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2010 Ford Mustang Shelby GT500 Zex High Output Nitrous System InstallationNitrous Oxide Takes A '10 Shelby GT500's Power And Torque To The Next Plateau From the October, 2010 issue of 5.0 Mustang & Super Fords By KJ Jones Photography by KJ Jones
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Thanks to Tom Thompson of... Thanks to Tom Thompson of AMP Performance and Bernie Longjohn at Speedworld Dragstrip in Wittman, Arizona, we were able to immediately go from the dyno to the quarter-mile to see how Aaron Aldridge's '10 Shelby GT500 responds to a good shot of nitrous. While the Mustang hobby has many, many facets, there are two sides that enthusiasts seem to be drawn to more than any of the others. The "show" side of our deal places emphasis on appearance. 'Stang owners hell-bent on having the baddest-looking Ponies on the planet. They often go to great lengths making the latest cosmetic changes-hot paint colors, trick graphics, slammed suspensions, and ultra-blingin' wheels. The other major component of hard-core 'Stangbangin', of course, is putting more go in the '86-'11 EFI cars that so many of us own and dig. As far as your power-mad, 5.0 Mustang & Super Fords tech editor is concerned, the more steam a 'Stang makes, the better! As many of you are well aware, Shelby GT500s arrived on the Mustang scene in 2007 with a huge horsepower advantage over their S197 brethren. That advantage was no accident, either. The steam came courtesy of an Eaton-supercharged, 5.4-liter engine that set 500 horses off and running. Yes, Shelbys arrived and quickly became the answer to power-mad Mustang enthusiasts' prayers. True to our passion for making 'Stangs better, we didn't waste any time trying to find ways to improve GT500 performance. A big Superman fan, the engine... A big Superman fan, the engine compartment in Aaron's GT500 is accessorized with body-color-matching (Grabber Blue) battery, radiator, and master-cylinder covers, and a fusebox lid that has received custom airbrush treatments by Mo Madrid of Bad Boy Designs in Peoria, Arizona. Prior to our nitrous experiment, the stock-blown 5.4 put down 518 hp at the feet, thanks to an AMP 2.7-inch blower pulley, Bassani after-cat exhaust, and Diablosport tuning. In our research, we found that basic bolt-on parts such as blower pulleys, cold-air-induction, exhaust pieces, and PCM calibrations easily carried GT500 rear-wheel horsepower past the 500 mark (using premium pump fuel), which certainly is impressive, considering the relatively low cost of parts and labor to get it done. Taking power to the next level requires making a move to harder-core replacements such as the larger superchargers or turbos. While we've gone through all of 'em and have seen first-hand that the blowers and turbos all are serious players in the big-steam arena. We also know that making a move to one of the next-level power adders carries a pretty stout price tag. So, with that in mind, we decided to investigate the effect that good-old nitrous oxide has on a GT500. In our opinion, "juice" is the original late-model-Mustang power adder, and without question, it's the least-expensive choice of the trio we refer to as "The Big Three." The Zex High Output Nitrous... The Zex High Output Nitrous System for '05-present Mustang GTs (PN 82242; $639.99) comes with everything shown. A mechanically capable enthusiast can easily install it in a driveway or garage. Note the small, square box among the components. This is the unit's electronic TPS switch, which activates the system at WOT. While the solenoids and jets are the braun in this setup, the ETPS definitely is the "brain" of the entire operation. The nitrous-plus-boost concept isn't new at all, and it's the type of upgrade that can be made with a good set of hand tools being the only requirement. Over the years we've seen how the gas can be used as an extra 'adder, and also for primary or secondary intercooling with blower and turbocharger systems (nitrous oxide also is used to quicken the spool speed of race turbos). Since we know how wild nitrous makes factory-blown, DOHC 4.6 engines in street-driven '03-'04 Cobras, we're confident adding spray to the Terminator's big brother will reap similar good results. Our mission with this exercise is to find out how good, by installing a Zex High Output Nitrous System (PN 82242; $639.99) on Aaron Aldridge's fresh '10 Shelby GT500. We selected the Zex unit for its simplicity and 100-250hp adjustability. That puts its range on par with the aforementioned boost upgrades that do wonders on stock and modified engines in '07-'10 Shelbys. For the sake of time and efficiency,... For the sake of time and efficiency, AMP's lead technician, Chris Ciolek (left) and Jesse Allen teamed on the installation and had our test Shelby ready for dyno testing in a few hours' time. As you'll see in the accompanying photos, the bolt-on and dyno tasks were put in the more-than-capable hands of Chris Ciolek and Jesse Allen of AMP Performance in Phoenix, Arizona. As an added performance treat, our friends in the desert also arranged for us to shoot juice at the GT500, in quarter-mile blasts at Speedworld drag strip, in nearby Wittman.  