saying you arent correct. It's possble that the max downforce in that car would be allways an advantage because of the capacity to generate high speeds quickly. If it is indeed true then the game as a flaw because it should be possible to add more downforce.
Depends on the track. Again you have more values than max or min, and that means the difference could be less marginal.
In fact you don't have it, so even if you need it you couldn't use it. To be more precise, you have some downforce, but it is insignificant.
Wrong. Depend on where you apply. Ceteris paribus, the more at front more oversteer, more at the back more understeer and vice versa.
You forget that increase top speed (transmission settings) doesn t increase engine power. If you increase downforce and engine top speed you will have two handicaps in accelaration in a straight line.
Just put your engine limiter to the min and then do another run (this is an extreme situation to prove the bolded text to be wrong), or if you want do some drag racing.
Max downforce = better exit speed. On a sweeper like the final corner of Monza, that kills any top-speed advantage a low downforce setup will give you. Monza is totally a high downforce track. I set all my cars to max, but I'm lazy
Again you have more than max or min values. Try decrease it a little bit and do another run.
Conclusion: There is a point where the benefits of high downforce aren't worth the loss of speed, if we consider that the game model is well made. For each track, each car, each set of tires, each tune you must find the equilbrium point between accelaration and grip.
- 9,053
- Murica
- BasedAckbar
Yeah but the speed you are doing is insanely more than a Bentley can pull off. At those speeds the difference is obviously huge.
Take any other LMP race car, not fantasy car, and you will only notice a negligible loss of straight line speed.
The X2010 is the joker card of the deck, and as such can only be comparable to itself.
- 1,835
- DrKrFfXx_
That plus the fact that lowest setting on the X1 is like 50/50 and the max is something like 150/200.
- 9,053
- Murica
- BasedAckbar
Yeah It's insane how much of breathing space you get with the downforce settings of the X1.
- 1,137
Hm, it depends.
The car weight has the side effect, that during turns, the centrifugal (sry if I use the wrong word, english isn`t my first language) forces are much higher and depending on the weight distribution, this can cause your car to over/understeer. This means your suspension gets diffent loads too, like rear-left has to take a higher load then front-right.
Also, when a car just starts, the car weight will slow it down, while the effect of the downforce is (aslong we are not talking about a fan car) very small. The amount of downforce created by a road car is VERY small at low speeds. Furthermore, (ok, now my english fails, don`t know how to name it different
) the air resistance/friction has a quadratic influence, so the downforce/drag ratio isnt linear.@Eunos_cosmos
As a summation, it is true, provided downforce generated front and rear is equal and centre of gravity of vehicle is dead centre from front and rear wheels. If not, then what you mentioned is not true. If it was, there is no need for adjusting downforce on the front or the rear. Downforce generated at the rear or the front will not add to the static weight and divide itself equally.
@alonsoF1fan
I think your explanation is quite clear. The word you are looking for is "centripetal".
As what you mentioned in the end, the drag force increases with the square of the speed, and the power required to overcome this drag force increases with the cube of the speed.
Cheers
As a summation, it is true, provided downforce generated front and rear is equal and centre of gravity of vehicle is dead centre from front and rear wheels. If not, then what you mentioned is not true. If it was, there is no need for adjusting downforce on the front or the rear. Downforce generated at the rear or the front will not add to the static weight and divide itself equally.
@alonsoF1fan
I think your explanation is quite clear. The word you are looking for is "centripetal".
As what you mentioned in the end, the drag force increases with the square of the speed, and the power required to overcome this drag force increases with the cube of the speed.
Cheers
- 7,600
- Exorcet
- OE Exorcet
GT5 is a max downforce game. You'll never gain anything from min downforce, excluding PP, that's my experience. Even on Sarthe, all min downforce does is slow you on the curves and makes you no faster on the straights (~5 mph even with LMP cars). I've tested it again and again.
Downforce in GT5 is completely wrong and needs to be overhauled. The X1 is the only car where you need to think about downforce. I think that the top speed can change as much as 30 mph with that car, which is the difference between the 600 hp Viper SRT-10 and Viper ACR in real life. For race cars it could be much much more depending on how adjustable the wing actually is.
Downforce in GT5 is completely wrong and needs to be overhauled. The X1 is the only car where you need to think about downforce. I think that the top speed can change as much as 30 mph with that car, which is the difference between the 600 hp Viper SRT-10 and Viper ACR in real life. For race cars it could be much much more depending on how adjustable the wing actually is.
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- 647
- Oregon
- madmyk
This conversation is a bit different than my understanding of downforce on cars. I'm no expert but let me explain what I am thinking...
I never thought there was a concept of downforce on production cars, where the car's weight is increased. Production cars are shaped like an airplane wing and therefore generate lift at high speeds. This lift reduces the effective weight of the car and reduces stability and grip around corners as speed increases, and even straight line stability can be reduced to dangerous levels at high enough speeds in certain cars.
So a wing on a production car is there to reduce lift, not to actually increase the weight of the car, in my way of looking at it. A wing still has the benefits that we are all talking about. I just wonder why the conversation is not in terms of lift and why it is not mentioned.
