Proper Weight Distribution Thread

[Thorin Cain]

You can add this months car of the month to the list too. Spyker C8 in GT6 has 52:48 but I have found a few sources which state it is 43:57. The closest I could get was 44:56 with full weight reduction and full ballast at rear.

And in answer to a previous post, I did find that it handled better once the weight distribution was changed, still a pig to drive though but a lot more predictable than before.

 

[Ridox2JZGTE]

Acura/Honda NSX - real life : 42/58, another mistake by PD. I built 2 replica with real world setup, and they are more enjoyable to drive than the stock/wrong weight distribution.

 

[brianwong]

Scirocco R IRL has like a 64:46 and in the game has 54:46 if I remember correctly (I'm on my phone at school right now)
Same with the Ford Focus ST except in real life it is 60:40

 

[DaBomm4]

Scirocco R IRL has like a 64:46 and in the game has 54:46 if I remember correctly (I'm on my phone at school right now)
Same with the Ford Focus ST except in real life it is 60:40

So, either PD has it right or both of you have it wrong, does the Scirocco have 64:36 or 54:46? If it had 64:46, that would mean it has an additional 10% that doesn't exist. Just trying to get the facts straight.

 

[brianwong]

So, either PD has it right or both of you have it wrong, does the Scirocco have 64:36 or 54:46? If it had 64:46, that would mean it has an additional 10% that doesn't exist. Just trying to get the facts straight.

64:36 in real life, PD has it wrong

 

[eran0004]

Has anyone considered that the cars weight distribution in game might include the driver weight rather than just being the weight of the car?

Sorry for the bump, but I think this is really interesting.

If we take the Alpine A110 as an example, the source of the 40:60 distribution also gives a weight of 635 kg. That would be 254 kg in the front and 381 kg in the rear.

Now, if we assume that fuel is not included, we can add fuel and see what happens. The Alpine has the fuel tank in the front, so by filling it up you'd add about 75 kg to the front of the car (1 liter of fuel is about 0.74 kg), bringing the weight to about 710 kg. The car in the game has a weight of 715 kg though, so another 5 kg is still unaccounted for. For the sake of this experiment we add that weight to the front of the car. Now we have 334 kg in the front and 381 kg in the rear, and a weight distribution of 47:53.

And then we have the driver. Now, the driver's seat seems to me like it's pretty much in the center of the car, but for the experiment we can assume that it's a little closer to the front than the rear and that the weight of the driver is carried 60:40 by the front, so for every 10 kg of driver weight, 6 kg goes to the front and 4 kg to the rear. In order to get a weight distribution of 50:50, the driver would then need to weigh 190 kg. This is obviously way too heavy to be realistic, so the conclusion has to be that based on these data and this calculation the 50:50 weight distribution is off even when fuel and driver is added to the weight of the car.

Spoiler: Bonus experiment: What if there's a denser fuel in the tank?

Bonus experiment: If we assume that the 80 kg difference between the 635 kg and 715 kg data is the driver and that fuel then adds on top of that, we can calculate the material that goes in the fuel tank, based on the density.

With an 80 kg driver and a 60:40 distribution of his/her weight, we have 302 kg in the front and 413 kg in the rear. To get a weight distribution of 50:50 we need to add 103 kg to the front (we'd actually get 49.51:50.49, but it can be rounded to 50:50).

We know that the fuel tank holds 100 liters in the game, so what we need then is a material that weighs 103 kg per 100 liters, or 1030 kg per cubic meter. According to Wikipedia there is a material that fits that description precisely, namely salt water. So we pour that into the fuel tank and we now have a weight distribution of 50:50!

Problem solved

 

[panjandrum]

I know it'll be great to have every car recreated exactly as they are in real life, but what's the point in getting the exact weight distribution if it makes the car a pain to drive? Have you tried and tune the cars after getting the right weight dist? Do they drive better than they do with the PD weight distribution? Everyone have a way to see things but imho i don't see the point in fixing this if the cars ends uncontrollable.

