1UZFE 340PS Tune

Building a 340hp Naturally Aspirated 1UZ-FE

1UZ-FE NA Power!

1UZ-FE Series Engines

The Toyota 1UZ-FE is a highly respected 4.0-liter V8 engine, known for its durability, smoothness, and overbuilt design. Originally developed for the Lexus LS400 luxury sedan, it was engineered to last hundreds of thousands of miles under stress while producing between 250 and 290 horsepower, depending on the year and variant. While not designed as a performance powerhouse from the factory, its strong aluminum block, forged internals in early versions, and advanced design make it an excellent platform for enthusiasts seeking more power. With the right naturally aspirated upgrades, the 1UZ can be transformed into a strong 340-horsepower street engine that maintains Toyota reliability.

The foundation of this build begins with improved airflow. The stock intake and exhaust systems are highly restrictive, prioritizing refinement over performance. By replacing the factory intake with a high-flow performance system and pairing it with long-tube headers, high-flow catalytic converters, and a cat-back exhaust, the engine can breathe far more efficiently. These bolt-ons alone typically deliver 20–30 horsepower at the crank while sharpening throttle response and adding a more aggressive exhaust note. At this stage, the engine is still daily-friendly, but the gains lay critical groundwork for later modifications.

The next major upgrade is tuning. The factory ECU is conservative, tuned for emissions compliance and quiet cruising rather than maximum output. By installing a standalone ECU or a piggyback system, fuel and ignition maps can be optimized for premium fuel. A professional dyno tune can unlock additional horsepower while also accommodating intake and exhaust modifications. Tuning is essential for extracting the full benefit of bolt-ons and ensures the engine maintains smooth drivability while safely operating with more aggressive settings. With proper calibration, this step alone can net 15–20 extra horsepower.

To reach the target of 340 horsepower, the 1UZ benefits enormously from camshaft upgrades. The stock cams are mild, built for luxury performance, but aftermarket performance cams increase lift and duration, allowing the engine to take in more air at higher RPMs. Supporting upgrades such as stiffer valve springs, titanium retainers, and upgraded pushrods ensure the valvetrain remains stable at higher revs. With cams and supporting hardware, the 1UZ wakes up considerably, adding 40–60 horsepower depending on grind and tune. This modification also shifts the powerband upward, giving the engine a sportier, more free-revving character.

Cylinder head improvements further maximize performance. Porting and polishing the heads reduce turbulence and improve volumetric efficiency, particularly in the upper RPM range. While aftermarket heads are rare for the 1UZ, carefully worked factory heads paired with performance cams can add another 15–20 horsepower, pushing the engine comfortably past 330 hp. At this point, the combined effect of bolt-ons, tuning, cams, and headwork results in a broad power curve that delivers usable street performance without sacrificing reliability or drivability.

In the end, the naturally aspirated 1UZ-FE with bolt-ons, cams, tuning, and mild headwork represents a balanced street build capable of achieving around 340 horsepower at the crank. This setup retains the legendary smoothness and durability of the engine while providing a dramatic increase in performance compared to stock. For enthusiasts, it strikes a sweet spot: enough power to transform the driving experience, without the complexity or stress of forced induction. It proves that the 1UZ, despite being born as a refined luxury engine, can be turned into a naturally aspirated powerhouse suitable for spirited street driving while maintaining Toyota’s hallmark reliability.

Every motor and transmission has a weakness. It is very important to address your motor and transmission for weaknesses before modifying them. 

Check with your local laws and regulations before modifying, swiping motors, and transmission..👈