5.0 Mustang & Super FordsHow To Engine
2011 Ford Mustang GT BBK Headers Install - Nature Hunt
BBK Seeks All-Natural Coyote Power With Its Tune-Free Bolt-Ons
Like you, we've been eagerly awaiting hot rod parts for the exciting new Coyote 5.0-liter V-8 in the '11 Mustang GT. Just about every speed-parts manufacturer we know is busting long hours over the fenders of a new GT, but one of the first to show us the results are the bolt-on specialists at BBK.
That was expected, as BBK carries a big torch for traditional bolt-'em-on-and-go bits. Electronic tinkering is all good fun, but mainly BBK supports those of us with real-world budgets and a hankering to turn a few wrenches on Saturday. That means BBK concentrates on the hardware and leaves the tuning to specialists, which in turn means the company gets its products to the market a little bit quicker.
For its first set of 5.0 Coyote bolt-ons, BBK has developed short- and long-tube headers, X-shape crossover pipes to match both headers, and a cold-air intake. There are more parts coming, especially a larger throttle body, but they're a little further down the development road, so we'll cover them later.
Frankly, we and BBK didn't expect huge increases from the short-tube headers because the Ford headers are so well designed and constructed, but the long-tubes-those had our horsepower appetites whetted. As for the cold-air kit, we thought there might be a bit there, but we were willing to let the dyno tell us how much.
BBK reports the development of its headers and X-pipes was straightforward. Fitment room in the new 5.0s is about the same or a little better than with the 4.6 and especially the 5.4 Mustangs. Installation follows typical modular practice. The cold-air intake is simple screwdriver (and Allen wrench) work; just remove the stock airbox, swap the mass air meter electronic module to the BBK inlet pipe, and install the BBK parts.
BBK planned for the Coyote headers and X-pipes to go on-sale at the beginning of October, with the cold-air intake following a month later. Pricing was not immediately available, but because construction of these parts follows conventional BBK practice, we expect they'll mimic other BBK header pricing.
The question comes down to which header-short- or long-tube-is the one to get. Obviously the short-tubes have the over-riding benefit of emissions legality. (BBK was working on a CARB Exemption Order at our deadline). Just as obviously the long tubes don't stand a chance of emission compliance because they move the catalytic converters, so they are an off-road part only. Either way, you'll gain power, and the cold-air inlet helps a little more. We'd throw in some custom electronic tuning to get the most from these hardware improvements.
On The Dyno
A ll of the BBK parts made more power, especially the long-tube headers, and as we all know, the stock 5.0 makes a ton of power with no mods whatsoever. To be more specific, the stone-stock 5.0 put out 362 rwhp. That's nominally 150 hp more than the Coyote's pushrod namesake, and more than 100 additional horsepower compared to the previous Three-Valve 4.6 engine.
But before we get any further into the hard numbers from the BBK test, let's recall that as with most chassis dyno testing where the engine management computer is still in complete control, important variables such as ignition timing are changing, mainly in response to rising engine temperatures. Thus, these are relatively casual dyno tests, so look for the general trends and try not to get hung up on a couple of horsepower here and there.
Furthermore, you must not compare our short-tube header figures directly to the long-tube results because the two were tested differently (see the sidebar Fourth vs. Fifth Gear). The short-tube results were taken from tests run in Fourth gear and thus are lower than the long-tube tests that were run in Fifth gear.
With that said, bolting on the BBK short-tubes showed they gave a substantial gain in torque below the torque peak, but at the midrange they lay down flat, before picking up 2 hp again around the horsepower peak. The dip is likely the engine management curtailing torque, but the short-tubes did worse than the long-tubes in the midrange, so there is something in the tube length as well.
A bigger, more established change came by adding BBK's X-shape crossover pipe to the end of the short-tube headers. This gave a gentle but definite lift up across the tach, but especially north of 3,500 rpm. The power peak reached 368 hp and 351 lb-ft of torque and in general the combination of short tubes, X-pipe seem to be worth 5 hp and 3 lb-ft over just the short-tubes in our test.
