5.0 Mustang & Super FordsHow To Engine
SSI Intake Manifold Dyno Test - Entry-Level Air Entries
We Take The New Bbk Intake Out To Meet Some Old Friends
No one around the shop could remember the last time we ran our 302 dyno mule, but it must have been five years ago. Fitted with a fresh set of AFR cylinder heads, the little beast started right up and made power immediately, so some things must come naturally.
When BBK introduced its SSI manifold for 5.0 engines, the company was sure to point out that the part was aimed at the basic bolt-on Mustang. An important distinction, as the 5.0 market has become so well addressed there is seemingly a part for every stage of development, and this certainly includes intake manifolds. BBK didn't want people confusing the SSI as some sort of racing intake, a well-founded concern given the SSI's tall height and unusual twin-plenum design.
Furthermore, after introducing the SSI, we began receiving a number of inquiries concerning 5.0 intakes-making it clear to us there is a whole new generation of 5.0 enthusiasts who weren't playing (at least not with real cars) when the mainstays of the 5.0 intake market were tested the first time around.
Our response was predictable-head to the dyno and demonstrate how the new and old intakes work. Because our intent was to work with the most popular intakes-the ones that get bolted to legions of daily driver 5.0 Mustangs-we gathered the venerable GT-40 tubular intake from Ford Racing Performance Parts, the Edelbrock Performer, the Trick Flow Street, and the new boy on the block, the BBK Single Stage Intake. All are aimed at stock-displacement 302 short-blocks running either stock or street-friendly replacement cylinder heads, stock or small replacement camshafts, and a general need to retain low- to midrange torque for daily-driver friendliness.
Of these intakes, the GT-40 is something of a standout. For starters, it was designed by Ford to work on what could be called the "GT-40 engine" sold in the '93-'95 Mustang Cobra and also offered by Ford Motorsport SVO, now known as Ford Racing, as an aftermarket piece. The GT-40 is easily the oldest intake in this test, having been designed by Ford's regular production engineers well in advance of 1989, when it was scheduled to appear on a 25th anniversary Mustang that was shelved before hitting the market. Old or not, the GT-40 has a reputation for not giving up torque while building good top-end power. So, it's a good yardstick-even if we did also toss a stock intake into the mix as an obvious comparison.
Age is also a factor with the Edelbrock Performer. This is the regular Performer, not the slightly sportier Performer RPM. It was Edelbrock's first Ford EFI intake, and about five years younger than the GT-40 when comparing when the two intakes were designed (but not necessarily introduced for sale). It was remarkable upon its debut for a notably tall lower casting, with tall, sweeping runners.
Aside from the brand-new BBK, the Trick Flow Street intake is the newest of the bunch. It uses the now distinctive, triangular-shaped plenum. More than a pretty casting, the big plenum has supposedly given the Trick Flow a top-end power edge over the earlier intakes.
Because all these intakes are designed for simple bolt-on 5.0 engines, we used our stock-displacement 302 short-block from Ford Racing Performance Parts as the foundation for this test. We then dressed it to replicate a current, typical bolt-on 5.0 engine and to provide a reasonably active air pump to stress our intakes a little. We didn't want to overdo the hot rodding, however, as these intakes are not designed to make maximum power on big-inch, all-hanging-out engines. The previously mentioned manufacturers have other intakes for that job.
In real terms, this meant a set of box-stock AFR 165 cylinder heads, a Comp Cams 258 Extreme Energy hydraulic roller cam measuring 208/216 degrees of duration at 0.050-inch of valve lift, 0.533/0.544 valve lift with our 1.6 ratio rockers, and a 112 lobe separation angle. This cam is recommended from 1,300-5,300 rpm "for stock H.O. or with mild modifications," according to Comp. Not a bad choice, but in retrospect we might have stepped up to an Extreme Energy 266 with its 1,600-5,600 rpm recommendation, 214/224 degrees of duration at 0.050-inch valve lift, and 0.544/0.555 lift with 112 lobe separation. This would have stressed the intakes more at high rpm and been too much cam to represent a typical, dailydriver 5.0 Mustang.
Other hardware of note were full-length headers with short exhaust pipes and no mufflers, an electric water pump, and an Accufab 70mm throttle body. The exhaust is beyond bolt-on standards, but we didn't want a restrictive exhaust killing top-end power.
As usual, we tested at Westech. The big news there was FAST engine management. The sidebar has more on FAST, but we'll note here the speed-density engine-management system gave us total control over engine management, with superb repeatability. Previously, we tested with EEC IV, and it does have its own, unknown agenda on fuel and spark depending on flows, temperatures, and other unknowns. We've become fairly good at deciphering some of these seemingly random moves, but FAST made every test stable and repeatable.
