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!