The Undercut Racing Manager Pick the motor, then build the factory around it

The engine is the only part you cannot manufacture. Everything else — chassis, wings, suspension, brakes, gearboxes, cooling, electronics, fuel system — you build in your own departments. The engine arrives from a supplier, and the choice you make on day one of getting started echoes all the way to the final flag.

This page is the deep dive on that choice: how to read the engine card, what partnership versus client actually means for your budget, why works status matters, and how the Engine department relates to the power unit you signed.

The engine card: what the numbers mean

Every engine in the supplier catalogue carries four headline stats:

Power — peak output, measured in an abstract unit. Higher power helps on straights and power circuits. On high-downforce, high-corner circuits it matters less than Aero.

Endurance — reliability floor across a full season. Low endurance means more mechanical failures, more DNFs, and more Repair Work Units spent fixing the motor instead of improving the car. A high-endurance engine is a low-risk engine.

Reliability — how the power unit holds up across a race weekend. This is the weekend-level version of endurance: a low-reliability engine might survive a full season but bin you in lap 18 of a long race with a coolant leak.

Potential — the ceiling the engine can reach through development. A low-potential engine starts strong but cannot grow with your R&D. A high-potential engine needs more factory investment to unlock but ends stronger.

Read all four before you sign. A high-power, low-endurance engine is a quali toy that costs you Sundays. A high-endurance, low-power engine is a taxi that cannot score.

Partnership versus client

Two deal structures exist in the supplier market. The rules are the same for engine, tyres, and fuel, but the engine contract is the most consequential.

Partnership — the supplier pays you a per-race fee and puts their name on your car. Works partnerships are the most prestigious and usually come with performance benefits (better parts, development bonuses) but also stricter happiness requirements. Miss the targets and the works status disappears, sometimes permanently.

Client — you pay the supplier for their power unit. The invoice is real money. In return you get a competitive engine and usually more flexibility on happiness requirements. A client deal with a strong manufacturer can be the smarter financial choice if a works deal would bankrupt you before the first podium.

The decision is not about prestige. It is about whether the per-race income from a partnership exceeds the invoice you would pay as a client, and whether the performance delta between a works engine and a client engine is worth the happiness risk. On a Small or Medium budget, client deals are often the right answer.

Works status and why it can disappear

A works engine — one with active works partnership status — gets development bonuses, better potential scaling, and the prestige of the brand on your car. In 0.5.4, an expired works deal used to block that supplier forever. The launch notes fixed that lock. Works status now behaves like a normal contract: it expires, you can renegotiate, and the supplier returns to the market if you let them go.

Before you chase a works deal, check whether you can satisfy the happiness targets for a full season. A works engine you cannot keep happy is worse than a client engine that stays stable.

The Engine department does not make the engine

This is the most commonly misunderstood sentence in car development. The Engine department owns:

• Gearbox
• Electronics
• Fuel system
• Cooling

The power unit itself — the thing that makes horsepower — comes from your supplier. Upgrading the Engine department makes your ancillaries better, not your engine’s peak power. That is why the engine supplier and the Engine department are two separate decisions.

A high-power engine on a weak Engine department still DNFs from cooling or gearbox failures. A weak engine on a high Engine department still cannot win on straights. The pairing is the product.

How to choose on day one

The day-one checklist on getting started says engine first, tyres second, fuel last. Here is the full thinking:

1. Read the next calendar card. If it is a power circuit (high straight-line speed, low corner count, overtaking easy), prioritize power. If it is a high-downforce circuit (many corners, tyre wear High, overtaking difficult), prioritize Aero and Handling over raw engine power.
2. Check your budget tier. Small teams should not chase works engine deals they cannot satisfy. A mid-tier client engine that stays reliable beats a top-tier works engine that walks after two missed targets.
3. Match to your driving pair. A high-CON, high-STA driver can manage a slightly fragile high-power engine better than a fragile driver who bins the front wing every time the turbo spools.
4. Factor the Engine department. If your Engineering is weak, prioritize endurance and reliability over peak power. A DNF from a cooling failure costs more than a slow lap from insufficient top speed.

During the season

You cannot change the engine mid-season. The supplier contract is fixed. What you can do is manage happiness through Marketing Work Units, avoid pushing the engine past its comfort zone (heavy Overtake Push on a low-endurance engine is a DNF tax), and use the Engineering department to address ancillary failures.

If the engine is costing you more than it delivers — frequent DNFs, cooling warnings every race — that is information for next pre-season. Start scouting alternative suppliers in pre-season phase 1, before you sign any other deals, because the engine shapes every other decision.

Engine and the rest of the wiki

The engine is on this page. The parts tier list ranks where to spend Work Units on the things you manufacture. The suppliers page covers tyres and fuel in the same framework. The car development page covers the Engine department as a factory unit. The race strategy page covers how a high-power engine changes overtaking and dirty-air dynamics on straights.

All of them are one career.