4.0 exhaust ???

[drofforev5]

Alrite i've been wanting an exhaust for the 04 for awhile and been throwing around the idea of building one. Somewhere i read that the 4.0s actually need some backpressure for maximum power. I love the straightpipe roar but seeing i drive it 90 miles a day and its illegal not an option. Anyway all the kit exhaust dont seem to be true duals. Plus when i put the exhaust in i want to add headers cause i hear they make a big improvement and i doubt these exhausts will bolt up. Anyway now im wondering what to do about mufflers i want a lot of noise but not deafening but mainly what will give me the most power. i no cats are to be considered too. . Looking at flowmaster mufflers but the seem a little tame. Any input will be appreciated. thanx

 

[Scotty J.]

JBA Headers, Cat Delete with a FlowMaster dumped just past the cab. You'll like how it looks and sounds.

 

[Downey]

JBA Headers, Cat Delete with a FlowMaster dumped just past the cab. You'll like how it looks and sounds.

your going to get in trouble for saying get rid of the cats, but that would sound sick i have no cats or mufflers on my truck

 

[FordRambler]

Flowmaster isn't tame. one of the best mufflers id say for sound wise. I have the 40 series dual out and my 4.0 has a real nice rumble to it

 

[Original_Ranger84]

Cat delete I would assume means remove one of the oodles of them from under the truck not all of them...

 

[Madracingalley]

Ok... First off.
I have tried 7 different exhaust systems so far, all on manifolds through cats

-Factory...Too dang quite, I can't hear myself shift.
-Factory, modded Cherry Bomb. little louder, litte gain of power
-Modded 2.5" Cherry Bomb 2.5 out the side. Sounded great, Bad torque curve.
-Modded 2.5" straight out the side. LOUD!!! LOST ALL TORQUE
-Modded 2.5" with Thrush Turbo to downpipe. Quiet. GAINED a Crap load of power
-Modded 2.5" Straight to 3" Flowmaster super 40 no tailpipe LOUD RUMBLE. Interesting torque curve. felt faster at first, yet after awhile it got real slow.

THE BEST I'VE FOUND
-Modded 2.5", to 3" Glasspack, to 2.5" 90degree curve out the side. Best I've found yet, although the way i have mine hung it created a cool sounding exhaust leak. If I could hang it right, It would sound way better. TORQUE AND POWER INCREASE 2 FOLD!!!

my 5 cents

 

[TheBeast]

Catless here. From the factory flange, 2.5 all the way back to a flowmaster, dualed out. Sounds good. May put a cat back on it though.

 

[Dweano]

Hey mtnrgr you seem all for cats. All the old timers around here are telling me to not bother with cats cuz i will get so much better power and mileage, but I personally do not beleive them and agree with you. But I have no facts to back me up haha. Keeping the cat on doesn't hurt economy does it? Sorry for the thread jack.

 

[Dweano]

Alright thanks man

 

[dirtracer81_2]

Ok heres what I got....I knocked everything out of my oval shaped things(secret word) stock piping back to where the original muffler was. I had a glasspack and didnt like it at all. I bought a turbo muffler it sounds better has alot of back pressure when you down shift at around 3000.. It sounds ok for the price I really want something else I would like a flowmaster but im not paying that big price.

As for gas mileage with no ovals I actually gained a bit im not sure if they were clogged or what but I will get anywhere from 17 to mid 18 mpg and mine is a 98 4.0 5spd 4x4 with 32 x 11.50s. Most of my miles come from the interestate but its still good mpg.

Ok my input on taking the stuff out of the ovals..
If I had it to do over again I would have never done it. It made really no sound difference with the muffler im using but I will not complain about the extra mpg.