SlipStream in GT5P

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niky
You're not going to "notice" a draft unless you're at a point where your car can't accelerate any further on its own and there's another car in front of you that's also at its top speed (which is the same as your own).
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Are you sure this is the case?

My Physics knowledge is nowhere near degree standard but I'd say it's better than most, is the effect of slipstream not simply the car infront of you is "punching a hole" in the air. Which means you don't have to, so effectively you have the same force going forwards but less force (drag) slowing you down?

In this case, you would not need to be anywhere near the peak of your power - simply at a point where the effect of drag is pronounced enough to be noticable. If, for example you were in 6th with your foot on the accelerator enough to keep a constant speed, if you lowered the resistance force, you would accelerate until you reached your new terminal velocity.

To me, I've never seen slipstreaming as extreme as in GT5p - example, at Fuji in F1 I've not seen 2 reasonably similar cars competing where one overtakes _before_ the start finish line. This is easily possible in GT5p.

In Gran Turismo you can exit a corner worse than the car in front of you and still gain the effect of slipstream enough to catch them on the straight and overtake without the need for outbraking.
 
bicycleshorts
Furthermore it causes "draft dodging", i.e. people zig-zagging down the straight so you don't catch their draft.
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That really makes me laugh, I'm relatively new to the massively disappointing world of Online racing with GT5P but the draught dodging (especially at Fuji) I find hilarious, do these zig ziggers not realise that when they dodge left & right the following car will just dodge with them and stay in their tow anyway? Esentially all they're doing is making an already long straight even longer.

My favorite tactic, if I'm in front going onto the straight at Fuji, is to let the following car have the draught and pass me, then I'll tuck in behind them, pick up their tow and time my re-pass to get them into turn 1 when they can do nothing about it.

Not long now till I get the 2 mill needed to buy the F1 car for my son, then I can go back to playing good racing games on my 360 and PS3 and forget all about GT5P. At least until PD give us the private lobbies, comms, damage and host defined events that any online racing game worth owing should have as standard.
 
If you watch a Nascar race at Talladega, you'll notice that cars will be able to pick up the draft from almost the whole length of the straightaway on a track that's 2.66 miles long..
 
This aint NASCAR though is it?

Also I've driven a NASCAR around Kentucky Speedway (Last June) in and out of a tow and you could hardly feel any difference, granted it was no C.O.T and I was hardly on the limit but I was touching 155mph, which in this game would be plenty to pick up a massive tow and gain a huge speed differential on the car in front especially from the 4 car length distance I was from the pace car but IRL it is barely noticable.
 
nasanu
Now that catch up logic has been removed, the absurd slipstream is my main concern for GT.
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Agreed. It makes for better battles, but I get pissed that I work so hard to get past someone, only to be passed again on the straightaway. In the mean time, the leader is in clean air pulling away.:yuck:
 
Ardius
Wait, how are you finding this extra downforce from Touring Cars? How on earth does a, for example, Vauxhall Vectra BTCC have more downforce than the Viper/Tuned, Corvette/Tuned or GTLM? Also, who says you can't run slicks in GT5:P?

I think for an easier comparison we could use the example of the Renault Clio Sport. I'm 95% certain I've never seen Renault Clio Sports achieve this much slipsteam as they do in the game at these distances.
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A "Tuned" car in GT has merely a laundry-hanger wing and an (invisible?) front splitter. Touring cars have all sorts of wind-tunnel tested canards, underbody trays, venturi tunnels, wings that extend past the top of the car, etcetera... I can't actually prove it, but if anyone has the time to go research how much downforce, say, a Mine's Skyline makes compared to an actual JGTC car, I'd wager to say the difference is greater than it is between said Skyline and a regular street car.

What I'm saying is... in all the series you guys cite as examples of how you can't overtake a guy on slipstreaming alone... you have race cars on slicks. In Gran Turismo 5 Prologue, you're racing with street cars. Whether they're on slicks or not, they're still not as accurate through a corner as a race car, and with the wide variety of skill levels online, there's a chance you can be draft-overtaking a guy simply because he's slow as molasses out of the previous corner.

Like some of us have said... look at Nascar. That's the one professional race series where downforce is a complete joke. No big wings. No canards. All the downforce you're getting is from the body shape... much like a street car. The draft dynamics in NASCAR make for some really spectacular slingshots... much like you'll see in GT5P with the street cars in the game.

The "feel" of a draft is really subtle... you'll be able to see it mostly in how fast your car is going.

Still, I'm open to the possibility of the draft being unrealistic... but I'll make up my mind as soon as I see grids full of LMPs and how it works there... :lol:
 
I'm not so sure that the whole street car vs race car thing is dead on.

Drag and drafting comes from the separation of boundary layer air around the car, as far as I know. The more separation, the more drag and more effective the draft. Wings and such on a race car will cause more separation as the interest of downfroce.

Street cars are looking for low drag (fuel economy or high top speed) so they don't disturb the air as much and create a weaker draft.
 
