A battery junction is used to connect the new pump to the auxiliary battery post in the fuse panel. | 
All the wires are checked, and then the green wire for the new pump is soldered to the grey wire for the stock in-tank pump and covered with a plastic boot. In retrospect, it probably would have been easier to just replace the in-tank pump with a high-output unit; however, the inline unit's 240-lph rating should be more than sufficient, considering this is the last mod we will be performing on the T/A. The 38-pound injectors are fine for these kind of power levels, but if we were planning any more power mods, larger injectors would definitely be needed. | 
We managed to reuse the SLP Smooth Bellows and connect it to the SLP 85mm MAF and ported throttle body. However, the tubing supplied in the kit didn't want to fit, so Doug cut some intake tubing that ECS had in stock. Lastly, he tightened all of the clamps, including those from the intercooler, and we were almost ready for testing. |
For "P" kits, Procharger supplies a black plastic airbox or this polished metal unit, (the metal box is standard on the "D" kits) and it couldn't look better. While you can't see the blower topside, the airbox gives you a hint at what lies below. | 
With Procharger's included tuning, the T/A made 407 hp and 402 lb-ft at 7 psi of boost on ECS's chassis Dynojet with the converter unlocked. With our previously installed performance tune and prior to the install, the LS1 made 301 rwhp and 348 lb/ft, making a total gain of 106 hp and 54 lb-ft. Next, ECS used LS1Edit to play with the fueling and add a few more degrees of timing. When all was said and done it made an additional 6 hp and 3 lb-ft. With the larger and more efficient intercoolers, horsepower climbed to 421 at 7.5psi while torque was relatively unaffected. | 
With the fuel system and blower install complete, it was time to upload the Diablo Sport tune and fire the blown LS1 up. When the motor was cracked off for the first time, I have to admit I got the same feeling, or should I say sensation, listening to the blower whine as watching Nicole Eggert's performance in this article's namesake (and you thought it was a reference to the Tommy Lee Jones movie--ha!). |
Whereas in naturally aspirated trim the Trans Am could leave on the wood, owner and test pilot Jay Heath had to dial back his approach a bit to keep the blown LS1 from breaking the M/T drag radials loose. Tire pressure was dropped on virtually every run until about 14 psi was set. Eventually, Heath whittled his ET down to 11.65 at 117 mph as we were running out of daylight. In a last ditch effort to really see what the T/A could do we sat NHRA racer and former HTP Associate Editor Evan Smith in the driver's seat. With the benefit of 70 fewer pounds of bodyweight and a different method of staging the T/A, Evan managed to score the best 60-foot on the day with a 1.63 and an 11.59 ET at 116 mph with a heat-soaked motor and hitting the rev limiter at the top of Second. With a cooler day and more tuning to accommodate the new setup 11.40s and possibly even 11.30s may have been in the cards. |  | 
For the testing, Procharger sent us an airbox and Y-pipe with bungs and sensors for detecting pressure and ambient temperature. This would allow the first measurement just after the blower and then a second after the intercoolers and the majority of the tubing. They also sent the new 4.5-inch intercoolers with the air scoops installed, as well as a few other odds and ends like another bypass valve, belts, a pulley and of course Engineer Ryan Bosch. |
During testing we noticed that some oil was being spit out of the dipstick tube and onto the intake manifold due to the increase in crankcase pressure (with the boost). Thunder Racing furnished Project LS1 with an oil breather to amend this problem, and if you are installing a blower or a turbo, we highly recommend picking one up as preventative maintenance. The Thunder Racing LS1 breather comes with a fitting that screws in place of the oil filler cap, which unfortunately did not fit under the Spohn strut tower brace. But since autocrossing wasn't exactly in the T/A's future, it was deemed a fair trade for a cleaner engine bay and healthier motor. | 
A nice stretch of open road was used to test the intercoolers, so we set out into the pinelands of Cream Ridge, NJ near ECS's shop. With the fresh air hitting the intercoolers at near track speeds, efficiency could more accurately be calculated. | 
Ryan compiled the raw data into these convenient graphs and as you can see there was approximately .5 psi less of boost drop off from the larger intercoolers. In addition the larger intercoolers were 10 percent more effective in cooling the intake air temperature, especially in the upper rpm range.... |
...At 6500 rpm intake air temperatures were only 62 degrees with the 4.5-inch intercoolers, meanwhile, with the smaller units, intake air was at 71 degrees. As you can see from the graph, as rpm and boost increased so did the disparity between the two intercoolers, proving the potential with higher boost levels. | | |
It is no secret that intercoolers are the most effective and safe way of resisting detonation in blower motors, plus they offer the opportunity to increase boost--and horsepower. In high-compression applications such as Gen III motors, this becomes even more important. In fact, Procharger says that with the stock 10.1:1 compression the Gen III LS1 can handle very little boost on pump gas safely. This is precisely why its kits are only available with twin high flow intercoolers.
