Hey guys, short question,
many Porsche 911´s on the Nürburgring Nordschleife make a noise like a bang when accelerating out of a corner.
In cockpit view you can see the front of the car rising up, the telemetry shows that the front springs are fully decompressed (the white bar that goes up and down is completely at 0 ) and the car then obviously does not react to turning at all.
I looked at a few troubleshooting guides for suspension tuning out there but I couldn´t find anything about this issue.
So now my question:
Where is the problem (damper/ spring/ ride height) and how do I fix it?
I tried to mess a little with the spring rates but it never feels right.
If the front springs decompress pretty fast, then you can try increasing the front rebound settings. Rebound dampening affects the speed at which the wheel goes away from the car, so increasing the rebound dampening should slow that down a bit.
Also just as a question: What Porsche 911 is it and what suspension+rebound settings currently, if you want to share?
Thank you very much for the help, I will try that out later and tell you if that is the solution for my problem =)
It happens with the 1993 Turbo S Leichtbau, and like I do with all cars I drive the first time, I don´t change anything in the upgrade- or tuning section.
I always drive the homologation setup first and then I usualy change what I don´t like or what I think would be a better choice of upgrades for the car (more power, less weight, you know what I mean).
But like I said, this suspension decompression was the only issue I noticed, but I didn´t know how to fix that ^^
The homologation of this car doesn´t have race suspesion, but the other car with this issue ( 1982 Porsche 911 Turbo 3.3 ) has, the settings are:
Springs:
F: 556.4
R: 570.3
Ride Height:
F: 7.6
R: 7.3
Damping:
Rebound:
F: 6.7
R: 6.8
Bump:
F: 5.0
R: 5.2
But I get the same issue in the 1995 911 GT2, 2004 911 GT3, 2012 911 GT3 RS 4.0…
But again, only on the Nordschleife, on any smooth(er) track the cars drive perfectly.
Well, I´m really interested in the tuning aspect of this game, so this is more text then I wanted it to be (as always when I talk about cars ).
But I really want to know what I do and why I do it, so I appreciate your help
Given your description of the problem, I am going to take a wild guess and say that the problem occurs at UPHILL corners, i.e. corners where the altitude increase at the same time. Nordschleiffe has many of these corners and 911s being rear heavy would amplify the problem.
The noise, I suspect is from front suspension topping out (?!?) since you have stated the telemetry screen shows ‘0’.
Everything being normal (car modelling parameters), the symptoms point to the fact that the suspension is too soft for the car. 7"+ ride height is plenty of wheel travel.
Rear bump should be increased to ‘slow’ the rear spring compression. Front bump should also be increased to match the stiffness of the rear. Then rebound should be adjusted to achieve overall dampening needed by the car. This is based on your feel. If the car feels ‘floaty’ then overall damping is too low.
Rear ride height, I would set it higher than the front: 1. slight increase in traction to the front during acceleration 2. better weight distribution in corner.
You have not mentioned the anti-rotation bar settings but use higher rear ARB settings to put more weight on the front in corners. ARB is for fine tuning so make sure the spring rate high enough.
In summary:
No turning in corner, ‘0’ on front suspension travel, front lifting up = overall suspension too soft
Increase spring rates & bump damping dramatically
Higher rear ride height than front (by 0.5" to start)
Higher rear ARB than front (by 10 points to start)
Thank you very much for this very detailed explanation!
You are right, this happens mostly uphills, also at Spa track, after the eau rouge, but it can also happen when accelerating downhills, especially when accelerating after coasting through a corner ( for example the right-turn between the sections “Kallenhard” and “Wehrseifen” if that means anything to you ).
I will test this as well =)
I really appreciate your time and efford to help me here, so thank you again!
[quote=Henny996;958223"Kallenhard" and “Wehrseifen” if that means anything to you
[/quote]
Those are steep downhill corners, especially Kallenhard. I suspect that corner would be the last place the nose would come up at corner exit. You sure the nose is lifting, not bottoming out?
In either case, the suspension (springs + dampers) are too soft. I recommend increasing front & rear spring rates by about 50% then assess the effects. Dampers can be adjusted AFTER spring rates have been decided on.
First, you are right, it is the rear of the car that is bottoming out…
I drove the KTM GT-4 before the Porsche yesterday, and the KTM had the front lift-off problem (I think there is a very small uphill-section after the right turn mentioned above, and there did the front came up).