We decided to place the Zex...  We decided to place the Zex nozzle directly in the middle of "the curve" in the cast-aluminum intake elbow. Nozzle position technically can be anywhere along the intake-air channel (6-18 inches from the throttle body is optimal), and, of course, must be directed toward the throttle body.  Nozzle installation requires...  Nozzle installation requires drilling an 11/32-inch hole and tapping it with an 1/8-inch NPT thread. Care should be taken during this task, to ensure the proper-sized opening is bored in the elbow and the nozzle fits snugly inside.  After securing the intake...  After securing the intake elbow, Chris replaces the throttle body and factory air-intake system, and installs a fuel-rail adapter that will feed gas to the fuel solenoid. Looking back, it probably would have been cool to expand on this overall effort by replacing those pieces with parts like Ford Racing Performance Parts 63.5mm Cobra Jet throttle body (PN M-9926-CJ; $649.95), VMP Tuning's high-flow inlet elbow (PN ELBOW; $299.99) and JLT's carbon-fiber Shelby GT500 intake tube (PN CFBCAI-GT500-10; $199.00), but we wanted to conduct our test on an "as-is" subject.  When the valves on all six...  When the valves on all six mother tanks are open, the nitrous-filling station at AMP throws down serious pressure (900 psi). Chris uses the full blast to verify that our Zex nitrous solenoid is leak free.  Zex supplies all of the AN...  Zex supplies all of the AN -4, nitrous and fuel hoses for the installation, as well as the appropriate fittings.  Mounting the nitrous-bottle...  Mounting the nitrous-bottle brackets normally requires drilling holes in the trunk and passing bolts through them to secure the brackets to the trunk's floor. Chris makes this process easier by positioning the bolts, then welding receiver nuts to the floor. We made drag-strip passes... We made drag-strip passes with Aaron's GT500 in its full street trim, and quickly learned that the factory Goodyear radials are no match whatsoever for massive torque his 'Stang puts down at the rear tires now.
A shout-out of props definitely goes out to Tom Thompson, owner of AMP Performance, for arranging a private test session at Speedworld Dragstrip in Wittman, Arizona, for our nitrous-sprayed Shelby GT500 and several of AMP's customers. Knowing that it would be futile to attempt using the 150-horsepower shot with stock radial tires, Chris reinstalled the 100-horse pills and attempted to achieve a "best pass" without making any suspension, weight, or other changes to the Mustang. As you probably imagine, managing 600 horsepower and almost 700 lb-ft of rear-wheel torque on stock rubber is quite a challenge. But Chris did a masterful, consistent job of launching smoothly and staying ahead of the point where the rear tires broke loose. A copy of the Shelby's best e.t. and mph on nitrous is included. Aaron plans to invest in a pair of sticky drag radials, and make a few suspension changes soon. Those upgrades, coupled with Zex's High Output Nitrous System definitely will make for some quick trips down the strip! On The Dyno
Our dyno testing for this project consisted of baseline runs, and then blasting Aaron Aldridge's '10 Shelby GT500 on the rollers of AMP's Dynojet after the Zex High Output Nitrous System was installed. Starting with jetting for 100 hp (52 nitrous/30 fuel) and with timing retarded 4 degrees, we were rewarded right away with a gain of a solid 100 ponies at the feet, and an immediate and huge torque increase, which is absolutely insane when you consider the 100 shot doesn't require any custom tuning beyond the timing change, and tests were done using 91-octane pump gas. With the Shelby being so comfortable with the first-level setting, we attempted to step things up by swapping in a 64 (nitrous) pill and 35 jet for fuel, which creates a 150-horse injection. (Zex calls for a 36 jet, but we somehow misplaced ours and so pulled the smaller pill from a cache of miscellaneous nitrous hardware.) The shocked look on Aaron... The shocked look on Aaron Aldridge's face says it all: "Is that right?!" Yes, Aaron, it most-definitely is! We started with the simple dose of nitrous (100hp jetting/91-octane fuel) and instantly brought the 2010 GT500 within the same power range as Shelbys that have been upgraded with bigger blowers. Pay close attention to the dyno data. The spray really put torque over the top on Aaron's 'Stang. While we're sure both horsepower and torque again will increase considerably with a 150 shot, our big gain came on the torque side only. "Using that 35 instead of a 36 for fuel may have something to do with the lack of horsepower increase, but I also think that timing can remain at 4 degrees retarded with the 150 shot," says Chris. "Zex's recommended timing changes are understandably on the conservative side. I retarded timing 6 degrees for the bigger hit, but I think it would've showed more power if the adjustment had not been made. Air/fuel is plenty safe with this system's 150-horse setting, so I know there's a lot more power that can be made with this Shelby using the nitrous system's bigger shots, with higher-octane fuel and more timing."
