The new Mustang is a great blank canvas for building a modern-age hot rod. With an all-aluminum multi-valve engine and state-of-the-art engine management, there's lots of stuff to play with. But unlike yesteryear, today's factory muscle is already tuned to the max. Gone are the days when a twist of the old distributor and a few turns on the fuel pressure regulator could give your EFI car a 15 or 20hp bump.
It's a tough proposition to improve on Detroit iron using just basic bolt-ons, but the aftermarket is giving it the old college try anyway. We decided to try a few of them on our resident 2005 Mustang GT five-speed. We started with a baseline dyno test on our Dynojet chassis dyno, then proceeded to test a full complement of Red Line synthetic fluids (sold together as the PowerPack), an Airaid intake filter system, then finally a Diablosport Predator programmer. The entire ensemble cost $752 (using typical street pricing), took about two hours to complete (not including dyno testing), netted us 17 rear-wheel hp, and didn't degrade fuel economy by any measurable amount.
Make no mistake, this is a difference you can really feel in the seat of your pants. The change in the sound coming from the engine room is vastly improved too. Since our test, drivability remains as good or better than stock and we've had no problems with check engine lights. Overall, we'd give these mods a big thumbs up. On the down side, the power improvements we saw weren't entirely in line with the claims being made by similar, competing products from other companies, but at least our vendors were honest in not making any outrageous promises. For that, we give them kudos. Turn the page and check out the detail...
After the baseline test, our...
After the baseline test, our first step was a Red Line PowerPack, PN 90214 for manual-trans '05 Mustang GT (JEG's price, $107.99).
Our test car is a completely...
Our test car is a completely stock Mineral Gray 2005 Mustang GT with a five-speed manual trans.
We used all the fluids in...
We used all the fluids in the PowerPack except for the gear oil (the Mustang comes with a synthetic factory fill, and we didn't have a new rearend gasket handy).
The next item on the docket...
The next item on the docket was the Airaid filter system, PN 450-172, for '05-06 Mustang GTs ($295.50, street price).
The Airaid kit fit perfectly...
The Airaid kit fit perfectly and needed no additional modification or cajoling to make it work.
The Diablosport Predator costs...
The Diablosport Predator costs around $349 (typical street price) and takes just a few minutes to complete.
Our last piece to test was...
Our last piece to test was the Diablosport Predator. We had the choice of removing the Airaid and testing a Predator for a stock car, but instead we ordered one designed to work specifically with the Airaid filter system.
Chassis Dyno Test Data2005 Mustang Gt
5-SpeedBaseline Test
263.94 Hp @ 5,200 Rpm
284.91 Ft-Lbs @ 4,300 Rpm
Red Line Powerpack
263.12 Hp @ 5,200 Rpm
282.64 Ft-Lbs @ 4,300 Rpm
Airaid Filter System
276.16 Hp @ 5,300 Rpm
294.10 Ft-Lbs @ 4,300 Rpm
Diablosport Predator
(Airaid 91 Octane Tune)
280.96 Hp @ 6,100 Rpm
294.07 Ft-Lbs @ 4,500 Rpm
Total Gain:+17.0 Hp And +9.1 Ft-Lbs