Muscle Mustangs & Fast Fords
Installing Eaton Detriot Truetrac Differential - Project Shake 'N Bake
We Gear Up And Make Some Needed Improvements To
As a project gets underway, it begins to develop a personality all it's own. Some are great on the dragstrip, some seem adept at carving corners. Our project car is no exception
Last month we took a basically stock '03 Mach 1, put it through a bunch of the normal tests, and it performed very well in all areas. Our baseline on the dyno was promising, and we were happy with the numbers we saw at the dragstrip. After stiffening the chassis, we decided it was time to add a few ponies and attack some of the driveability issues we had with our mildly modified Mach, now known as Project Shake 'N' Bake.
To get underway, we headed to Blow By Racing (BBR) in Boca Raton, Florida. Our good friends Chris Jones and Matt Frith were quick to bring us in and get things underway. The first order of business was strapping our Mach 1 to BBR's Dynojet 224 to spin the rollers and get a baseline. Just 296 rwhp and 314 lb-ft of torque later, we went to the other side of the shop to take apart the Mach 1.
Things started off with the removal of our existing exhaust. With the stock manifolds and Magnaflo X-stlye midpipe out of the way, we removed the driveshaft, allowing us to disassemble the 8.8-inch rearend.
The stock housing had never been touched before we removed the cover. The stock 3.55 gears still resided in the housing and offered decent daily driveability, but it didn't offer the performance we were looking for. After a lengthy battle removing the stock bearings and races, Frith was ready to install the new differential parts.
Randy's Ring and Pinion sent us everything we needed to beef up our 8.8, including a master overhaul kit, which included all new bearings and seals to freshen our rearend. With the stock equipment removed, Frith quickly bolted the Yukon 4.10 gear set onto the Eaton Detroit Truetrac differential. The Truetrac is a huge improvement over the stock differential, and will add all the strength we need on the dragstrip and road course.
With the new pinion installed, Frith installed the Truetrac, along with the new bearings, and began to set backlash. Once backlash was set at 0.009 inch, some paint was applied to the teeth on the gears to ensure they mesh properly.
When everything was in its proper location, Jones shifted his attention to the new Yukon axles. The 31-spline Yukon axles offer a massive strength improvement over the stock shafts. Before sliding our new shafts into place, Jones pressed the new ABS rings into place and installed the 3-inch Racing Wheel Studs from Steeda Autosports.
With our rearend fortified, the last thing to do was bolt on the new differential cover and fill the rearend with fluid. Fore Precision Works sent us its Solid Rear Axle differential cover. The solid billet construction adds a ton of strength over the stock cover, and the preload bolts help prevent deflection of the main caps under heavy acceleration.
After buttoning up the rearend, the guys at BBR switched their attention to the engine. AmericanMuscle.com supplied us with a set of stainless steel long-tube headers and an X-style midpipe with high-flow cats from SLP. These aluminum-ceramic-coated headers use 1 3/4-inch primaries and venturi-style velocity collectors to optimize exhaust flow.
The next addition was the SLP X-style midpipe assembly. Exhaust flows into the high-flow catalytic converters and X-style midpipe, before exiting through the existing Magnaflow cat-back exhaust system.
With the work on the underside of the Mach 1 finished, Jones and Frith lowered the lift and began working under the hood. Being that we purchased our Mach 1 with over 85,000 miles on the clock, a full tune-up was in order, and AmericanMuscle sent us everything we needed for our Mach.
We started by draining all of the fluids and added Royal Purple 5W-20 synthetic oil and a K&N oil filter to ensure the moving parts stay lubricated. Next we removed the stock coils and spark plugs, and replaced them with ZEX Power Tune plugs, which are designed for naturally aspirated applications. We also added 4V Pro Series coils from Granatelli Motor Sports to handle our spark needs.
After completing the tune-up, Frith shifted his attention to the air intake system. When we purchased our Mach 1, it had a nitrous oxide system on it that we didn't plan on keeping. Removing the system meant we would have a cold-air intake with a hole it. Instead of patching the hole, we decided to install a new piece from JLT Performance.
After a long conversation with Jay Tucker, owner of JLT, we made the decision to go with its Carbon Fiber '99/'01 Cobra kit. We did this for two reasons: one, the design of this kit will allow for plenty of clearance when we put our strut tower brace on, and two, the kit is worth a few more horsepower with the mass air meter and air filter mounted in the fender. The downside to this kit is the shaker that we love so much is now just for looks, but we can live with that.
Once the boys at BBR finished all of the mechanical work, it was time to strap our Mach back on the rollers so Jones could handle the custom tune. We turned to SCT for a Livewire handheld flash programmer, along with the Pro Racer Tuning Software to whip our ECM into shape. Although the Livewire comes with a bunch of tunes preloaded, we really wanted to maximize the potential of our Four-Valve. Jones made quick work of writing a tune and he set our Mach 1 up for its new gears, headers, and cold-air intake.
After a few dyno pulls, our Mach 1 laid down just shy of 310 rwhp and 321 lb-ft of torque, giving us a gain of 13 rwhp and 7 lb-ft of torque. Although our gains were not ground breaking, the biggest strides came in driveability. Our problem with a hanging idle is no more, and our Four-Valve accelerates smooth and quickly.
Once we got back to MM&FF command central, we bolted on the Mickey Thompson drag radials and headed back to Bradenton Motorsports Park for 1,320 feet of fun. With a little bit of added power and a healthy dose of gearing, our Mach 1 reacted well and laid down an impressive 12.83-second e.t. at over 107 mph.
Though we didn't see huge gains on the dyno, our Mach 1 reacted well to the added mods. The car feels strong and has picked up just under 0.7 seconds in the quarter-mile. Not bad for a mild daily driver.