Real life vs. GT4

[NicksB]

first of all please don't think "not again..."
for the last half hour i searched and manually flipped through quite a few pages and threads on this forum and i couldn't find something similar to what i'm about to post here. if it does exist, please tell where (maybe i'm blind? )
also: i believe this belongs here, as this is neither a race report nor tuning advice/whatnot...i hope i'm right


i always loved to play simulator games, obviously to have the opportunity to drive cars in a way as close to real life as possible with commercially available technology. but, somehow, this never transferred to playing gt4...why? i don't know...i just had enough fun simply taking a nice selection of cars around some real and some interesting fantasy tracks...so i went to change that:

in the past few days, i read up on some of the gt4-physic analysis threads that a few users have made here and thought about what to do with the information, besides have more fun in the game by myself.
now, i have had the game for years and only (fairly) recently got to thinking about what to do to make it more of a realistic experience.

first i tried to adjust my driving style, to make it fit better to how i actually drive my own car and whichever car i had the opportunity to get my hands on so far in my life.
the obvious next choice was to adjust to in-game physics concerning the car's weights and behavior under the weights influence (before that, as mentioned above, i mostly just drove, without noting how any of this influenced the driving).

all this and a lot more finer details helped to get gt4 into a somewhat realistic experience.

and now, finally, why i made this thread: with all driving style adjustments made and especially a lot of hours spent on comparing the tire selection available in gt4, i decided to record the results of my testings in a nice little (so far...it's gonna grow with time...here as well, if there is any interest on your side?) excel sheet, which i just thought i might as well share with everyone here.

so, here's the excel sheet:

it should be pretty much self explanatory, but if there are any questions to it, or if you require any more detailed information about the cars i used, feel free to ask.

maybe just one addition: saying "as little kerbs as possible" excludes the large, wide one on the start-finish line, since that is important to take the corner right (and it's also used in real life...looking at best motoring videos, where most of the times on the given website apparently come from anyway, for example)

small deviations (less than 1 second, i reckon) of the times can easily explained due to differing weather conditions and environmental temperatures. i cannot, however, explain some of the 2 or more second differences. maybe you have some input towards that?


after testing those cars, i took some of the cars in the exact same configuration and went on a few trial runs on the nürburgring. shockingly...well, see for yourself: (i did not yet make an excel sheet for it)

(real life times again taken from the same website. they list the times of the 'sport auto supertest' runs, driven by horst von saruma. very accurate, clean and comparable driver)


car - RL time - GT4 time

BMW M3 CSL - 7:50 - 8:11.826
BMW Z4 3.0i - 8:32 - 8:55.205
Audi RS6 (C5) - 8:20 - way past 9 minutes, didn't even bother to finish the lap

however: (and i really do not understand this one)

Mercedes SL55 AMG - 8:12 - 8:16

this time, for the nürburgring run, the car in real life was, just as it is in the game, the 2002 version, so it should have almost the exact same power/weight ratio, considering everything, down to the sometimes extreme deviation of listed power to actual (if measured on a dyno) power

albeit the in-game-lap being a bit sloppy (it was the first of the trial runs, just to see if it is at all feasible to even try) i also kept in mind, that the real car most likely had the 250kph limiter, so i tried to not surpass that speed in the game. looking at the replay, the most i had was 251kph, so i think it's fairly accurate.

whatever may be the cause of the extreme differences of the first 3 cars, while one is almost exactly accurate, i will try and find out...more testing is in order.

p.s.: interesting thing i noticed during the testing: the sl55 has, just as in real life, its electronic helpers interfering, even when they are all disabled (no aids in the setup screen)...guess that comes as news only to me

 

[Parnelli Bone]

Hey man, welcome to GTP. 👍 I'm surprised nobody has commented on this thread after an entire day + some hours!

Good lord, what a thread! It's gonna take some time to digest, to be honest, which is a good thing. We've lately had a couple new members who (to put it nicely) haven't got much going on upstairs, if ya know what I mean.

Question: N1 tires on all those cars? What's that supposed to represent? Curious.

 

[NicksB]

Hey man, welcome to GTP. 👍 I'm surprised nobody has commented on this thread after an entire day + some hours!

