467 Horsepower V8. Any Questions?
It’s a good day for engineers when they’re tasked with redesigning a 416 horsepower high-performance V8 to produce even more power and higher revs. The 5.0-liter V8 in the Lexus IS F made its mark. Now it’s the RC F’s turn.

Taking the sound and feel of instantaneous torque of the LFA V10 engine as inspiration, the engineers essentially kept the cylinder block and replaced most other parts. Thanks mostly to all-new cylinder heads, higher compression and lighter internal parts, horsepower has soared by 51 hp to 467 hp, and the engine can now rev to 7,100 rpm vs. 6,800 rpm in the IS F. The compression ratio has been raised to 12.3:1 (from 11.8:1), boosting torque across the entire engine speed range. Improved engine and transmission cooling systems handle track-day driving.

Here’s where Lexus got creative. Uniquely for a Lexus performance engine, the new 2UR-GSE V8 runs on the Atkinson cycle when operating at cruising speeds, to help enhance fuel economy. It’s a trick picked up from the brand’s hybrids. In the Atkinson cycle, the inlet valves are held open longer than normal to allow a reverse flow of intake air into the intake manifold, thereby decreasing pumping loss and increasing thermal efficiency.

Lexus redesigned the VVT-iE (Variable Valve Timing-intelligent Electric motor) technology to extend the range of inlet camshaft timing adjustment for the Atkinson cycle. The instant more power is called for, the engine switches to the Otto cycle.

Special features of the RC F engine include titanium valves, forged connecting rods, an optimized exhaust layout to more effectively harness exhaust pulses and an air-cooled oil cooler for optimum durability.

New or redesigned parts include:

• Cylinder heads and cam covers
• Crankshaft: crank pin diameter, connecting rod big-end bearing size and crank counter-weight size are all reduced, to reduce reciprocating weight
• Crank main bearings and caps
• High-strength forged connecting rods
• Pistons and piston rings
• Titanium inlet and exhaust valves
• Intake manifold and throttle body
• Redesigned Variable Valve Timing-intelligent Electric motor (VVT-iE)
• Revised Lexus D-4S dual injection system
• Four-into-one exhaust headers and heat insulators
• Oil pan and baffle plate
• Alternator clutch system
• Engine and transmission oil coolers
• Spark plugs

Digging Into the Metal

• The new cylinder heads improve the 2UR-GSE engine’s breathing with improved porting and a high-flow/high tumble ratio. In addition, intake surge-tank capacity has been optimized, as have the intake manifold runner length and diameter.
• The new oil pan baffle shape reduces agitation and hence friction, while new air-to-oil coolers for the engine oil and transmission fluid increase track suitability.
• The Lexus D-4S dual-injection system has been redesigned, with higher injection pressure of 2,611 psi and improved fuel atomization.
• The throttle diameter was increased by 10 percent, from 3 to 3.3 inches (84 mm).
• A new intake camshaft profile increases valve lift and suits the Atkinson cycle, while improvements to the electronic VVT-iE system have expanded its range of operation for increased fuel economy and performance.
• New four-into-two exhaust headers help reduce interference and hence further improve engine breathing. The larger-diameter exhaust system is designed to reduce backpressure and sound amazing, especially under acceleration. At the same time, the main muffler keeps things from getting too rowdy at lower speeds.
• As a final touch, the new 2UR-GSE engine has a one-way clutch on the alternator pulley.