How to adjust setups for GT3s in v1.9?

Could you please share this process of defining the dampers thru the Motec sheet?

 

Haha i remember the race at Spa, first time I'd seen you. You were bloody quick if I remember correctly, started at or near the front, but I think you fell back (not sure what happened) and had to work your way back - you passed me with such ease . Was happy to finish 4th though.

Not sure how it compares overall, but you were certainly one of the quickest I've seen.

 

@NetracingEurope.org - Ok sure thing. Firstly, I don't use motec that is illegal... People could use free programs Race Studio 2. Secondly, I am no pro or Einstein in the mind so I am sure the more advanced guys will pick apart what I do. I actually hope they do as this is the only way I continue learning.. Thirdly, unfortunately these day's I have had to give up the rig & wheel and revert back to a xB1-e controller. Its ok however feeling the subtle feedback of the dampers is all but gone. Believe it or not you can still feel the setup changes you make and I know a few quick drivers out there on controllers. "hman" is one that comes to mind. For me AC does controllers very well compared to rF2 & pCars and I actually feel a state of being connected to the road. I knoiw many will say thats crazy and its just not sim racing however thats another argument best left for another day. Everyones hardware massively varies. In my rF2 days I use to follow a simple guide "GTR2 MoTeC i2 Pro Beginners Guide.doc - MOTEC_eng.pdf". Thesedays I follow other guides such as "A-Guide-To-Your-Dampers-Chapter-from-FSAE-Book-by-Jim-Kasprzak.pdf" and read what the gurus have to say on the forums..

ACTI is nice plugin which comes with all the little extras you need I keep it fairly basic and mainly look at the damper histogram over a whole lap. Sometimes a I pick a braking point or corner that is giving me some trouble and look at what the dampers are doing though this phase. After making all my necessary setup adjustments I then start playing with the dampers by feel as I know what direction I want my setup to go and I also look at what the damper histograms look like. Based on the histogram I can tell if I need to tighten or soften the dampers or move them more towards bump or rebound etc.. One limitation on the damper histogram I have not been able to get around is setting differing crossover speeds for bump & rebound. Also users will have to guess the crossover speed as this information is encrypted by Kunos. I know some will/have gotten around this. I have a rough idea what they should be for GT cars. This will help understand the slow/fast %. For me some cars are more difficult than others to setup.

I am not sure if this is what you wanted however please feel free to pick away..

 

@Georg Siebert - Very true. Thank you, please keep us in mind when its finished Regrading the GT2 damper info, thank you that makes sense. My GT2 setup has taken completely new approach and I am not overly happy with it. I have always found the 458 GT2 to understeer allot and because of this I find it hard to follow your balanced hz advice or ARB advice.Give me a little more time to play with it and I would welcome your advice. Regarding the GT4 setups, I feel a little funny about posting other peoples setups. Maybe I am wrong in my feeling...?

 

And this is exactly where I struggle. Would be nice to get this explained in detail if possible. Thanks

 

ok mate. hang tight ill get some examples of what i don't want to see and what i would prefer to see from a histogram... Its starting to get late here so ill do this in the morning

 

Maserati GT4

Been testing your setups today:

Old
- very stiff in pitch & roll
- pronounced high speed understeer
- no oversteer
- less lateral force than expected
- ok low speed stability
- good braking stability
-> (Nür GT | H | 2:09.0xx)

New (11.2 test)
- much softer springs, still stiff in roll
- less understeer
- no tangible oversteer
- still low lateral force
- ok low speed stability
- ok-ish braking stability
-> (Nür GT | H | 2:08.6xx)

The lateral force excerted by the tyres is a function of the slip angle. If the slip angle increases, so does the lateral force, up to a maximum. It falls sharpy after that.


(http://racingcardynamics.com/wp-content/uploads/2014/10/Figure4.jpg), adapted from Milliken & Milliken, Race Car Vehicle Dynamics


You can increase this lateral force with more tyre load. A stiffer spring / ARB requires more force to compress / twist, hence more load on the tyres. The maximum force shows at a smaller slip angle however.


(http://racingcardynamics.com/wp-content/uploads/2014/11/Post1.1Figure7.jpg), adapted from Milliken & Milliken, Race Car Vehicle Dynamics


An adjusted setup for you to try below:
01_masgt4_adj.ini
- few, but significant changes from New (11.2 test)
- springs, front ARB & dampers the same
- more rear ARB
- much less negative static camber
- small adjustment to toe front

- roll center more to the front
- much less high speed understeer
- oversteer occurs only out of very tight corners without throttle modulation
- low speed stability still there
- much more lateral force (more cornering performance)
- braking stability still there, either leave brake bias to 66%, or reduce it to 65,5% on the fly if you feel confident
-> (Nür GT | H | 2:08.3xx), 0.3s off my personal best with this combo

Try the adjusted setup on Magione & Nür GT and tell me how you like it.

