3SGE 240PS Tune

NA Champ!

A 4th Gen 3S-GE Motor

Building a naturally aspirated 3S-GE to produce around 240 horsepower at the crank is a balance between performance and practicality. Unlike an all-out 250 hp race build, which requires extreme compression, massive cams, and a sky-high powerband, the 240 hp goal allows for a slightly more street-friendly setup without sacrificing the excitement of a high-revving engine. The strategy revolves around strengthening the bottom end, improving the breathing capacity of the cylinder head, and optimizing fuel and ignition systems while keeping an eye on reliability.

The bottom end begins with forged pistons in the 11.0–12.0:1 compression range, which is high enough for strong power yet manageable on premium pump fuel, or even better, on E85. Forged connecting rods from reputable brands such as Eagle or Manley ensure durability at sustained high RPM. ARP fasteners for both rod bolts and head studs keep everything clamped together securely. The stock 3S-GE crankshaft is robust, but precision balancing is essential to handle the 8,000 rpm range. A lightweight chromoly flywheel in the 5–6 kg range sharpens throttle response and complements the engine’s high-rev nature.

Cylinder head work is key to unlocking extra power, but for a 240 hp build, mild porting and polishing is sufficient to smooth airflow without sacrificing low-speed velocity. Stock-sized valves, or at most +0.5 mm oversized, maintain midrange torque. Upgraded valve springs and titanium retainers from brands like Supertech or Ferrea allow for high-lift camshafts without valve float. Cams in the 288–296° duration range with 10–11 mm lift strike a good compromise between peak power and drivability. Solid lifters or shimless buckets (depending on engine generation) ensure consistent valvetrain performance at high RPM.

For induction, individual throttle bodies (ITBs) in the 45 mm size provide excellent throttle response and airflow while preserving midrange torque. Matching velocity stacks tuned for a power peak around 7,800 rpm, along with a properly ducted cold-air feed, make the most of the cam and head upgrades. On the exhaust side, a 4-2-1 header is a smart choice for this power target, as it improves scavenging in the midrange compared to a 4-1 race header. A free-flowing 2.5-inch mandrel-bent exhaust with a high-flow catalytic converter or race muffler ensures minimal restriction.

Fuel and ignition upgrades ensure the engine can feed and burn the extra air efficiently. Injectors in the 370–440 cc range, paired with a high-flow in-tank pump like the Walbro 255, provide adequate fueling headroom. An adjustable fuel pressure regulator allows fine-tuning during dyno sessions. A standalone ECU from Haltech, Link, or Motec offers full control over ignition timing and fuel mapping, while a coil-on-plug conversion improves spark energy and reliability at high RPM. Together, these systems allow for precise calibration, which is critical to extracting safe and consistent power.

Finally, reliability is preserved with key supporting modifications. A baffled oil pan prevents starvation under hard cornering, while an upgraded oil pump and thermostatically controlled oil cooler maintain stable lubrication and temperature during extended high-load operation. An aluminum performance radiator from Koyo or Mishimoto ensures coolant temperatures remain stable. A lightweight pulley set and an upgraded performance clutch round out the package. With the right tuning and careful assembly, this combination delivers a lively, high-revving 240 hp engine that pulls hard from the midrange to redline, while remaining more forgiving and versatile than a max-effort 250 hp build.

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..👈