The final test in conjunction with the short-tube headers was BBK's prototype cold-air intake. This was definitely a happy rpm addition, building power starting at 3,500 rpm, but with authority from 5,000 rpm to the power peak, where it added a solid 7 hp to the party. And, as you'd expect, it gave a big throaty roar in the process.
All told, the combination of short-tube headers, catalytic X-shape crossover, and cold-air inlet was worth just shy of 12 hp and about 8 lb-ft of torque at the peak compared to the stock baseline. Remember, too, that this is measured with the transmission in Fourth gear; the same tests in Fifth gear would add a horsepower or two, and an easy 10 lb-ft of torque.
* These are dyno results from tests conducted on BBK's in-house Dynojet chassis dyno. All tests with short-tube headers were run in Fourth gear; those with long-tube headers were run in Fifth gear. Therefore, figures from the two test series should not be directly compared.
Fourth vs. Fifth Gear
There's a "gotcha" lurking in the new 5.0 Mustang's six-speed manual transmission. Unlike every previous manual, the new Ford gearbox uses a 1:1 ratio in Fifth gear, not the industry standard Fourth gear.
This is of no concern when driving, but it definitely skews chassis dynos, which assume a 1:1 transmission ratio. In other words, if you dyno a '11 Mustang in Fourth gear-all too easy for a dyno operator to do as he's always done it that way-and you'll get numbers lower than expected.
As you've already guessed, we fell into this trap during this article, and curious as to the effects, we baselined the car in both Fourth and Fifth gears. We found horsepower was little affected, but torque was noticeably off. In our case, peak horsepower was 1.58hp less in Fourth gear (absolutely within the margin of error on this car/dyno combination, so statistically insignificant), and 11.62 lb-ft of torque less in Fourth gear.
To save a whole day in the shop re-running tests, we've opted to present the short-tube header part of this test in Fourth gear and the long-tube header examination using Fifth. This means you can't accurately compare the short- and long-tubes directly, but the relative improvements are easy enough to spot.
In the future, we'll double-check that testing starts in the standard gear for '11 Mustangs-Fifth. In the meantime, it's something to keep in mind when considering '11 Mustang chassis dyno tests you conduct or read about.
Long On Power
After the short-tube testing, we stood down for a couple of days waiting for the first set of long-tube headers to emerge from BBK's prototype shop. But then the testing shifted into Fifth gear, with a new baseline set with the car returned to totally stock condition. This time the baseline figures came in almost square, the horsepower at 360 and the torque at 361 lb-ft.
Because the long-tube headers can't be run with the stock H-pipe, the long-tube test setup was simple-the long-tubes and their matching X-shape crossover pipe. So Mike Briggs, BBK's lead prototype tech and media liaison specialist got to pull the stock headers off for the umpteenth time and the long-tubes went on.
When the tires stopped singing on the rollers, the power had jumped 29 hp to 389 and the torque gained just a couple to reach 363 lb-ft, as shown in our charts. Actually, the absolute peaks-which naturally fell at rpm points not shown in our charts-were 391 hp and 367 lb-ft of torque. Anyway you look at it, the BBK long-tubes gained at least 25-almost 30-horsepower. That's a solid gain you can feel from behind the wheel.
Furthermore, the torque muscled up far more than the measly 2 lb-ft the peak would indicate. Looking at the full arc of the torque curve, it's clear the long-tubes add generous torque down low-about 34 extra lb-ft at 3,000 rpm-but then the torque curve plunges back to the baseline values from 4,100 to 5,500 rpm. At 5,500 rpm, the torque shoots right back to where it would have been had it not taken its midrange dip.
Two things are notable about this torque dip. First, its unfortunate, intentional-by-Ford placement falls right across the Coyote's torque plateau, robbing it of a higher peak value. Secondly, the midrange dip is likely a result of Ford's engine management software getting its tentacles around the ignition timing or electronic throttle in order to calm the party. One wonders what ecstasies await with electronic tuning.
Finally, because the prototype cold-air intake was busy posing as a pattern for its production tooling, we were unable to test it with the long-tube headers.
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* Baseline and long-tube tests were run in Fifth gear.