A basic guide to setup changes

[EvilClive]

We often hear that members simply run with the default setup and maybe only adjust the gearing for longer/shorter tracks. The reason for this is that they do not really feel confident in making adjustments, or are scared of what horrors they might discover if they do.

Someone over in GTL land compiled this document several years ago to help their members and I have been trialling it against GPL cars to see if the same physics rules apply within the different software.

From what I have discovered it appears to work very well, so if you want to make the car that you drive behave a little more as you would like it to,  now is the chance to give it a go.

Here is a ( very ) basic guide to car setup adjustments. This is not meant to be a guarantee of a perfectly handling car, but it might help you to create a car that behaves more as you would like it to.
You might need to adjust one or more of the parameters to achieve the desired result.
Be aware that you should test any changes on warm tyres, so give yourself a couple of laps before pushing to the limit )
You might also find that what you change makes the car better in some corners, but less so in other corners. You will have to decide what gives you the better lap times or which setup is easier to drive for a full race.

Car understeers into corner.
Soften front bump
stiffen rear rebound
soften front springs
harden rear springs
increase coast side of diff

Car oversteers into corner
Stiffen front bump
soften rear rebound
harden front springs
soften rear springs
reduce coast side of diff

Car understeers mid corner
Soften front roll bar
stiffen rear roll bar

Car oversteers mid corner
stiffen front roll bar
soften rear roll bar

Car understeers on exit
Soften front rebound
stiffen rear bump
Raise power side of diff  From experience this is wholly dependent on your right foot!! In a perfect world ( which this isn't) you apply as much gas as the tyres will accept without spinning and the slip in the diff does the rest.

Car oversteers on Exit
stiffen front rebound
soften rear bump
raise/lower power side of diff. From experience this is wholly dependent on your right foot!! In a perfect world ( which this isn't) you apply as much gas as the tyres will accept without spinning and the slip in the diff does the rest.

One final thing to consider is Brake balance. Ideally you should be able to brake hard and no tyres lock up. A locked tyre will not offer much retardation! So if you see your front tyres smoking into each corner try moving the balance towards the rear by a couple of clicks. Be aware that the closer you get to 50/50 the easier it is for the car to swap ends under braking if the rear wheels lock. However, more bias towards the rear will allow the car to rotate into the apex more easily. It is a balancing act for each driver.

If you do adjust the diff settings, it might also be worth trying one more, or one less clutch as well (or instead) as that can affect how the rear end behaves.

If you find that this helps, print out a copy and keep alongside your computer so that you can refer to it when you have a problem. Eventually you will know what to do and can discard the guide.

[EvilClive]

My intention with the original post ( and my thanks to the guys at UKGTL for providing it ) was to show the basic physics that are affected in changing setup parameters. In the original post I deliberately avoided discussing the major issue of diff settings and that was not accidental. I think I have read more opinions and articles about diff settings within GPL than anything else, and I confess that I have been very confused at times. More about my take on diffs later.

Here I think that it is helpful to think of a "SETUP" as a complex algorithm ( which it is!), so making an adjustment to one element might impact the current effect of another parameter. So, it is a complex balancing act to balance your car to your liking. Just look at the current F1 teams as they make continual adjustments to the aero/mechanical setup, searching to find the mythical sweet spot. We at GPL are not quite in that complex a maze, but it certainly is not A+B+X=C. Where X = you.

For myself, I know that I cannot drive any car quickly if I am not confident and comfortable with the setup and the way the car responds. That does not necessarily mean that my progress around the track is ultra smooth and precise ( although that might improve my times even more!) but that I absolutely know that I can put the car where I want it to be, even if that is sideways, and still maintain complete control of where I am going. My setup has evolved to allow that.

The effect of the changes are quite real in terms of the direct software responses, if the car was driven robotically by the AI for every lap they would become clear. Most of us are not robots and many of our inputs become increasingly erratic in the heat of battle. This is where the true aliens reveal themselves as they are able to maintain a smooth, calm and consistent performance under extreme pressure which maximises their pace.

