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

High flow cats

  • Thread starter Thread starter 87whtecoupe
  • Start date Start date Mar 4, 2013

87whtecoupe

New Member
Jan 28, 2009
10
0
2
Mar 4, 2013
#1
  • Mar 4, 2013
  • #1
I have an 02 gt with longtube headers, offroad x-pipe and slp loudmouths. It sounds fantastic, but my daily is under the knife at the moment so the gt is currently my DD. It doesn't get good mpg's on the highway, it's terrible. I'm considering installing some cat converters, but will high flow cats improve fuel economy? Or should I just stick with the regular ones? Plus I may be getting old because the sound is starting to annoy me.

P.S. my everyday driver is an 88 turbo coupe, it gets 20 city/ 32 highway. It is currently in the middle of a brake conversion.
The mustang gets less than my 03 Durango, which is rated at 15 city/ 20 highway.


Thanks.
 

trinity_gt

10 Year Member
Jan 31, 2003
3,125
81
99
Canada
Mar 4, 2013
#2
  • Mar 4, 2013
  • #2
Cats will not help the fuel economy of the Mustang. They will mellow out the exhaust sound though...

Check for dragging brakes, slow/lazy/contaminated O2 sensors, tire inflation etc.
 

snowman23

Member
May 2, 2005
242
6
19
"in every direction"
Mar 5, 2013
#3
  • Mar 5, 2013
  • #3
I have the MRT catted H on my 04 GT which has 2 high flow cats rather than the 4 stockers. Definite change in tone/volume of exhaust. Slight increase in throttle response. No change in fuel economy. That being said, is one of my favorite mods to date. Good luck.
 

The Mach Life

Member
Dec 27, 2012
33
1
8
Traffic Ville, Virginia
Mar 5, 2013
#4
  • Mar 5, 2013
  • #4
I had gotten mid-high 20's a few time in my 00' GT. Not kidding however when I say you have to baby it big time to get there.

Cats will only help with sound.

Do you have a CEL? What gearing? Is it warming up completely? I had to change my thermostat twice in less than 5 years time. That was worth a couple MPG every time it started sticking.
 
You must log in or register to reply here.

Similar threads

Fox Xtremely high fuel consumption
  • PonyGTrider
  • Apr 11, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 9 10 11
Replies
213
Views
4K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 9, 2026
PonyGTrider
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
903
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Apr 18, 2025
limp
Fuel 19lbs EV6 fuel injectors, what fuel pressure???
  • PonyGTrider
  • Jul 11, 2024
  • Fox 5.0 Mustang Tech
  • 6 7 8
Replies
144
Views
11K
Fox 5.0 Mustang Tech Jul 25, 2024
PonyGTrider
Exhaust recommendations to save my poor aging ears.
  • CWBx
  • Sep 3, 2021
  • 2005 - 2014 S-197 Mustang -General/Talk-
Replies
2
Views
1K
2005 - 2014 S-197 Mustang -General/Talk- Oct 30, 2021
96stangfl
9
S
Fox 1992 LX 5.0 convertible
  • Scott_S
  • Jan 17, 2022
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
30
Views
4K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 4, 2022
Gs1987GT
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?