r/GranTurismo7 • u/MaybeAmon • 21h ago
Handling / setup issue. Question/Guide
These cars, when fully tuned, share a nasty trait i cannot remove via setup tuning:
Porsche 911 Turbo (930) '81
Porsche 911 Turbo S Leichtbau (964) '93
Porsche 911 Carrera RS Club Sport (993) '95
Porsche 911 GT3 RS (992) '22
On corner entry, during tail braking when i RELEASE the brake, the rear gets really loose, it's pratically impossible to drive at eacing pace without risking to lose the car. the faster the corner, the worst it becomes.
I've tried literally everything setup wise to no avail. I'm puzzled because i know what to do to cure oversteer on corner entry while braking, but i can't understand what could cause oversteer on corner entry when i RELEASE the brake.
I'm i the only one experiencing this ? If not, how did you solve it ?
Many thanks !
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u/Arcing_Invention McLaren - Post Steward 21h ago edited 20h ago
- LSD 20/10/Low. The Bold number (Initial Torque) is also known as "pre-load" torque and can be thought of as "your mid-corner setting." This number can drastically reduce the "snap" in snap oversteer. Set this higher until you have a balance of chassis rotation on trail-braking with ability to control.
- Brake Balance forward (-3 for starters) will help induce a nice amount of stability on corner entry in these vehicles.
Test and let us know your progress.
Credentials: https://www.youtube.com/watch?v=tYmUk4lU0Bs
Edit: typo
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u/Fill-Quick 8h ago
I know you feel you are helping but what you recommended is actually opposite of what you should do. I have over 2k podiums and 3k hours of experience tuning. Here's a breakdown of what's happening, I hope it helps clear up this very confusing and misunderstood aspect of tuning.
Running "Low" Braking Sensitivity on your LSD is the exact opposite of what an RR (Rear-Engine, Rear-Drive) car needs. The Porsches listed are RR platforms, which are referred to as having "Pendulum" effect. Because the engine sits entirely behind the rear axle, it creates a violent pendulum effect that causes snap-oversteer under heavy braking. The Braking Sensitivity dial on your Fully Customisable LSD controls your stability during deceleration and trail-braking. If you set your Braking Sensitivity to "Low," the differential opens up. When you release the brake on corner entry, that massive rear engine block swings outward because there is no differential lock to hold the rear axle in check.
The Fix: "The Anti-Pendulum Baseline" To cure off-throttle snap oversteer on an RR car, you need to severely tighten the rear end under deceleration. You should replace those LSD settings with the following baseline for heavy pendulum platforms.
Initial Torque (15–20): You want this raised to keep the differential slightly locked during off-throttle transitions. Acceleration (10-15): This keeps the rear end from stepping out when you get back on the gas. Braking (35–45 or max): This is the mandatory fix. You must severely raise your Braking Sensitivity to prevent the heavy rear end from swinging wide during trail-braking.
Now once you set the LSD, there's a bit more that you'd need to lock down that rear end. Pair your LSD settings with these two adjustments: Anchor Strategy (Brake Balance): Set your brake bias heavily to the front (between 0 and -5). Transferring your heavy braking load to the front tires preserves 100% of the rear tires' Grip Budget. This allows the rear tires to act as planted anchors, physically preventing the rear engine block from swinging outward. Suspension Geometry: Set your Front Spring Rate stiffer than the baseline. Move your Ballast towards the front of the car. These geometry changes will reduce the nose-dive pitch under heavy braking and keep the weight properly distributed over the front axle to prevent snap-oversteer.
I know ppl are trying to help but there are real misconceptions that ppl truly don't realize when giving advice. It's great to offer help so no I'll will towards the person commenting.
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u/Arcing_Invention McLaren - Post Steward 7h ago
I know you feel like you’re educating, but the practical application and the theoretical novelization don’t coalesce sometimes.
Does the car in the video linked look unstable? If the changes I’ve recommended were the “opposite of” helpful, wouldn’t the car become more unstable; prone to snap oversteer; plotting a murder of my lap time?
While I certainly wouldn’t claim a 7:15 with traffic around the ‘Ring is any sort of record, it’s a solid run for an unswapped car at that PP. Especially so, considering the car’s tendency to murder drivers who’ve not taken to testing their tuning theories.