Good lord, what a thread! It's gonna take some time to digest, to be honest, which is a good thing. We've lately had a couple new members who (to put it nicely) haven't got much going on upstairs, if ya know what I mean.

Question: N1 tires on all those cars? What's that supposed to represent? Curious.

thank you

as for your question: i suppose you mean which specific brand/make/model the n1 tires are supposed to represent in real life? nothing, actually. they were just the tires that made the car feel just about exactly right. having an fwd car myself, i drove around getting a feeling for how it becomes noticeable when grip is lost, then i tried to remember how it felt when i drove some rwd cars.

i then compared lots of videos to that experience and i'm now confident to somewhat tell how a car should feel under sporty driving, if i found a quality video of it. most of it was best motoring, obviously, as they have nice shots of the steering wheel, where you can see how the driver reacts to the movements of the car while entering a corner and such.

after that, i cranked up the ffb setting in the game and now it's fairly easy to note when a car loses grip in either direction (over/understeer), except for braking hard into a corner, already turning slightly, then, usually, it's just loads of understeer before you know it...abs does somewhat work in the game, but on higher-performance cars (for example the m3 csl), it isn't as confidence-supporting as it should be in real life.

anyhow: the n1 tires give a very exact feeling of the cars behaviour. for example the sl55's electronic helpers that i mentioned..disabling the aids in the game and setting the ffb high, you can easily feel the stuttering of the esp (english: tcs, i suppose). dive into a slow corner, feel the ffb in the wheel simulating (by slightly rattling, obviously) the minute appliences of the brakes to keep the back from stepping out or the front from sliding away. (got that idea from gt5p, by the way, as it's a lot more obvious there)

whereas the n2 and n3 tires already have almost too much grip to feel those slight influences. it's also a great deal easier to recatch a car that has it's tail stepping out than with the other two tires. i find that they have a strange buildup of grip levels, never mind the fact that all three severely understeer under full throttel preassure.
example: feel the back going wide, flooring it to still get it round the corner, but, unlike in the lap before [recreating the circumstances], it ever so slightly goes just a little bit wider and then, suddenly, just goes straight into the sand, because the front tires suddenly have zero grip. that's easily avioded by going just a few kph slower, obviously, but the set-in of the understeer is severe and sometimes unpredictable...

as for real life coutnerparts...considering that the tire-widths differ with each car (a small citycar suzuki has much thinner n1 tires than a bmw m5...again, probably only news to me), i presume even the compound varies from car to car...at best, i can guess that the n1 tires represent the wheels put on the cars in the factory

 

[kemikakadet]

Have you read Scaffs tuning guide? There's a lot of interesting informtion in there, particularly the tyre section. He deduces that the N2 tyres are the most realistic model for the BMW M3 CSL. Obviously it won't be the same for all cars, but N1's won't always be the most accurate choice.

 

[Parnelli Bone]

Got it^^

I've been liking to think N1 tires are the crappiest one can buy in real-life....all those off-brand types places like Cosco sells....4 for $100 or whatever. lol

N2 tires are like a good set of all-season radials with a name we can trust. Yokohama. Pirelli. Michelin. N3s are warm-season tires, better grip for paved surfaces.

That's just how I like to think of tires in GT4, but hell, I could be wrong. I haven't got the benefit of real-world experience driving on the limit. Granted, there are many different levels of traction, wear, and temperature capabilities from real-life that aren't represented in our game. What PD tried to do is give us (at least) some generic tire types with various levels of grip, but they don't always figure well with what the real-life counterparts would provide.

 

[NicksB]

Have you read Scaffs tuning guide? There's a lot of interesting informtion in there, particularly the tyre section. He deduces that the N2 tyres are the most realistic model for the BMW M3 CSL. Obviously it won't be the same for all cars, but N1's won't always be the most accurate choice.

i read the part in the pdf, yes. i do not doubt that the values he recreated are accurate, but the problem with n2 tires...well, i tested a bit more today, see for yourself below:

Got it^^

I've been liking to think N1 tires are the crappiest one can buy in real-life....all those off-brand types places like Cosco sells....4 for $100 or whatever. lol

N2 tires are like a good set of all-season radials with a name we can trust. Yokohama. Pirelli. Michelin. N3s are warm-season tires, better grip for paved surfaces.

