Shelby GT500 Tune
Tuning the 2007+ shelby mustang
Ford sends the new Mustang out with a conservative tune
One of our customers purchased a new Shelby and we had the opportunity to start flogging and seeing what the new Mustang was capable of at the rear wheels, both totally stock and with tuning at this first dyno session.
Unfortunately the weather was rather warm here in Michigan (mid August) during the tuning of the new Shelby, about 88 degrees in the shop where the dyno sits. We didn’t give it a cheater type extensive cool down, and no icing. All the runs where made with about 15-20 minutes in between the pulls.
We made two base pulls with the car totally stock with the exception of a 20” wheels and a very large 315/35/20 in the rear. The first pull was a disappointingly low 382 RWHP and then after a 15 minute cool down, the next totally stock pull jumped right up to 407 RWHP and 425 ft lbs at peak TQ. This is all it would show totally stock. I’ve heard of some making as much as 420+ RWHP but this is all we could get. I attribute some of the low base RWHP to the fact that it has a heavier and larger 20” wheel and tire combo and poor air quality.
When I got my hands on the Shelby tuning software a few weeks ago as the Shelby’s started to surface at the showrooms, I noticed at a quick glance that judging from the looks of the fuel and above all the spark tables, that Ford SVT may have seriously de- tuned this car from the factory. Without seeing one yet, I had guessed that I could probably find somewhere in the neighborhood of 25-40 RWHP from just tuning alone. After tuning many other 32V type mod motors I’ve become familiar with what these motors like for both fuel and spark for both great power and above all, reliability.
All it took was some additional spark and leaning out the A/F just a little, and we managed to find what we think is a very safe 475 RWHP and 450 RWTQ tune with no other changes. As I predicted from originally just looking at the tune and then applying some of the changes I felt would work, It looks as if Ford left somewhere in the neighborhood of about 85 to 90 HP untapped (at the flywheel) from just tuning alone! From previous experience we believe that the tune we’ve developed for the new Shelby is safe and will not detonate with 93 octane fuel.
As the comparison dyno graph shows, we picked up 68 RWHP, and 35 ft. lbs of TQ at peak and extended the rpm range as well. This tuning has made a very noticeable difference from off idle right to 6500 rpms when driving and experiencing the car in the real world.
I feel that the new Shelby with the stock blower and a pulley change and some exhaust is on its way to well over 525 RWHP. I also feel that the gear of choice because of its weight and taller tires then pre ’05 Mustangs will be either 3.73’s or 4.10’s.
Alternative Auto now offers the Shelby 93 octane tune on an Xcal-4 for $400.00. (Pricing subject to change.)
Our tune for the 07 Shelby does address many other areas as well as A/F and spark.
Throttle response is greatly improved, Cooling fan is turned on earlier, idle is slightly higher and many other tuning improvements are made like rev limiters and speed limiters etc. Call the shop for more details.