Exhaust noise & performance options

[Supercharged Vipermad]

The mufflers are just upstream of the rear exhaust tips. I just reach under the back of the car, grab the two knobs, and give them a twist. 10-20 seconds total to switch modes.

 

[Supercharged Vipermad]

As part of my ongoing data collection efforts, I've been taking decibel readings inside my '01 RT/10 with the roof on. Stock, the car is actually pretty quiet. However, after installing the Belanger headers & exhaust and high-flow cats in my '01 RT/10, the noise level inside picked up substantially -- not enough to bother me, but enough to cause spousal friction

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Hennessey and APEX Motorsports both recommended using Power Effects mufflers to gain some control over exhaust noise without sacrificing any power. These mufflers have a butterfly valve in the middle which is rotated with an external knob; in "quiet" mode they send all exhaust gas through a series of baffles, while in "performance" mode they allow the exhaust to go through a straight-through tube. Per Hennessey, in "performance" mode there is no performance penalty vs. normal 3" straight-through mufflers.

Here is the data I collected with my '01 RT/10:
Stock:
62 dBA Idle
79 dBA 70 mph cruise 5th gear
77 dBA 70 mph coasting

Belanger headers & exhaust, high-flow cats:
72 dBA Idle
83 dBA 70 mph cruise 5th gear
79 dBA 70 mph coasting

Add Power Effects mufflers, quiet mode:
67 dBA idle
79 dBA 70 mph cruise 5th gear
77 dBA 70 mph coasting

Power Effects mufflers, performance mode:
68 dBA idle
82 dBA 70 mph cruise 5th gear
78 dBA 70 mph coasting

Subjectively, with the mufflers on "quiet" the car is not much louder than stock at idle, and the same as stock at speed. The loudest cockpit sounds are wind noise and engine whirring. With the mufflers on "performance" the car interior is still much quieter at cruise or idle, but is almost as loud as with the Belanger mufflers at WOT and has the same raspy snarl and rumble which I love but my wife could live without.

I'll have final dyno results for the mufflers after my ECU finishes its adaption cycle. Preliminary results are that the "quiet" mode loses 20 HP and 20 ft/lbs vs "performance". Given the noise level decrease, and hiven that it takes 10 seconds to switch from one exhaust mode to the other, I'm very happy with this modification.

 

[Fred(DrivingSchool)Kinder]

Ben, we can compare V10 "notes" when my car is finished. It has the TNT tunable muffler. Adjustable from inside the car, special feature not from TNT.

 

[Supercharged Vipermad]

Several of you have asked for details on these mufflers. Here they are:

Brand: Power Effects
Model: "Power Capsule" 12"
Cost: $675 retail including 4 flanges
Installation time: ~3 hours, requires welding
Weight: unknown, but mufflers are aluminum
Sources: Hennessey motorsports (www.hennesseymotorsports.com), Apex motorsports (www.apexmotorsports.net), direct from vendor (www.powereffects.com)
Fitment: will work with stock or aftermarket rear-exit systems
More info: www.powereffects.com (not much info on website)

 

[BurnR8]

I got the best price directly from powereffects....I really like the system and so do my neighbors....I completely yarded out the cats and muffles and it reduced the heat in the cockpit by a great deal.....open pipes were too harsh on the ears so I went with the power effects to get back-pressure and save my hearing...no one will be sorry if they add these on....it cost me about $200 in labor to get them welded on

 

[JimDavis MT 97GTS 650R]

I have had the "tuneable" exhaust on my 650R for the last year. Compared to the Borla system I ran before Hennessey modified the car, the Power Effects system really cuts down on that annoying drone while giving great sound. Inside the car, the adjustable system doesn't seem much different in overall noise between the wide open setting and the quiet setting. Coupled with the complete Hennessey 650R engine package, you can hum quite a radicle tune and still communicate with your passenger with out going nuts! A good choice for Vipers equipped with rear exit exhaust. Very easy to adjust.

 

[Topawam]

Re: Exhaust noise & performance options

Post from the past...
Just wondering if anybody else has used them since, and looking for feedback.
Thanks
Btw, this is for a friend, not related to my search in power of my other post.

 

[Racer Robbie]

Re: Exhaust noise & performance options

How about some links to the other makes mentioned above becides the power effects.

 

[ViperJoe]

Re: Exhaust noise & performance options

WHAT.......no WOT readings?

Come on man, leave the spouse at home and......put yer foot in it!

LOL!!!!