Homologate a car
The order matters. Each step gates on the previous one — reorder them and you waste PI. Walk the list top to bottom for any new build, then use the smells table to audit existing builds.
Build order
- 01
Pick the discipline
Do Lock in road / dirt / cross-country / drift / drag before touching upgrades.Why Every upgrade tier's PI-efficiency is discipline-dependent. The same Race-slick tire is the right answer for S1 road and the wrong answer for dirt — and the PI penalty changed in FH6 to make this more punishing. - 02
Set the target class
Do Choose D/C/B/A/S1/S2/X/R. Class caps in FH6: D 500, C 600, B 700, A 800, S1 900, S2 998, X/R uncapped within slot.Why Class boundary determines the PI budget. A 800 PI A-class car will outperform a 701 PI A-class car despite both being "A". Build to within 0–3 PI of the cap. - Do Keep stock unless a swap clearly serves the discipline. AWD swap = 30–80 PI; RWD swap from factory AWD = usually a net loss.Why Drivetrain conversion is the single biggest PI commitment. Get it wrong and your budget for everything else collapses.
- Do Only swap if PWR clearly improves. Verify before and after.Why A bigger engine that ruins weight balance is a worse car. Many factory engines are already PI-efficient.
- Do Default to centrifugal SC for road; twin turbo only on large displacement; positive-displacement for drift/drag.Why Aspiration shape matters as much as peak power. Wrong choice = lag or unusable torque.
- Do Suspension class to match discipline (Sport for B/A road, Race for S1+). One brake tier. Race weight reduction.Why Chassis fundamentals make every later upgrade work. Skipping them is the classic "fast in a straight line, undriveable in corners" build.
- Do Match compound to surface. Try front tire width before bumping compound a tier.Why FH6 made front tire width a first-class lever. Often beats a compound jump on PI cost.
- Do Front splitter first (cheap PI). Rear wing only if rear unhooks in fast corners. Widebody only if you need the wider tires.Why Front aero is usually free PI; rear is expensive drag. Widebody is cosmetics unless you use the unlocked fitment.
- Do Race differential mandatory. Sport transmission at B/A, Race at S1+. Skip Race clutch unless on M/C input.Why Stacking Race-tier on all five drivetrain parts wastes 15–25 PI. Diff unlocks the tuning sliders; the rest are budget calls.
- 10
Power top-up: hit the class cap
Do Use engine internals (intake, exhaust, ignition, fuel) to dial PI to the ceiling.Why Power last, after the car can handle it. Internals are cheap PI per HP and trim cleanly. - 11
Fine-tune with weight, driveline, flywheel, tire width
Do When you're 1–5 PI over the cap, these are the surgical trims. When you're 1–5 PI under, these are the cheap top-ups.Why Small adjustments here let you keep upgrades you want elsewhere. The driveline + flywheel pair quietly removes rotating mass too.
Build smells (audit existing builds)
Spot any of these on a build and you have PI to reallocate. The fix column points to the cheapest swap.
- Race-tier on all five drivetrain partsDrivetrain Parts (Diff / Trans / Driveline / Clutch / Flywheel) →Keep Race diff; downgrade transmission to Sport at B/A; skip Race clutch on non-M/C input. Reclaim 5–15 PI.
- Race slicks on a dirt or cross-country buildTires (Compound & Width) →Switch to rally or off-road compound — FH6 made this a hard PI penalty.
- No brake upgrade above D-classBrakes →Add one Sport brake tier. 2–5 PI, fixes lockup and trail-brake understeer.
- Widebody installed without wider tires or aero useAero & Body (Wing / Splitter / Widebody) →Remove widebody — you're paying drag and PI for cosmetics.
- AWD swap on a light low-class carDrivetrain Conversion (FWD ↔ RWD ↔ AWD) →Revert to factory drivetrain; spend the 30–80 PI on tires and weight.
- Twin turbo on a sub-2.5L engineAspiration (Turbo / Supercharger / N/A) →Switch to centrifugal SC or single turbo — twin turbos lag without payoff on small engines.
- Race clutch on Automatic or Manual inputDrivetrain Parts (Diff / Trans / Driveline / Clutch / Flywheel) →Skip it — the simulation doesn't model your shifting; the upgrade does nothing.
- Sport / Race suspension on a dirt or off-road buildSuspension Class →Switch to Rally or Off-road suspension — Sport/Race binds over bumps.
- 5+ PI under the class capWeight Reduction →Top up with weight reduction, driveline, flywheel, or front tire width. Free lap time.
- Rear wing on a long-straight speed circuitAero & Body (Wing / Splitter / Widebody) →Remove rear wing or drop a tier — the top-speed loss outweighs cornering gain.