I have a 2003 F150 Super Crew FX4, 4x4, 5.4ltr V8. It feels alittle sluggish, so I'm putting on Flowmaster 40 series single in , dual chamber, dual out, with 3in SS tips. Then I ordered a K&N cold air intake which I will install when it comes in. Has anyone else done this and what difference did you feel? Did you get any better gas MPG? What about performance? I was also thinking about getting a computer tuner if I was not satisfied.

I pull a travel trailer once a month and want proper performance when towing.

 

if you want more power with a nice mellow sounding exhaust go to www.gibsonexhaust.com i installed a single swept side exhaust system on my 03 f 150 with the 4.6 engine and it woke the engine up. it definetly has more horsepower and torque and it has a nice agressive tone when you get on it. it doesn't have that annoying drone everyone has on their trucks. it's power range is from 1800-3000 rpms, perfect for low end power and towing. the system ran me about 300 bucks but it was definitley worth it. it was so easy i did in my own driveway. it took me all day but i tried to do it right. it looks, sounds, and performs better than any other aftermarket exhaust on the market.

 

I had that exact set up on my 99. I also noticed that when i installed the FM I lost a little low end. But I dumped it so.. Also the K&N did add a little go but not too much. My suggestion is get a tune up, clean the Throttle body, MAF, clean injectors, and run some sea fom in that(this worked great on mine) Then if you dont see much improvement, let me know and I have a Superchips Micro Tuner for you that will fix all that!!

 

A Microtuner will do way more for performance than the other two combined. If you want performance improvements by changing the exhaust, avoid Flowmaster and other baffle style mufflers as they do not flwo as much air as straight through designs. Also, avoid custom hacks from local shops. They don't dyno test their work.

 

You are going to most likely notice reduced mileage, as you won't be able to keep your foot out of the floorboard. All the talk of reduced low end is a bunch of horsechit. If you can notice a loss of 2 or 3 pounds of torque, then you my friend would need to go to work for NASA. Flowmaster flows better than a conventional factory exhaust, and made a name for itself on some of the worlds fastest drag race mustangs. (they wouldn't put crap on their cars) I will agree however, that adding little things like exhuast and intakes won't signifigantly increase your bottom line HP numbers (you would however notice more of an increase with the intake than you'd experience loss of TQ with the muffler since everyone here has an *** that is better than a dyno)

 

Ahhh...the lovely newbies...answering one question with something competely different.
But Bowkil, I'v done the same thing you have. I started off with a Flowmaster 40 series, si/do with 3 1/2 tips. That woke it up in the power and especially the sound dept. I got a 1 MPG increase from that. Soon after, I got a K&N FIPK. Also helped with the power. Now I have an Edge Evolution Programmer, and everything is great!

 

Z, that didn't sound like a newbie, it sounded like a vendor pushing product.

Thats like me saying I want a new ferrari and you telling me about the great lambo down the street

 

I have dyno experience adding these three things individually and all together. When adding just a cold air intake on a vehicle, we actually lost power. The engine can only inhale what it can exhale. The better it breathes in and out the more power you will achieve. As with why we lost power on the cold air, I cannot say. Next we put just catback exhaust on. Gained a lot of torque (around 20 ft lbs,) and some horsepower. The tuner did the most and definetly woke the engine up from hibernation. The next thing we did was the Cold air and cat back combo. Big improvement. After that we installed the tuner in the dyno room (only takes a few minutes), and ran it with all three. It is amazing how much these three items will compliment each other and make an engine come alive. If you want the best bang for your buck, spend the 800- 1000 dollars (depending on the components you buy) and install all three. You will notice the power and love it!
Hope this helps

 

Shoot, I dont know about Nasa but I definetaly lost some low end grunt. Anyone of my friends who have F150 feel the difference from mine to their stock 5.4s.