Fix It Up Tuning Basics: Engines, Transmissions and When to Upgrade

Tuning is Fix It Up’s profit multiplier: a tuned car is worth more than the sum of its parts — but only when you upgrade the right things on the right car. Here is how the system works and how to avoid burning money on it.

The Engine Families

Fix It Up’s engines come in families that players commonly reference by cylinder count and displacement — V6 (3.8L), V8 (4.0L and 4.2L) and V10 (5.2L) are the ones you’ll see discussed most. The general rules:

• Bigger engine families support higher value ceilings. A V10 build has more headroom than a V6 build — but also costs far more to buy and tune.
• Match the engine to the car’s tier. Dropping a top engine into a cheap car rarely pays back; the car’s base value caps what buyers will pay.
• Tune within your bankroll. A half-finished V10 project locks up cash that could be flipping. Finish builds you start.

Transmissions Matter More Than You Think

A strong engine with a mismatched transmission underperforms — both in how the car drives and in what it’s worth. When you upgrade an engine tier, budget for the transmission upgrade at the same time. Think of engine + transmission as one package purchase, not two separate decisions.

When Tuning Is Worth It (and When It Isn’t)

Tune when:

• The car is mid-tier or higher — enough base value to amplify
• You plan to sell on the auction house or to players, where buyers pay for performance
• You have spare bankroll after your normal flipping cycle

Skip tuning when:

• The car is a cheap junk flip — repair it, sell it, move on
• You’re still learning repair costs — tuning adds a second layer of cost uncertainty
• The money would leave you unable to buy your next project

A Sensible Upgrade Order

1. Full repair first. Damage caps value harder than stock parts do.
2. Engine tune second. The main value driver.
3. Transmission to match. Unlocks what the engine paid for.
4. Everything else last. Cosmetic and secondary upgrades polish the final sale price.

Community Tune Metas Change With Updates

Exact “best tune” configurations for each engine (the V8 4.0 vs 4.2 debate, V10 5.2 setups) shift as the developers rebalance updates — update 3.4.1 is recent as of this writing. We’re testing engine-specific setups and will publish per-engine tune pages as results firm up. Until then, the framework above — repair fully, tune proportionally to car tier, always match the transmission — holds in every patch.

Got your first tuned build? Take it to the auction house rather than instant-selling it. The money guide covers how to price it.