Since detonation is such a concern, Procharger opts for bar-and-plate-style intercoolers, which owner Dan Jones says is the most effective type of air-to-air intercooler. "It allows more pathway for air and the flow path becomes more effective, even though pressure drop is slightly higher than an extruded tube intercooler. By favoring effectiveness the decrease in temperature over other companies allows an increase in ignition timing that will make up for the loss of pressure."
Procharger's latest manifestation of this philosophy is a new intercooler upgrade option, which adds an inch of width to the twin high flows, now totaling 4.5 inches. Now, you might think that increasing the overall size would increase the amount of boost drop-off from routing the charged air through these babies, but that is not the case. In fact, since the passageway in which the air moves in and out of the intercooler increases, so does the boost. And that increases the effectiveness of the cooling. "If we just increased the depth then this would not be the case, however we made the intercoolers deep enough to begin with and adding width helped achieve more flow," Dan said.
Dyno and Track Numbers Explained
In the past few installments of our Project LS1 series, changing the torque converter and switching dynos has resulted in varying power readings. The naturally aspirated peak of 347.4 horses and 347.1 lb-ft of torque came after SLP's long-tube headers, exhaust, and LS6 intake. Soon afterward, the stock converter was swapped for a 3,500-stall TCI Super StreetFighter, which dropped our ETs from 12.85 to 12.36. After the converter was installed, the dyno horsepower never quite measured up to its former peak, even after a few more mods.
Due to variations between dynos and because we wanted a true back-to-back comparison, we re-baselined our Trans Am on ECS's Mustang dyno before the Procharger went on. ECS prefers to leave the torque converter unlocked while dyno testing, and the numbers came in at 301.5 horses and 348.9 lb-ft. On the same dyno with the converter unlocked, the Procharger with the larger intercoolers and some PCM fine-tuning netted 421.4 hp and 405.8 lb-ft of torque. While this 119.9-hp gain represents a 40 percent increase in power over stock, locking up the converter or doing this test on a six-speed LS1 would have put the power gains more in the ballpark of Procharger's advertised 50-55 percent range.
GMHTP tested this T/A's new converter in March 2004, and 54-degree weather and low humidity allowed us to break into the 12.3s on drag radials. This was a great ET for the mods, but most of the time the car ran 12.4s and 12.5s.The weather at Jersey's Raceway Park wasn't nearly as accommodating when we tested the Procharger kit. Seventy-degree temps and high humidity no doubt affected the supercharger's performance, yet the T/A still managed an 11.5 at 116 and change. Owner Heath is very happy with his Pontiac's power boost on the street and at the track, and reports an awesome seat of the pants feel with only a slightly higher coolant temperature seen on 90-degree-plus days.
Dan went on to say that the beauty of this intercooler upgrade is "it gives added insurance against detonation in areas where only lower octane fuel is available, and it gives the ability to upgrade the motor and add boost. Since our blowers are rated at much higher than they are used with the base kit, you can just crank up the boost or feed a bigger motor, and the intercooler will still maintain its effectiveness.