Street cars create a stronger draft if they're bigger... many race cars are designed to disrupt the air flowing over the rear wing, to prevent it. That's why part of the new Formula One rules includes changes to the rear wing to increase drafting.
 
I don't think the F1 rule changes are to increase drafting, just to reduce loss of down force as one car approaches another.

As I said earlier I've never felt any slip stream effect at 120mph or so on the autobahn whereas in the game, even at that speed, you can feel the effects. I haven't tested recently but in the game I could feel the effects at 70mph if I was close. Well, this morning some muppet pulled out right in front of me at around 70mph, even with almost no distance between us I couldn't feel a tow.

It's also worth keeping in mind that most mass produced cars are designed to lift at the front and not generate down force. I believe this is done to ensure "safe" under steer.
 
Try the begginers k series online in the Cappuccino. Try it with and with out any one in front of you.
 
Lift? No... most modern cars are designed not to lift. I dread the thought of some engineer saying:

"Hey, this Corolla is too pointy... let's give it some front end lift so it'll understeer."

"But that would make it incredibly dangerous at over 100 mph."

"Who cares? Nobody drives at those speeds."

There was a generation of Corolla in the 90's that had froint-end lift. Not on purpose... but as a flaw in the design. Really hairy to drive at triple digits. Come to think of it, many old Japanese cars were. Take a brand-new Corolla (arguably the most understeery car available nowadays) and peg it to the floorboard. The nose stays arrow straight. No lift.

Understeer is engineered in through suspension design. Softening the rear swaybars, adding some rear camber, changing the front suspension geometry. Nobody purposely makes their cars capable of flight anymore, that's just criminally dangerous. :lol:

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Funny. Just the other day, I managed to catch a draft at 130 mph on my way to 140. The car literally slowed like a brick when I pulled out of my buddy's slipstream (I only have about 175 hp). There wasn't much of a feeling of change, but the difference in pace is dramatic. It was easy to see because both cars had nearly equal power and top speeds. But at those speeds, with that power-to-drag ratio, we were just as close to the limit as your common PP630 car would be at 300 mph.

You're not going to feel the difference so much as see its effects. But the effects are most apparent if you have, like I said previously, cars which are all at the point where they will not accelerate any further under their own power.

Drafting is more noticeable in NASCAR because those are relatively slow racecars (750 hp pushing a large frontal area) compared to, say, Formula One cars which have so much power, they're still accelerating hard when they enter the braking zone at any track. And it's worse at sprint races, where they're limited to below 500 hp. In NASCAR, people can catch a draft at over a hundred meters. Problem is, with the restrictors, the cars slow like a brick when they leave the draft, so a good slipstream pass needs a lot of planning.

But back to F1... power... that's why you don't see more draft-overtakes in the top level of motorsports... too much acceleration. But if you watch the lower-level races... there's a huge advantage to a draft if the circuit is long enough.

In GT5P... your cars are making an average of "just" 200-600 hp, with cars that are much slower than tube-framed, carbon-bodied and bewinged racecars... mixed in with cars both faster and slower than you (due to the vagaries of PP balancing) on the straights... with different gearing (tuned) too. Catching enough draft to outright pass (given the right situation... if the other car has exited the previous corner faster than you or even at close to the same speed and has more power, catching a draft doesn't help as much... it just keeps you from getting left behind.

Again, I haven't made up my mind. Until I can take a car that's avaiable to me in both GT5P and in real life and do a back-to-back test (using a tow car that's available in both GT5P and in real life) on a preferably non-windy day (crosswinds and headwinds hamper drafting in real-life), I can't make a definitive statement on the accuracy of drafting physics.

Is it my imagination, or is the draft less in Spec III than Spec II?

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My mistake about F1 wings... yeah, it is indeed to reduce turbulence and allow the driver behind more downforce.
 
Well, as concerns lift: Yes you are right about suspension etc., but I was told by people who work in wind tunnels at Jaguar, Honda and Toyota that there is an element of lift built into most mass-production cars. I'm not talking about take off levels of lift though. It's not my are of specialism (I work in IT) but that's what I was told and I've certainly experienced the front end go light above 160kmh (indicated, probably not actual) on a couple of family "run-abouts".

As for F1, there are still a few straights where the cars aren't really accelerating at the end, look at the in car footage on the straights at Barcelona. I did see a couple of slip-stream overtakes and attempts in this seasons F1. I also remember the teams talking about giving each other a toe when they were still racing in the US.

Please don't misunderstand me, I'm not saying there should be no slip-streaming, I'm just saying it seems to pick you up from too far back and work from too low speeds. You're also right that it's better in Spec III, I probably need to play the new Spec a bit more!
 
I haven't driven a recent or recentlydesigned car (2000 and up) that seems to lift at high speeds. Of course I don't have hard data on lift, but it isn't something you want on a street car. Even enough to let the front end go squirrely is quite dangerous for cars designed for sale in the European market.

It'll be interesting to see how the slipstream physics pan out in the full GT5. With a wider variety of cars and more high downforce racecars (and hopefully racecar events), we'll be able to study the phenomenon in greater detail. ;)
 

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