2005 Mustang GT Performance Tune
Delivers a Proven 20 RWHP Gain
Using the latest software from SCT and their new Xcalibrator hand held flasher weve developed a new performance tune for the 2005 Mustang with the new 3-valve 4.6L and 5-Speed manual transmission that unlocks performance and throttle response.

Our new tune has corrected the number one complaint with the new ‘05 Mustang - "laggy" throttle response from the fly-by-wire throttle control. The new 3-valve mustangs no longer have a throttle cable going directly from the gas pedal to the throttle body. They now have a ?throttle-by-wire? system to open the throttle based on your input at the traditional gas pedal. Ford’s new throttle-by-wire on the Mustangs has a few intentional shortcomings. It is intentionally programmed stock to NOT snap the blade open as quick or at the same rate the driver moves the pedal. Additionally the stock program begins to shut the throttle blade as you approach the stock rev limiter, this ?eases? the engine into the rev limiter as opposed to ?slamming? into it. This causes an awkward, incorrect power-shift, negatively affecting the ability to drive the car aggressively to achieve maximum acceleration and ET by power shifting.
Our test car started out with 87 octane in the tank as recommended by Ford to use in the manual. The base line pulls from the car averaged 265 RWHP and 276 ft lbs of Torque. After switching to 93 octane and a few other tweaks in the computer and removing the latest in emissions devices that is in the intake track of all the new Mustangs, we found 20 more RWHP.
The new Mustang has a device in the intake track thats what we call a Pre-Catalytic Converter. This device catches vapors that are emitted from the engine after its been running and is then shut off. Just after a hot engine has been turned off they can emit unburned fuel from the intake track. This device absorbs those vapors and stores them until the engine is started again, then letts the stored vapors get sucked back into the engine to be burned off. Removing this alone was worth about 4-5 RWHP!
We also found the new Mustangs Air/Fuel ratio to be very rich at Wide-Open-Throttle (WOT) after the engine got above 4500 RPMs. We observed an 11.8:1 factory ratio with our very accurate Non-tail-pipe style O2 sensor. We adjusted it to keep the A/F ratio at WOT at a more optimal setting of 13:1.
After switching to 93 octane premium fuel we got more aggressive with the timing while on the dyno. This improved low and mid range power with some gains in the high revs also.

The new 3-valve Mustangs also have computer-controlled cam timing. By modifying this we found some additional high rpm power and extended the power and torque curve as well.
By removing the Pre-Cat, switching to premium fuel, and implementing a well-thought-out computer tune/flash we gained 20 RWHP and substantially better throttle response. The new flash can be felt immediately, even under light to moderate throttle conditions.
This is an excellent initial performance tune for anyone looking for noticeable gains.
In the future we will be testing long tube headers and other exhaust components on the 05 GTs and many other performance bolt-ons as they become available.
We will be developing a performance flash/tune for V-6 very soon.
Xcalibrator Flash Tuner
The Xcalibrator Flash Tuner will reprogram your Ford ECM with the custom performance tune that we load onto it. Before installing the new tune it will download and save your factory calibrations so that the vehicle can easily be returned to stock.
- Can hold up to 3 Custom Calibrations
- Retains Factory Calibration for easy restoration back to the stock calibration
- Easy installation. No tools necessary
- Easy to use push button & LED interface
- Quickly Flashes PCM via OBD-II diagnostic port
2005 Mustang Alternative Auto Performance Tune and SCT Xcalibrator2 $399
Please call the shop for more info and ordering. 586.463.0010.
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