Ugh! Because if the cars become uncontrollable with the proper weight distribution then THE ENTIRE PHYSICS ENGINE IS BORKED! Period.

However, you've brought up a good point. I've had zero luck getting RR cars to behave properly in GT6. In fact, I had to stop driving any RR cars in GT6 because the physics were so far off that it was screwing up my RL motorsport habits. Muscle memory is an amazing thing, and if my RR cars in GT6 don't drive like my real-life analogs, then that muscle-memory builds-up and eventually my inputs when driving my Porsche and VW began to deteriorate. Interestingly, GT4 had the opposite effect; everything I learned in GT4 translated properly and directly to RL motorsports, and everything in RL Motorsports translated directly and properly back to GT4 (again, I'm talking specifically about RR cars here, since that's where my RL experience is).

So I think PD might have essentially tried to "fake" a significant part of the physics engine by just adjusting weight distribution on cars that aren't correct. However, all this really does is produce cars that, while they may be more "controllable" don't actually drive anything like their real-life equivalents... As I result I've lost all faith in the GT6 physics engine and PD in general. Something is deeply and fundamentally hosed...

 

[Ridox2JZGTE]

I have RUF CTR Yellowbird replica, 38/62 distribution, corrected weight 1200+kg, corrected high lock LSD, with comfort medium aimed to replicate Tsukuba lap record at 1:06.12, and it did 1:05s with no assist Drives like a Ruf Yellowbird, it can be handful, but can also be corner carver with smooth input.

 

[panjandrum]

I have RUF CTR Yellowbird replica, 38/62 distribution, corrected weight 1200+kg, corrected high lock LSD, with comfort medium aimed to replicate Tsukuba lap record at 1:06.12, and it did 1:05s with no assist Drives like a Ruf Yellowbird, it can be handful, but can also be corner carver with smooth input.

But do you drive a car with a similar chassis in real life? We can discuss what "feels" right all day long, but unless we are talking about a comparison with RL experience then there is no way to judge. I can tell you that, regardless of how I fiddle with the weight distribution, I am completely unable to get the YB / BTR to handle like RL 911s of the era (and the RUFs did use the same suspension, so sure, there should be SMALL difference, but not the gargantuan void between RL and GT6 that is there). The GT6 VW Beetle also handles nothing like mine, even when mine was in completely stock trim... Doesn't matter what I do with the weight, all it does is produce "50 different shades of wrong".

 

[Ridox2JZGTE]

But do you drive a car with a similar chassis in real life? We can discuss what "feels" right all day long, but unless we are talking about a comparison with RL experience then there is no way to judge. I can tell you that, regardless of how I fiddle with the weight distribution, I am completely unable to get the YB / BTR to handle like RL 911s of the era (and the RUFs did use the same suspension, so sure, there should be SMALL difference, but not the gargantuan void between RL and GT6 that is there). The GT6 VW Beetle also handles nothing like mine, even when mine was in completely stock trim... Doesn't matter what I do with the weight, all it does is produce "50 different shades of wrong".

Could you describe the handling IRL that you want to achieve ? I will post the replica soon, maybe your input could help me make it better I was a passenger a couple of time in 930 Porsche, but they were near stock and on the street. I do consult with Porsche owner on a forum when I built the Yellowbird replica, mainly about the specifications. I also have some inboard videos at the track for reference, one is at Spa with boost up CTR ( 1.35 Bar ), my replay ( CM tire ) and the video bears uncanny resemblance.

Have you tried Assetto Corsa CTR ? They said it was good.

From my research, Porsche purposely dialed in understeer through torsion bar rates on 930s, the spring rate ratio was very close. The old 930 has inherent oversteer, putting higher rate/size rear torsion bar ( high ratio ) helped with low speed - giving neutral handling but hurt the high speed ( oversteer at high speed is bad ) My Yb replica uses coilover rate based on a tuned 930 IRL ( colover conversion ) with similar weight.