We’ve all known a Ford Bronco Raptor was coming, but nobody in the public Broncosphere has known for sure how Ford Performance planned to endow the Bronco with F-150 Raptor-worthy performance—would it do so using an EcoBoost V-6 (and if so, which one?) or a Coyote V-8? Well, now we know: The Ford Performance gang has worked its magic on the 3.0-liter EcoBoost twin-turbo V-6 from the Explorer ST, modifying it extensively to suit the Bronco Raptor’s mission, which is to “reward the revs.”
That means the engine should produce meaningful power all the way out to the far reaches of the tachometer while the standard 10-speed automatic transmission’s gearing ensures that power is easy to explore the top of the tach. Here’s what it took to turn a family SUV motor into a desert stormer for a hardcore 4×4, plus the modifications needed to get that power safely routed to the ground.
What’s Under the Bronco Raptor’s Hood?
You’ll recall that the 3.0-liter EcoBoost is basically a bored and stroked EcoBoost Nano family sibling of the compacted-graphite-iron-block 2.7-liter powering other Broncos, so it bolts in with relative ease. Relative to the Explorer application, this Bronco Raptor 3.0 features unique cylinder heads that eliminate the exhaust-gas recirculation and emphasize maximum air flow into and out of the engine.
A giant high-flow intake airbox and filter drop air straight down into the turbos on each side, helping to reduce the overall restriction on the low-pressure side by 50 percent. The turbos themselves are new for the Raptor, and the plumbing to, from, and through the intercooler is improved to lower restriction. The combustion chambers flow more air, then aft of the turbos there is a full true dual exhaust system with 2.7-inch pipes and a new-to-Bronco four-position active-valve (Quiet, Normal, Sport, and Baja) that reportedly helps deliver a total drop in backpressure of 20 percent.
The combined effect of all these mods is greater “boost durability,” which means the boost sustains to enhance high-end power and prevents that feeling of power falling off a cliff as you near the engine redline. The new Baja drive mode also activates an anti-lag turbo calibration that further maximizes performance during high-speed desert running. As of press time, the team is still six weeks or so from finalizing the engine’s state of tune and certifying it with the EPA, but we’re assured it will make north of 400 horsepower. Considering this engine makes 400 hp at 5,500 rpm and 415 lb-ft at 3,500 rpm in the Explorer ST, we’d expect a healthy increase in peak power, probably at a higher rpm, with peak torque rising less but remaining available over a wider plateau.
Driveline Mods
It takes a lot more torque to get a big 37-inch tire spinning than it does a 30-inch 255/70R16 or even a 35-inch 315/70R17 Sasquatch tire—especially if one tire ends up pulling the entire vehicle, due to locked axles and slippery conditions under the other three tires. Then there’s the driveline shock that comes when a big, spinning tire suddenly finds traction and stops or slows upon landing from, say, a jump. To cope with these magnified driveline forces, both front halfshafts and both ends of the stronger front drive shaft get beefy constant-velocity joints—no simple universal joints here. The outer hubs and bearings are also strengthened.
Following the torque aft, the rear drive shaft is also beefed up and it feeds a stronger new Dana 50 Heavy-Duty AdvanTEKrear axle (up from a Dana 44) made of thicker (9-mm) steel tubes capped at each end by a unique forging that helps widen the track. The differential is fitted with a bigger, stronger 235 ring gear (up from 220) and pinion, retaining the Sasquatch model’s 4.70:1 axle ratio. Ford Performance developed both these axles and fits them to the Bronco DR race truck. They increase the track width by 8.2 inches front, 6.7 inches rear, relative to the Sasquatch package.
Upstream of all this, the transfer case gets a stronger clutch for 4A automatic on-demand engagement, but it carries over the 3.06:1 low-range ratio and overall 67.8:1 crawl ratio. The standard 10-speed automatic is unchanged but for a revised torque converter and the addition of a second transmission oil cooler.
Fearless Bronco Raptor 0-60 Time Prediction
Ford doesn’t estimate acceleration times, but it says the base Bronco Raptor’s curb weight should come in just under 5,750 pounds. If we conservatively estimate engine output at 430 horsepower, that gives a weight-to-power ratio of 13.4 pounds/horsepower. That’s almost exactly what we measured on the last Ford F-150 Raptor 37 pickup we tested (13.3 lb/hp), and that full-size truck took 5.6 seconds to hit 60 mph on the same tires, with virtually the same transmission and a slightly taller axle ratio. So we’re guessing the smaller truck will improve on that just slightly and lay down a 5.5-second 0-60 time, shaving at least a second off the quickest Bronco time we’ve measured.
Keyword: How Ford Upgraded a Family SUV Engine for Bronco Raptor Duty