The brainchild of auto industry legend John DeLorean, then the head of a design team responsible for the birth of the Tempest line, the Trophy 4 produces 110 hp (82 kW) ( gross) at 3,800 rpm and 190 lb⋅ft (258 N⋅m) at 2,000 rpm with a single-barrel carburetor (as fitted with manual transmission using regular gas, and 120 hp (89 kW) with premium) 130 hp (97 kW) with regular gas (and 140 hp (104 kW) with premium), as fitted with automatic transmission and 155 hp (116 kW) at 4,800 rpm and 215 lb⋅ft (292 N⋅m) at 2,800 rpm with the optional four-barrel carburetor and automatic transmission. The Trophy 4 weighs about 470 lb (210 kg), as compared to the 650 lb (290 kg) V8 it was based on. This degree of commonality enabled it to be produced on the same lines as the V8, allowing substantial cost savings.
It shared most of the 389's tooling and up to 120 of its parts. The Trophy 4 engine is a short-stroke, 45-degree inclined inline four created from the right bank of the 389 V8 for the debut of the Tempest in 1961. It was dubbed by Pontiac the Trophy 4, playing off the racing success that had earned the 389 V8 engine the nickname Trophy V-8 after just two years of competition. Created from one bank of Pontiac's powerful 389 cu in (6.4 L) Trophy V8, its only application was in the first generation Pontiac Tempest. This is basic hot rodding-doing stuff on your own.The Pontiac Trophy 4 engine (also called the Indianapolis 4, or Indy 4) is a 194.5 cu in (3.2 L) inline four-cylinder engine produced by the Pontiac Motor Division of General Motors for model years 1961 through 1963. "This is how guys did it back in the '50s. But that's OK because the Tempest is still go for its original mission: having fun and inventing new ways to go fast.
"A rollcage just screams race car, but it has to happen," he says. That addition will negate much of the car's sleeper image, but as Rob sees it he has no choice.
#63 PONTIAC TEMPEST INSTALL#
Rob knows there's more there to be had with additional tweaking, but the next order of business is to install a full rollcage so he can be both quick and safe. At 25 psi Rob has run a best of 9.86 at 149 mph, and that was "banging, popping, and missing all the way down the track," he says. And he's confident he can turn the screw up to 30 or 32 pounds if need be. With some tuning experience under his belt, Rob now calculates that he can make 1,162 flywheel horsepower at 5,800 rpm with 27 psi. "You can add 100 to 150 pounds to the nose of the car or to the rear of the car," Rob observes sagely.Įarly on in the learning curve the LeMans was strapped to the chassis dyno, where it made 875 hp at the rear wheels at 22 psi boost. But in practice we haven't experienced any significant turbo lag." The aft-mounted turbos also aid weight distribution. "At first we thought it would produce turbo lag, so then we figured maybe that would help launch the car off the line. "It doesn't sweat all over the place and make a big mess like an aluminum tank will." The remote rear turbo installation was mulled over carefully. (Rebuild kits are $40.) A big fat charge cooler resides in the trunk, adjacent to an insulated plastic picnic cooler that carries the ice water. The Holset HT3B turbos on the LeMans are from a Cummins-powered earthmover, and "you can buy them all day on eBay for 150 bucks each," says Rob.
Now, 40 years later, guys are finding that it is the cheapest path. That was essentially the only supply path at the time. Back in the early '60s when rodders began to experiment with turbos, the blowers themselves were mainly pirated from diesel truck and tractor engines.
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