The biggest problem with any setup advice is that it is, by definition, entirely subjective, and not at all objective.  Any adjustments that you might make to your setup are made as a result of what YOU perceived to be a problem, and only you and your driving style can evaluate any improvement or a backward step. I am wary of those who offer specific setup advice like " ...run the shocks at 1:4 on the front and 3:5 on the rear and reduce the front roll bar to 60lbs". I do not doubt that the generous advisor means well and has found that those settings work really well for them and their driving style. But unless you drive in the same way that they do, you will not gain much, if any, benefit. Plus those values are compromised by all of the other variables within their ( and your) setup.

 I firmly believe that this why we often hear the plaintive cry of the Desperate Setup Searcher as they look for a silver bullet to improve their performance. They find a setup posted on the Track Database that promises almost World Record lap times with a full tank of fuel, and download it in excited anticipation of increased performance. Rarely are the results encouraging and even rarer are those who suddenly join the ranks of the aliens. After a few laps with the new super setup the downloader is often left totally disillusioned and the next post on the forum reads "I just cannot drive Crankshaft Charlie's setups, they are terrible!".
 Occasionally you might find a setup that feels, and drives, much better than what you previously used, but my advice would be to note how differently the car behaves with the downloaded setup compared to what you used before, then compare the settings. Maybe create a copy of your old setup and graft the damper settings from Charlie into it and see what happens. Or revert to your damper settings and import the roll bar values. Can you discern the difference? What has changed? More importantly, does it suit your driving style??
 
I believe that it is not the alien setup that is necessarily terrible, but the manner in which it is being used. If Slowcoach Sid is trying to drive the download in the same way as he sedately drove the default setup, then he will never extract the same lap times as Charlie has shown to be possible. Also remember, that the time that might be posted with a setup is the BEST time that was achieved, there might have been 100 laps that were slower, perhaps a lot slower?. It might be more relevant for the offered setups to also show the slowest laptime that was achieved?


Any changes to the various parameters within the setup pages of GPL will affect the way that our virtual car SHOULD behave. The list above is a good starting point, but once again, it depends upon the driver being consistent with their inputs to see/feel the difference.  My experience suggests that I should run 10 laps to evaluate any changes. This allows the tyres to reach their operating temps and the driver to assimilate the difference.
A quick note of warning here re tyre temps.....Sometimes setup changes have a positive/negative on tyre temps and what was stable before now overheats dramatically. A hot tyre will have a huge negative impact on the handling, so the holy grail in setups is to discover faster lap times but with tyres that are at their optimum temps. If the tyre temps are too low, then it is almost certain that you are not pushing quite hard enough. If the temps are too high but your pace has not improved, then the changes might not be going in the right direction, so try a click in the other direction?. One caveat here is that the changes might be correct, but that you are not making the best use of them? Try braking earlier /later, taking some corners a gear higher/lower or try and adjust where you get back on the power and how fiercely. This is not so easy as it sounds as old driving habits die hard.

[EvilClive]

My intention here was to write an explanation of how various diff settings affect car behaviour in GPL. It was to be simple, direct and not involve the technical theory behind the operation of a differential with all the ramp angles and thrust etc.

That article was half written and I went to look for some extra info and to confirm some parameters and came across this....

If a picture paints a thousand words, then a video probably replaces a million! Plus you won't have to read my boring articles!!!


If you want a simple understanding of diffs and settings, take a look at this and think yourself lucky that I did not post my article!!!

https://www.youtube.com/watch?v=awLhSsy5IqY

The only comment that I would add to this excellent video is to play with the diff settings alongside an existing favourite setup, but adjust nothing else until you have found what suits you best. Changes to roll bars or shocks can mask/enhance the behaviour of the diff settings.
Once you have settled on the diff that feels most comfortable, then you can set about tweaking other parameters to search for even more improvements. But always remember to save a) your original "safe" setup, and b) save each progression of changes with a suffix like Brab 67 1,2,3 or  BRM 67 a, b, c,. There is no worse feeling than realising that you have been adapting your faithful old tried and tested setup for the last hour and have no saved copy and no way of remembering exactly what it was that you have changed