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Otaliema
"" grab a C7 standard type and dive with that head to Laguna Seca and give it a go with front camber at 2.1 rear at 0.8 on SS tires drop the back to 98 and the front to 118 set about 11kg springs rear and 8 upfront with a 6/4 4/6 damper you should pull a 1:30 .xxx with conservative driving but you can feel the tail slipping out and shaping back in furring the corner with that set up just be nice to the gas! Ohh 600pp how ever you want to set it up do a mid/mid trans set up on it as well keeps the wheels under control.""

In short a C7 built to 600pp running 1:30.XXX at Laguna Seca on Sport Soft Tires.....

The Peanut Gallery is "liking" the post...

Is it just me or doesn't 1:30 at that track with 600pp on SS tires seem rather slow???

It is...

I built a 550pp C7 on SS tires and run 1:30.474 in less that 5 laps, and I hate Laguna Seca, I haven't driven TT there since GT Spec 1.02...

Up the PP to 600, lap 1 gets 1:29 and lap 2 I hit 1:28, and see 1:27's 1:26's out of the set up if grinding. I don't even see buddy nailing 1:30 if he turns off ABS...

Reversed ride height is said to be glitch tuning because they say ride height in GT6 is broken. Its not that at all, but rather poor suspension settings.

Raising the front end to help rotation IMO is a direct result of a poorly tuned suspension. Most often either an over stiff or overly soft front end.

Its important we understand that one mistake can lead to many. When a mistake is missed, often other aspect of the suspension are used to "fix" the problem, in doing so the potential of the car is being compromised. Since settings are being used to accommodate a bad setting someplace else those settings are not being used for what they should and so they are not in the optimum setting.

How can both a set up that's too stiff have the same effect as a set up that's too soft?

Its actually quite simple. If the front end is low and the front end is too soft, the travel under compression will max out quickly and as soon as travel runs out the front goes from soft to solid, acting as if is more than stiff, it acts stone stiff, no more suspension settings effect, its a stone. Removing grip from the front end.

If too stiff there is not enough weight to compress the front end maxing travel quickly, and when travel is maxed out the stiff front end becomes SOLID, bringing the same effects as hitting bump stops.

Both situations will get back LOST rotation by raising the front ride height.

Its important to note a few details

Stiffening anything on either axle effectively removes grip from that axle, on the front this leads to under steer, on the rear it leads to oversteer.

Raising ride height on one end does 2 things here that need to be considered. It raises the roll center of that axle while it pushes the COG to the other side, since they are raising the front the COG is pushed rearward.. It also increases the travel on the front end under compression.

On a set up that's too soft, it will use the extra travel to delay maxing out travel and in doing so delay/ eliminating the under steer that comes with. Other compromises are made to accommodate the bad set up.

On a set up that's too stiff, it will use the raised roll center to increase rotation, & in doing so the car will have more initial rotation at turn in but it will tend to under steer in the corner when riding the limit, more compromises get made to deal with mid corner rotation, and then some more to deal with exit rotation. All in all a very compromised set up.

There is the strong possibility this is also playing a role in the Camber removes grip theory prior to 1.09. As the compromised set ups may not respond well to proper camber tuning. It wasn't such a big deal I guess up to 1.09, but with the new dynamics Bad settings are having a greater bad effect on handling. While good settings just keep on being good.

I expect as PD improves physics this will continue, and each update proper set ups stay proper while bad set ups keep getting worse.

It seems the crappier a 1.08 tune is on 1.09 the crappier the tuning used on the car is.


I am not excluded as I have had to tweak some cars for the new physics, I'm glad that ride height, camber, and most of my tuning was done well, and most often if anything does need adjusting, its very little and quite easy.

