I have a 2004 F150 FX4 Supercab, I'm wanting to replace the exhaust on it. I am considering just replacing the stock muffler with a magnaflow s.s. muffler, or a flowmaster super 40. What is your opinion. Also is the magnaflow cat-back system worth the money over just replacing the muffler.

 

Yeah, what he said??? Also, si/so or si/do?

thanks

 

Chosing between the two companies when just replacing the muffler should just be based on sound preference. Baffle vs. straight through are distinctly different tones. I prefer Magnaflow's smoothness but Flowmaster has the larget following.

I think you get 3-5 wheel horsepower by just chaning the F-150 muffler and more like 8-12 wheel horsepower by doing the whole thing.

 

Hi I have a Flow Master S/S system all the way back
nice sound don,t know the MPG increase, but It helps, I hope.
It gets a little droney at 50 MPH but , most speed limits are above or below that. Dave

 

I had the Magnaflow SI/DO on my truck but it just did not sound as good as my old Flowmaster 40 series did. This Saturday I changed it to the Flowmaster Super 40 SI/DO using the same pipes I had from the Magnaflow system out the rear. I have the 4.6 engine.

I got my Flowmaster sound back at low speeds and around town. Like dk9141 said there is a distinct droaning at 50mph or more specifically at 1500 RPM but it really is not bad. I did a two hundred mile round trip Sunday at highway speeds and above 55 mph I could not make it drone.
The Super 40 is much better for day-to-day living then the old 40 was. It is suppose to flow better also. Performance wise I feel no difference in the Flowmaster Super 40 and the Magnaflow I removed.

I don't know if this helps or makes the decission harder but my vote is for the Flowmaster Super 40.

 

simple answer for a simple question. do you want sound or performance. b/c i paid $377 for my magnaflow. isnt loud but my truck does breathe alot better. plus the pony gains! so, easy decision, are you gonna try to put every ounce of performance, or do you want it to sound mean??

semper fi

 

I felt no "seat of the pants" difference in performance between the two. I'm probably the only one crazy enough to switch out a perfectly good muffler just for the sound and so may be the only one here able to give an actual side by side comparison...

I did not dyno either.

If I remember correctly (the gray matter isn't what it use to be) there was a seat of the pants improvement when I switched from the non-delta flow Flowmaster 40 to the Magnaflow. I think this Super 40 flows much better then the old 40 does.

There ain't nutten like the growl of a Flowmaster on a V-8

 

Now is it better to have the duals or stay with the single. People i have talked to say it is what you want, the look of the dauls or not. Or is the performance better with dauls.

 

WLF:
Nope you are not the only one to do that. I plead guilty also,
crazy old man ,I guess! Dave

 

Personally I think it is a matter of taste. I like the look of the duels out the back.
There is a lot of back and forth about backpressure. On a recent show on Speed Channel Two Guys Garage they put an aftermarket muffler on a 2003 f-150. They did not identify the motor size but did say it was a V-8. They first measured the back pressure at the Oxygen sensor with the stock muffler and while gunning the engine there was zero, none, 0, notta backpressure at the oxygen sensor while gunning the engine. The same was true after the install. The premise was to install a new muffler that creates a vortex or vacuumed to further increase flow. I think flow is much more important than anything else and I think the stock 2 1/2 inch pipe will handle just about anything a stock or slightly modified F150 will put out.

 

Well...three years ago I had true 2 1/2" duals with 40 series flows and 3" tips put on my 5.4. I sware there was a power increase...despite what some people say. All I know is, whenever I fire that truck up...I fall in love all over again.

MR

 

Thank God! Magnaflow all the way! If you tow, the SISO catback system is great. It's easier on the front of your trailer, and won't choke you todeath if you let the truck idle while you're hooking up.

-Mike-

 

I totally understand. The Magnaflow is a nice system.
As far as towing, I've had duels for 18 months or more and tow a small 5th wheel about 4000 miles a year. Never have smelled exhaust.

Yesterday I ran into a neighbor at the local Walmart. He asked me what I did to my truck, "sounds good"... NUFF SAID...

I'll include this picture so you can see the trailer in the back.

 

I love the rumble of the mufflers but i don t want to have yell over the sound to talk the person beside me. So will i get noise with the flowmaster dauls.

 

Had a Magnaflow installed with the same SI/SO 2.5" setup as a previous Gibson. The Magnaflow gives me a nice sound with acceleration but is generally quieter, which my allergy stopped . I need less downshifting now in the Texas hill country than I did before.
Good luck.