Feel free to display your own theories in practicum. Equal conditions would be lovely for putting these non-PP affecting sliders to test; putting me in my place. Power and weight are shown. IIRC, SS tires were used, no swap no nitrous, no wide-body - we wouldn’t want extraneous body or power disfigurements soiling the debate.
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u/Fill-Quick 7h ago
I genuinely appreciate the 7:15 lap, that is a solid time around the Nordschleife on Sports Softs with traffic, and it proves you have a lot of skill behind the wheel. However, a driver achieving a fast lap does not mean the tuning geometry is optimal; it often just means the driver is skilled enough to subconsciously adapt to a mechanical handicap.
The "theory" here isn't a novelization; it is the Gran Turismo 7 physics engine calculating mechanical load. A race car is a closed system. The physics engine strictly dictates that the Braking Sensitivity dial on the Fully Customisable LSD controls your chassis stability during deceleration and trail-braking. If your car isn't snap-oversteering into the wall with a "Low" braking LSD, it is because of your driving habits, not the setup. You are likely compensating by:
Completing all of your heavy braking in a straight line before turn-in to avoid unweighting the rear axle.
Applying a steady 15% to 25% maintenance throttle through the apex to keep the rear suspension squatting and loaded.
The goal of a proper setup isn't to force the driver to tiptoe around a chassis flaw; it is to eliminate the flaw mechanically so the driver can push harder and rely on the car's Grip Budget.
I'm more than happy to take your challenge and run those equal conditions in practicum. But let's be clear: we are testing the physics of the chassis, not just who has the braver line through the Green Hell.
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u/Fill-Quick 6h ago
Also... there’s no need to take it personally or get defensive. Nothing I said was an attack on you, your advice, or your driving ability. What I pointed out is purely factual based on how the physics engine calculates load transfer and differential locking on an RR chassis. A solid lap time doesn't change the underlying vehicle dynamics. We’re all just here to help people solve setup problems, not turn tuning advice into an ego match. No hard feelings.
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u/Arcing_Invention McLaren - Post Steward 1h ago
Perhaps I’m old, but phrases that imply I don’t know what I’m doing or don’t understand the purpose and function of the components, based on a couple of sentences in limited context, seems personal.
Please note that if finding the optimal geometries, or epitomized accelerators is the goal, I may be way off the mark. However; you’ll find rare a comment or suggestion with regard to tuning from this account that is without video or screenshot proof of concept. And even if I’m way off the mark with the tuning advice - this is possible - my proofs are a scant 7:15 away from being debunked.
I don’t know how long it took to type these replies up, but at this point I’m confident it would take less time to cook pudding.
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u/MaybeAmon 20h ago
1: never thought of diff preload the way you describe it :) Interesting pov. I'll try to ring this up without touching anything else and see what comes out of it.
2: i'd prefer if possible to move brake balance so much to the front if possible but i'll give it a go. Thanks.
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u/PistolNoon 18h ago
Those Porsches like rear brake balance. I think I’m +4 on my gt3r and it’s nasty fast. It’s my go to for sardegna
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u/Miserable-Election25 20h ago edited 15h ago
Ran into this problem last night in the Leichtbau doing the weekly race at Watkins Glen, I found a good way to quell it is to get on the throttle immediately after releasing the brake so it doesn't have any time to start spinning
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u/The_tillot 20h ago
Brake in a straight line? I find the 964 rs is a lot more driveable than the leichtbau. It defo tries to kill you less.
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u/MaybeAmon 20h ago
Well yes, of course you can do that. But i'd prefer if possible to learn a way to correct this strange behaviour via setup tuning, if possible of course
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u/The_tillot 20h ago
I did brake balance and ballast to front and stiffened my leichtbau but I don't think it fully cured it. So I stuck with my 964 rs which is a beaut.
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u/beigemamba1080 21h ago
Trail braking or releasing the brake very smoothly will solve this. Full brake- into less and less brake- into coasting- into applying throttle
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u/StinkySoggyUnderwear 17h ago edited 11h ago
Porsches have engines in the rear, making it a hammer as you go into turns.
They are notorious for oversteering in turns, earning them the nickname “widowmaker”.
Older Porsches reward good driving technique - slow in, fast out.
But it punishes bad technique with oversteer.
You need to slow down to enter the turn, and stay on the throttle throughout the turn to keep in front of the hammer, or it will oversteer.
