The rear gears were next on our agenda. Bruce Ponti of AntiVenom went to work removing the stock ring and pinion, and made quick work of the 8.8 internals. With the FRPP gears, the swap was relatively quick and easy, and we were ready to hit the track. Both the transmission and the rear were then filled with Amsoil Severe Gear 75W-140 synthetic rearend fluid and Dominator 5W-20 synthetic racing oil respectively.
With everything loaded up, we headed to Bradenton Motorsports Park for a few more passes down the 1,320. Due to time restraints, we didn't have the opportunity to change the transmission calibration.
After filling the tank with VP Race Fuels' VP100 (StreetBlaze) 100- octane unleaded fuel, we headed into the burnout box. The first pass was made with some caution in case the 1-2 shift didn't occur. We were pleased when the first shift was significantly quicker and harder than in previous attempts.
The Nitto drag radial barked as the 6R80 shifted into Second, but unfortunately, that was the best shift of each run. As our AMSOIL GT scooted down the quarter-mile, each subsequent shift became lazier. It launched much better, but the engine was over-revving and the shifts were very lazy, killing any gains off the line.
Nevertheless, we were pleased with the new higher-stall converter that allowed the engine to zip into the higher rpm range with ease. With the shifts happening a solid 800-rpm higher than programmed, the engine was out of its power band. Couple this with slow shifts and the soupy, 90-degree, humid Florida air, and you have less than favorable conditions.
Our best attempt netted us an 11.27 at 122 mph, and although this was about 0.05 seconds slower than our previous best, we were very pleased to see a strong improvement in the 60-foot. Previously, our blown Coyote got through the short section in 1.71 seconds. The addition of the PA/Circle D torque converter and FRPP gears dropped the short time to 1.58 seconds, and all this with no change to the transmission tuning.
Even though we didn't find the big performance gains we were hoping to see, the groundwork is laid for some seriously quick e.t.'s once we spend more time altering the parameters in the Copperhead ECM.
4 The stock driveshaft has...
4 The stock driveshaft has a joint located close to the center of the shaft. Though this absorbed most of the driveline vibrations, it’s very heavy, and the joint can be a weak link when big power is applied.
5 AntiVenom EFI of Seffner,...
5 AntiVenom EFI of Seffner, Florida, rolled into our Snap-on Tech Center ready to rip into our ’11 Mustang. Kyle Miller made quick work of removing the stock driveshaft and prepared the trans to come out.
6 When laid side by side,...
6 When laid side by side, it’s easy to see the difference between the two shafts. The value of the one-piece driveshaft is instantly apparent when you have to move both of them. The stock unit weights in at a heft 41 pounds, while the PA shaft tips the scales at only 22 pounds. Losing 19 pounds of rotating weight is never a bad thing!
7 Before we knew it, Miller...
7 Before we knew it, Miller had the transmission out of the car and we were ready to remove the stock converter. When doing so, be sure not to bend the transmission lines or damage any of the wiring.
8 It’s easy to see the difference...
8 It’s easy to see the difference between the stock and aftermarket converter. The PA/Circle D unit (right) is much beefier than the stock converter. You don’t have to look much further than the mounting tabs to know this is a stout piece.
9 Next to go was the shock...
9 Next to go was the shock flexplate. It was quickly replaced with PA’s SFI-approved flexplate, which will keep us NHRA legal.
10 With the new flexplate...
10 With the new flexplate in place, it was time to install the new torque converter. As per PA’s instructions, we added half a quart of automatic transmission fluid to pre-lube the converter. We added AMSOIL Low Viscosity Fuel Efficient ATF to match what was already in our 6R80.
11 Miller then slid the...
11 Miller then slid the new converter onto the input shaft of our six-speed auto. After a little rotating and some gentle pushing, the converter was seated, and the trans was ready to be reinstalled.
12 BMR Suspension sent us...
12 BMR Suspension sent us one of its driveshaft safety loops for the ’11 Mustang (PN DSL017). Its three-piece design makes installation very easy, and the correct transmission angles are maintained.
13 Before bolting the transmission...
13 Before bolting the transmission crossmember back on the 6R80, a spacer supplied in the kit is installed between the trans and crossmember. This keeps the transmission in the stock location so the angle of the output shaft remains the same.
14 The driveshaft loop then...
14 The driveshaft loop then simply bolts in between the crossmember and floor. Once the driveshaft is reinstalled, the loop slips over the driveshaft and bolts to the plate mounted between the floor and crossmember.
15 Moving down the driveline,...
15 Moving down the driveline, the next order of business was swapping the stock 3.15 ring and pinion for a set of 3.73s supplied by Ford Racing Performance Parts.
16 To add some extra strength,...
16 To add some extra strength, we also added a billet differential cover from UPR Products.
17 Bruce Ponti of AntiVenom...
17 Bruce Ponti of AntiVenom EFI made quick work of the 8.8-inch rearend. Once the limited-slip differential was removed, Ponti swapped ring gears. Once the pinion was removed, the pinion bearing was pressed off and the shim was swapped to the new pinion.
18 Ponti reinstalled the...
18 Ponti reinstalled the pinion with the factory shim and a mock up bearing to measure pinion depth. With marking compound, he checked the engagement pattern on the drive and coast side of the gears. The pattern was nearly perfect on the first attempt, so he removed the pinion and pressed a new pinion bearing on for the final assembly. The differential was reinstalled and the backlash was set at 0.006-inch, according to FRPP’s specs.
19 Next, we installed the...
19 Next, we installed the UPR differential cover using silicone to ensure there are no leaks. We finished the rearend by filling it with 21/2 quarts of AMSOIL Severe Gear 75W-140 synthetic rearend fluid.
20 Lastly, we installed...
20 Lastly, we installed the new aluminum driveshaft.
21a Before heading to the...
21a Before heading to the track, we drained the engine oil and filled it with fresh AMSOIL Dominator 5W-20 synthetic racing oil...
21b ...We also added AMSOIL’s...
21b ...We also added AMSOIL’s Dominator Coolant Boost to ensure the car runs cool in the Florida heat.
22 When we got on track,...
22 When we got on track, we weren’t rewarded with the 10-second timeslips we were hoping for. The combination of heat and humidity, coupled with very soft shifts left us in the same e.t. range as our last outing, with a best e.t. of 11.27 at 122 mph. We were very happy to see the converter and gears doing their job as our 60-foot time dropped from a previous best of 1.71 seconds to 1.58 seconds, with a 1.60 being about the average.