That's just how I like to think of tires in GT4, but hell, I could be wrong. I haven't got the benefit of real-world experience driving on the limit. Granted, there are many different levels of traction, wear, and temperature capabilities from real-life that aren't represented in our game. What PD tried to do is give us (at least) some generic tire types with various levels of grip, but they don't always figure well with what the real-life counterparts would provide.

hm..i did a bit more testing today, sadly it doesn't appear to be a good day for it...somehow i barely got some clean laps at all..it's just one of those days

anyhow, a few more times now stand, none of which are made with lines all over the place (which happened a few times today... ), but all, again, as clean as i could manage, this time though with a bit more kerb, considering the track it was necessary.

as you can see, the times are quite accurate, so i don't know what changes inbetween the accuracy of the values measured/compiled by Scaff for the n2 tires and using n1 tires to set times...i hope i will have a better day tomorrow, then i will see to driving the same cars from this test with n2 tires, to see how much they deviate. regardless, it appears that the n1 tires are very accuare to set times on small circuits, now i will have to find out if i'm just a plain bad driver, or what else might be the reason that the times differ so much on the nordschleife...much to do, much to do...

 

[NoQuarter]

Excellent thread, and obviously you have spent a lot of time researching/testing...kudos. 👍

I'm just now returning to Gran Turismo after about a two year hiatus. In my humble opinion (which applies to all my statements in this post), GT4, while a step up in the physics from GT3, is still a bit off from real life when it comes to traction dynamics, and while the N tires most accurately match the real life physics, once can still get away with a few things under extreme cornering conditions, which vary considerably from car to car and track to track. There has been plenty of analysis about this, specially now that GT5P has redefined the GT physics and GT5 promises to deliver even more accuracy (we hope).

All that being said, the "gray area" of the physics in GT4 is masked to a degree by an individual's driving style. I've seen people who were superb real life amateur race drivers (autocross, track days, etc.) absolutely baffled by some conditions, and I have seen drivers who were not of legal driving age make some spectacular runs in GT4...

Your analysis and testing methodology would be lend itself to having others test using your paradigm, and it would be interesting to see the results of such testing...once the GT5 physics is out, it would be cool to see this testing applied as well.

 

[Parnelli Bone]

The one thing you're not factoring in, Nicks, is the 'fear factor', which Jeremy Clarkson and others dealt with when racing on a videogame, and then switching to real-life.

In other words, you're pushing those cars to make similar times to real-life on N1 tires, which is great, but it's been well-documented that somebody sitting in his chair while racing doesn't = somebody actually racing a real car. The person in the real car won't be able to push his car with nearly the same capacity as a videogamer.

In other other words, somebody able to push a car to make such a time on crappy all-seasons doesn't necessarily equal somebody racing a virtual car, since the virtual car driver isn't risking injury or his life.

On the other hand, you've explained that you weren't having such a great day testing today...you were 'all over the place with lines' and such.

A real-life tester making an absolute benchmark time will be choosing consistent lines. It sounds like your time on N1 tires could have been even lower than it was. I'd advise practicing up further, and testing again on N1s before you move on to N2s. 💡 just a thought.

 

[Balocco]

The one thing you're not factoring in, Nicks, is the 'fear factor', which Jeremy Clarkson and others dealt with when racing on a videogame, and then switching to real-life.

I've driven my car, a Scion xB, quite a bit in GT4 and while it behaves almost scarily like my car does in real life, I push the virtual car a lot harder than my real one, because in the game you aren't sitting like you would at the dinner table in a rather tall car and having that seating position act somewhat like a lever to make the body roll while cornering, which in actuality is no worse than in any other car, feel like the car is going to roll over.

There are lots of things that a game like this, no matter how good it is, just can't convey.

 

[Lucas]

After more than two years of playing GT4 I have noticed that traction on some cars, if not all, seems to be terribly modeled. For example, I could not come even close to the Dodge SRT-4 and Honda Civic SiR-II's 1/4 mile times in real life, and that was with S2 tires. I don't want to imagine how different would the times be with N tires.

 

[Parnelli Bone]

After more than two years of playing GT4 I have noticed that traction on some cars, if not all, seems to be terribly modeled. For example, I could not come even close to the Dodge SRT-4 and Honda Civic SiR-II's 1/4 mile times in real life, and that was with S2 tires. I don't want to imagine how different would the times be with N tires.

