Flowmaster vs Magnaflow mufflers

Discussion in 'Classic Mustang Specific Tech' started by SadbutTrue, Sep 17, 2008.

  1. I love my flows and they've served me well, but since I put the new heads on the car is just ridiculously loud at idle and when cruising. It sounds great and gets attention, but its impossible to have a conversation, shakes the whole house when I start it, etc. I hate to get rid of them because they're not that old and i love how they sound when I'm on it, but I think I need to.

    How much quieter at idle are Magnaflows? I've heard nothing but good things about them (how they make more power than Flows/others, are nasty when you're on it but tame when you're just idling around, no Flowmaster drone, etc).

    Are there any good clips of mild SBFs with them? And any examples of how much better they are than other aftermarket mufflers powerwise (ie dyno graphs)?

    If there are other options I should consider, let me know.
  2. Only heard them once with a SBF, and it was stock. Really sounds like butt. Didn't like them at all. With a built SB, maybe different though.
  3. Magnaflow will be very very tame at idle and cruise. They come alive at WOT though.

    For a DD I'd go the Magnaflow IMO.

    I would go deaf listening to mine daily, its freakin LOUD
  4. MagnaFlow Performance Exhaust - American Muscle Sound Files

    Here are some sound clips on the MagnaFlow site-

    1. My opinion is SERIOUSLY biased as I am the Western Regional Manager for MagnaFlow-
    Just want to make sure that is perfectly clear...LOL

    2. I have them on my 66 with a 351W and put them on my uncles cars which one has a 347 and the other has a blown 302

    The more built the car is, the better the MagnaFlows sound in my opinion...as the MagnaFlows seem to let you hear more motor, less resonance...if that makes any sense...

    They seem to be alot more throaty at idle, with out the tinny sound-

    On my 428 car, I did have to lower the idle down after switching to the MagnaFlows, because the car was breathing so much easier, the idle went up by about 500RPM- this was also going from H to X at the same time though too....

    I can talk on the cell phone at highway speeds in any of the cars mentioned above- all of which are putting out in the 350-400 crank hp range-
  5. Haha, knew you'd chime in :D :flag:

    More opinions?
  6. magnaflow FTW. they are used extensively in late model cars. my daily driver cobra sounds mean with them. you won't be disappointed

  7. I dunno, I had them on my car and it made it sound so tame I couldn't stand it. Maybe it was because it was a 2 1/2" system or what but :shrug:

    I loved the way they sounded at WOT however. Like I said, for a DD, they are the best choice IMO.
  8. How long have I been trying to get you to put Magnaflows on EVERYTHING ?

    Its about damn time =)

    You wana take yer car to my guy this weekend and get a quote ?
  9. Weelll you still won't get me to say that anything sounds better than Flows at WOT. :D But outside a couple friends who are way into muscle cars, the flows are just too much around town and at idle.

    But maybe. Might be easier to take it by one day after work next week, do you know when he's oopen this weekend?
  10. I dont care for the sound Of Magnaflows on "old" cars. On newer cars they sound great.

    Being as they are quieter, i would like to try ONE to quiet down my exhaust(Borla XR-1 4" race muffler), but i am too cheap to put the money out.:p
  11. What about getting the 50 series Flows? I'm assuming you have 40 series now.
  12. I just put a 2 1/2" magnaflow system on a few months ago. Took off a pair of Flowmasters I put on about 15 years ago in high school. I loved the sound of them but man the drone was terrible and they were pretty loud. Guess I am getting old LOL..... Anyway the Magnaflows are OK sounding at idle, I haven't gotten a chance to drive the car yet as I am sorting out a brake issue. It sounds good when its reved, and is quiet at idle. Made the wife happy thats all that matters. I would still preffer the flows.... but my ears couldn't take anymore.
  14. Friend had the 50s on his big block buick and I didn't really care for them. If you get Flows, go 40 series or go home imo.

    Sounds like we're in a similar spot, except that I hit the 'old guy' plateau about 7 years before you. Hmm...

    The Flows were fine with the stock engine, but with the new heads the whole package just feels a few orders of magnitude louder. Unfortunately I don't spend enough time on the gas revving to make it worthwhile, I don't think. Still, its gonna be hard taking those Flows off :(
  15. I have 40 series flows w/ 2 1/2" pipes on my car with a mildly built 289. I love the sound but they definitely drone at idle and certain other RPMs at cruise. The car is not my DD so I tolerate the drone but if it were I would probably go w/ something else. I've not heard the Magaflows and I know it does make a difference if you have an h pipe, x pipe or neither but many people seem to like them.
  16. Most people that like SlowMasters are the people that like them because they make the car sound a lot meaner then it is.
  17. +1

    Had flowmasters on my mustangs back in my 20s. Now I'm 40 next month and have installed magnaflows. I'm sure the neighbors love the magnaflows too.
  18. I installed the 2 1/2" Flowmaster system on mine behind shorty headers and and H pipe. I have it run all the way to the back throught the GT valance. They are not as loud as I thought they would be, but I installed a lot of sound deadening.

    I had previously installed $1000 worth of stereo items, now sometimes I don't even turn it on, I just listen to the stereo exhaust. :D
  19. Not sure why all the hatred towards the 50-series Flowmasters. My wife's 427 'vette has them and it sounds perfect. Not too loud, not too tame, which it sounds like what you're after. I'd take them any day over Magnaflows, but to each his own...
  20. magnaflows make more power than flowmasters as well........