What's wrong with Porsche?

The thread is here: https://forums.forza.net/turn10_postst112724_2012-Porsche-GT3-RS-Suspension-Problem.aspx

The tune is available in FM7 just search for my gamertag Sp3c7r3. I got it dialed in and it handles pretty good now.

The suspension is a problem on all Porsches, except maybe the Cayman GT4, I upgraded it to A class and it handles like a dream with the stock tune it gave. Besides that one all the base setups for the Porsches are garbage. Springs are WAY too soft and results in the front tires lifting under acceleration. If you hear a loud THUD sound that means the front tires had lifted and landed back on the ground.

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A lot of cars are sold homologated in FM7 and aren’t stock, that can be why they have not realistic reaction. That homologation system gives automaticaly parts to the stock car without any tuning to make them drivable. It would have been less confusing to let us buy cars stock and after that let us do the homologation by ourselves in order to really know which part has been changed and what tuning have to be done on it.

Agreed. I strip pretty much every car I drive of its auto-homologation setup, and do my own.


try driving the 1973 Porsche Carrera RS auto homologated arround the ring. i have made som photos of it. if i get the time later on i will share them.
short comment for the race on the ring with the carrera: the car is absolutley undrivable if you want to race hard with it. it lifts up the front to the point where only one tire is left on the ground. (i have taken photos of it, lol)

i have made another Carrera RS with a PI of A700. i spent allot of time tuning it and cant seem to get rid of it but it gets better atleast. But untuned autohomologated this car is a laugh.
To me the 997 GT3 RS 4.0 is allot better then the carrera is untuned.

Would you mind sharing those photos in this other thread where we are documenting this:



i shure will do when i get the time needed after work. that thread was the reason i even bought the car because i didnt think it would be that bad. but it is…

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I’m playing on a G920 too and love all my Porsches.
In fact 95% of my time is spent on the Nordschleife and I write down the times of every car I drive arround it.
Nearly every class has a Porsche on top of my leaderboards.

One thing I have to agree. You absolutely have to tune every single car in Forza when driving with a wheel Setup.

So most everyone here is in agreement that Porshe, Mercedes, BMW, Ford, Chevorolet, etc are handing over the decel and acel settings? Along with suspension and how their cpu controls brakes and everything else to a video game developer?
Do we really believe that is the case? So then in irl Mercedes will know what BMW is doing to make their car better. And all this info for free by buying a racing game. Lol.
C’mon guys, sometimes the devs guess right and a car handles close to real life, sometimes they are way off as the devs aren’t “engineers”.
I think to many people are over thinking this aspect of a video game. You can model the interior, you can model the exterior, the engine and all the visible pieces. But, I guarantee you that car manafacturers aren’t giving over their ecu tuning to anyone.

Mechanical things like the diff settings, spring rate and the like are very easy to get data for, even if the manufacturer is not handing them out, the aftermarket is all over it.

What becomes tricky is more modern cars that have dynamic, electronically controlled things. Those algorithms are likely proprietary and may require more data points as input and more processing power than can be afforded by ANY simulator, let alone Forza.

So mechanically, I think even Forza does a pretty good job, but there are other things that certainly come into play in modern cars that the simulators won’t be able to reproduce.

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I can measure the rate of a spring in my garage with a bathroom scale, a ruler, and whatever heavy objects I happen to have within reach. With a cheap angle finder and a set of precision rulers I can completely map out my car’s suspension geometry and calculate the effective wheel rate, actual spring frequencies, scrub radius, SAI, etc. Using a laptop and some tools of questionable origin I can load whatever firmware I like to my car’s ABS module allowing me adjust the coding on the ECU that handles the ABS, traction control, and stability control. I’ve even owned cars that had open source software available that allowed me to actually tune the engine to get more performance out of it.

Mercedes doesn’t need BMW or Turn 10 to give them any data, because they’ve probably completely disassembled and reverse engineered any of BMW’s latest products very shortly after they went on sale.