Same goes with the '05 Mustang GT. Real-life has these cars pegged somewhere in the 5s from zero to 60 mph, yet even with soft sports in the game, I couldn't get any lower than 6.7 if I remember correct, which is terrible for a modern-day sports coupe, even on radials. Only when I put R3s on did the GT start to get close to real-life. 👎


That being said, there are PLENTY of cars that do make similar acceleration runs from game to real-life, although it's hard to say they're perfect comparisons because I use S2 tires for most of my track tests.

 

[NicksB]

The one thing you're not factoring in, Nicks, is the 'fear factor', which Jeremy Clarkson and others dealt with when racing on a videogame, and then switching to real-life.

In other words, you're pushing those cars to make similar times to real-life on N1 tires, which is great, but it's been well-documented that somebody sitting in his chair while racing doesn't = somebody actually racing a real car. The person in the real car won't be able to push his car with nearly the same capacity as a videogamer.

In other other words, somebody able to push a car to make such a time on crappy all-seasons doesn't necessarily equal somebody racing a virtual car, since the virtual car driver isn't risking injury or his life.

On the other hand, you've explained that you weren't having such a great day testing today...you were 'all over the place with lines' and such.

A real-life tester making an absolute benchmark time will be choosing consistent lines. It sounds like your time on N1 tires could have been even lower than it was. I'd advise practicing up further, and testing again on N1s before you move on to N2s. 💡 just a thought.

hm..this gives me the idea to compare just how much the braking-points differ to real life. as much as it is possible to do so, with off-board/flyby/helicopter/whatever views of cars anyway...

undeniably there is the fear factor. very obvious to anyone who's ever driven a bit on the sporty side. i had the opportunities to sit on the passenger seats of some VERY interesting laps and tried to take every bit of how the driver reacts while feeling what the car does. however: to nitpick on your choice of jeremy clarkson...
first to get something out of the way: long story short, i love top gear, i recognize that jeremy clarkson is capable of driving a car fast, i am not trying to bash anyone or anything here...
the problem i have with his comparison test (which, by the way, is the only game-RL comparison i know...should look that up as well, while i'm at it ) is that he's not a racing driver. they DO have the stig and if he were to have been in the seat of the nsx, the whole thing would've looked VERY different. lets stop it at that, not to get this thread into a fight...i don't know this forums' stand on top gear..

back to the game

take for example the last batch of times on the motegi ring: you may remember that the motegi track in the game had exceptionally strong black marks into and within the corners, to indicate braking-points andd the general driving line, however, with the n1 tires, i had to brake A LOT (at least 10 to 20 meters) earlier to get a clean line into and through the corner.

take for example the third straight on the 4800m version, that's the almost 90° one leading under the first of the two tunnels. with the m3 csl i approached that corner with just about 180kph (last number i remember seeing, before i had to concentrate on the line...will check that tomorrow as well) and i have to brake well before the 2nd-to-last (100m? i think..need to check) mark to get all the way down to about 60kph.
looking at the video in comparison: in the nsx-r, the foot goes hard on the brake a good 20 meters before the same second-to-last-mark (good thing there's an internal shot with the footwork right there... )

okay, now that this is already this long a post again, i guess i stop now and continue tomorrow
also, i think within the next week, i will try to put up some videos on youtube, for you to get a better idea of how these laps are made.


also a very important thing you all need to remember: this is all about lap times, not 0-60 and such. since it appears that there's quite a lot of different work to make comparable statistics than laptimes, you can't simply compare them. technicall, yes, it should be possible to put them in correlation in real life, but, as said on this forum so often: it does not necessarily apply to the game.

 

[ItsHim]

On Top Gear - you should find some "James May and Jackie Stewart" footage on the interweb, which was done after the Laguna Seca episode, so that's maybe more of a genuine "ordinary bloke becoming a racing driver" story. Very worthwhile and entertaining.

On GT4 vs reality

When I get back behind the wheel in GT4 after a long break, I catch myself not racing but driving round the circuit. I rather handle the car like I would roughly in RL. Amazes me every time, there's something GT4 must do absolutely right. And I usually cure myself by doing a driving mission, chasing some vintage cars round NYC for example. After half an hour I'm really 15 seconds faster because I pushed myself beyond that "oh that's too fast" barrier and I start racing again.

