V8 4.6L SOHC

What it is

The bore measures 90.2 mm, the stroke 90.0 mm, and the compression ratio is 9.4:1. Those figures, and the 4.601 litres they compute to, match the Ford Modular 4.6 with two-valve PI heads. Nothing else here was copied from one. Ford rated that engine at 260 hp at 5,250 rpm and 302 lb-ft at 4,000. The torque on the dyno comes out of a Wiebe heat release solved against crank-slider geometry, with the plenum, the runners and the collector filling and emptying around it.

Nine point four to one is a compression ratio built around regular fuel. The preset carries 92 octane, which is the RON reading of the 87 on an American pump. Knock never registers: the trace sits at 0.000 from 30 percent of the redline to the top. Raise compression to 13.5:1 and it peaks at 0.150. Drop the fuel to 80 octane instead and it peaks at 0.166, both worst around 4,200 rpm. The model finds knock when there is knock. This engine gives it nothing to find.

One camshaft over each bank, two valves per cylinder. Volumetric efficiency peaks at 0.97 and holds a floor of 0.84 down low, and that spread is what makes the pull flat. The firing order, 1-3-7-2-6-5-4-8, is quoted in Ford's own numbering, which runs 1 to 4 down one bank where most American V8s alternate across the vee. The preset carries that convention because it decides which cylinders share an exhaust pipe. Each bank gets its own here, and both pipes carry the 90-180-270-180 spacing you hear from a cross-plane V8.

Things to try

• Pull Redline down from 6,000 and the breathing peak comes with it. VE peak rpm is capped at 80 percent of the redline, and the 4,800 this engine ships with sits on that cap, so the whole curve slides left rather than ending sooner.
• Take Compression from 9.4:1 up toward 13.5. Nothing happens for a long way. By 13.5 the knock trace peaks at 0.150 around 4,200 rpm, which is where an engine built for regular fuel runs out of margin.
• Stretch Stroke past the 90 mm it ships with. Friction here is charged on mean piston speed rather than on rpm, so the added displacement hands part of itself back as rubbing, and the bill grows with revs.

Seen in

Ford Mustang GT (1999–2004)

Runs this engine

The 4.6 two-valve with PI heads in the trim it is rated in, 260 hp, and the car most people picture when they hear Modular V8.

Photo: Sachith Ravishka Kodikara · Pexels

Ford Crown Victoria Police Interceptor

Runs this engine

The same 4.6 two-valve in softer trim, and the car that carried this engine through two decades of American police fleets.

Photo: Marjorie Matias · Pexels