Moved

GTP Quote: TheBull

"What i have found is ,if your car is lacking front end grip ,camber is not the answer

What i did initially was lower the ride height to compensate but where lowering the ride height isnt possible ,lowering or tightening the spring rate to give more mechanical force across the front axel pushing the car down onto the road

The next point is balancing the springs ,if i put too much force on the front spring the rear will spin out ,meaning there is an inblance in the springs

How i work out how to balance the springs is as follows
(using a Nascar as an example)

Total weight of the car is 1565kg
with a 54-46 weight split

If you divide 1565 by 100 you get 15.65 then times by weight split
15.65x54 = 845kg front
15.65x46 = 720kg rear

The springs also mimmick this front bias split

spring rate range
10.54-24.55 front
9.34 - 21.0 rear

There is a reason why the front spring is higher and has more range than the rear

now take the spring at its softest point 24.55 and 21.0 respectively

845kg / 24.55 =34.4 front
720kg/ 21 =34.3 rear

at its stiffest spring point

845kg /10.54 =80.1 front
720kg/9.34 =77 rear

How to work them out
If for example i`m racing Daytona and my set-up requires an 18 front spring then i need to stiifen the rear spring to prevent my rear from sliding out i do the following

845 /18=46.944 or 47

i then divide with that number against the rear weight of the car

720 / 47 = 15.31

meaning 15.31 is your new balanced rear spring

However that doesnt mean you car is set at this point .its just the balance point according the weight bias

From here you simply adjust the spring to how you want the car to react
for oversteer add or soften rear spring
for understeer minus or tighten rear spring


please note i have been using this theory since the last physics change on GT5 i do not know if this works on any other car except Nascars ,If any of you road course tuners would like to test this ,please feel free to post results

Thanks".

That ignores the leverage factor of suspension geometry that IS simulated. Its difficult to see on a Nascar because the front and rear of the Nascars in GT6 have close to an equal leverage factor. Unfortunately for TheBull & Dolhaus not many cars have such a close leverage factor.

Come on, these guys are seemingly intelligent but come up with some retarded shit..

To calculate the leverage it takes some math, but unlike TheBull & Dolhaus, what I show you will work on every single car in the game, and not just one even that one is only by fluke that the leverage front and rear is near identical, otherwise it would flop on that car too.

Weight x weight split %
Front
1565 x 54% = 845
Rear
1564 x 46% = 720

We don't have to, but I like to anyways divide the weight supported on the front by 2, because we do have 2 springs supporting that weight, not just 1 .

So spring supports

Front
845/2 = 422.5
Rear
720/2 = 360.0

Now we want the Leverage Factor. We do need to keep in mind this will not provide us the actual "leverage" factor, but instead provide us with the difference in leverage front to rear. Meaning how much more or less kg/mm is required to balance the springs.


With our springs supported weight we divide the Spring Rate by the supported weight, we can do this for either min setting, max setting, or default settings it doesn't really matter, they have a very small difference as spring rate increases, going with default spring rate IMO is the best choice.

Front
Min
422.5/10.54 = 40.09

Default Setting
422.5/16.80 = 25.15

Max
422.5/24.55 = 17.21

Rear
Min
360/9.34 = 38.54

Default Setting
360/14.59 = 24.67

Max
360/21.00 = 17.14

The difference front to rear (even though on this particular car is small) is the leverage factor difference.

For the front divide the rear by the front. For the Rear we do the reversed and divide the front by the rear.

Front
Min
38.54/40.09 = 0.96
Default Setting
24.67/25.15 = 0.98
Max
17.14/17.21 = 1.00

I would round these all to 1 even though there is a difference its negligible, usually they are all very close IMO I like using the default settings for my calculations.

Rear
Min
40.09/38.54 = 1.04
Default Setting
25.15/24.67 = 1.02
Max
17.21/17.14 = 1.00

I would round these all to 1 even though there is a difference its negligible, usually they are all very close IMO I like using the default settings for my calculations.

So looking at the NASCAR I calculate a 1 to 1 leverage factor. Its only because when using a Nascar with 1 to 1 leverage that indeed his math appears to work. The PROBLEM is most cars in Gran Turismo are NOT 1 to 1, This reveals the error in his math as if it were to be applied to a different car (a car not 1 to 1) it would not work.

Let's take a BMW Z8 as our example

1610 weight, 49/51 weight split

Front SR
Default Setting
3.61

Rear SR
Default Setting
6.38

Unlike our Nascar we can see right away the rear is using stiffer springs. This is indicative of the leverage factor on the rear applying greater force on the rear spring requiring a stiffer spring.

Doing the math quickly to get the supported weight on each spring

Front
(1610 x 49%)/2 = 394

Rear
(1610 x 51%)/2 = 410

Following the same process as our Nascar to get our Leverage factor

Front
Default Setting
109.27

Rear
Default Setting
64.35

UNLIKE our Nascar we can see our leverage factor will have a difference much greater than the Nascar, and using "TheBull's" method would not work...