Anyway, on the Nordschleife, I doubt there is brake fading, which is a shame, isn't it. And, on N2 tyres, it's hard for me to catch that "perfect" time span when tyres are at their grippiest. Usually I realise it too late, and when I have realised it, I tend to push too hard for too long. Mind you, that tyre wear thing is what keeps me coming back to GT4, because it adds so much fun and variety to gameplay and I only do the longer races anyway.

I also noticed that braking for that right hander on Motegi, you'll have to brake earlier than you would think. No idea if this can be fixed by tuning, I'm not that kind of person.

But, in conclusion, even after having a lot of next gen racing titles, GT4 even on a dated CRT TV but with a G25, has some real punch. For a 5 year old game, that's amazing. And some of my friends were drawn immediately into the game, despite we all got accustomed to HD games.

 

[RaidoGT]

You'll never get GT4 to behave real close to real life because it's not really a simulator. It's an arcade game with sim leanings (and as such, a pretty decent one), but it still has several built-in 'fudges' to make it easier to drive for the general gaming public. Unless it's reverse-engineered on a pc and re-burnt to a modified DVD, you'll never be able to get these fudges out of the physics.

For one thing, PD put in a rear-end stabiliser fudge that sticks the rear end to the track more than it would in a sim or real life. This is part of the reason, imho, why many players stated that GT4 cars tend to feel 'understeery' and that making it do donuts is so hard. This affects rear-wheel cars especially, but not exclusively.
Secondly, although N2 are closer to real life sports tyres than S2 for most street cars, the tyre model is still very much simplified. For one thing, if you accelerate with spinning tyres from a standstill, the car will always move ahead dead straight, you don't have to correct at all unless you do something drastic. Again RWD cars are most affected by this.

You can easily feel the differences if you load up a similar car in GT4 and a sim like GTR2, iRacing or rFactor. For instance, the 1992 SiR-I/Sir-II Civic which came out for rF not too long ago. Although some things are similar, driving both cars is very different. There's hardly any sensitive feel in weight change, brake and suspension feel, tyre grip or engine behaviour in the PS2 game; its driving model is much 'cruder'. Where GT4 loses out, ultimately (apart from the fudges and the ultra-crappy robotic AI) is in feedback, or rather the lack of it - it's much 'duller' to drive than a sim and of course a real car, but that's only natural since it's old technology by now. For a 2004-era arcade game, it doesn't even do a bad job - but as such, it also has some fierce limitations these days, of course.

 

[sdkflu]

by far, the most realistic road tires in GT4 is the N1 tires....
the different lap times in Nürburgring, real life vs GT4 with the N1 tires, is the difficulty of large track of Nürburgring and the driving skill of the players from the professionals drivers... small tracks like Tsukuba, is by far more easy to follow the best line,
and the help from more practice, more laps in small tracks...

the of GT4 physics is very good for the age and the power of ps2...
the problem is the tire model at the low speeds...

also need a good steering wheel, like Logitech DFGT, with all driving steering aids off, active steering off, simulation on...

the best combination for realism in GT4, is the stock ROAD cars, with N1 tires, and one of the upgraded suspensions (sport, semi-racing, racing)... for better setup with each track ...

happy gaming !!!

GT4 videos...

http://www.youtube.com/watch?v=a0X5Fc8R18c

http://www.youtube.com/watch?v=-zK1TFJEu0E

 

[NicksB]

ok, i had some time the past few days and did some more laps. will update this post, when i have finished the excel sheet, sometime this evening, probably. few cars on fuji, some more in tsukuba and a few on the ring. massive fun and a good workout with the mine's r34 gt-r on tsukuba and a stunning result on the ring with the c12 s 7.0 zonda...

question: how do i make videos like

....