| Baseline | ZEX 100 |
| RPM | HP | TQ | A/F | HP | TQ | A/F |
| 2,500 | 220.94 | 464.16 | 12.52 | 318.31 | 668.71 | 13.59 |
| 3,000 | 277.99 | 486.68 | 11.50 | 375.03 | 656.56 | 11.68 |
| 3,500 | 333.38 | 500.27 | 11.71 | 431.04 | 646.82 | 11.36 |
| 4,000 | 384.82 | 505.28 | 11.70 | 489.20 | 642.33 | 11.35 |
| 4,500 | 428.04 | 499.58 | 11.43 | 537.09 | 626.85 | 11.42 |
| 5,000 | 464.24 | 487.65 | 11.18 | 575.70 | 604.73 | 11.82 |
| 5,500 | 503.69 | 480.99 | 12.07 | 607.29 | 579.92 | 12.02 |
| 6,000 | 512.92 | 448.99 | 12.73 | 617.56 | 540.58 | 12.77 |
| ZEX 150 | Difference |
| RPM | HP | TQ | A/F | HP | TQ | A/F |
| 2,500 | 314.30 | 660.28 | 15.79 | 93.36 | 196.12 | 3.27 |
| 3,000 | 411.82 | 720.98 | 11.02 | 133.83 | 234.30 | -0.48 |
| 3,500 | 440.91 | 661.63 | 10.77 | 107.53 | 161.36 | -0.94 |
| 4,000 | 504.72 | 662.70 | 11.13 | 119.90 | 157.42 | -0.57 |
| 4,500 | 551.54 | 643.73 | 10.48 | 123.50 | 144.15 | -0.95 |
| 5,000 | 585.22 | 614.73 | 11.04 | 120.98 | 127.08 | -0.14 |
| 5,500 | 609.20 | 581.74 | 11.19 | 105.51 | 100.75 | -0.88 |
| 6,000 | 613.94 | 537.41 | 11.96 | 101.02 | 88.42 | -0.77 |
 Rich Shelly loads the Zex...  Rich Shelly loads the Zex 10-pound Blackout nitrous bottle. A digital scale is used to measure the bottle's weight, which should equal about 24 pounds when a tank is completely full.  Did you know nitrous oxide...  Did you know nitrous oxide boils/becomes liquid (at -129 degrees Fahrenheit) as soon as it is injected. Nitrous actually reduces intake-air temperature, which increases the air's density. Since cooler, denser air has more oxygen atoms per cubic foot, an engine's ability to burn more fuel becomes much greater, and thus promotes the increased horsepower that nitrous oxide is known for.  There's 18-feet of nitrous...  There's 18-feet of nitrous delivery hose in the High Output Nitrous System. While Zex suggests running the line outside the 'Stang (below the body), Jesse routes hose from the trunk through the interior, and then out to the engine compartment through an OEM hole in the firewall.  With mounting nitrous and...  With mounting nitrous and fuel solenoids in a Shelby GT500's engine bay being uncharted territory (until now), a little brainstorming and basic engineering was required for making it happen. Chris developed a really simple, solenoid-mounting bracket out of a small strip of flat metal, and then attached the assembly with one of the fuel-rail fasteners to the passenger side, and close to the firewall. The position is perfect for synching both the fuel-supply, and the nitrous-supply lines with each solenoid.  Wiring the system is one of...  Wiring the system is one of the more time-consuming tasks in the installation, especially when you're trying to maintain a neat, factory-like appearance under the hood. Chris routes the nitrous, fuel, and Electronic Throttle Activation solenoids' 12-volt source (taken from the fusebox) through a 20-amp, mini-relay that is included with the system. A 30-amp mini-fuse also is tied into the electrical works, to protect the system in the event of a short.  Zex uses its Pro-Series nitrous...  Zex uses its Pro-Series nitrous (0.110-inch orifice) and fuel (0.156-inch orifice) solenoids with the High Output System. The adjustable system can be calibrated to make between 100 to 250 additional horsepower on '05-'09 Mustang GTs, and we'll determine how much with Shelbys once Aaron's GT500 is strapped down on the dyno.  Programming the ETAS is a...  Programming the ETAS is a two-person deal, especially when the solenoid is installed on the passenger's side of the Mustang. The procedure is a choreography of cycling the ignition, depressing a push-button, paying attention to red and green LED indicators and holding the pedal at WOT, which ultimately enables the switch to "learn" throttle position. It's important to note that a white, TPS resistor wire must be used to link factory TPS wiring to the ETAS. Installing this resistor wire wards off the potential of receiving intermittent Check Engine Lights that are common when an ETAS is used with drive-by-wire systems.  A micro-switch like this is...  A micro-switch like this is a tried-and-true option for activating nitrous at wide-open throttle. It can also be tied into the ETAS logic. Using this switch essentially creates a more-direct way of using the throttle pedal for turning nitrous on, and more importantly, off, in the event of a problem.  Nitrous and fuel jets, also...  Nitrous and fuel jets, also known as "pills," are the final pieces in our Shelby GT500 nitrous experiment. Zex provides a map that details the correct jetting pairs, fuel-pressure requirement and details on timing retard, for each level (100 to 250 hp).  Jesse cracks the bottle open...  Jesse cracks the bottle open and it's time to make some steam on the dyno!
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