• Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Do Flowmasters hurt performance?

  • Thread starter Thread starter mjh78
  • Start date Start date Dec 3, 2007
  • 1
  • 2
Next
1 of 2 Next Last
M

mjh78

Member
Oct 12, 2007
22
0
7
Dec 3, 2007
#1
  • Dec 3, 2007
  • #1
The previosu owner of my car had some aftermarket mufflers welded in. Everything is stock I'm sure. I would think these are probably flowmaster mufflers. They do sound really good, but if I get the RPMs up to 3 or so and cruise to a stop...a lot of popping from the exhaust. Is this an indication of too much backpressure or something? Are these things robbing me of some power?
 

Spro

New Member
Nov 3, 2007
73
0
0
IL
Dec 3, 2007
#2
  • Dec 3, 2007
  • #2
Pretty much normal to hear them pop and no they arent robbing power.
 

M.P. Cobra Fan

New Member
Aug 10, 2007
19
0
0
Atlanta GA
Dec 3, 2007
#3
  • Dec 3, 2007
  • #3
+1

No problems at all. That is just how flows sound. Personally I love the sound.
 

SVT32VDOHC

waiting for the next hack atta
Founding Member
Nov 22, 2001
3,501
28
119
Motor City
Dec 3, 2007
#4
  • Dec 3, 2007
  • #4
I didn't have any popping at all with my Flowmasters. I have had 11 or 12 Mustangs, most having flows, never had popping.
 

fobra559

At least it's more erect and not floppy anymore.
Nov 1, 2007
721
0
0
Lindsay, CA
Dec 3, 2007
#5
  • Dec 3, 2007
  • #5
I have flows and like the above posts, I have no popping sound nor do they rob power.
 

2000fordstanggt

Member
Sep 6, 2005
404
1
16
Westland, MI
Dec 3, 2007
#6
  • Dec 3, 2007
  • #6
my girl "pops" mostly when cold and slowing down in gear. hardly at all once shes warmed up though.
 

Mossberg

Active Member
Jul 21, 2003
0
1
36
ATL, Shawty
Dec 3, 2007
#7
  • Dec 3, 2007
  • #7
No popping with my Flows either.
 

M.P. Cobra Fan

New Member
Aug 10, 2007
19
0
0
Atlanta GA
Dec 3, 2007
#8
  • Dec 3, 2007
  • #8
Every car I have had that has had flows has had a popping when I came off high RPM's or downshifted.
 

BlackGT4.6

New Member
Jun 15, 2005
103
0
0
In.
Dec 3, 2007
#9
  • Dec 3, 2007
  • #9
if it pops like that it has an exhaust leak. The popping is the exhaust sucking in air and then it explodes.
 

2000fordstanggt

Member
Sep 6, 2005
404
1
16
Westland, MI
Dec 3, 2007
#10
  • Dec 3, 2007
  • #10
i know 100% that i do not have an exhaust leak though. how bout you m.p.?
 

BurningRubber

10 Year Member
Dec 6, 2004
1,865
24
58
Dec 3, 2007
#11
  • Dec 3, 2007
  • #11
With an offroad mid pipe it can/will pop, even sometimes with a catted mid pipe it can pop on deceleration.

An exhaust leak on deceleration would sound more like a hiss or air being sucked into something.
 

2000fordstanggt

Member
Sep 6, 2005
404
1
16
Westland, MI
Dec 3, 2007
#12
  • Dec 3, 2007
  • #12
BurningRubber said:
With an offroad mid pipe it can/will pop, even sometimes with a catted mid pipe it can pop on deceleration.

An exhaust leak on deceleration would sound more like a hiss or air being sucked into something.
Click to expand...

right, when i first bought the car it had a stud broke off the exhaust manifold and it sounded...embarrassing. now i hear something rattle near the back right around 2k rpm. where are the heat shields?
 

georgio440

Member
Nov 22, 2007
195
0
17
Walnut Creek, CA
Dec 3, 2007
#13
  • Dec 3, 2007
  • #13
My Magnaflows do it. I personally love the crackling/popping. My old Dakota did it, too.
 
