no throaty sound with new 40 series flows

Discussion in 'Fox 5.0 Mustang Tech' started by leveling, Oct 12, 2005.

  1. I just installed 40 series flowmasters on my 89 mustang gt conv. and it sounds like my stock mufflers did. All the posting about the 40 series mufflers talk about how great the sound is. I am getting a very stock sound and do not know why. What gives?
  2. i also have them on my 92 vert gt, make sur theyre not delta flows by looking at the serial number on the outlet side of the case- 2 1/4 inch outlet =42443 2 1/2 inch outlet= 42543 these serial numbers are from the originals, if the ones you have have a 9 in front of these serial numbers they are delta flows

  3. Are you still running the factory cats/H-pipe???

  4. They WILL get louder. Mine got louder after about a couple weeks.
  5. It takes a month or 2 depending on how much you use your pony...the heat makes "changes" to the medal over time... :flame:
  6. The metal changes? How? Changes shape? If it's so weak that the baffles, themselves, change shape from heat and pressure, that's some seriously wimpy steel they're using in their products. If Flowmasters had any sort of packing/insulating material in there, then I could see there being a break-in period, a-la Dynomax UltraFlows and Hooker Maximum Flows (they sounded TOO quiet on mine for the first month or so before the sound packing settled in, then they got wicked under WOT). But unless Flowmaster's changed their designs yet again, they're just a bunch of holes and triangle deltas of solid metal welded into them - nothing at all to "break in."

    I'd say whatever it sounds like now is what it's gonna sound like for good ... until they rust out. :)

    (On a totally unrelated note, the animated silhouette of this iPod Nano chick next to the Quick Reply box is making me crack up. Looks like she's fanning away a fart... :D )
  7. ehh mine go louder as well over time i enjoy the deepness of them, but i have lt's, and an X pipe w/no cats. it sounds like your still on your stock H
  8. I've got MACs and it took 3 weeks for them to sound the way they do after 2 months.
  9. I dont understand how they can break in either since its just metal with holes in it... but apparently alot of people say it happens i just dont understand how its possible.
  10. It's all about the off-road H-pipes.
  11. With a catted X-pipe or H-pipe your car will be quiter than one that isn't running catalist's. My car is very loud with an O/R H-pipe and some 40 series flows.
  12. :nice: sounds mean as hell
  13. mine is just now startin to get louder had them bout 3 weeks now and the more i drive the more i love the sound.
  14. I put my Flows on in 2000 and the sound has not changed at ALL, there is nothing but Chambers inside of flowmasters, there is no packing to burn out of them! I kinda think you Guys are hearing what you think you want to hear!
  15. I'm pretty sure, ALL muffler grow louder with miles... It's not that its cheap metal or what not, it's that they break in, they get used to the way the exhaust flows through them, all metal expands and contracts due to heat and cold conditions, when they expand and contract so many times, they change shape, and they change sound considerably, it's awesome... my prostreets are gonna prob be really mean from the start, can't wait till they break in lol
  16. I had the same feeling about the Super 40's I just put on my 82, they seemed quieter than the Thrush Turbos I took off.

    But they do have a deeper note. I have no tailpipes, and they dump a couple feet in front of the axle, so that my affect it also.
  17. Its all about the total package. Headers with an off road x or h along with those flows will make a difference BIG time.
  18. I dunno. The physics and such of it just don't make sense. The baffles would have to physically change shape for them to "break in," and I just don't see that being a realistic possibility - those delta shapes are welded top and bottom to the casing, so there's really nowhere for them to flex/bend.

    Only theories I have to explain a sound change on Flows:
    - Computer re-learning the air/fuel mix and such, but only if you disconnect the battery at the same time as the exhaust change;
    - Minor exhaust leaks at the flanges develop as the connections settle into place over bumps, turns, and heat cycles;
    - The existence of that obnoxious Flowmaster drone at most RPM's becomes more and more impossible to deny after the initial "newness" of the exhaust wears off, and one is faced with a subconcious decision to either love it or hate it.

    Either way, I figure the side-exit Flows will be louder than the average cat-back setup, but again, you'll have clearance problems and you might be bothered by the fumes wafting up to through the windows at stoplights. (On mine, I found it quite enjoyable. Carbon monoxide and vehicle emissions make for a groooooovy high... :D )
  19. My car with 1.5" longtubes, stock modified offroad H, and delta flows with tailpipes is very loud, and i love it. I hope it doesn't quiet down too much when i put cats on it.
  20. To the original poster.

    Are you still running the stock mid pipe with cats?