Slipstream in GT5

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It all started because the cars were going over 220mph in the 80's, and there was a crash that took out the flagstand in Talladega that almost killed the official, but, the restrictor plate actually makes racing more exciting because it bunches up the packs. Before they instituted the restrictor plate, the finishes were between 3 or 4 cars, now over 20 cars have a chance to win the race on the last lap.
 
WolfRacer543
There's actually a lot that could be done with aero.

Slipstreams: As people have been talking about.

Wind direction and speed: Say you're driving head on into a 30km/h wind (the average wind speed in many cities is around 25-30km/h), compared to a 30km/h tail wind, when you're driving 150km/h, that's a difference of 180 to 120km/h wind speed. Since downforce and drag vary with velocity squared, (180/120)^2 = 2.25 times more aerodynamic force. So you'll be getting more than double the downforce and drag driving into the wind compared to the wind pushing you along. Then you include all the possible yaw angles and your aero forces will have huge variability with wind speed and direction.

Full Aero map: By this I mean how the aero changes due to the pitch and roll of the chassis. Undertrays and front wings in ground effect have massively varying force depending on their ride height, it can totally shift your aero balance back and forth from left to right and front to back as your car pitches and rolls.

Aero isn't something like "you have x newtons of downforce", in reality the aero varies massively as a car goes around a track. Accurate slipstreaming is just one part of it.
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Earth
Things that need to be fixed with GT5's draft:

  • Draft potency depends on the car's shape and drag. Ex: openwheel cars should draft better then stock cars because openwheel cars produce more drag and thus punch a bigger hole in the air for the following car to follow
  • Two cars nose to tail should both go faster. This is because driving right behind someone's bumper takes the air off their rear spoiler and the nose of the trailing car so they both go faster
  • Aero Loose and Aero Tight should be modeled. Running close to someone's rear in a high speed corner should make you understeer and should make the car in front oversteer.
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Thanks for that information.
It would really be amazing if GT did all that :crazy:
 
I can't help thinking that if they've gone to the trouble of securing the license and putting Nascar in the game they must have looked at slipstreaming otherwise, as Earth points out, it'll be as boring as us haters are expecting it to be.

The evil part of me kinda hopes it is so I have ammo for my flame cannon but, tbh, if there is something interesting to do there I'd rather it was as authentic as possible. I might even end up enjoying it.
 
So you want PD to dumb it down to make it more fun? Doesn't sound fun to me.

I find it very annoying when someone is sticking to my tail simply because of bizarre slipstreaming physics. It was happening to me tonight at suzuka.

Slipstreaming is not a major part of motor racing, but in GTP it is often a deciding factor. Even if you look at F1, cars that should benefit greatly from the effect because of their huge drag, down a 1km+ straight they can only gain a few car lengths at most.

I am quite sure this is PD's idea of fun racing; rubber band AI and monster slipstream. We got the rubber band taken care of, but we missed the slipstream.
 
In GT5 prologue it feels like your getting a slipstreem from a 18 wheeler truck trailer. The amount of wind lost is too much.
 
ralph89
In GT5 prologue it feels like your getting a slipstreem from a 18 wheeler truck trailer. The amount of wind lost is too much.
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Agree. I picked up like 15 mph at daytona in a Ford GT. Probably the most slippery car in the game. My opponent could get my draft from as far back as 1.25 seconds. It was ridiculous how PD modeled the slipstream.
 
nasanu
So you want PD to dumb it down to make it more fun? Doesn't sound fun to me.
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No. I want PD to make the slipstream smarter, more realistic.

nasanu
Slipstreaming is not a major part of motor racing
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I'd beg to differ on that point, especially regarding Nascar. I'm no expert, in fact I slag it off at every available opportunity but, as far as I'm aware, drafting plays a huge part in that sport.
 
P3nT4gR4m
No. I want PD to make the slipstream smarter, more realistic.



I'd beg to differ on that point, especially regarding Nascar. I'm no expert, in fact I slag it off at every available opportunity but, as far as I'm aware, drafting plays a huge part in that sport.
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Since when is nascar motor racing? :P

Anyway even in nascar the effect isnt that great. Its common to see a car pull out of the slip and only have enough extra speed to get along side the other car. Its nothing like GT.
 
Earth
The question is, would it be safe for PD to let the cars race at Daytona unrestricted when they are so low tech and handle so bad?
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Uhm...in what way would it be unsafe for PD or the drivers...? I always thought I'm safe on my couch...:nervous:
 
nasanu
Since when is nascar motor racing? :P

Anyway even in nascar the effect isnt that great. Its common to see a car pull out of the slip and only have enough extra speed to get along side the other car. Its nothing like GT.
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Your argument works against the point that I think you were trying to make. If a car is apparently catching up in the slipstream, then pulls out and suddenly can't pass (because of the sudden loss of slipstream), then it implies that the slipstream has a pretty big effect.

However, I do agree with what you are saying. There should be a realistic slpstream option in GT5. I have no problem with having a more pronounced one as a means to slower cars to catch up in fun (standard physics, whatever...) races. It's a better option than rubberbanding.
 
I hope they can get the splitstreaming and the restrictor plates right, otherwise, NASCAR at Daytona won't work. With GT5P splitstreaming, this wouldn't be possible.

 
The interesting thing about aerodynamic drag is how it increases, or the speed-squared law.

If you go from 20 to 40km/h you double speed, but quadruple drag.

From 20 to 60 that's three times the speed, nine times the drag.

From 20 to 100 is five times the speed, 25 x drag.

This is why the top speeds of cars are much closer than you'd think given the massive disparity in power, the drag just builds up so quickly. Doubling the horsepower doesn't double the top speed.

