I’ve been tuning for a good amount of time now, and I’d say the best place to start in tuning is to know what’s going on when you change the settings, and why things work.
Before I get into most of the meat, you’ll want to turn on the telemetry if you haven’t already in FH4. Telemetry gives you a lot of valuable information for tuning, so it’s an absolute must. Go to settings > controls, and you should see an option that looks like Anna/Telemetry, switch it to Telemetry. Once it’s set, then all you need to do is go out of the pause menu and press/hold down on the d-pad. The telemetry menu should pop up. Then if you press left or right on the d-pad you can look at the other menus.
Mostly everything involving handling involves improving tire compliance. You want the tire to have a good contact patch (The “footprint” of the tire, the amount of tire in direct contact with the ground), good downward load on the ground, and good temperature. And of course you need to keep the tires on the ground.
Tire Pressure
Since the tires are the only contact the car has with the ground, they’re obviously pretty important. You can’t have a functional tire without pressure. In Forza I don’t really ever touch the tire pressures much, I usually leave it at 30 psi. The only times I ever do change it is if the pressure difference between the front and rear wheels of the cars is different. When the tires are at operating temperature, they gain pressure. If the front tires are at 33.5 psi and the rear are at 32.2 psi, then I would decrease tire pressure in the front by 1.5 psi to try to equalize it. 32 psi is a good pressure at operating temperature for tires in Forza, so if your psi is anywhere above 33 psi or below 31, then adjust accordingly. But for the most part, cold tire pressure can be left alone.
Gearing
Gearing deals with how long or short your gears are. Cars with shorter gears have you shift a lot more and allow for more acceleration, while cars with longer gears shift less and have more speed. Choosing what’s right for your car depends on the amount of traction you have, the weight of the car, and the amount of power.
The most important thing about tuning gearing in Forza (In my opinion) is tuning first gear and final drive:
-First Gear: For tuning first gear, you want to get the most speed from a stop without bogging down (When your RPM drops down to around 1 or 2 thousand and your start is really slow) or losing all of your power to traction loss. The former means your first gear is too long (Geared too much toward speed), the latter means it’s too short (Geared too much toward acceleration). You’ll want to tune final drive first before you do this.
-Final Drive: For tuning final drive, you want to reach redline in your highest gear at your top speed. If your car uses 6 gears and a redline of 7,000, then you want the needle touching 7,000 RPM in 6th gear at top speed. I usually tune this on the highway along with tuning first gear afterwards.
You should tune the other individual gears after you tune first gear, because changing first gear will change 2nd gear, changing 2nd gear will change 3rd gear, and so on.
Another thing to note is the amount of gears you use. Race transmissions let you use 6 gears at the least, but 6 gears may not always be the best. You’ll want more gears for cars without a lot of torque, like little four cylinders or small Ferrari V8s. As for big, torquey HEMI V8s, it’s best to use 5 or even 4 gears with longer gears so they can use more of that torque.
(There’s a lot more but I’m too lazy to type it all down at the moment, but you can take a look Here.)
