• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Slow after Dynomax install

  • Thread starter Thread starter fastrev
  • Start date Start date Aug 23, 2004
F

fastrev

New Member
Aug 5, 2004
14
0
0
Aug 23, 2004
#1
  • Aug 23, 2004
  • #1
I replaced my Flowmaster mufflers (don't know the model) with Dynomax Super Turbos. The Flowmasters were so loud inside I couldn't hear my stereo. I have a noticable loss of power. My car used to put you back in the seat before the install, now it's very slight. I thought they had a good flow rate. Did I miss something? I have an H pipe. I'm bummed!


I welcome any suggestions!
 

DMAN302

My mom says thanks for the pearl necklace.
Nov 8, 2003
2,120
2
59
windsor, Canada
Aug 23, 2004
#2
  • Aug 23, 2004
  • #2
Muffler will NOT affect your performance...I think you are being fooled by the exhaust note change. Mufflers add NOTHING to a stocker except sound.
 

mustangsquared

Founding Member
Jun 8, 2002
828
1
16
new bern nc
Aug 23, 2004
#3
  • Aug 23, 2004
  • #3
I disagree...muffs and cats create back pressure...you need some for torque...put a 3 inch exhaust on a stocker and it will feel sluggish from the lack of back pressure/torque. I doubt that the muff change created a HUGE change, but it may have created a small one. I lost torque when I punched my cats out.
 

DMAN302

My mom says thanks for the pearl necklace.
Nov 8, 2003
2,120
2
59
windsor, Canada
Aug 23, 2004
#4
  • Aug 23, 2004
  • #4
I will never believe anyone who says a stocker gained any advantage from changing muffler A to B when both are good quality mufflers..I have gone from stock to 2-1/2" LT's with an H to flowmasters an yes the car sounds bad ass but SOTP was negligable. If you are going to tell me that this person has experienced net HP + or - of 2% with a muffler change only then you need to shake your head. Yes backpressure is a factor, and yes 3" exhaust is excessive and will affect you BUT Flowmasters to Dynomax swap alone will NOT affect anything but sound period, and that is ALL he has indicated he has changed..not pipe diameter nor header style.
 

stangbear427

Active Member
Nov 11, 2002
2,401
1
49
New England
Aug 23, 2004
#5
  • Aug 23, 2004
  • #5
I'm with both of you on this one- it logically follows to me that especially if it was a stocker, going to a quieter muff would increase power since it's putting some of that necessary backpressure back into the loop. It isn't always the case, but usually louder= less backpressure. ON that note, if this is a 347 with 12psi of vortech on top, than it only makes sense that the quieter Dynomax's cut down the umph a bit. Brand to brand differences on a stocker are mostly in the imagination. However, he never said the car was stock, did he? I think we need more clarification of the combo here before jumping down each others throats for saying the same thing two different ways... just my $.02
 

89MustangGX

I have nothing productive to add!
Jul 3, 2001
10,262
1
0
Mill Creek, WA
Aug 23, 2004
#6
  • Aug 23, 2004
  • #6
The DynoMax's usually make more power than Flows -- it's just the nature of the muffler. What you are experiencing is probably all in your head.
 
F

fastrev

New Member
Aug 5, 2004
14
0
0
Aug 24, 2004
#7
  • Aug 24, 2004
  • #7
It wasn't in my head!

Well it wasn't in my head, it was in my gas tank!
Just after I installed the mufflers I filled up at a different gas station than usual. I realized this today and filled up at my usually station this morning. She's running good again!

And you all thought I was loosing it
 

DMAN302

My mom says thanks for the pearl necklace.
Nov 8, 2003
2,120
2
59
windsor, Canada
Aug 24, 2004
#8
  • Aug 24, 2004
  • #8
????????????????????????????????????
 
You must log in or register to reply here.

Similar threads

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
9K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 6, 2026
from6to8
For Sale 3-owner 1987 Mustang GT, $18K obro, Lancaster CA
  • Bill Cool
  • Oct 6, 2024
  • Fox Body Mustangs For Sale (1979-93)
Replies
4
Views
2K
Fox Body Mustangs For Sale (1979-93) Oct 13, 2024
nickyb
J
Progress Thread Family member 1989 GT- Backstory and updates
  • JRC99
  • Apr 19, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
15
Views
1K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Oct 26, 2025
JRC99
J
C
Quiet Exhaust
  • Crigano
  • Mar 27, 2022
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2 3
Replies
48
Views
6K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jul 3, 2022
chrlsful
C
87 LX 'Vert
  • fun331
  • Jun 15, 2023
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
27
Views
4K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Oct 30, 2024
Mustang5L5
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 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?