Dynomax Ultra Flo Welded Mufflers (race Magnums)


New Member
Aug 14, 2006
Worcester, MA
Just curious if anyone runs these mufflers and what they sound like? I'm used to the traditional rumble of Flowmaster 40 series but I just ordered a pair of Dynomax Ultra Flo Welded mufflers for my car. I guess they are formerly known as Dynomax "Race Magnums" I hope they aren't too quiet, I like to hear my car. Any feedback or video clips would be greatly appreciated. Thanks guys.
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I've had the Dynomax Ultra Flo welded muffler catback #19483 on my vert for a month now. I absolutely love it!

I replaced the 2 chamber Flowmaster catback with it. NO comparison! It still has nice muscular volume behind the car, which is GREAT but is MUCH quieter inside the car with very little to no drone. Very pleasant driving experience.

I'm running FRPP 1-5/8"ceramic coated headers, UPR offroad X pipe (no catts) so volume and drone was out of hand with the 2 chamber Flowmasters. My ears rang while driving.:notnice:

These Ultra Flo's mated with my headers and the offroad X sounds awesome and really makes my Trick Flow cam sound great at idle.

Yep I'm a fan:nice:
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What is the loudness factor compared to Flowmasters? Can you still hear the car coming from down the street or are they pretty quiet?
Yes although not as loud as the Flowmasters, the volume is still there outside as I can still hear my car echoing off other cars, buildings, ect, ect.
The best part for me is the fact that it's a much quieter inside the car with the windows and top up.
I've had them on a car and loved the sound. Flowmasters are great but 1. every mustang has them and 2. that stupid drone around 2000 rpm drives you crazy on long trips.

Not to throw a monkey wrench at you, but I recently changed from 40 series flowmasters to MAC SS flowpaths on my vert and I love the way they sound.
After a 7 reply round of applause, do you really need a sound clip? Buy them, you will love them. There is an old Duttweiler bench test on them still on the internet somewhere. The Ultraflow flowed 118% over a straight 2.5" pipe, so there is obviously no loss in performance either.

Over the Years I've read various Threads/debates concerning Hpipe vs. Xpipe, chambered mufflers vs. open (flow through) mufflers.

There never seems to be an actual winner of those debates. People typically get to arguing. But in my own case with my "seat of the pants dyno" I feel my current offroad x with this Dynomax catback makes slightly more power than my old settup of offroad hpipe and 2 chambers.

I do plan to go to the dyno in the next couple months to get a check up and also see how it does now compared to my old numbers.

In short: Get them , you'll like them.
It's been so long since I've had my 96 Cobra, but I had DynoMax Ultra Flow and they were quiet at idle, crusing speeds and even wide open throttle. I do have to say that they did become louder at WOT than you'd think if you only heard the car idling.

I always would smoke people back in the day car made 400+ RWHP, and then tell them I just had exhaust done. LOL. That pist off a lot of ppl.
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@Onefine88 what size pipe are you running for x and tail? whyd you switch from h to x? I like my oem setup but when i get to the top end here shortly it would be a shame for exhaust to be the choke point..
The X pipe is a 2.5" offroad x from UPR. Not sure what the tailpipe size is. I can measure when I return home from work but it is whatever came on the Dynomax catback.
I swapped to an x-pipe purely for sound reasons. I've had catted x-pipes in the past on this and other Mustangs.

When I did the top end kit and supercharger this past fall I removed all emissions items including the catts and tried an offroad h-pipe. With the increased volume that came with it all, I realized real quick that I like the sound of the x-pipe better so I swapped for the UPR and love it.