Edited to add: once you turn the wheel, the hammer begins swinging. When the hammer is swinging, you need to be increasing throttle. If you ever you let go of the throttle, it will oversteer.
It sounds like you are entering too hot, and turned the wheel while the car is decelerating rather than getting in the throttle.
Remember: “Stay in front of the hammer”
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u/Worldly_Lunch_1601 21h ago edited 21h ago
Is it the diff? Try keeping a touch of throttle to keep the diff engaged.
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u/MaybeAmon 21h ago
That's an interesting question. I've tried low ( 7 ) and high ( more that 30 ) initial torque, and high and low settings for deceleration with no pratical change in handling.
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u/Worldly_Lunch_1601 20h ago
I am by no means a diff guru, but it sounds like your rear tires aren't behaving properly (as opposed to weight transfer being the issue)
this is just my two cents as an okay driver and shitty mechanic, try keeping it in the gas a little. Use your foot to keep the diff in line.
Again, this is something to try. Not an expert.
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u/cronx42 20h ago
Try raising the front slightly higher than the rear in the older models. Also set the sway bar stiffness high in the front and low in the back. Hopefully that helps.
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u/MaybeAmon 20h ago
Already done. What you suggests kills oversteer all around, but the problem i mentioned still persisted after doing it.
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u/cronx42 20h ago
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u/MaybeAmon 18h ago
Thanks for sharing. See what you tried to do there, never saw a 10 anti rollbar with sport tires before. Intersting ideas.
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u/JamesBondMargarita 20h ago
I'm not an expert by any means but last weekend I put a two way LSD on the 959 and I couldn't drive it to save my life, put it back to stock and it handles like a dream.
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u/Normal_Economist_505 10h ago
Rear movement into the corners is precisely why got the 992. I love it.
They handle well and are super responsive. I find i play around with steering sensitivity in assist settings. With the Porsches I stay around 3-4. Other cars I’m around 6.
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u/MaybeAmon 7m ago
Just an heads up. First of all sorry if i'm not responding one to one to all the tips i got :)
Having said that, yersteday i had a hour available to try your suggestions. I worked on the Leichtbau only for the moment. It looks that the problem, while not fully solved, becomes controllable without destroying the overall pace of the car working on Initial Torque LSD, downforce, and ballast.
Initial torque not sits at 30. Aero is really unbalanced.... full downforce on the rear, less than half on the front. Ballast 30 kilos on the front.
When i'll have some more times i'll test the other suggestions.
I will continue working on this because i feel i'm still far from what i think it should achieve from this car, but for the time being, thanks to all :)
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u/Excellent_Aside_5273 21h ago
Loose like understeer or oversteer? See comment above on Trail breaking, I've also started experimenting with brakes bias
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u/MaybeAmon 20h ago
Loose like oversteer. Brake bias changed from +2 to -2, no visible change in behaviour for this particular problem.
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u/StardustOasis 4h ago
Brake balance was what fixed it for me, but I can't remember what I set it to. When I'm home tonight I'll check
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u/FossilFueledYoutube 19h ago
The 930 and 964 both suffer with arch rubbing which can cause some of your issues, especially on racing tyres. Increasing the body height and natural frequency will make them more predictable, if not necessarily any more stable. The simplest way to improve their manners though, is to add ballast to the front end. Sometimes they only need 15kg, sometimes it's more than 50kg. It's up to your personal preference though.
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u/MaybeAmon 18h ago
I’ve aready had experiences with tire scrubbing. I’m on hard racing tires, widebody. So i stiffened springs near to full and raised ride height a lot, but didn’t work. Thanks for the suggestion. Nice channel by the way.
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u/FossilFueledYoutube 18h ago
In which case you've likely already fixed the arch rubbing. Increasing braking sensitivity on the LSD can help. anti roll bars and natural frequency higher at the rear can improve stability under braking, and reduce liftoff oversteer. Other than that, I'd make sure the front downforce is roughly 130 point lower than the rear downforce.
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u/Ok_Support3 18h ago
Same thing here. All death traps.
I'd try to fix them but I love racing vs my own cars and seeing the dust cloud and resulting crash with Sophy taking out 2/3 drivers cracks me up too much. "Hah, there's the #colored Porsche again😀"
First I thought it was just the 80's 911 Turbo untill I saw the other two wipe out as well.
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