Muscle Mustangs & Fast Fords
Project Smog-Legal Killer - Power to the Pavement
Turning our smog-legal horsepower into forward motion.
It's been said that power is nothing without control. Well, whoever muttered those words must have been a proper gearhead because there's nothing more frustrating than losing a race because of insufficient traction or bum drivetrain components. Unless you're an Internet hero, excuses like "I don't have traction" or "I can't powershift" don't cut it.
If you're just tuning in, last month we tied up some loose ends on our Smog-Legal Killer with an MSD shift light, AEM Failsafe wideband gauges, and Flex-a-lite electric fans. The mods were aimed at improving our shift points, protecting the motor from a lean condition, and freeing up power.
Speaking of power, after ditching the stock mechanical fan, our coupe gained 11 hp and 22 lb-ft of torque at the wheels on the dyno at Advanced Engine Development (AED) in Shingle Springs, California, for new totals of 523 hp and 530 lb-ft of emissions-friendly horsepower.
Before the chip tune, we visited Sacramento Raceway (when it was making 422 hp and 419 lb-ft) and made a best pass of 11.99 at 121 mph. Say what? Yeah, you read that right—just an 11.99.
The trap speed was proof of the available power, but with a stock T5 transmission, axles, and control arms, and a worn Traction-Lok differential, our 60-foot times were hovering in the 2.0 to 2.2 range. The weathered components were hurting our e.t.'s. Forget high-rpm launches or powershifting. Instead, our best launches were achieved with mild clutch slip, followed by WOT after the chassis settled down in Second gear—anything more and we'd see one-tire fire.
With the sticky Mickey Thompson ET Radials aired down, we again came up empty-handed as a hard launch snapped a stock axle. OK, so hard launches were out. How about power-shifting? We think not, since the stock T5 was getting louder by the run and any hard shifting resulted in grinding and crunching. In other words, we had plenty of power and no way to put it down. To say it was frustrating would be an understatement. We had to do something.
Its drivetrain and suspension flaws were glaring, but instead of getting overwhelmed at the massive undertakin,g we decided to tackle the project one step at a time, starting with a call to the Mustang gurus at Latemodel Restoration Supply (LRS).
It only took a short conversation with Jonathan McDonald of LRS, one of the in-house Fox-body specialists, to devise a plan. First on our list was addressing our traction issues with some key mods. Our initial reaction was to dive straight for the race-ready parts, but McDonald reminded us that a proper street car needs to perform well at the track and still remain civil when in public. With that in mind, we dismissed the thoughts of a spool and suspension components with Delrin bushings. Instead LRS had a different plan of attack: affordable mods for the street and strip.
"Before ordering parts, it's a good idea to decide what direction you'd like to take your ca, and ultimately where you'd like it to end up, that way you can buy the appropriate parts to reach your goals," McDonald said. "A spool and suspension components with Delrin bushings are awesome at the track, but can be too extreme for some people on the street—it pays off to have a solid plan of attack," he added.
With the notion of a well-rounded street car that also ripped at the track, we decided a rearend overhaul was in order. With the help of LRS, we selected a slew of Ford Racing Performance Parts (FRPP) and LRS components. An FRPP Traction-Lok with '03/'04 Cobra and GT500 carbon-fiber clutch packs (PN M4204F318C), an LRS rear-gear installation kit with FRPP 3.73 gears (PN LRS-4209FRB-K), 31-spline Moser axles (PN MOS-A883151SN), and SVE upper and lower control arms (PN SVE-5649AT) rounded out our roster of power planting mods.
The Traction-Lok is undoubtedly one of the most versatile differentials for performance, price, and longevity. Sure, a True Trac might be better for corner-carving and a spool can be more advantageous in a straight line, but neither can handle cornering and launching as well as a Traction-Lok.