Hey, guys. Justin with americanmuscle.com here with a stage three Power Pack Bolt-On Build-Up for all 2010 through 2012 Shelby GT500s. So, the stage three power pack focuses on taking our lightly modded Grabber Blue Shelby behind me to the next level, and even further. To do so, we're going to make sure the car is ready to move some serious air by eliminating bottlenecks both on the intake and the exhaust side of things. We're also going to add a few more pounds of boost to the car and see what kind of numbers are possible with that factory Eaton supercharger in place. Finally, we're going to take care of some preventative maintenance just to be on the safe side.
Now, before we get started, a friendly reminder to go ahead and click on the link below to subscribe to our YouTube channel, especially if you're a big fan of boost. Blower cars, turbo cars, we've built them all, and you can check those out by going through our YouTube channel. Since we already have a 2.6" pulley installed on the car now, our options for adding more boost with the factory Eaton blower still in place are pretty limited. In fact, the only way to really do so, besides going down to a 2.5" pulley, which we really didn't want to do, is to add a lower overdrive balancer.
So, we installed the Innovators West 10% Overdrive Balancer. This balancer along with a 2.6" pulley is actually a very popular combination with other GT500 owners out there for a couple of different reasons. For starters, Innovators West claims that their balancer actually weighs less than the factory balancer, so you're going to reduce some of that rotational mass, which is always a good thing.
In addition, by enlarging the diameter 10%, our car should now be seeing an additional three or so pounds of boost more, bringing our grand total up to around the 15 or so pound mark, which should be enough to peg that factory boost gauge. This is pretty much the tried and true safe limit of efficiency with a stock blower here, without porting it or adding additional forms of cooling like meth injection or running E85 fuel.
If you start spinning these M122 blowers up any faster, heat becomes a serious problem, and at that point, the efficiency goes down, and those power numbers really start to drop. Once you start getting around 550 wheel horsepower in these cars, that factory twin 60mm throttle body just becomes a huge restriction, so it had to go. In its place now, I installed the Ford Racing Twin 65mm Cobra Jet Throttle Body.
Of course, the larger twin 65mm opening will let more air into the engine, which is what we're after, and since it is built by Ford Racing, the quality, the drive by wire electronics, all that stuff are completely dead on, as you might expect. Finally, the cherry on top, I guess you could say, that nice polished billet construction looks great under the hood, especially alongside that JLT carbon fiber intake.
Now that we've opened things up with the intake, let's check out the exhaust. One of the biggest performance killers with any exhaust system are the factory cats. So, in their place now, we installed the stainless steel off road X-Pipe. This should really help improve the exhaust flow here on our Shelby and should give our tone a little more bite. Since we are getting rid of the factory cats, we wanted to pick an axle-back that would still give us a good sound without being overly raspy, but at the same time give us some performance benefits. After all, this is a power pack here.
So, we selected a customer favorite, the MagnaFlow Street Series Axle-Back. Now, this axle-back paired with that off-road X-pipe could still give us a very angry tone, worthy of a GT 500, but at the same time, it's not going to be obnoxiously loud. In fact, listen up for a quick sound clip.
With this many mods, and with us really pushing the limits of that factory roots blower, heat is inevitably going to be an issue. So, even though these '11 and '12 Shelbys came with larger intercoolers from the factory, we wanted to make sure this thing was going to stay cool even on the hottest days. So, we installed the AFCO Pro-Series Heat Exchanger, which did include dual 10-inch electric fans to help keep things even cooler. In fact, if you guys want to click on the link below, you can read up more about the AFCO back on our site, but regardless, just a solid upgrade when trying to deal with heat on these Shelbys.
With all of our stage three modifications in place, time to get Mike J. and the Bama Performance team in here so we can get a tune for all our new mods. At the end of the stage two power pack, our 2012 GT500 was making 532 horsepower and 523-pound-feet of torque at the rear wheels. With all the stage three modifications installed, the power pack was now making 589 horsepower, and 600-pound-feet of torque at the rear wheels, giving us a peak gain of 57 horsepower over our stage two numbers, and gains of 65 horsepower, and 83-pound-feet of torque throughout the curve.
So, to recap, our baseline run with our 2012 GT500 gave us 503 horsepower, and 475-pound feet of torque. With all three power packs installed, the car is now making 589 horsepower, and 600-pound-feet of torque, resulting in a peak gain of 86 horsepower over those baseline numbers, and gains of 117 horsepower, and 135-pound-feet of torque throughout the curve.
That's going to do it for the third and final power pack here featuring the 2010 through 2012 Shelby GT500. Let's be honest, bone stock, these Shelbys are no joke, but over the course of three different power packs, which featured more boost, some basic bolt-ons, and of course, a quality tune from the Bama team, this thing is now more ridiculous than ever. Guys, don't forget to check out our other power packs and remember, for all things Mustang, keep it right here at americanmuscle.com.