Gran Turismo 201 - The "science" of Tuning: Feeling the Car's Every Twitch (EH Team edition)
Not all of us are given to tuning cars well right away, I definitely started that way. The first car I tuned in GT6 was the Premium Renault Clio 2011, and it was kinda fastish but there was a massive problem, nearly every curb the car touched suddenly meant I was driving a front wheel drive bicycle for the next few seconds. So my first few months of GT6 were a little rough around the edges, but I've slowly begun developing and perfecting tuning philosophies for all the different car layouts over time. I have also found 3 things that are the absolute platform of the car and most everything else needs to be changed if any of these attributes are changed significantly:
- weight distribution
- spring rates
- ride height
These three things in that order are the absolute structure of your setup, and should be left alone for the most part except for minor tweaks. All the other attributes should be adjusted around these settings, transmission included. Here's an analysis of each piece of the car that can be tuned.
- Ride Height - should be set low but not too low, staying generally 10-20 above the minimum is advisable. On tracks where high amounts of speed are carried through banked corners this should be set higher to accommodate for the overall compressing of the entire suspension so to ensure the car does not bottom out (scrape the track) at any point in the corner. It can also be used to adjust the effectiveness of downforce.
- Spring Rate - making a large change in this area will cause most other settings to be irrelevant to the car. High spring rate (above 19-19.50 in race cars and 13-13.50 in road cars) is unadvisable because the entire system can be thought of as a team. When the springs or any other component are taking the brunt of the work it causes the car to grip less and cause more tire wear. Low spring rates (these vary more from car to car) can help the car turn better but also increase tire wear, and can do more so than high spring rates.
- Dampers - a setting somewhere in the middle of the range will do you good to start in most applications, ovals being the exception with very low settings. One of the most effective settings of the dampers that can be adjusted is the rear extension. Raising it will bring understeer to the car and lowering it will bring oversteer. Adjustments of this particular setting should be done as a standalone tweak and most times a change of just one notch will be enough for the car. Adjusting the compression works the opposite, going up brings oversteer and down brings understeer. This idea applies the same way to the front dampers.
- Anti Roll Bars - high settings of this part of the car are generally recommended. Even adjustment front to back will keep the balance of the car broadly the same, but going up in settings will do as the name says and decrease the amount of roll over the car has. Differing the correlation of the setting front to back will change the handling, with higher rear settings increasing oversteer and higher front settings increasing understeer.
- Camber - not much to explain here since it still doesn't really work. So set at Zero front and back and carry on.
- Toe angle - can be a very useful setting for a specific condition of the car, which is a lack or surplus of turn in to a corner. Using positive front toe will decrease turn in to some degree and using negative front toe will increase turn in. The rear toe can be used for overall stability of the car, especially when exiting corners. Positive rear toe will increase stability and negative rear toe will decrease it, but do be careful when adjusting toe in any form because too much in either direction can increase tire wear a noticeable amount.
- Brakes - the higher this setting is, the higher your braking force will be. Higher front settings can increase understeer on turn in and higher rear settings will increase oversteer on turn in. Having higher overall settings, it will do this with ABS off, can bring the car close to locking up the tires so adjust here according to taste. Changing the setting of your brake bias will usually mean you need to adjust your differential braking sensitivity a little bit.
- Transmission - You know what this thing does as an everyday job, what you may not know is what it does as a side job is help the car handle depending on the rpm run through the corner. The higher the car is in the rpm range the more it turns through corners, and turns a little less through the corner when the rpm are in the low to mid range. This doesn't necessarily apply to front wheel drive cars because higher rpms push out the drive wheels of any car through the corner.
- Differential - this piece of equipment can be rather vexing at times, so here's a slightly easier way to adjust it. The initial torque controls how much the inside wheel turns while the throttle is being applied, and the acceleration sensitivity controls the outside wheel in the same situation. Adjusting up will increase rotation and down will decrease it. The braking sensitivity controls the stability of the car when the throttle is not being applied, regardless of the brakes being applied, however the difference is far more noticeable when brakes are not being applied. Adjusting this up will increase turn in understeer and adjusting down will increase turn in oversteer.
- Downforce - you know this one's day job too, adjusting it can be tricky though. When making a change to the front or rear the amount you can do that will improve the car's handling is somewhat correlated to how much is applied to the opposite end of the car. This means it can take a few runs of adjustments to really dial in the settings so always be patient with it.
- Ballast Positioning - fairly simple adjustment that affects the weight distribution, but some cars can be found to have more speed potential with a slightly rear biased balance, adjust with care.
Some things I have found out with certain layouts on platform are interesting indeed. I find on Front drive layouts it's better to send any ballast you may be forced to carry to the front of the car. What you should also do is have the rear springs significantly higher than the front to help promote turn in. This allows for exceptional adjustability of your line through pretty much any given corner by playing with the throttle.
FR cars have a tendency to vary in where they like the higher spring rate to be.
MR cars have to have something be relatively soft in the rear, usually dampers, to keep them from constantly spinning out.
RR, still in trial and error stage, definitely the most messed up of the bunch because no car does the same thing as another.
4WD in front engined layout, most of the adjusting you'll do will be in the differential and is very difficult to master.
4WD in mid engine layout is given generally to oversteer but can be remedied to some extent by sending a bit more power to the front. They are also not as differential dependent as their front engined brethren.
Feeling each thing in what the car is doing can be a little difficult because there are different varieties of how things happen, so here's a little list of some things that happen and what you should adjust to fix them
- Sudden massive oversteer causing spinouts - check ride height is high enough, raise rear extension, lower rear springs
- Sudden oversteer exiting a corner - lower differential acceleration, lower rear compression, raise rear extension raise rear ride height slightly and add a little rear downforce
- Apex oversteer - lower rear springs, lower differential acceleration, raise front anti roll bar or lower rear anti roll bar
- Lazy controllable oversteer - raise rear toe, lower differential initial torque
- Corner entry oversteer - raise differential braking sensitivity, bias brake more to the front, raise front ride height slightly
- Understeer in any of the above situations can be fixed most of the time by going the opposite direction in the adjustment for fixing oversteer.
Hope all of this is helpful to you and anyone else who reads it. Here's to better tunes and competition.
)!!!
👍 
My respect to you!... 
). You deserved that win. The Problem with is that Suzuka spreads the field of cars more than spa and Daytona.