I’d be stunned if they didn’t have any engineers on staff. I’ve developed software, and most people who are proficient at writing code aren’t subject matter experts on things as specialized as auto suspension design. Years ago I worked on software for air traffic controller, and we had air traffic controllers on staff… because knowing how to write Fortran and C++ isn’t enough when you’re writing software like that.

But you don’t need an actual engineer to know that modern cars don’t bottom out so harshly over bumps you might roll over on even the worst race track, small time aftermarket tuners and autocrossers know that. Even I know that, and I’m just somebody who has spent entirely too much time reading about auto suspensions, which basically makes me nobody.


Fine, but then why has T10 – who have been developing games for years – gotten it so wrong with the various Porsches? As much as we like to joke around here that they didn’t, they obviously play-tested this game and would have found the GT2 RS etc. to be really unruly with the settings they chose.

Good question. I think the majority of cars are more than a little off from real life. I’ve owned both a Lancer Evolution 9 MR and the X MR. Neither of those cars drive or act like the game simulates.

Perhaps, they figured hey we have a tuning and upgrade section. Let the community work out the settings to make the cars behave properly. I do agree that the 4.0 RS behaves weird, but the cover car drives fine for me. Same scenario with mid engine high power cars like Ferraris in FM6. The 458 drives great but the gtlm version wanted to spin constantly. Hopefully they are better on FM7.
Porshe, well this is the first time that T10 had rights to them during development. Perhaps it is going to take a few iterations to get them adjusted better. Not a whole lot of manafacturers making rear engine rear wheel drive cars. I would expect some quirkiness and tjrottle control needed to drive fast.

The '95 911 GT2 aka “993” is by far my favorite of all the Porsche’s but I have a very hard time controlling this car, does anybody else feel the same?

It just seems like, whenever I’m not driving in a straight line, the thing is sliding everywhere. It’s currently stock, and I have no experience tuning (this is my first Forza!) so does anybody have any tips what adjustments I can make on this particular car to make it a little easier for me to handle?

Are they not legendary IRL for being difficult to drive?

Hit up the Tuning Forums for excellent advice and even some good general formulae in Spreadsheet form that can give you a good baseline tune, from which to fine tune whatever vehicle you might encounter.

I like CaesarsWrath’s spreadsheets myself, and even had a hand in helping evolve the spreadsheets a couple of years ago as I liked the formulae so much, I created a spreadsheet for myself to make it easier to use.

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This is great advice, sounds like I need to stop by there as well as tuning is not my strong point and I’d like to learn it. Thanks!

Fix Porsche GT2 RS 12
This car is broken, do wheelies in high speed corners and isnt a setup problem is a physics problem. Fix it T10, thanks.

Just saw this thread. Look over at the default tunes on Porsche compared to other manufacturers. The cars are lifting because they didn’t even bother to edit the default tune. nearly everything is set at 50 percent which isn’t the case for other cars.

The GT2 RS settings I can understand because they were working off a prototype. Everything else seems to be laziness.

Default tunes suck in most games anyway.

Turn 10 sets all differentials to 70/35 regardless of the car’s layout, which is obviously hogwash. In a 911 it’s pointless to use 70% accel diff because the car has great traction out of corners.

[Mod Edit - thread merged - MM]

So Turn 10 obviously have some kind of agreement with Porsche what with the GT2 RS being (disappointingly) the cover car for Forza 7 plus an achievement for completing a race in every Porsche etc. Which begs the question: if Turn 10 are all pally with Porsche… why have they made their cars handle like absolute dog turd?

I mean seriously every single modern variant of the 911 is absolutely appalling to drive. Lolloping around in fast corners with a front wheel off the ground. Is this Turn 10’s idea of a joke? Make a partnership with a manufacturer then dump all over their cars?

Have you ever driven one in real life? 911’s are a handful. rear engine, rear drive, more than adequate horsepower, they get incredibly tail-happy when you push them to their limits, which you do more so in a game than even in real life.