In the time spent trying to fix the LT1's misfire, we unfortunately missed our window to track test the new setup before Englishtown closed for the winter. Rather than sit idly by for it to reopen, we decided to head back to TT Performance in Passaic Park, New Jersey, to beef up the driveline. Since the 100,000-mile-plus 4L60E has seen better days, and a simple shift kit wasn't going to cut it, TCI Automotive offered up one of its Super StreetFighter 4L60Es to test, as well as a street-friendly Saturday Night Special torque converter. These two alone could significantly reduce 60-foot times, but what better way to put the stock LT1 into its powerband than with a 3.42 ring-and-pinion from Motive Gear? These notoriously quiet gearsets are perfect for daily drivers like the Formula, and its modest ratio will keep the Rs down for better gas mileage during highway driving, while still providing an enormous improvement over the stock 2.73s. In addition, the slipping stock posi was also canned in favor of an Eaton posi, which, unlike the stocker, features rebuildable clutches strong enough to last well into the 10s. For extra security, Moser hardened 28-spline axles would also be introduced to the refurbished stock 10-bolt. A TA Performance Differential Girdle and stud kit were the last prayers in keeping the puny 7.5-inch weakling alive.
While the fresh tranny and rear would provide both increased reliability and performance, they would not be able to assault the rear tires as much as the 3,400-pound Formula would like. To that end, BMR Fabrication was called upon for an adjustable torque arm, lower control arms, and relocation brackets to transfer weight to a new set of Nitto drag radials. The old combination, even with the headers and rocker arms, could barely spin the tires without power-braking-but with the new converter, gears, and BMR suspension components, I doubt this will be an issue any longer. The strong, tubular adjustable chrome-moly LCAs in the Street variation we chose have greasable polyurethane bushings and don't sacrifice a bit of ride quality. Similarly, the adjustable torque arm will enable proper weight transfer with its rock solid 1.25x.120-inch MIG welded tubing, and the adjustable nut will help keep the optimum pinion angle intact. Some may wonder why Nittos are the drag radials of choice, but consider three important benefits: they are the most streetable, they hook exceptionally well on the street (as well as the track), and they seem to be the best sticky tire to preserve the stock sized 7.625-inch ring gear.
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The Formula's 4L60E had so many miles on it that simply putting in a shift kit was no longer feasible. Since it is a daily driver and reliability is a chief concern, the Pontiac was given a clean slate with the TCI Super StreetFighter 4L60E. TCI says this tranny will hold up to 600 hp, naturally aspirated, and it has proven reliable on greater than 525 hp with nitrous, thanks to Alto Red Eagle clutches, Kolene treated steel plates, improved lubrication, high line pressure, and many more hi-po features. A manual/automatic valvebody allows manual shifting-and use of the fully automatic function. Each unit is blueprinted, inspected, and dyno-tested to ensure quality before leaving TCI's facilities. |
The converter of choice was TCI's Saturday Night Special. Although it carries many of the same features as its other high- quality converters-including furnace-brazed fins, a hardened pre-ground pump hub, and computer balancing-the Saturday Night Special is considered an entry-level converter because it carries a 2,000 to 2,200 stall speed. A looser converter would have yielded better performance for sure, but since driveability and gas mileage are a concern, we kept it conservative for this round of mods. Once the Formula graduates to engine mods, we may trade this 12-inch lockup converter for a 10-inch 3,200- to 3,500-stall converter like the StreetFighter. | |