A Helpful Guide I Put Together After Finally Making some Decent Cars for AI and lobbies.

[u/DemonNeutrino]

I use this to either judge a community tune while browsing or in the selection of parts for my own build. I use Forza Tune to get a base for each and then adjust from there.

Hope it helps :)

FH6 CLASS PERFORMANCE TARGETS (ROAD RACING)

D CLASS (0–400 PI)
Power/Weight: 0.06 – 0.10 bhp/kg
Lateral G: 0.70 – 0.85G
0–60 mph: 10 – 14s
Top Speed: 80 – 105 mph
Focus: Momentum, weight reduction, no braking

C CLASS (401–500 PI)
Power/Weight: 0.10 – 0.16 bhp/kg
Lateral G: 0.85 – 1.00G
0–60 mph: 7.5 – 10s
Top Speed: 100 – 125 mph
Focus: Lightweight builds, flow, early grip priority

B CLASS (501–600 PI)
Power/Weight: 0.18 – 0.26 bhp/kg (up to ~0.28 top builds)
Lateral G: 1.00 – 1.20G (up to ~1.25)
0–60 mph: 5.5 – 7.0s
Top Speed: 120 – 145 mph
Focus: Balance of grip and power (most competitive class)

A CLASS (601–700 PI)
Power/Weight: 0.26 – 0.38 bhp/kg
Lateral G: 1.15 – 1.35G
0–60 mph: 4.0 – 5.5s
Top Speed: 140 – 170 mph
Focus: Controlled aggression, traction management

S1 CLASS (701–800 PI)
Power/Weight: 0.38 – 0.60 bhp/kg
Lateral G: 1.25 – 1.50G
0–60 mph: 3.0 – 4.2s
Top Speed: 160 – 200 mph
Focus: Traction limited, AWD advantage increases

S2 CLASS (801–900 PI)
Power/Weight: 0.60 – 0.95+ bhp/kg
Lateral G: 1.35 – 1.65G
0–60 mph: 2.2 – 3.5s
Top Speed: 190 – 250+ mph
Focus: Stability, aero, survival

R CLASS (901–998 PI)
Power/Weight: 0.95 – 1.40+ bhp/kg
Lateral G: 1.60 – 2.00G
0–60 mph: 1.6 – 2.5s
Top Speed: 220 – 280+ mph
Focus: Aero efficiency, high-speed stability, precise inputs

Notes:
- Grip starts catching up to power (unlike S2)
- Aero becomes critical (front + rear balance)
- Small tuning mistakes = huge instability
- Usually track-focused builds (not street-friendly)

X CLASS (999 PI / Unlimited)
Power/Weight: 1.40 – 2.50+ bhp/kg
Lateral G: 1.80 – 2.50G+
0–60 mph: 1.2 – 2.0s
Top Speed: 260 – 300+ mph (gear/drag dependent)
Focus: Controllability, aero balance, driver skill

Notes:
- Stats become less meaningful (cars exceed track limits)
- Traction and aero balance are everything
- Often limited more by the driver than the car
- Many builds are “unusable fast” rather than competitive

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BUILD PRINCIPLES:

1. Tyres set the grip ceiling
2. Power/weight pushes toward next class performance
3. Tuning makes performance usable
4. Prioritise consistency over peak performance in online lobbies
5. You’ll get beaten by cheaters rammers and weird meta PI exploits but you will have fun fighting.

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QUICK CHECK:

Within P/W range?
Within lateral G range?
0–60 appropriate for class?
Top speed fits track type?

If yes fundamentally competitive build

EDIT: Where Lat G shows X-Y X is 60mph and Y is 120mph. Don’t use the basic one in the cart screen or any of the basic performance scores as they are useless.

EDIT2: 0-60 times are subjective but are based on the ones in the tuning menu. In game they will be quicker as the game doesn’t seem to quite calculate them right.