Calculating the leverage factor and we have

Front
Default Setting Leverage Factor
0.59

Rear
Default Settings Leverage Factor
1.70

SO to keep the Spring Rates Balanced taking into account the leverage factor

I take the front Spring Rate setting I like 6kg/mm and x it by 1.70 = 10.20

OR if I decide to balance the front off the rear setting

10.20 x 0.59 = 6.00

So taking into account the leverage factor, a balanced rear spring rate for a 6.00kg/mm front spring would be 10.20kg/mm

The thing that is great about Gran Turismo is they simplify the setting adjustment ranges so we don't have to do any of that math to balance out springs.

PD Makes it easy for us and these over complicated math methods are often not needed at all.

If you were to adjust the spring on the Z8 to 6.00/10.20 you would see both front and rear have the adjustment sliders in the same position, only the numerical value is different.

So to keep springs balanced you just need to keep the adjustment sliders equally full.

This is not necessarily the ideal spring set up, its a good place to start. From a balanced spring set, you dial in the handling as needed. Softer front with stiffer rear to reduce understeer/ increase rotation or Stiffer front with softer rear to reduce oversteer or reduce rotation.

I pushed this back to front, this is important info for Tuners.

Unfortunately after some testing today, Ive come to the conclusion that camber gain is not only the same on all cars, but its also the same no matter what your ride height is set to.

Lowering ride height should reduce negative camber gain on compression and raise positive camber gain on extension, while raising ride height should increase negative camber gain on compression and reduce positive camber gain on extension.

I've kept camber setting to zero all around then hit Eigar Nordwand's jump with both max and min ride height. In both cases camber gain was identical at approximately 1.5 degrees both on compression and extension. This is a correction as I had previously estimated 2 degrees on 1.07, I measure 1.5 degrees perfectly on 1.09

Max Ride Height
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Min Ride Height
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To measure the 1.5 degrees I first checked that comp and ext had equal camber gain neg vs pos. Then I added negative camber setting until the wheel arrived at zero degrees dynamic camber on extension.

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Tire Flex Simulated or Not?

Tires tires tires. For a while now its been generally agreed upon that GT doesn't simulate tire flex, and therefore tuning to account for the effects of tire flex is moot.

I come after much physics testing and say that is false, wrong, actually impossible. Tire flex or more importantly the effects of tire flex IMO are simulated in GT6, slip angle, camber thrust, even footprint are simulated.

No we can't change tire pressure, and no visually I can't make out any tire flex. Does that mean tire flex effects are not simulated? No, not at all in any way. No tire pressure adjustments only means we can't alter these effects through tire pressure manipulating. No visual tire flex is also meaningless, so they didn't waist time or processor power to recreate something that is never looked at IRL. What real life race team actually analyses how much visual flex the tires have, it really doesn't matter visually, and IRL we don't have the GT camera and freeze time ability to get intimate with visual tire flex. The important thing is the effects.

PD doesn't need to visually simulate tire flex to recreate a slip angle or camber thrust, even footprint can all get easily recreated and it takes no visual representation at all.

I wanted to post this position here, as I can prove with certainty that effects of tire flex are simulated I want to see how people can be certain tire flex is not simulated given how the cars handle in GT6. Its also a common belief that the visual position of the wheels and how they relate visually to the track is not representing the grip physics being simulated. I've never agreed with this, its possible those who think that way are only confused because they don't realize the tire flex is what's not visually simulated, the entire physics IMO revolve around the visual representation of the wheels position to the track taking into account the effects of tire flex on the direction.

I had a real face-palm moment when I realized how I've been overlooking the obvious. While we all account for these effects if we agree they are simulated or not, we have no choice feeling out adjustments, I was just discounting how important tire flex is in GT6 when tuning, and I wasn't tuning my cars giving tire flex as much consideration as I should.

Next time I am playing with GT6 I'll dump the column names of the tire data. There is a lot of data fields related to the tire data as it was taken from Yokohama's simulator and placed into GT6. I think you may be pleasantly surprised as it does confirm some of your speculations.
There is definitely more information taken into account for grip than the visual aspect would lead you to believe.

Epic as always FarSideX, that would be cool, I can always use direct data to help me trying to feelfigure it out lol, and always glad to see a theory pan out well.

Pretty sweet Yokohama and KW getting into the GT6 physics.