Recieved Flowmaster Hushpower axleback mufflers from American Muscle one day after ordering online. Had them installed by local shop which also took the opportunity to change my oil (8 quarts of Mobile 1 synthetic) and rotate tires.

In the hands of professional mechanics with my 2011 GT Premium Automatic on a lift, It took shop owner Charlie Waddell less than an hour to do the install, without even glancing at instructions. He did a fine workmanlike job and allowed me to hand out in the work area and watch and ask dumb questions. There were two instances in the removal and replacement of the mufflers where he required a second set of hands from his brother Chris, so you do-it-yourselfers might want to have someone nearby to call on for an assist.

The Hushpower sound is very subtle, the YouTube clips do not do it justice. The idle is very deep and quiet; as the name suggests, it is of the "talk softly and carry a big stick" variety. Just what I had in mind.

On the road, exhaust noise in the cockpit directly correlates with throttle opening. At neutral throttle (as in maintaining steady speed on level road) no increase in noise whatsoever, handy for driving in the presence of the po-po. Neutral or coasting throttle opening also mean that anything resmbling the dreaded 2000 rpm "drone" is just not there. A gentle pass or nudged throttle for uphill grades produces a kind of deep and hollow hum, nothing to get upset over, though you might want to crank the sound system up a notch or two.

However, the five-oh may look up if you pass them at WOT in your own 5.0. The noise is not obnoxious, but it is several decibles above stock. It is of such low frequency that it will not attract the same attention as the raspy, hgiher-pitched "aggressive" mufflers.

As far as performance is concerned, there is no comparison between the gains achieved with the Hushpowers and the increase in power with a Bama tune and Airaid CAI. The tune and intake mods give you an immediate and undeniable boost in power that truly feels like the 25 or so rwhp the magazines are reporting. The Hushpowers (which American Muscle says you do not have to reflash another tune for mufflers alone) do not add much, if any, power, though AM does show a dyno graph in their ads that look like a 5-to-10 rwhp gain. I have no before-and-after dyno info to bear that out. Actually, the perceived power is less as with the stock system the Coyote made all that power noiselessly, except for that distinctive "Whoooosh" from the intake hose to the firewall. Now that the same acceleration is accompanied by a bit more noise, the engine seems to be working harder. But I am aware that this is all auditory perception; by the seat-of-the-pantsometer it still hauls ***, but the gains are subtle.

If you are looking for a well-made exhaust system with a deep rumbly idle and a non-obnoxious driving sound, the Hushpowers are an intelligent choice at $419 delivered from AM.

But if you are looking for a serious gain in hp through exhaust mods, you have to replace headers and midpipe too, and throw another tune at the ECU.

 

Nice write-up. I feel the same way about my hushpower too.

 

I enjoy my hushpowers when I am taking it easy...it's got an awesome deep rumble. I just get dissapointed when I roll my windows down and want to hear it roar...it just gives a muffled glasspack sound at WOT. I'm going to see about removing my resonators to see if that will allow it to open up a little and not seem so muffled (I know they are "hush"powers). I may be switching to the bassani catback if removing the resonators doesn't give me the sound I want. I went with Hushpowers because of the price, but may be reconsidering my choice to get a more raw muscle sound.

 

They ARE quiet -- went out for a 75-mile drive with the wife last night and Chris (who comes from a family of gear-heads and has driven the Mustang several times) didn't notice the increased noise, even when loading groceries into the trunk with the motor idling.

It was also not offensive enough to be pulled over by the cop in the unmarked fuzzmobile who pulled alongside and then behind me after I executed a WOT merge onto the Interstate (good thing I slowed down before he could get a read on me).

According to my somewhat pessimistic mileage guage I am averaging 21.5 mpg, about 2 mpg better than with stock mufflers. That will probably work out to 22.5 mpg when I divide trip miles by gallons used at next fill up.

 

Any annoying drone like most say? Have any video?

 

There is a drone, but it I only hear it when going up a hill in 6th gear between 1800-2000 rpms, but just shift down to 5th (where you should be anyway going up a hill at a low speed) and it is completely unnoticeable. Other than that one situation, I never hear a drone...which will probably change if I take out my resonators...guess we'll just have to see

 

Is it normal to get gas mileage improvements by simply installing axle backs? I know I'm new, but I've never heard of that before. I'm hoping it's true so I can justify (to the wife) swapping out.

 

To wife: yes dear, i'm getting WAY better gas mileage.
To self: No freakin' way. Period.

 

I notice the same thing but the drone is minor...down shifting helped.

 

i am going with hushpower catback

 

SO TRUE

Jus' gotta know how to talk to 'em. You'll learn....

 

Nice! I've been married 4 years and am still clueless. I'll probably never learn. One of my problems is that there are too many projects on the go, the new 11 GT and a 74 big block Vette.

 

Step 1. Plant the seed, a la "40 year old virgin" i.e...you know honey, I've been wondering blah blah blah.... Or, hey baby, I was wondering if you thought it would be a good idea to get a car with better gas mileage/more comfortable seats for my sore back/the car I think I deserve for all these years of hard work I've put in..etc..Its all in the delivery, tone, and "intentions"

Step 2. Let it grow. Patience is key. Get her "involved" in some decision making, or make her think she is

Step 3. Make good thought out decisions on redirecting funds that would otherwise go to silly savings accounts. Be smart, there is a justified "reason" out there somewhere in your brain for every mod you make.

This technique will be difficult to execute if you live paycheck to paycheck. I have managed to work this technique AND stayed very happilly married. Its all about being smooth, and have your research done, your speech and delivery carefully thought out. And most of all, a sensible plan to fund the mods/projects

Note: This tactic is also scientifically proven to work with regards to firearms. A woman is easily sold on the protection of her body and her children. I have gone from a single pistol to a full arms room in the last couple years using this very technique. It took me7 years or so to get this system down, but have been reaping the rewards for the last 6 years without a hitch. Yes, you will occasionally possibly have to deflect the random suggestions that you are responsible for financial strain in the family. Change the subject. Pass gas. Whatever it takes. Problem solved.

 

So anyways, yeah, hushpowers. Since I am down to my last mod decsion for a while, I am wondering if the hushpowers will be worth it on an AT vehicle. The only sound I get now is at 50-100% throttle as is. With an MT you can really get the sound while revving, especially at low speeds, and am thinking that the Roush grille I've been considering will be a more worthy mod at this point. Since I am strictly held to in the $400 range, I am limited here on options. The feedback I am getting on the Roush axle back is pulling me in that direction too. Ahh, decisions decisions.

 

Jus' gotta know how to talk to 'em. You'll learn....[/quote]

... or let 'er drive the 'Stang to appreciate the mods. Honestly, wife bugs me all the time. "Why do you have to be with me every time I drive it?"
sez Chris. "I want to go tooling around by myself."

It's the words "tooling around" that bother me. She's used to her Corolla and Tundra and cackles a bit too gleefully when she tromps the loud-pedal on the GT.

Don't want to see Mustang or wife wrapped aorund a tree.