I raced the Porsche after that and it did the same noise, just this time IN the corner and from the rear of the car, I just mixed that up, I´m sorry
My fault, and anyway like you said, it wouldn´t make any sense the way I described it ^^
Happens with 911s IRL, but the fact it also happens with other cars in the game means it probably shouldn’t be this way.
As others said, you might want to increase front rebound and rear bump at the same time, as when you accelerate the rear will compress and the front will decompress. A 911 does not need plenty of rear grip, because its weight distribution already gives it good grip out of corners.
Finally, cars with default Race suspension are not always tuned correctly when stock. People love to bash on the 2012 GT3 RS without realizing it’s the tune that’s wrong and not the car. The default tune in both FM6 and 7 is extremely soft and leads to excessive roll. T10’s fault for sure, but the cause is different.
The springs and dampers are, both IRL and in Forza,calculated for the weight of the car (I think).
My theory about the issue in game:
When you install a heavy weight reduction on the standard springs and dampers, the setup will be way too hard.
When you install race springs (therefore lower ride height) without using any weight reduction, the setup will be too soft, because you have less suspension travel but the same weight.
And because the game does not compromise or adjust the setup to the “new” situation, some cars feel weird to drive.
Well, it is just a theory, but I will drive the Porsches completely stock, no engine upgrades, no tuning, no suspension, standard tires and so on…
If my theory is right, this should be balenced and good to drive…
I appreciate all of you spending your time with testing and helping me!
Feel free to add me on xbox if you are interested =)
I´m always looking for fast people, especially on the green hell ^^
The track is not far from where I live, so that could explain my obsession with it =)
I can confirm your theory with similar experimentation. The McLaren 720S can be homologated with Race weight reduction on the stock suspension, but, if you do that, the springs are too stiff (obviously). So the optimal build for the car is stock weight and Race suspension.
Of course, in Forza not everything applies to all situations, but it seems to me that, every time you change the weight distribution, you must upgrade your suspension and sway bars to Race in order to compensate. And Race sway bars are almost never optimized for the car from the start, they’re always 29F/23R or something like that.
Took it for a spin on Spa with the pre-tune parts installed and found it to be undriveable. Dangerously oversteered, and since the PI stopped me from adding moore tires in the rear I
reduced them in the front instead, from 275 to 255. This gave me some PI-points to spend on upgrades so I added a sportsgearbox + racingbrakes + adjustable rear wing. A set of SS-wheels gave the Porsche the right look and got the PI down to 700. You can skip the racebrakes and upgrade the rear tires (to 325) instead, tyour choise.
Not the easiest car to tune this but I think I got it tamed after some laps. Needs some fine-tuning still but feels ok with this settings:
I also took the Porsche Leichtbau for a spin according to build as described by unfairlane (went with 325 rear tire: 402 hp, 2870lbs) and these are the settings I came up with:
This here quick tune setup is about the same as you get from Forza`s presets. If someone worked in my carshop and gave a customer a setup like this I would have fired him.
Those number slook pretty good to me. One key thing to notice is the damper settings
Rebound 8.0 7.7
Bump 4.6 4.4
Note how Quicktune sets the rear dampers a little lower than the front, even on a rear-heavy car? That is why I love Quicktune because on fast and bumpy track like the Ring, it really settles the car down.
Yup, I did notice how quicktune made up a setting that might moore or less fit a front-enegine car but definetly not a rear-enegined Porsche. The challenge with these models is just that, to tame their lively wobbling rear-ends.
Have you tried out my settings for it? And noticed how calm and controllable the Porsche feels with a good setup?
I know, you don´t address me directly, but please don´t get me wrong, I appreciate everyone´s help here in this topic (especially if someone is nice enough to create a whole tune just to help me out!).
I just had some busy days and therefore I wanted to test the “handmade” tune/setup first.
Really hope you don´t get this wrong.
Of course I will test everyone´s advice and setups here.
I do have a tuning calculator on my phone as well (Forzatune 7) but SOME of the track/tune combinations this calculator creates is either just slightly better than the standard (homologated) tune, or gives you the feeling that you have to figure out the rest of the settings yourself to create a very good tune.
And that is exactly what I noticed when I decided to open a topic in this forum.
One part of my enthusiasm for unfairlane´s setup is the finished product, but the other part is the fact that he “tamed” the car by himself.
But again, please don´t think I appreciate your help here any less than other´s!
@Henny: just curious - do you have any updates on how the Porsche handles with QuickTune settings as compared to unfairlanes suggestions or your own attempt?
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