Handsome as the polished Kenne Bell blowers are, the standard, less-expensive black finish
The mass-market Coyote, however, has a stock redline of 7,000 rpm. This is something the Coyote engineers worked some to get, not only with the shorter stroke, but also with a lighter valvetrain. When used as surrogate parts during Coyote development, the GT500 valve-train wasn’t able to make it to 7,000 rpm, so there’s one big advantage to the Coyote. It simply runs faster, and since horsepower is torque times rpm divided by 5,252, more rpm is a direct path to more horsepower.
Indeed, when looking at the horsepower and torque graphs, the 5.0 and 5.4 typically run near each other until 6,000 rpm, and then the 5.0 keeps on climbing another 1,000 rpm or more. Right there that will put the Coyote well ahead of the 5.4 Shelby.
Another Coyote advantage is compression ratio. The GT500 puffs up 8.4:1 compression, while the Coyote puts the squeeze on things with 11.0:1 compression. This is significant because compression is a fundamental aspect of power production. The whole idea in a piston engine is to build cylinder pressure, and higher compression puts more oomph into the power stroke.
Kenne Bell is known for extensive dyno testing, but it does go to the track, too. Here the
The rule of thumb is four percent more power per point of compression, and the Coyote has 2.6 more points of compression than the 5.4. Multiply 2.6 by 4 percent and the Coyote should make 10.4 percent more power than a 5.4, or so it says here in the brochure. Looking at our data, at 15 pounds of boost the 5.4 makes 654 rwhp, so 654 hp times 10.4 percent gives us 722 hp, and we see the 5.0 Coyote put up 720 hp at that boost. Of course, the Shelby used a manual transmission and the 5.0 was an automatic, which is worth 20 rwhp on Kenne Bell’s dyno, so the power differential is even greater than the raw dyno data indicates. But we can safely say the compression accounts for a measureable portion of the 5.0’s power gain.
Another Coyote advantage is breathing. We don’t have hard data comparing GT500 and Coyote heads, but the Coyote engineers have assured us that the 5.0 heads are some of the best-flowing V-8 castings ever to roll off a Ford assembly line. Thus they are clearly ahead of the GT500 units. We do have data on camming, where the GT500 valves lift about 12 mm and the Coyote’s 13 mm, so there’s a breathing advantage in favor of the Coyote as well. We’re not sure how much it really matters at streetable or pump-gas power levels, but the Coyote sports more sophisticated exhaust manifolding than the GT500 as well.
There is one thing you might consider a 5.0 advantage that isn’t directly in play during these dyno tests. That’s the 5.0’s sophisticated Twin Independent Variable Cam Timing. It is not important here because at wide-open throttle, the cams are adjusted to their maximum power setting and don’t vary during the run. Therefore the 5.0 has no particular cam-timing advantage over the less adjustable 5.4 engine.
Just in case you are wondering what a KB Coyote blower looks like polished, here’s a peep.
Yet, there still could be a small, but measureable advantage to TiVCT. Because the cam timing is variable, that allows the engineers to build in a more radical cam lobe profile, which makes more power. The reason TiVCT allows a more radical cam is because the variable timing feature allows toning down the valve event timing at low rpm or part throttle for a smoother idle, lower emissions, more low-end torque, better mileage, and crisper throttle response during less than all-out driving. All that and you still get all the glory at full throttle and high rpm.
Inevitably the 5.4 in the GT500 will go away, as it has in every other Ford application. Luckily the 5.0 is more than a worthy replacement, even if it is almost half a liter smaller in displacement. It certainly makes the prospect of an Ecoboosted version quite titillating, but that will remain speculative for the moment. What we do know now, is that there might just be a replacement for displacement after all-technology.