I never thought there was a concept of downforce on production cars, where the car's weight is increased. Production cars are shaped like an airplane wing and therefore generate lift at high speeds. This lift reduces the effective weight of the car and reduces stability and grip around corners as speed increases, and even straight line stability can be reduced to dangerous levels at high enough speeds in certain cars.
So a wing on a production car is there to reduce lift, not to actually increase the weight of the car, in my way of looking at it. A wing still has the benefits that we are all talking about. I just wonder why the conversation is not in terms of lift and why it is not mentioned.
- 1,973
- Florida - USA
- Flsurffisher
Cause it's about downforce. Weather it really works in the game or not and if so to what extent. When we talk "downforce" we're talking about racing. The theory is the more downforce the greater the stability of the car and the better the handling expecially in corners; but the negative effect is a loss of straight line speed. The opposite is true with less downforce.
Go into the game. On a car with a tail fin click on tuning. Then go into body and aero. In areo click on the ? (question mark) it'll give you a good explanation of the concept. Like Exocet said the results in GT5 really are minimal. On a highspeed track like La Sarthe a min dowforce car should crush the same car at max DF. On the Nordschelife the opposite should be true. Max DF should crush min DF and it doesn't.
- 647
- Oregon
- madmyk
I get what we are talking about. I guess I was just asking about the concept of lift and why it is not discussed. If there is no disagreement there, the point I could make is that production cars probably do not generate enough downforce to actually increase the weight of the car and should not see much of decrease in top speed. A race car with enough downforce would see more of a top speed reduction.
- 9,143
- United Kingdom
- neema_t
There's no definite answer to this 'do I use high or low downforce?' question, because it depends entirely on the circuit and the car. If you're in an aero body like an F1 car, they depend on downforce to have any grip while cornering because the car is too light. If you have a poorly balanced car, too much downforce on one end will cause problems (the Speed 12 handles far better without a wing, for example). It, like all tuning, is circumstantial and has to be considered with the overall balance of the car in mind, not to mention the circuit you're driving on. Having said that, it's probably safe to maximise the downforce for any circuit, as long as the car's handling isn't ruined.
For those saying that weight has an effect on top speed or high-speed acceleration, it doesn't. Low speed acceleration is all about weight and torque, high speed is about aerodynamic drag and horsepower.
Also I can't believe so many of you completely missed the point of FishHunter's test, then went on to insinuate a lack of intelligence on his part. That speaks volumes. I think a lot of you just wanted to show off about how much you know about aerodynamics...
For those saying that weight has an effect on top speed or high-speed acceleration, it doesn't. Low speed acceleration is all about weight and torque, high speed is about aerodynamic drag and horsepower.
Also I can't believe so many of you completely missed the point of FishHunter's test, then went on to insinuate a lack of intelligence on his part. That speaks volumes. I think a lot of you just wanted to show off about how much you know about aerodynamics...
- 7,600
- Exorcet
- OE Exorcet
Lift and dowforce are the same thing, they just point in opposite directions. Another name for downforce is negative lift.
The loss of speed from downforce is not related to weight, but drag. Weight has next to no effect on a cars top speed (and the often assumed-to-be-the-same concept of mass has even less effect). Top speed is reached when engine power = drag power. Downforce (and lift since it is the same thing) will create drag just by existing. There is no escaping this. It's called induced drag, and it's a result of pressure distribution around a lifting body throwing (basically wasting) energy into the air.
Induced drag is why some airliners have their wing tips bent upwards, they want to weaken the vortices that cause induced drag. The same reasoning promotes end plates on car wings. Since all lift produces induced drag, that means a positive lift road car will have it too. The only way to avoid losing speed from lift/downforce is to make not make any at all.
Your conclusion is still somewhat valid though. Most road cars do not have "serious" wings and they don't really produce much drag. Even sporty cars such as the Murcielago SV and 911 GT2 easily break 200 mph (and their non winged versions' top speed), hinting that the wings are only producing a little force. On the other side of the fence, the Viper ACR, Mosler MT900, and F1 cars all have their top speeds greatly limited by aero-component drag.
- 1,137
Well, as long as we talk about downforce generated by wings
40% of the downforce generated by an F1 car comes from the diffusor. Todays F1 cars are even able to produce downforce without moving, thanks to the exhaust blown diffusor.
And decades ago Brabham destroyed the whole grid with the fan car.
Before accusing other people of things you should get your facts right. The grand prix cars from 30s-early 60s did produce less downforce then a modern sports car (infact, they had skinny tires and zero wings/spoilers/flat underbodys), weight about 500-800kg, the engines produced 300-600hp...
And even today, in F3 for example, in some races (street circuits) you see some drivers driving without the rear wing.
And the craziest example, the Ferrari 126C from the 81 F1 season. The downforce produced by this car was nothing compared to the downforce competitor cars or modern F1 cars can/could produce and yet this car had a very powerful turbo engine - and still it won at Monaco and in Spain -two very tight tracks- in the hands of G.Villeneuve.
Heck, I can even remember a race in the 82, where D.Pironi raced this car without a frontwing while G.Villeneuve had one...
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