KJ Jones Senior Technical Editor
August 23, 2010
Photos By: KJ Jones

On The Dragstrip
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.)

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."

BaselineZEX 100

ZEX 150Difference

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