It all started with a visit to SLP Performance Parts. We stopped by to purchase one of the company's Ram Air hoods for hobbyist Kelly Holloway's '99 Trans Am. This non-Ram-Air F-body suffered a front-end collision (a lifted pickup backed into it), and the owner decided to ditch the damaged stock, flat hood for the better-looking twin-scoop hood. While shooting the breeze with the SLP guys, they mentioned the company's new PerformancePacs (350, 375, and 400hp). Intrigued, we decided to test the Stage 1 Pac on this stock T/A
While the dyno can show us power increases, we like to see how much lower the e.t.'s can go with popular bolt-ons, so a strip test was scheduled. The 350hp Pac is comprised of "jointly engineered induction and exhaust components," according to SLP, and consists of a FlowPac cold-air induction system, which includes the high-flow airbox lid; a cold-air induction package; a high-flow Blackwing air filter and smooth bellows; and the Loud Mouth II modular stainless exhaust.
Because the T/A is 8 years old, we added a new set of Performance Distributors LiveWires as well.
At The Strip
On our way to Raceway Park in Englishtown, New Jersey, we stopped by SLP to pick up all the boxes for the PerformancePac. Amazingly, they all fit in the back of the T/A with the rear seat down. Sharp HPP readers will remember that SLP added power and efficiency to my wife's '00 Grand Prix GT with its high-quality parts ("Six Sense," Nov. and Dec. '05 and Jan. '06), so I was looking forward to the performance improvements on this F-body.
It was March and we were blessed with cool 48 degree temps when we arrived at Raceway Park. We felt it wise to start testing with the cold-air system on this great-air day. It was inspiring to see this box-stock non-Ram-Air baby run a 13.33 at 103.36 on its baseline pass. Two minutes later, we hot-lapped it to a 13.35 at 103.22. For all testing, launch rpm was 1,200, the shift point was 6,000 with the shifter in Drive, and tire pressure was 40 psi in front and 28 psi at the rear. The result was this 80,000-mile world-class powerplant turning e.t.'s identical to automatic 3.23-equipped T/As back when they were new. With that consistency, we knew we had a great test mule.
We got to work on the cold-air induction, but at 12:30 in the afternoon, we were off to a late start. This upgrade ended up taking over three hours to install, but it turned out to be well worth the effort when we scooted down the strip to a much-improved 13.11 at 105.21. A gain of over 0.2 and nearly 2 mph is similar to picking up 20 hp. Unfortunately, we didn't have enough track-time left to test the Loud Mouth exhaust.
On our next track visit, it was a typical May day with worse weather conditions (mid-60s, higher humidity, and lower barometric pressure). Naturally, our baseline was a slower 13.24 at 104.71 with a 13.27 at 104.60 hotlap. It was to be expected with the less-than-favorable weather conditions. However, this Bird was performing with the same dead-on consistency as the first test. Now with a solid baseline, we were ready to remove the stock restrictive exhaust.
When we laid the stock and SLP plumbing side by side, the difference in the two systems was apparent. The stainless mandrel-bent pipes of the Loud Mouth II muffler don't appear to have any obvious flow restrictions, unlike the stock pipes and muffler. Once the new tubes were in place, we couldn't wait to start it up to hear the healthy tone.
We went to the line with the temp gauge just coming off the 160 degree mark, the same as the other baselines and test. Out of the hole, the LS1 felt slightly more sluggish, and it showed when the board lit up a 1.98 60-foot (0.01 slower), although the mid-range and top-end pull felt noticeably better going down the track. We were pleased when the clocks posted a 13.14 at 105.99, a full 0.1 and more than 1-mph gain over baseline. On the hot lap, we slowed to a 13.18 at 105.58.
Next up was the LiveWires ignition wires. We didn't have time to change the 80,000-mile original plugs but felt the wires could shave e.t.'s given SLP's in-house testing results. After a knuckle-busting hour, the LiveWires were installed. The motor fired right up, ran smoother, and the throttle response felt better. This kept our hopes up for more reduction in the e.t. department. When the 60-foot lights read 1.97, we knew we were on a good run. The T/A turned a 13.10 and now the trap speed was over 106. If we had been able to test all the products that cool March day, 12-second e.t.'s may have been possible.