B

[BlackDiamond]

New Member
Sep 19, 2005
119
0
0
Dec 3, 2007
#14
  • Dec 3, 2007
  • #14
Mine only pops if I disconnect the IAT connection on the intake, maybe yours is disconnected?
 

eliteJAE

Member
May 29, 2007
0
1
16
Stanford University
Dec 3, 2007
#15
  • Dec 3, 2007
  • #15
i have flows and i get that throaty popping sound when i engine brake or decelerate, seems normal, other mustang at school does the same, no exhaust leaks on his for sure.
 
G

GTtopLESS

New Member
Nov 8, 2007
79
0
0
Dec 4, 2007
#16
  • Dec 4, 2007
  • #16
I have catted X with Flow 50 series cat- also have slight crackle when letting rpms rev down. I think it sounds tight
 

lazerred02

New Member
Nov 19, 2004
190
1
0
FT Stewart, GA
Dec 4, 2007
#17
  • Dec 4, 2007
  • #17
2000fordstanggt said:
right, when i first bought the car it had a stud broke off the exhaust manifold and it sounded...embarrassing. now i hear something rattle near the back right around 2k rpm. where are the heat shields?
Click to expand...

I sometimes hear that rattle around 2k also, I checked all my exhaust connections. They were all tight and no leaks, thats weird how it just happens right at 2k and thats it.
 

M.P. Cobra Fan

New Member
Aug 10, 2007
19
0
0
Atlanta GA
Dec 4, 2007
#18
  • Dec 4, 2007
  • #18
2000fordstanggt said:
i know 100% that i do not have an exhaust leak though. how bout you m.p.?
Click to expand...

No exhaust leaks here!
 

04GTMustang

New Member
Feb 28, 2006
348
0
0
Stafford
Dec 4, 2007
#19
  • Dec 4, 2007
  • #19
my guess would be if other peoples flows are not popping u might have an exhaust leak somewhere. I know ive got a leak somewhere with my exhaust i think its where my xpipe connects to the manifold. but i have a sort of rattle sound around 2k and under when im hitting the gas. its not a ping type rattle. and it pops on decel but im pretty sure all borlas pop a good bit on decel lol.

i would check everything again something may not be lined up properly and ur just not seeing it.
 

Twista

Active Member
May 7, 2004
510
2
29
@ the z00 in chicago
Dec 4, 2007
#20
  • Dec 4, 2007
  • #20
when i had flows the ONLY.. i mean ONLY time they popped is when i did something stupid.

Thats:

Revving the engine up in gear while driving when the engine was cold as ****. As the revs would drop the flows would POP like pop corn REALLY REALLY REALLY loud. didnt do that much and yes its bad for the engine, but thats the only time it would POP like that.
 
  • 1
  • 2
Next
1 of 2 Next Last
You must log in or register to reply here.

Similar threads

G
Quiet my 2015 GT on the cheap
  • gsrblack
  • Feb 12, 2025
  • 2015 - 2023 (S550) Mustang -General/Talk
Replies
6
Views
715
2015 - 2023 (S550) Mustang -General/Talk Apr 16, 2025
gkomo
Engine Suggestions on an engine rebuild. Stock cam/GT40Ps or aftermarket on both for a fun weekend driver?
  • MadSquirrelTech
  • Apr 28, 2026
  • Fox 5.0 Mustang Tech
  • 2
Replies
23
Views
578
Fox 5.0 Mustang Tech May 7, 2026
MadSquirrelTech
Place to Avoid: Jamison Auto Group in Gulfport, MS
  • D Durden
  • Oct 20, 2025
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • 2 3
Replies
45
Views
2K
1965 - 1973 Classic Mustangs -General/Talk- Feb 4, 2026
nickyb
Progress Thread Progress Thread- From6to8's 1994 Cobra Supercharger install
  • from6to8
  • Sep 25, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 20 21 22
Replies
420
Views
8K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 6, 2026
from6to8
S
Upgrade Advice on an 89 GT Convertible NJ
  • SteakDad
  • Apr 17, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
10
Views
817
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Apr 18, 2025
limp
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?