KJ Jones Senior Technical Editor
October 6, 2010
Photos By: KJ Jones

On The Dyno

BaselineGearsExhaust7,000 RpmTune

CAI7,000 RPMTuneTune 2HeadersGears vs. Headers

A gear swap was our first upgrade. Automatic-equipped '11 GTs receive a freeway-friendly 3.15 rear end gearset at the factory, which does absolutely nothing for the quick acceleration most enthusiasts want from their rev-happy, street-prowling 5.0 'Stangs. Making a change to 4.10s is recommended, but keep in mind that the lower gear ratio does lower rear-wheel horsepower. We saw a 20-horse drop, which comes in addition to the 20-fewer ponies that the automatic trans brings.

After-cat exhausts typically are among the first bolt-on upgrades that are added to late-model Mustangs of any heritage. Magnaflow has jumped to the front of the pack for Coyote-powered '11 'Stangs, and we didn't waste any time installing its new 3-inch setup on Evo's Grabber Pony. Dyno testing was performed in three modes (6,500-rpm limit, 7,000-rpm limit, and 7,000-rpm limit with a custom tune), with only slight gains showing after rev limits were increased to the new 5.0's maximum and Jon massaging the processor. From a sound perspective, the free-flow design of the kit's Competition mufflers gives the Coyote a nice growl at idle, and a deep, deep bark when the hammer drops to wide open.

Cold-air induction systems top the list of easy first mods for EFI 'Stangs. Thinking back to how well they worked on pushrod 5.0 engines, we approached our exclusive opportunity to try C&L Performance's brand-new CAI with confidence that we would see significant increases in power and torque (over the previous mods). Again, our dyno procedure included tests with the PCM calibration returned to factory stock and a 6,500-rpm rev cap, then increasing the rev limit to 7,000 rpm, creating a custom tune with the no-tune reducer sleeve still installed (Tune), and then removing the tube altogether and dialing-in a final calibration (Tune 2). Jon's custom tune (basically a fuel increase to compensate for a lean air/fuel ratio with the reducer sleeve removed) brought on the normal gains we've seen with such systems, and really ramped our excitement about making big steam when the long-tube headers were installed.

In our opinion, long-tube headers have always been a necessary evil for late-model Mustangs. The bigger, smoother-routed tubes are necessary because as a system, they allow exhaust to exit an engine more efficiently. This helps bring up rear-wheel-torque levels. With almost all of the bolt-on products we're testing being "firsts" for '11 'Stangs (with the exception of the gears), we closed out the project with American Racing Headers' 1 7/8-inch long-tubes. Installing long-tube pipes is the heavy-lifting portion of this exercise, but the result definitely is well worth the work. With tuning (richening fuel), which is mandatory with this upgrade because of huge scavenging effect of the headers, Evo's Grabber '11 put nearly 375 ponies down at the feet, which we consider to be remarkable all-motor horsepower when you consider the fact that approximately 20 horses were gone at the outset of our experiment (due to the automatic trans and 4.10 gears).