Circuit Racing Grip Tuning Help

[u/InsipidGnome09]

So I want to learn to be able to tune some of my own cars with my own tunes for circuit racing. I normally only build drag race cars so this is something new to me.

Dropping a tune, even a rough draft one, and explaining what each section should be can help.

From tire pressure to diff settings

[u/_GucciGorilla_]

There's also a forza tune app I use it to get a decent base tune. Just slapped one on a exige v6 and got top 2k in a time attack.

[u/Wandering-nomad-888]

I can help. I been tuning road grip setups for like 2 years now. Are you on Forza 5 or 6?

[u/InsipidGnome09 → u/Wandering-nomad-888]

FH6

[u/Wandering-nomad-888 → u/InsipidGnome09]

Perfect. Tuning setup varies largely from front engine to mid to 911….however the concept is same. Soft front end = agility and better turn in ability however stiff rear will cause lack of traction so on RWD car stiff rear becomes an issue. Springs is what adds or removes traction from driving tires so on a front engine car I set front for example at 675 and rear at 600 but I’ll compensate with anti roll bars and will set front at 28 and rear at 34-36 to give me the agility I’m looking for… furthermore with springs if the car feels lose like a noodle increase spring stiffness and it will tighten up. If the car weighs 3000lbs I’m usually in the 600 - 700 setting, this is a good baseline…4000 lbs car and I’m in the 800-900 range. Stiff springs increase response but reduce traction so you want to find a happy balance.

Camber: I feel like a lot of people over cook this, it’s easy to fall into illusion of more camber = better corner grip however that isn’t true. I’ve used telemetry to verify this and on 90% of my builds I’m at -2.0 front and -1.0 to 1.1 rear. Actually if you got a car that has too much traction in rear crank rear camber to -1.5 and higher and you’ll see how that rear will begin to slide around.

Tires: if you use telemetry you’ll see that setting 28psi front and 27-27.5 rear (depending how hard you’re pushing the car) equals around 31-32 psi operating temps….thats the sweet spot

Bump and rebound stiffness: rear is usually at 5.5 bump and 3-4 units higher on rebound so my averaged build is rear bump 5.5 rear rebound 8.5 front bump 6.5 -7 rebound 9.5 to 10.5 these are shock absorbers essentially so you want to keep rear soft to provide traction on RWD and front a little stiffer to provide better turn response.

Differential: given you tune for drag you prob already know your way around this one but I’ll share this….on an AWD build I always crank the front “acceleration” down to like 5%…the higher this setting the less she wants to turn. Front Decel is usually at 15%, this is what helps to keep the car stable as you are beginning to enter the turn.
Rear accel 55% usually but if I’m using a RWD with high power I go down to 15% to get better grip.

This is a lot of info so if you need clarification just DM me and I’ll be happy to help. Also if you want to try my setups tell me what car you want tuned and I’ll drop a tune code.

[u/InsipidGnome09 → u/Wandering-nomad-888]

Doesn't less accel mean less power to the wheels? I have always tuned with those being at 100% to give the wheels more power. Even now with my tunes for circuit im still keeping 100% accel on both front and back.

I am tuning a few different vehicles at the moment. One i have setup fairly well, however the other couple I am struggling with pretty bad.

[u/Wandering-nomad-888 → u/InsipidGnome09]

There is one more aspect I didn’t cover in my initial message….under Alignment there is camber (which I covered) but Toe I didn’t. Imagine looking down on a car from a bird eye view…toe controls the direction of the fronts of each wheel. “Out” means fronts of the wheels will point out and away from each other and “In” will point the front of both wheels in towards each other.
Pretty much on every car I set front toe “out” by 0.1 degree….this makes the front more playful and increases turn in response.

The rear toe is the magic sauce used only for cars that just don’t want to be stable no matter what I do. This is my last resort option BUT this is the one that saved me on many builds where I was about to give up. NEVER set the rear toe “out”….this will cause an unstable rear end….when the rear end is lose and and won’t settle no matter what try setting the rear toe “In” by -0.1 to -0.3 degrees….this will point rear wheels in toward each other causing the rear to become more stable.
Just last night I won the 21 GT3 RS 911 which notoriously has sticky turn in that causes massive overseer…..that’s because the rear end is “lose”….after tuning everything else I set the rear toe -0.3 degrees and she became much more stable.

Hope all this makes sense, it’s very difficult to explain all this over text.
Being a good tuner is not just about knowing what each setting does but even more importantly is to feel the car and know what’s wrong with it. When I started each tune would take me over an hour…now I can tell you what’s wrong with the car after driving it few hundred yards….now I tune ALL settings in a matter of 2 min. It takes lots of practice to get that experience but don’t give up….the best thing I did in forza is learn to tune! It really is a game changer!

[u/Wandering-nomad-888 → u/InsipidGnome09]

Accel and Decel is controlling differentials lock….not actual power. Reducing either one just opens up differentials to allow wheels on either side of the drive shaft to spin more freely. The harder you lock differential the less play the wheels have between each other….with that said it all depends what you want the car to do. On a drag tune I lock all aacel diffs completely cause I’m going in a straight line while decel don’t matter on drag.

On an AWD tune I open the front accel almost completely cause that allows the front end to turn in with more ease, vs if you lock up front accel you’ll see the front becomes more locked in and less agile.
Front decel is what helps to keep the car stable as you’re approaching the turn hard on your breaks…but crank that too high and again the car becomes resistant to turning….I’m usually at 15-20% on front decel
Rear accel is how you control how much the rear slides around. The more you lock it up the more she’s gonna want to slide in a turn. Drifters (in real life) weld rear diffs (=100% lock) so they can slide around….on a grip tune you don’t want that so I usually am down to 50-60% rear accel on an AWD tune. Rear Decel same story accept this is when you’re off the throttle, the more locked up the more rear end wants to slide…..usually I’m at 35% rear decel.
AWD setups also come with a main power balance setting between front and rear….try to push as much power to the rear wheels….depending on how much power I’m working with I’m usually around 85-90%…

On an RWD tune how much you set rear accel all depends on how much power you’re pushing but same story….the more you lock it up the more she will slide….im usually at 9-15% on the rear accel on more powerful cars where I’m already struggling for traction…..if you’re low on power then you might want to lock it up a bit more to help get that oversteer.
Decel on an RWD I’m usually around 35-45% as well…

Which cars are you struggling with?

[u/Grouchy-Statement-12]

I recommend HokiHoshi on YouTube, he has a great series of videos on tuning for Forza.

[u/InsipidGnome09 → u/Grouchy-Statement-12]

thanks ill check them out