So, how did the intakes run? As expected, the obviously under-matched stocker made snappy torque down low but choked big time at the top end. The Trick Flow Street was top-end happy, with the greatest torque loss way down low at cruising rpm, but with redeeming power right around the power peak of 5,400 rpm before nose-diving at 5,800 rpm. The Edelbrock did a good job of keeping low-end torque and making top-end power, but without besting any other manifold in the process. And the GT-40-well, old or not, it's really, really tough to beat the factory. It made stock torque at the bottom, hit with the best torque and power gain in the midrange, and ran out the back door with the best of them at the power peak.
As for the new BBK, it was a little confused in the lower rpm, sometimes keeping pace, other times dropping off through the midrange and then returning for a good power peak, just topping the peak-meister Trick Flow by 1 hp, 100-200 rpm higher in the process. What's interesting about the BBK SSI is the way it kept on making power on the overrun past the power peak. It's at least 10 hp better than anything at 5,900 rpm, for example. Our guess is, the single throttle body, twin-plenum layout, which requires the air to change direction 180 degrees in some spots, loses ground until its big plenum volume can start making a difference at rpm levels a bolt-on 5.0 just touches. It would be interesting to put a healthy 347 under this intake, which we just might do one of these days.
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Then there is cost. Let's not forget, the stock intake is free. Up to 3,600 rpm it leads the way, and that's where the vast amount of plain old driving around (read: "fuel economy") takes place. Of course, by 4,500 rpm it's 20 hp down, so you won't win any races with it. But if you have to save up your lunch money for one of these other intakes, the free stocker will get you around with little shame. If you could find an Extrude Honed intake at a swap meet, you'd do even better, but then you'd be spending money.
To compare typical street prices, Summit carries three of the intakes. Its in-house Trick Flow brand Street is a bargain at $395, and if you don't need large fuel rails for your application, it's a good buy. Summit offers the Edelbrock Performer for $495.95 and the involved-to-build GT-40 for $599.95. The GT-40 runs a little better than the Edelbrock but costs 100 clams more. Brothers Performance is the outlet for BBK goods, and the SSI is $569.99 from them. That seems much more of a bargain when you recall the SSI includes high-volume fuel rails. As elsewhere, fuel rails can fetch hundreds of dollars by themselves. If you need fuels rails, the BBK suddenly looks all high heels and fishnets to the checkbook.
Only you can decide which of these intakes best fits your engine-and-wallet combination. But it seems you can hardly go wrong in the process.
Fast At Last
After a decade of doing our best to run electronically fuel-injected Fords on the dyno, we've finally come across a piece of technology that gives us strong confidence in the results. That technology is FAST-Fuel Air Spark Technology-an aftermarket speed-density engine-management system marketed under the FAST brand, which is part of Competition Cams. Its main attraction to us while testing is total control of spark and timing, without the seemingly random and uncommanded changes endemic to EEC IV and V, and the '05 Mustang's Spanish Oak processing.
Like many successful devices, FAST isn't a revolutionary breakthrough but rather an intelligent refinement of existing technologies. We like that it comes from an established industry leader; one can make an investment in it with the reasonable expectation that tech support, parts, and developments will be there tomorrow. We also appreciate that FAST doesn't try to do everything from opening the garage door to datalogging the temperature-rise time of the trunk-lamp bulb filament. It's designed for real people working with real engines, with simple pull-down menus and intuitive, easily read tables. The tuner can adjust the full suite of tuning parameters using click-and-highlight targeting, or overwrite absolute values, if desired.
FAST tuning is based around a Volumetric Efficiency table with percentages in rpm versus VE. It takes a minute to get comfortable with the VE units, but once you do, it is easy to compare the software percentage to the torque curve plotted by a dyno run. A few keystrokes to bump the VE table up or down wherever the torque curve dips, along with a few trial and error dyno pulls, quickly deliver the fuel and spark the engine wants. From there, the powerful closed-loop operation optimizes power automatically. It's fast and easy tuning-and it doesn't change unless you tell it to.
Users at Westech say FAST is user-friendly and offers a usually wide range of closed-loop compensation. The early FAST system on hand at Westech's dyno does not have a built-in datalogger (an auxiliary device from FAST is available for logging with the early FAST boxes), but a soon-to-be released upgraded FAST will incorporate datalogging. There is no knock sensor, but a GM sensor and sensor module can be wired in. Idle air is also GM based-a Ford would need to add a GM IAC motor, which FAST sells. An advantage of the GM IAC is it can be remotely mounted, unlike the Ford unit.
FAST uses a few GM sensors, such as the MAP sensor, and is fully supported with its own line of fuel injectors, wiring harnesses, and so on. Still, you don't have to run FAST injectors-it works with nearly any high- or low-impedance injector out there, including the 150-lb/hr lawn sprinklers. Likewise, you have a choice of a universal wiring harness or one of FAST's vehicle-specific harnesses (Mustangs are fully supported). Various forms of batch fire are typically used, although a more complex sequential-fire strategy is provided as well. In short, FAST seems to have everything a tuner needs, yet it is simple enough to use without six years of ITT Tech. Expect to see more of it in future 5.0&SF dyno tests.