Above about 50-70km/h the major source of reistance to a vehicle moving is the air resistance. Mechanical friction (transmission, rolling resistance) comes a poor second. That's why driving at 80km/h rather than 100 make a surprisingly large difference to fuel economy.

As far as drafting is concerned the faster the speed the greater the draft effect, and at 160km/h you'll get much less of a draft than at 180km/h because of the speed-square rule. In fact, what really happens is that the total drag for your vehicle remains more or less the same, but you avoid the penalty of the extra drag. So it's not 'getting more draft' it's really 'avoiding greater drag'.

The draft effect is not dissimilar to the wake of a boat on water, there's a indentation in the fluid behind the vessel as it moves. However, boats hydroplane (skim on top of the water) at speed so as they go faster their drag can decrease so it's not a perfect analogy.
 
i think everyone has the same opinion about GT5 huge slipstream... but here's a little sample of how ridiculous this is:



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^^^Totally agree on the video. Even in GT5p you can get a huge amount of slipstream from a Honda integra. Worst is, even the cappuccino can reach 160mph with slipstream. They should fix the top speed limit, too. It's quite annoying driving a GTR doing 210mph were in reality it can only reach 196mph.
 
snowgt
Your argument works against the point that I think you were trying to make. If a car is apparently catching up in the slipstream, then pulls out and suddenly can't pass (because of the sudden loss of slipstream), then it implies that the slipstream has a pretty big effect.
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Not at all. The car is not passing because the speed it gets from the slip is only a few k's extra. Its not like they are closing in at 40kph then stopping dead when they hit the clean air.

It implies that the effect is small and easily lost.
 
nasanu
Not at all. The car is not passing because the speed it gets from the slip is only a few k's extra. Its not like they are closing in at 40kph then stopping dead when they hit the clean air.

It implies that the effect is small and easily lost.
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It also depends on how close the cars are to their respective top speeds. If you've used a draft to get to 240km/h when the car's max speed without draft is 235, you'll be going losing speed once out of the draft. If you use the draft at 220 you should be able to hold the speed advantage once out of the draft, getting to 235 quicker than you otherwise would have done.
 
The strongest draft I have ever seen, openwheel cars at high speed, still child's play compared to GT's draft

 
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about the video i've post before... note that i used the f1 cars to compare because:
-they can reach high speeds (which is an important factor for the car in front to leave a longer slipstream effect on his tail);
-in indianapolis circuit F1 cars only use a bit of down force which also allows to reduce the air resistance..
(so we'll get the higher level of what this effect can do in races)

adding to this... the the distance between both 370z is larger than the F1's but it is possible to catch the slipstream...

but even with all of that.. the 370z still overtaking 1st... :ouch:

@P3nT4gR4m: want close races!? :)
huge slipstream inst the answer... WTCC cars look like 370z tuned and they try to use slipstream but they need to struggle to overtake.. and thats hot, fun and they can't get more closer to each other.. :D

 
nasanu
Not at all. The car is not passing because the speed it gets from the slip is only a few k's extra. Its not like they are closing in at 40kph then stopping dead when they hit the clean air.

It implies that the effect is small and easily lost.
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Do you realize what happens if you lose the draft at a place like Daytona? If you get out of it chances are you could easily drop to the back of the pack in seconds. There have been several instances where a fast car got stuck driving by himself with the only way to catch up being a caution.


@ 370Z vs. f1 video, you can't really compare the two since the 370z will produce a stronger slipstream than an F1 car since it's just bigger. Although I do think PD needs to reduce it as it does seem a little to strong.
 
Justin
@ 370Z vs. f1 video, you can't really compare the two since the 370z will produce a stronger slipstream than an F1 car since it's just bigger. Although I do think PD needs to reduce it as it does seem a little to strong.
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ok.. read again what i've write.. you will think better :) and if the car is just bigger.. the WTCC cars are the same and you dont see slipstream in the same measures as the 370z..

the car is bigger but the speed is lower.. 👍 the relation speed/size its not linear though...
 
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MeAgainstYou
i think everyone has the same opinion about GT5 huge slipstream... but here's a little sample of how ridiculous this is:



edit:
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Drafting is a combination of speed, drag, horsepower, and distance.

In this video the speeds are way different (over 100kph), drag on each car is way different (wings and openwheel vs coupe, so the F1 car has more drag), horsepower is way different (300 vs 750 Im guessing), only the distance is similar.

Even so the Zs should have not drafted like that.

I'm sure there is some mathematical equation that could take into account all 4 combinations that make up drafting and could tell you how well a car should draft.

The problem is Gran Turismo doesnt take into account all four areas that decide how cars should draft.

For example in GT draft potency is the same 150 yards away as it is 5 yards away.
 
here is a good explanation with some great pictures : http://www.cd-adapco.com/press_room/dynamics/v201/bigger_better_motorsport_CFD.html

examples:
nascar_streamline_5.jpg


very_large_simulations.jpg
 
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If PD get this right then online will be even more epic and challenging :D Overtaking in prolouge is way to easy! To be honest I think PD will do something about it :sly: :drool:
 
I believe it will be different in professional physics mode (exactly like in reality) and standard physics mode (as in Prologue).
 
I aint asking for much here. I don't care if they simulate it accurately using ohms law or pythagoras' underpants or any of that malarkey. It's gotta be pretty easy to trick using a simple - factor per car X speed travelled = area/magnitude of effect - formula.

Doesn't need to be ultra realistic or anything just a rough modifier that's toned waaaaay down from prologue.

As has been stated already in the thread - slipstream isn't that big of a deal IRL so why bother making a big deal of it in game?
 

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