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Discussion Starter #1
(videos to come soon)
  • Drone concerns - at 40mph, the car creates a ear pressure/humming sound when under moderate to heavy pedal pressure. This can be eliminated by reducing the amount of pedel pressure with your foot or dropping down a gear to accelerate.
  • Loudness concerns - Turn your radio to volume to 13, you can barely hear the MBRP exhaust note while cruising and is almost like having the stock exhaust on. WOT sounds like listening to a Harley drive by with your windows up in loudness comparison.
  • Cruising 65mph - unless you really keep your foot down on the pedal above 30% or so, the exhaust does not hum and is just barely louder than the stock exhaust. Sometimes it sounds like your exhaust note is 1-2 car lengths behind you and trying to catch up because it gets so quiet.
Background: I mentioned about a month ago that I was planning on installing the MBRP exhaust for the 5.7L Auto R/T along with a few mods and to also address the "drone" issue that people had been having. Finally, after getting back from overseas :woot:, I had a chance to get the exhaust installed today.

Modifications: MBRP 5.7L Exhaust Auto w/ MDS, C&L CAI, 85mm TB, Predator 93 CAI Can Tune (increased shift firmness, turned off MDS)

Installation: The installation was done at a local muffler shop. They charged $175.00 for the installation and it took less than an hour. I was originally going to do the installation myself with a couple of buds, however, it's hard to beat 30 years of exhaust/muffler experience and it did save me a lot of time and trouble with old exhaust disposale.

After installation driving away, the exhaust did have visible white smoke coming off of it. This only lasted about 5-10 minutes and I believe someone mentioned there is a protective film that is on the exhaust that burns off as you go. Yes, you will smell it as it kind of smells like burnt rubber and the fix they had was to wipe down the exhaust prior to installation.

Drone concerns - at 40mph, the car creates a ear pressure/humming sound when under moderate to heavy pedal pressure or if you leave your foot on moderate/heavy pressure to the pedal to cruise at this speed; this ear pressure/humming sound did cancel out other noises (radio specifically). The humming happened when the car was slowly accelerating and in comparison, under quicker acceleration, there was no humming sound. Initially it did rattle the inside of the cabin but after about 5-10 minutes of driving from the exhaust installation place, the rattles went away. The humming immediately goes away around 45-50mph or when accelerating; bottom line, when the transmission shifts down a gear to accelerate. You can either slightly lighten the pedal pressure from your foot to get rid of the humming sound or drop a gear in manual mode to completely eliminate this ear pressure/humming sound. Whatever gear it is cruising with moderate pedal pressure in around 40mph is causing this ear pressure/humming.

Loudness - comparision to stock. At normal acceleration and cruising, you could barely hear the stock exhaust. With the MBRP, windows closed, it is only slightly louder than stock other than when you really start to accelerate. If you turn your radio to Satellite Station 23 (my fav) and turn the volume to 13, you can no longer hear the exhaust note while cruising. At WOT with the windows up, it is loud and you will definitely be able to hear the exhaust note and I had to increase the radio up to 17-18 to hear it. You could compare WOT to listening to the loudness of a Harley driving by with your windows up. As you are accelerating, you will hear this exhaust. It's equivelant to x2 or x3 loudness of your stock exhaust with your windows up. Want a comparison; stick your fingers in both ears and hum like you were accelerating. That's equivalent to what you might hear.

Free flowing exhaust - You can easily cruise the car without having to put a lot of pedal pressure down. With the stock exhaust, once you let off the gas pedal, the car would start cruising/slowing down on it's own. With the new exhaust, you can easily let off the pedal and the car will cruise on it's own and not really slow down. It is definitely more free flowing and less restrictive. Also to mention, this was cruising at 40mph (the ear pressure/humming noise range) and to surprise you, when you let off the gas, the hum/rattles/ear pressure/humming whichever you call it, does not occur.

MDS/Fuel Economy - this will be posted as a follow-up once I get numbers for mileage. With a Predator canned tune, you definitely can notice when MDS kicks in and does not so it was my preference to turn it off. I will say that my original fuel economy without the Predator was approx 20 mpg and it has now been reading between 22-23 mpg. In the end, a big portion of fuel economy is about how you drive it.

Idle Rumble/In gear - Initially starting the Challenger, it has a higher sound but deep growl that echos off the pavement. As the engine warms up, the rumble deepens and lowers and the engine pulsates slower. Once you place it in Drive, the engine drops really low in sound. I listened to a Dodge 2500 with Flowmaster 40s on it this morning and the Challenger sounds growly/rough/tough in comparison.

Engine Revving - the engine growls/throaty ROARs when revving. The best comparison to the difference between Stock sound and MBRP sound can be heard in the following video link .

I'll keep the forum going with future updates but this is what you get for now.

Satisfaction wise, I can hear the exhaust, the car sounds like American muscle and I'm quite pleased with the results :bigthumb::SM127::woot:; ahh and it's good to be back in the United States driving my '09 Dodge Challenger R/T.

43 Posts
I just put my MBRP on my SRT 8 6 spd. I get the described "drone" pressure at 70 in 6th. I second all you observations.

I wonder how much the drone pressure is affect by if you got the T-409 or the T-304 steel system...
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