If you're buying exactly one prototype in iRacing, this is the one I tell people to buy. I said as much in my GTP class guide: the Porsche 963 is the default pick, the most popular GTP car on the service, and the most forgiving way into the fastest closed-cockpit racing iRacing offers.
This page is the full car-level guide — what the car actually is, the verified numbers, how the hybrid behaves since the overhaul, and how I'd approach setting it up. Same deal as my Dallara P217 guide: I never raced a 963 in real life. My prototype-adjacent experience is F3, F2 and GT3 machinery, so I'll tell you what transfers from that and what I've learned from the sim itself, and I'll only quote numbers I can verify from official sources.
The real car, briefly
The 963 is Porsche's LMDh prototype — the car that brought them back to top-class endurance racing in 2023 after a five-year absence. Spec hybrid system, spec Xtrac gearbox, a Multimatic chassis, and Porsche's own 4.6-litre twin-turbo V8 on top.
It has been ruthlessly effective. The factory Porsche Penske #7 car won the Daytona 24 outright three years running — 2024, 2025 and 2026 — and Porsche took the IMSA GTP title in both 2024 and 2025. When you pick this car in iRacing, you're picking the reference car of the real GTP era. That also explains the practical advantage: everyone runs it, so there's more setup material, more onboards and more race craft reference for the 963 than for anything else in the class.
The 963 in iRacing
iRacing added the 963 in the 2023 Season 4 build (September 2023), in the same release as the Acura ARX-06. It costs $12.95, same as every car in the class.
Verified tech specs, straight from the official iRacing user manual:
| Spec | Value |
|---|---|
| Engine | 4.6L twin-turbo V8 + Bosch MGU hybrid |
| Power | 671 bhp (500 kW) combined |
| Torque | 497 lb-ft (673 Nm) |
| RPM limit | 8,158 rpm |
| Gearbox | 7-speed sequential, Short or Long stack |
| Dry weight | 1,030 kg |
| Weight with driver | 1,187 kg |
| Fuel tank | 89 L |
| Wheelbase | 3,148 mm |
No clutch needed — it's a straight sequential with downshift protection, so the box simply refuses a downshift that would over-rev the engine. Shift when the lights go blue and it won't argue with you.
One thing worth knowing before your first lap: GTP cars in iRacing run without ABS. You get adjustable traction control (gain and slip, both changeable from the F8 black box while driving) plus brake bias, bias target and bias migration. Braking discipline is on you, and that's where most of the early crashes in this class come from.
How it drives
The 963's balance leans toward stability, and that's exactly why I recommend it first. The front end pushes a touch rather than snapping into oversteer, wheelspin on corner exit is the most manageable in the class, and its Le Mans-spec efficiency makes it honest on the big circuits.
Coming from GT3? The two adjustments that matter most: braking and commitment. This thing stops from 300 km/h with downforce a GT3 car simply doesn't have, so your braking references need to move hundreds of metres later — but without ABS, the last 20% of the pedal is a negotiation, not a stomp. And in fast corners you have to trust aero grip that your instincts say shouldn't exist. That trust is built in laps, not in the garage. If you've read my tire wear guide, the same rule applies here amplified: slide the car and the stint falls apart.
Mild understeer is a feature over a race distance. In a 45-minute IMSA sprint your tyres and your heart rate both stay in the window, and traffic management — the actual skill of multiclass racing — is far easier in a car that doesn't threaten you mid-corner.
The hybrid: what's actually current
Important, because there's stale information everywhere, including in official places. Since the 2025 Season 4 build, iRacing's hybrid system was overhauled for every hybrid car. LMDh cars like the 963 now run the hybrid automatically: deployment blends with the combustion engine under a rulebook-style power cap, targeting roughly 50% state of charge, with no driver-selectable deploy modes.
The official 963 manual (dated March 2025, before the overhaul) still describes five driver modes — No Deploy, Qual, Attack, Balanced, Build. Ignore that section. It describes the old system. You drive the current 963 as a pure combustion car and let the electronics do the hybrid work; regen is blended into the brake pedal cleanly enough that you mostly won't notice it.
I wrote up the whole system — including why the Ferrari 499P deploys differently — in my iRacing hybrid system explainer.
Setup: where to start
iRacing ships 12 official setups for the 963, and they're better than people give them credit for: Baseline, High/Medium/Low downforce, a Daytona oval-aware variant, a dedicated Daytona 24H setup, and six Fixed-series variants including Le Mans and qualifying trims. Start there before touching anything — the fixed setups in particular are what the whole field runs in the official IMSA fixed series, as I covered in fixed vs open setup racing.
When you do start adjusting, the official manual gives you the aero targets to work around: the 963 generates peak downforce at roughly 45 mm average rear ride height and 25 mm front. More rake shifts balance forward (oversteer), less shifts it rearward (understeer). Three tools cover 90% of your balance work:
- Rear wing angle — the first and simplest balance change. One click is a lot; if you want more than that, switch to a different base trim instead.
- Rear pushrod length offset — changes rake, and with it aero balance, without touching your downforce trim. Higher = more rake = more rotation.
- Diff preload — the underrated one. More preload calms the car on entry and off-throttle; less lets it rotate. You feel this at turn-in more than anywhere else.
Ride heights are also where setups fail scrutineering, so if you're experimenting, read my tech inspection guide before you wonder why the sim won't let you grid. And as with every car on the service, tyre pressures are the cheapest lap time in the garage.
If you want a wider baseline library to learn from, my setup archive covers the setup fundamentals cluster across classes.
Where to race it
The 963's home is the IMSA iRacing Series — B-class (4.0 SR), running every two hours, 45-minute races in the open-setup version and 35 minutes in fixed. It's the best multiclass racing on the service and the full format is in my IMSA series guide. GTP also headlines the endurance calendar, and Season 3 2026 finishes with Le Mans week starting September 1 — the low-downforce setups exist precisely for that.
If you're not B-class yet, that's fine. Buy the car anyway if it excites you — you can practice, test and run hosted sessions with any license, and the seat time while you climb the ladder through something like the GT3 route or the formula ladder is exactly what makes the step up stick.
FAQ
How much does the Porsche 963 cost in iRacing?
$12.95, the standard price for current cars on the service. It's paid content on top of the subscription, and it went into the sim in the 2023 Season 4 build.
What license do you need to race the 963?
The IMSA iRacing Series requires a B-class road license at 4.0 safety rating, in both the open and fixed versions. There's no license requirement to buy, practice or race it in hosted sessions.
Does the iRacing Porsche 963 have ABS?
No. GTP cars run traction control only — gain and slip are adjustable from the F8 black box — plus brake bias, bias target and bias migration. Clean braking without lockups is the single biggest skill separator in this class.
Can you change hybrid deploy modes in the 963?
Not anymore. Since the 2025 Season 4 hybrid overhaul, LMDh cars manage deployment automatically around a 50% state-of-charge target. The five driver modes described in the official manual are the pre-overhaul system.
Is the 963 good for GTP beginners?
It's the one I recommend first. Most forgiving under braking, most manageable on exit, and the most popular car in the class, which means the most setups, onboards and reference material to learn from.