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2008 Dodge Challenger SRT8 SLP Performa...
Slp Performance Parts Exhaust System
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2008 Dodge Challenger SRT8 SLP Performance Aftermarket Exhaust System
Comparing Hemi Goodies For Your New Challenger
By Dan Foley, Photography by Dan Foley
April 20, 2010
The PowerFlo X-pipe slides right into the front pipes aft of the catalytic converters. The clamps were slid over the pipes before installing the PowerFlo X-pipe. This mid x-pipe will fit the factory front pipes or the SLP front pipes for their headers. This SLP X-pipe is the start for any of their three available exhaust systems (Loudmouth, Loudmouth II, and PowerFlo).
The PowerFlo X-pipe slides right into the front pipes aft of the catalytic converters. The
Seen here is the SLP PowerFlo X-pipe and PowerFlo mufflers (SLP's quietest) next to the stock X-pipe and mid-muffler. The PowerFlo X can be used with any of the three SLP mufflers. Better exhaust flow, and less restriction and weight, means more power and lower ET's. This adds up to a great sounding exhaust that won't set off alarms. The complete PowerFlo exhaust features four mufflers to keep interior sound levels low without that dreaded drone.
Seen here is the SLP PowerFlo X-pipe and PowerFlo mufflers (SLP's quietest) next to the st
We tested the sound level (decibels) of each muffler type using the Loudmouth tailpipes. Top to bottom: PowerFlo, Loudmouth II, and Loudmouth. The PowerFlo muffs were tested with the Loudmouth and the PowerFlo tail pipes. We tested a total of four different exhaust configurations. Each exhaust configuration was tested for interior decibels at idle and at a 50-70 mph blast using our trusty Radio Shack sound level meter. The exterior was tested at 30 feet and 3,000 rpm. Only the stock and the PowerFlo exhaust were tested while the Challenger made a pass going down the track.
We tested the sound level (decibels) of each muffler type using the Loudmouth tailpipes. T
We started sound-level testing with the Loudmouth exhaust system. Yes, it is loud! Standing 30 feet from the rear of the SRT8 with the Hemi at 3,000 rpm, it produced 97 decibels. Rev it to 5,000 rpm and the meter measured over 100 decibels. Interior decibels at idle (windows up) measured 87. At a 50-70 mph blast, interior sound was a loud 100. Some people like noise. The stock exhaust produced only 77 decibels on the same full throttle 50-70 mph blast. Here's the audio from the Loudmouth II. At 30 feet 3,000 rpm: 91 decibels. Interior idle: 81 decibels. Interior full throttle 50-70 mph: 95 decibels. We next wanted to try the PowerFlo mufflers with the Loudmouth tail pipes. This configuration sounded great! At 30 feet, 3,000 rpm sound lowered to 85 decibels. Interior idle 75 decibels, interior 50-70 mph 91 decibels.
We started sound-level testing with the Loudmouth exhaust system. Yes, it is loud! Standin
Here's the complete PowerFlo exhaust system with the four PowerFlo mufflers. It keeps interior resonance to a minimum-this way Sam and his wife can enjoy the tunes. All dyno and strip testing was performed with the stock and the PowerFlo system. SLP claims the PowerFlo system delivers only 2 horsepower less than their Loudmouth exhaust. The decibel numbers dropped to these levels. At 30 feet, 3,000 rpm: 82. Interior idle: 72. 50-70 mph: 88. The stock exhaust produced 83 decibels of sound going down the quarter-mile, while the PowerFlo showed us 88 going down-track.
Here's the complete PowerFlo exhaust system with the four PowerFlo mufflers. It keeps inte
Seen here is the before-and-after look going from the ugly, restrictive factory air cleaner assembly to SLP's high-flow induction.....
Seen here is the before-and-after look going from the ugly, restrictive factory air cleane
....The Blackwing Cold-Air-Package (PN D21003) has shown to be worth 7 hp and 6 lb-ft at the wheels. It is part of SLP's 475 HP PerformancePac.
....The Blackwing Cold-Air-Package (PN D21003) has shown to be worth 7 hp and 6 lb-ft at t
Another part of the 475HP Pac is the 25-percent underdriven balancer/pulley (PN 100235). It is dyno-proven to add 9 hp and 10 lb-ft to the rear tires. It's lighter than the stock balancer and is 100-percent steel construction and SFI approved. Also featured are taller retention walls that reduce the chance of belt slippage and thrown belts.
Another part of the 475HP Pac is the 25-percent underdriven balancer/pulley (PN 100235). I
With the SLP/DiabloSport II handheld tuner (PN D27013T) the 475 HP tune was downloaded before we began dyno and strip testing. The handheld tuners are software specific to SLP's performance parts upgrades and their PerformancePacs. These handheld units can adjust transmission shift points/firmness, engine rev limits, coolant fan speed/temperature adjustments, along with many DiabloSport tuner features.
With the SLP/DiabloSport II handheld tuner (PN D27013T) the 475 HP tune was downloaded bef
We headed over and strapped down the Challenger to SLP's in-house SuperFlow 840 dyno. Impressive peak power gains of 41 horsepower and 46 lb-ft of torque were realized.
We headed over and strapped down the Challenger to SLP's in-house SuperFlow 840 dyno. Impr
These dyno graphs show how much power was realized at the wheels and at the crank (SAE Corrected). At the wheels, power went from 359 hp and 355 lb-ft (stock) up to 400.2 hp and 401 lb-ft of torque.....
These dyno graphs show how much power was realized at the wheels and at the crank (SAE Cor
....Looking at the SAE Corrected Engine Power graph, the numbers rose from 433 hp and 430 lb-ft up to 479 hp and 480 lb-ft torque. The added gains (46 hp and 50 lb-ft) were definitely felt in the seat of the pants.
....Looking at the SAE Corrected Engine Power graph, the numbers rose from 433 hp and 430
We then hit the track and let this baby rip. Unfortunately, weather conditions were not similar to our bone-stock baseline (baseline 61-degrees, 35 percent humidity, 30.08 barometer, vs. 475 HP Pac w/68-degrees, 81 percent humidity, 29.91 barometer). Low e.t. was a respectable 12.59 at 112.29 mph and we ran a string of 12.60s. The humid, bad air served us notice that with good air 12.40s were waiting to be unleashed by this new Hemi Challenger.
We then hit the track and let this baby rip. Unfortunately, weather conditions were not si
SLP Performance Parts
1501 Industrial Way North
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By Dan Foley
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