How much HP will a 4" mufflex with Flowmaster muffler support?
#1
TECH Apprentice
Thread Starter
iTrader: (3)
Join Date: Jan 2002
Location: St. Charles, IL
Posts: 398
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech20year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
I have been searching and can't find any results...... I have heard that the flowmaster used in the 4" mufflex flows like crap. Some reports of picking up 28 rwhp by switching to a borla xr-1 in place of the flowmaster???
I had it on my car and LOVED the way it sounded. I took it off due to being heavy and trying a true dual set up with bullets. Well, the duals are going on another car and I am contemplating putting the mufflex back on this car. It will be a 6.0L heads cam motor with A4 and SS4000 yank. Hoping for 450-470 rwhp.
Question is..... how much hp can the flowmaster muffler support effeciently?? Would I pick up 25 hp with a different muffler or another true dual setup??? I don't care about 5 rwhp... however 25rwhp is a BIG deal. Anybody have a before/after dyno result?
Thanks
I had it on my car and LOVED the way it sounded. I took it off due to being heavy and trying a true dual set up with bullets. Well, the duals are going on another car and I am contemplating putting the mufflex back on this car. It will be a 6.0L heads cam motor with A4 and SS4000 yank. Hoping for 450-470 rwhp.
Question is..... how much hp can the flowmaster muffler support effeciently?? Would I pick up 25 hp with a different muffler or another true dual setup??? I don't care about 5 rwhp... however 25rwhp is a BIG deal. Anybody have a before/after dyno result?
Thanks
#2
TECH Addict
iTrader: (1)
Join Date: Nov 2001
Location: Michigan
Posts: 2,161
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
You'll have to do a search.. I know I have seen some write ups about it. Guys have also switched to the magnaflow, and been happy with the results. If my memory serves me, it was more than 5 hp gain by getting rid of the Flowmaster.
#3
TECH Apprentice
Thread Starter
iTrader: (3)
Join Date: Jan 2002
Location: St. Charles, IL
Posts: 398
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech20year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
I searched under mufflex and flowmaster. Find a bunch of stuff, but not what i am looking for. Plenty of how the transverse spintech sucks and the same with the flowmaster cat back. However, nothing on the mufflex with the flowmaster.
#5
TECH Apprentice
Thread Starter
iTrader: (3)
Join Date: Jan 2002
Location: St. Charles, IL
Posts: 398
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech20year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
I don't want to do this test myself since I am buying new headers and don't want to spend money on a Y if I am going to end up true dual again.
#7
TECH Apprentice
Thread Starter
iTrader: (3)
Join Date: Jan 2002
Location: St. Charles, IL
Posts: 398
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech20year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
The any of the straight through mufflers will work and flow well..... straight through is obviously minimal restriction... BUT how will it sound???? I don't want it to sound like azz or be super loud. I just wish flowmaster could get thier **** together and make something flow well while sounding good.
Trending Topics
#10
TECH Apprentice
Thread Starter
iTrader: (3)
Join Date: Jan 2002
Location: St. Charles, IL
Posts: 398
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech20year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
I had FLP long tubes, 2.5" y with 3.5" flowmaster merge going to 4" mufflex. After I shot the muffler off the car when it was loose one day.... I started thinking it was a RESTRICTION! Then I chopped the y, put in magnaflow 2.5" X, and ran 2 24" long dynomax bullets side by side where the single int pipe use to go. I had awsome ground clearance and it sounded good. Those headers are now looking tired (dull grey and been patched where the emissions fittings fell off) and that setup is going on my road race car. I had planned to buy new headers for the other car and since I still had the mufflex, I was going to maybe put it back on. I tried to run the duals on each side, but had a lot less ground clearance that way. Only issue I had was to make sure the drive shaft didn't come down and rub on the muffler. I may go that route again, but am not sure....... I just loved the way the mufflex sounded.
#12
TECH Apprentice
Thread Starter
iTrader: (3)
Join Date: Jan 2002
Location: St. Charles, IL
Posts: 398
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech20year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
That is what i was thinking. IF i go with a Y, it will have the dual 3" to single 4" flowmaster merge. I'm not even going to mess with the dual 3 to single 3 stuff......
#15
Launching!
Join Date: Mar 2004
Location: SUGAR GROVE TOWNSHIP ILLINOIS
Posts: 266
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
![Grin](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_grin.gif)
![Devil](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_devil.gif)
I use to live in St Charles also...
#19
TECH Apprentice
Thread Starter
iTrader: (3)
Join Date: Jan 2002
Location: St. Charles, IL
Posts: 398
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech20year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Probably will be stuck going back to true duals......
#20
9 Second Club
iTrader: (23)
Join Date: Oct 2002
Location: Mastic Long Island N.Y.
Posts: 1,150
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
I made my own muflex style setup. 3" custom Y into a flowmaster merge out to 4 inch over the axle with a Hooker max flow 4 inch muffler. This gained me 14RWHP over the SLP dual dual that had a Kooks 3" Y catless as well.