5.0 Mustang & Super FordsHow To Drivetrain
2012 Ford Mustang Boss 302 Drivetrain Upgrade
Revamping a Boss 302’s drivetrain makes every shift more fun
Let's face it -- Mustang folks' favorite pastime is planning, saving, and installing upgrade mods, then finding some open pavement to test them out. It's a way of life.
For those of you lucky enough to own a Boss 302, it's hard to find anything undesirable about the car. Even a thorough search in the Ford Racing catalog or a comparison to the Boss 302 R-model will result in few optional upgrades. We traded an '11 GT that suffered from both clutch and transmission issues for a '12 Boss.
Although wheelhop is much less prevalent with the Boss 302 than the '11 GT, it's still there. With that said, a driveline upgrade seemed inevitable. As such, we put together a plan to bolster the Boss.
Since we had the shifter, driveshaft, and transmission out, we chose to swap out the imprecise stock shifter, drop a few more pounds off the rotating mass via an aluminum driveshaft, and add a safety loop to keep it legal. Of course, these are a welcome additions to any '11-and-up Mustang.
To head off any clutch issues, we turned to SPEC. Its Stage 2+ assembly features a multi-friction disc featuring a full-faced configuration, with carbon-graphite on one side and Kevlar pucks on the other. With the carbon-steel insert, the all-aluminum flywheel sheds 10.2 pounds of rotating mass.
Speaking of dropping weight, the folks at The Driveshaft Shop have put years of research into upgrading the factory two-piece driveshaft with a stronger unit that is capable of supporting 900 hp, basically removing the weakest link from the car's dragstrip performance. In addition, with the 17.2-pound savings from the lightweight, one-piece, aluminum driveshaft, you lose a total of 27.4 pounds of rotating mass from the drivetrain.
Of course, with lighter mass and greater grip, we need to transmit all the power to the pavement. We decided to bid farewell to wheelhop courtesy of BMR Suspension's lightweight aluminum lower and adjustable upper control arms.
Here we outline a real-world install you can perform on jackstands in the comfort of your garage. Just make sure you're near a dealership or you can trailer the car there to get the crankshaft re-phased via an OBD Misfire Monitor Neutral Profile Correction. It's a necessity after any clutch change on a Coyote or RoadRunner engine.
Horse Sense: Before driving your car after a clutch swap, you must reset the Onboard Diagnostics Misfire Monitor Neutral Profile from the IDS toolbox. Select Powertrain, then Service Functions, then Misfire Monitor Neutral Profile Correction, and follow the prompts. Yep, you'll need to take it to a dealer or to a shop that has the necessary electronic hardware to perform the reset.
On The Dragstrip
We would have never believed the Boss could get any better, but it was like someone swapped the car for the FR500 at the Boss Attack driving school at Miller Motorsports Park! The car revs and responds much quicker. We gained 12 hp and 10 lb-ft of torque at the rear wheels.
The SPEC clutch is awesome, as it now allows you to slip it a bit more to improve 60-foot times, from a 1.87 best to a 1.82 on stock tires. And wheelhop is non-existent, at launch or between gearshifts! The shift pattern feels like one-half the lever travel it originally was. We didn't have similar atmospheric conditions to compare e.t.'s, but it ran 12.17 on the factory tires before; after, it ran a 12.03 at 108.5 mph.
In addition, we wish could have gotten some road course time comparisons, as the rear is much tighter in the turns and rolling out of them on the throttle is even more of a thrill. The car is definitely set up for sticky tires now, so we'll keep you posted when we get 'em bolted on, as she should be a solid, mid-11-second performer with hook!