We used a friend's bone-stock '99 T/A (LS1, auto, 3.23) to strip-test SLP's 350hp Performa
A big, bulky, baffled stock air-cleaner setup doesn't satisfy the LS1's hunger for airflow
The stock paper-element air filter restricts airflow. This paper filter was new for a fair
This stock radiator-support/air-cleaner base and the air dam underneath were removed for s
After reading SLP's instructions, two square holes were cut in the airbox base. Not visibl
The stainless scoop is mounted in the high-pressure air stream in front of the radiator. I
Improvements of over 0.3 second and 3 mph aren't to be taken lightly. SLP's 350hp PerformancePac proved to be a real power adder, visual appearance (underhood, underside, and outback) is an added benefit of these upgrades. In our case, considering the age of the T/A's stock plug wires, Performance Distributors LiveWires were a worthwhile addition as well.
For those who desire even more power, SLP also offers PerformancePacs for 375 and 400 hp.
|Strip Test Results |
|March 23, 2006—Temperature, 50 degrees; Humidity, 35%; Barometer, 30.15 hg |
|Run ||Temp ||Mods ||60-ft ||1/8-mile /MPH ||1/4-mile / MPH |
|1 ||48° ||Baseline, box-stock LS1 || 1.96 ||18.57 / 82.86 ||13.33 / 103.36 |
|2 ||48° ||2-minute–later hotlap ||1.96 ||8.58 / 82.81 ||13.35 / 103.22 |
|3 ||50° ||SLP’s cold-air induction ||1.93 ||8.45 / 84.36 ||13.11 / 105.21 |
|4 ||50° || Hotlap ||1.94 ||8.46 / 84.32 ||13.13 / 105.07 |
|May 9, 2006—Temperature, 65 degrees; Humidity, 61%; Barometer, 29.93 hg |
|Run ||Temp ||Mods ||60-ft ||1/8-mile /MPH ||1/4-mile / MPH |
|1 ||62° ||Baseline || 1.97 ||8.54 / 84.07 ||13.24 / 104.71 |
|2 ||62° ||Hotlap ||1.97 ||8.55 / 83.84 ||13.27 / 104.60 |
|3 ||64° ||SLP Loud Mouth II exhaust ||1.98 ||8.49 / 84.90 ||13.14 / 105.99 |
|4 ||64° ||Hotlap ||1.98 ||8.52 / 84.60 ||13.18 / 105.58 |
|5 ||65° || PD LiveWires ||1.97 ||8.45 / 85.10 ||13.10 / 106.21 |
|6 ||65° ||Hotlap (hot motor, heatsink) ||1.96 ||8.50 / 84.52 ||13.15 / 105.57 |
|Parts And Prices |
|Part ||Part No. ||Price |
|350hp PerformancePac |
SLP Loud Mouth II exhaust with dual tips
SLP FlowPac cold-air system
“350HP PerformancePac” fender badges (pair)
|Performance Distributors LiveWires || |
|Tested Parts Total || || |
This is the high-flow, washable, reusable air filter. According to SLP, "The Blackwing fil
The stock air-cleaner assembly was taken off as a one-piece unit for removal of the mass a
On top is the stock baffled, restrictive air-cleaner lid. Below, the smooth SLP lid can mo
After hearing the Loud Mouth exhaust on other cars, we thought it was a little too "loud."
SLP's cold-air induction system with the smooth bellows (included in the FlowPac) has a mu
Externally, you can't tell the difference between these two polished, stainless beauties.
Underneath this typical T/A tail is the restrictive and too-quiet stock muffler. The dull
Swapping an exhaust system at the track for same-day testing can be a challenge, but the S
We prefer the looks and the powerful sound from the new SLP exhaust. It's all stainless fo
Hidden in a crowded engine compartment, the stock wires lack the appeal most gearheads wan
Visually, the construction and appearance of the LiveWires is much better than stock. SLP
Still hidden but more noticeable, the LiveWires give the LS-series engine some performance
Here, the T/A launches towards another low-13 after trying the power extras. Consistently