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Ford Mustang - Open-Pipe Test - The Livernois Crew
Is The '05's Factory Exhaust Restrictive? Livernois Motorsports Finds Out.
It's like going back to school all over again, but this time, the curriculum consists of learning how the clean-sheet '05 Mustang responds to aftermarket performance offerings. Over the coming months we'll be testing the new 'Stang's reaction to everything from the most basic of engine bolt-ons, to power adders, to suspension hardware, to who knows what. Funny, school was never this much fun the first time around.
This time, our travels take us to Dearborn Heights, Michigan, and the sprawling Livernois Motorsports shops, home of Dan Millen's all-conquering 10.5-inch Outlaw. We came to see how Darryl Bassani's '05 GT exhaust kit works (and sounds), and to see if Livernois' tuning guru, Greg Banish, had found any particular areas of the Mustang's factory calibration that needed immediate attention. Naturally, he did.
As an unexpected bonus, at the time of our late-December visit, the Livernois crew was in the process of prototyping its first nitrous installation on an '05. While we got there too late to follow along with a how-to, check out our sidebar for a look at some useful hardware for those of you with giggle gas on the shopping list.
OK, recess is over, it's time for some schoolin'
Exhausting The DynoSome explanation is necessary as you check out the accompanying dyno charts. Livernois' dyno-dude, Greg Banish, opted to run our tests without going into the calibration and locking torque converter operation on the car's 5R55S automatic transmission. In other words, he left lockup operation in pure stock form for all recorded runs, meaning the converter started locking up at wide-open throttle somewhere around 5,200 rpm. This causes a rather obvious spike in the power curves but also messes a bit with the dyno's rpm correlation above that point. As the converter locked, Greg could actually observe rpm on the factory tach dropping from 5,200 to about 5,000, in effect changing gear ratios in the software mind of the Dynojet because of how it calculates engine speed. So, while the power figures are still considered accurate on our charts, the corresponding engine speed reference points above the spike may be a couple hundred rpm optimistic. Note that once the converter locks, horsepower is higher (the efficiency of lockup), while torque is lower (no more torque multiplication from the converter).
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Observation number one: The Bassani exhaust made a surprising amount of power, and was notably louder than the factory plumbing. We're not sure whether the gains were more the result of the mufflers, or the new cats and X-pipe. From what we hear, the odds-makers would go with the cats. Had we had more time, it would have been interesting to run the car with the factory mufflers and Bassani cat X-pipe to see what kind of power/sound resulted from that combo. Maybe next time.
Observation number two: Air/fuel datalogged during the runs indicates that the factory calibration is cognizant of catalytic converter temperature at high rpm. If the processor senses that the cats are getting hot, extra fuel is added to cool them, and this sudden enrichment is immediately detrimental to power. Most of the great upper-rpm gains made by the recalibration were a result of Greg commanding a fixed wide-open throttle A/F ratio that eliminated this drop-off. Incidentally, Greg tunes using Superchips Custom Tuning software and Xcalibrator hardware.
Observation number three: Overall, the factory calibration seems extremely sensitive to temperature. Even though atmospheric conditions remained constant during the time span of our before-and-after testing, Greg was careful to perform our charted test runs at similar levels of engine temp. At one point, we tried two runs back to back, and saw power levels drop by 20-30 hp across the board. Understanding all the nuances of the new processor's calibration may take some time yet.
Giggle Gas GearA few work bays away from where we did our Bassani install, the Livernois electronics crew was in the midst of its first nitrous installation on an '05, based on a Nitrous Express Ford EFI kit. This gave us a chance to have a look at some of the ancillary hardware used to accomplish and enhance the project, starting with the progressive controller box visible just below the car's power distribution box shamelessly sporting the "Detroit Speedworks" decal