 

Nice! I'll check out the setup and report back. One question, I'm not sure I understand the graphs you posted, specifically the 2nd. I get that lateral load increases with slip angle before falling off, but do the different colored lines represent different tyre loads? If so why does increasing load result in peaking at a higher slip angle (i.e., the 8000 N chart peaks beyond the 4000 N one). Is that right or does it peak at a lower slip angle?

 

Also, what drove you to change the camber? I always feel like I'm guessing

 

"A stiffer spring / ARB requires more force to compress / twist, hence more load on the tyres. The maximum force shows at a smaller slip angle however"
More vertical load means the maximum force will happen at a larger slip angle, not smaller...

To answer Tom's question, the reason the optimum slip angle tends to be higher at higher loads is due to the fact that the sidewalls are being compressed, allowing for more slip angle (measure between contact patch direction and direction the actual tire is pointing) before the same amount of actual tire scrub occurs.

 

@TomSc
The load peaks at a higher slip angle. The graph is correct.

 

As an additon,
the tyre exerts force through adhesion and hysteresis, their combined force (Fy) rises linearly with slip angle. So one might think increasing slip angle by increasing load is a valid approach, but as Niels Heusinkveld explained in the video a couple of pages ago, tyres don't like load and the overall resulting friction coefficient is therefore lower. The front was too heavily loaded, with an increased rear ARB, the load distribution is now more even. Both stiff ARBs are ok in this instance, because the springs are relatively soft. This car has no ABS or TC - you'd need stiff ARBs through the S-curves and chicanes on Magione, Nür GT and Spa for instance, especially to keep the car stable.

The lateral force from camber - known as 'camber thrust' - is a couple of times lower than the one from slip angle, so it doesn't contribute to the total lateral force as much as slip angle does. With an increasing slip angle - from stiff ARBs and more load on the tyres - the additonal lateral force from camber begins to decrease, known as 'camber roll-off'. So there is a point at which more negative camber starts to be detrimental. The more negative static camber, so the more negative dynamic camber angle through the various tyre situations, the more chance of this dynamic angle to tipp over its maximum lateral force. In this situation the tyre looses traction and the car goes sliding. That is why I reduced the camber angle and gained more lateral grip in more situations.


(Milliken & Milliken, RCVD, page 48)

As you might have figured by now, the tyre is one of the most, if not the most influential factor in vehicle dynamics and how it actually behaves is even now not completely understood.

 

@Georg Siebert & @mclarenf1papa - it sure would be great to get you both in the same room and hear you philosophies Not like i would fully understand it all however it still would be nice..

 

@Georg Siebert - Thank you for providing the GT4 setup. Even though I really enjoy driving this car for some reason I have not got on top of it and have been a little more of the pace compared to the super fast guys.. I really like your setup direction. I found the high rear bump an interesting choice however it works really well. For me I had to drop the front tyre pressures a little, particularly the LF as I could not maintain 33PSI around Nurb GT. I also preferred a little more mid corner turn in as I found the setup was a touch understeering for my style. I tried - 1 click on the ARB which was faster for me however it was not great in the high speed corners so I found 0 bump on the front was what I needed. It saved me an extra 0.5 sec and I was able to run 208.3-6.. I am playing with some very slight alignment adjustments to see if I can crack the 207s.. Cheers

 

I think this forum will do just fine.

Happy you achieved the gains you were looking for ,)

 

I wonder why (If this is true) no devs have fixed it. I know kunos will say "it's a dev app, not for end user) and I also wonder why no one has made an app with that kind of info either for modder or for setting up the car, though @Aristotelis would say it's old school rules the damper %critical etc

Sent from my Moto G (4) using Tapatalk

 

You've answered your own question

 

These tires still don't work for GT3s. Most race cars feel balanced in terms of grip and power and the GT3s with V10 tires feel anything but balanced. Such a huge departure from V7, in terms of both grip and feel, which makes me question why we didn't get V8 and V9 tires so we know the direction kunos was headed.

 

Hmm, it seems for me that the false sprung/total masses displayed in the Car engineer are NOT the values the engineer is using for the calculations - It calculates still correct with 1188 kg sprung mass (488GT3).
If I put the the ride frequencies from the car engineer to my excel sheet, setting the correct weights of the car in this excel sheet, i will result in the wheel rates that I set at the setup screen in AC.

 

It's using the correct values, but displaying incorrect values on screen? Have you tried other cars?