Droning while driving

[PonyExpress]

Looking for some advice...

I recently bought and installed the "Pypes" axle-backs onto my '06 GT. Although I really liked the factory sound, I wanted the rounded-edge polished look so I bought the new ones. Although the new exhuast note is nice, I find there's some droning at low rpms when I shift. Is there a simple fix for this or do I need to consider another axle-back product?

[rocket_rick]

Pony, unfortunately the 1800-2000 rpm drone is fairly common in Mustangs with aftermarket exhaust. We've installed a number of different types here and the only one that actually gets rid of it is the Roush resonator exhaust. Eliminates the muffler altogether and has two resonator tubes in the tunnel ahead of the axle. Has a deep muscle car tone to it when you're on the throttle but goes away in cruise. Now that's mated to the stock headers and h-pipe/cats. With long tube headers and hi-flow cats, it gets 'much' louder.:D Still less drone than others though. We've also noted less drone in the JBA axle backs.

One alternative if you were happy with the sound of the stock mufflers is to weld a nice rolled edge tip on them and put them back on the car. Gives you the look you wanted but keeps the original sound. We have a couple of sets here that we could mod for you and swap them out if you wanted to go that route.

If you're finding that you're getting the drone right at your favorite cruising speed because you're right in that RPM band, another solution is to raise the differential gear ratio to 3.73. Raises the RPM band for a given speed and at 70 will put you over 2K. Side benefit is added acceleration in lower gears. Fuel mileage impact is minimal.

If others out there have tried different brands and not experienced the drone, please reply.

Let us know if we can help you, Pony.

[PonyExpress]

Rick,

Thanks for the insight. Glad to hear it wasn't the product I chose and is a fairly common issue. I had been thinking about welding on some tips to the stock set-up as they put some nice sound in it for this year from the factory. I always see the claim of a HP gain from these aftermarket axle-backs (some say 5-10 HP gain). Is there any truth to these statements in your experience?

BTW - I still plan on coming by soon to run the base dyno on my car that you previously mentioned. Just trying to find the time.

Thanks again for your help!

Steve