GT4 videos...

http://www.youtube.com/watch?v=a0X5Fc8R18c

http://www.youtube.com/watch?v=-zK1TFJEu0E

i had recorded a few laps with a cam off the tv screen..it doesn't have bad quality, but it does have quite big file-sizes, so uploading it to youtube would take ages. is there a better way? didn't find anything in searching the forum

 

[sdkflu]

ok, i had some time the past few days and did some more laps. will update this post, when i have finished the excel sheet, sometime this evening, probably. few cars on fuji, some more in tsukuba and a few on the ring. massive fun and a good workout with the mine's r34 gt-r on tsukuba and a stunning result on the ring with the c12 s 7.0 zonda...



question: how do i make videos like


i had recorded a few laps with a cam off the tv screen..it doesn't have bad quality, but it does have quite big file-sizes, so uploading it to youtube would take ages. is there a better way? didn't find anything in searching the forum

nice ... i wait to look your informations and opinions from your tests...

driving and practice with Ν1 tires are also very good option for increasing the driver's level in situations such as weight transfers, understeer, oversteer, braking, drifting... et...



ok... for recording GT4 replays and upload...

i connect ps2 to the input of video recording in a desktop dvd recorder, the picture I saw regularly on television, and wrote the replay, I did finalize the dvd-rw disc to be read by computers, of course processing for smaller file size and good image quality, you may need a video editing program

I hope you understood what I write, because my english in writing is quite limited... sorry...

 

[NicksB]

so, here goes

this time, i changed the setup of the Ruf RGT a bit, keeping in mind, that the real porsche gt3, considering it's been set up for the nordschleife, does not have 0 camber and any car maker rarely exceeds 1° of camber. so i tried to find a usable middle ground...somehow this is probably still very wrong, but it worked, considernig the time

i was very surprised to get the Zonda round the track so well and with such a fitting time. it is, without a doubt possible to get even closer to the real time, without going corner-cutting or somesuch.

greatest surprise was the mine's gt-r...i hadn't driven the car anywhere near serious (or, if i remember correctly, not even with a wheel back then..) and doing so now, with a clear goal in sight...my goodness, impressive.
of course, the most interesting thing you might notice about that run are the S1 tires. hard sports tires seemed to be the obvious choice, as the real time was set in a time attack, with a maximum of two go-hard laps per set of tires (i think they are limited to 3 tire sets though, if i understood everything right...no matter to the game, obviously ) and those tires were, you guessed it, the slick'est semi-slicks that are still road legal.

i looked through the game to see if there are more cars that were used in several different time attacks, but most of which i found were set in the year of-, or after the release of GT4, so...well, it would've been nice to see if the S1 tire choice would be necessary for all of the tuner cars....

as i don't know what to do next, maybe i could draw a conclusion, i'd say, for lap time comparisons to real life, the N1 tires are the obvious choice. i suspect, if gt4 had a selectable tire width, especially for both front and rear differently, it could be significantly improved (some cars have very big rubber height [what's the word...] and too small alloys. just now (hence the edit) i thought that i need to take a closer look next time, how the tires look in the game, i suspect that the physics are somewhat relating to the actual polygon-placement of the virtual rubber...if, as i fear (but don't know), the tires are equal in width and rubber-height on front and rear, there could be a significant closing up to real times on the longer tracks (namely nordschleife)...just a thought though
well, for now, i guess i wait for GT5 to be released, since i've compared pretty much all the cars i could find in game and real life on the same tracks...i would've loved to try this with race cars, but i can't find any useful resources for laptimes of any race-class that is in GT4...

now off to have some more fun with the nissan and later i'll see to get some videos online..somehow..


addendum:
tested a few quick and relatively slow paced laps of the m3 csl on tsukuba with n2 tires. over 2 seconds faster than real time and over 1.5 seconds faster than gt4 with n1 tires. so, at least for this short a track, those tires are much too fast to compare. it's unlikely that it will be any different, but i will try that out with a few other cars as well....
another few laps were with the '98 honda integra type r (dc2)...real time is 1:09, but i couldn't get the car anywhere near that...at best something around 1:15 with n1/n1 and 1:13 with n2/n1...very strange.

last but not least, i will have to correct myself: the laptime with the mine's gt-r up there was not with a bone stock car. at some point in time, i must've installed a fully customizable LSD, with which i then drove this time, since i neither noticed that it was there, not that it didn't belong. i now set the LSD to "standard" (no upgrade) and drove a bit again. and would you know it, it does oversteer just as in real life fine fine, now it's as it should be. everything else still as it was in the first run, s1 tires, unchanged sport suspension (in there by default). working up a bit of a sweat, i got me a nice and clean 0:57.241, so only 200ths of a second slower than the real time