i went from a magnaflo si/do to true dual straight pipes on my 04 not as loud as you think but has lost power on bottom end thinking of putting an x-pipe in to see if it helps love the straight pipe sound done mine lightning style. there is drone from 1500-1800 rpms but thats what i like to hear them pipes sing
alright i got a 03 4.6 and i've run all 4 cats and true duals straight pipes for a year and today i put on 2 dynomax bullets cuz i was sick of the loss of the low end torque. its a very noticeable loss and it sounded like a rat rod, cool but not worth it at all. next weekend i will be taking off the cats and putting on an x pipe. DO NOT do true duals without a muffler it absolutely sucks on the low end. and be wary of flowmaster, they got great sound but alot of baffles that kill flow and power
2003 4.6. FX4. T-bars maxed.
285/70/17 Cooper STT. K&N FIPK II.
X-pipe w/ Dynomax Race Bullets.
TSC black diamond plate toolbox.
Husky custom floor liners. CARR hoop IIs.
Cobra Ultra III CB. 4' Firestik. Line-X bed.
Custom front winch bumper. #94106 Maggie Cats. 12500lb Tuff Stuff winch.
Ranch hand rear bumper. Nerf bars. PHP Gryphon.
i went from straight pipes to a 14" magnaflow and i love the sound 10 times better because i no longer think loud exhaust is cool like in my high school days. I do think i get worse gas mileage now though with the magnaflow...Maybe it was because I had such a free flowing exhaust or something...Keep in mind i have magnaflow hi flow cats on my truck also so they made my straight pipes way to loud. As you can see in my clip
by Dirtyd88 @ screenfx
8.5 inch lift-37's,True Dual Straight Pipes(Dumped/H-Pipe) with Magnaflow High Flow Cats,6k HIDs Heads/Fogs,2 10" Pioneer subs,UWS tool box,Much more.Exhaust Clip- http://www.youtube.com/watch?v=WXqE-KU0AN4
I do think i get worse gas mileage now though with the magnaflow...Maybe it was because I had such a free flowing exhaust or something...
physically you are still runniong straights. Inside the Magnaflows is a packed case and its direct flowing same size pipe, so there should not be any difference than straights. The X pipe will help you.
__________________ 2007 Ford F-150 Lariat Supercrew 5.4L 4x4
i absolutly adore the way my truck's 4.6 sounds with no exhuast under it, i have duals into the cats then like 2 feet of pipe and thats it. low bassy tone and it barks when i get on it. i think it was the reason my plugs fouled early tho and why my egr is bad? im thinking of running some more pipe to get a little more back pressure out of it tho. i put on a pair of glassback a few months back and it didnt really change the sound too much when i punched it, buti didnt like it cuz i couldnt hear the rumble as good in the cab at idle and i mean hell i do stuff to my truck for me so i took them off the same day.
I really never liked the sound of most Ford motors. It was just something about the overlap of the exhaust valves around 1.5K R/m.
However I have been running the same Flowmaster SI/SO system for the last 9 years, and wouldn't want any thing else. When my OEM rusted out I replaced the complete "cat-back" with mandrel bent 3", and 2.5" dia. stainless steel pipe; along with the aforementioned Flowmaster muffler. Most of the OEM installs that I have seen have short bend 2.25" pipe from the converters outputs.
I tried the "muffler-less" hook up but couldn't stand it for any given time. In an Expedition the exhaust drone was intolerable, and no improvement in performance could be determined.
It is possible to tune the sound performance of a given installation by changing the relative positions of the components. For a given exhaust system you can change the sound parameters significantly by moving the muffler either forward or rearward of the OEM position to effect such a change. Basically the sound will be a little louder and deeper if you move the muffler rearward of the standard position. That is either behind or above the wheels (Differential) toward the bumper.
Mounting the muffler closer to the engine for a given installation will result in a "softer" sound at lower R/m's due to the capacitive reactance of the muffler with respect to the reluctance of the length of pipe following the muffler to the rear. Moving the muffler behind the differential has the opposite effect. I have had good experiences substituting the 2.25" pipe for 2.5" mandrel bent pipe which gives me a definitive improvement in both lower R/m torque and sound. Mandrel bending gives a more gentle flow path resulting in better flow.
Due to the rear window my exhaust is still placed behind my PS rear wheels.
Member SAE, Society of Automotive Engineers AES, Audio Engineering Society MACS, Mobile Air Conditioning Society
I love my straight pipes. They were a little too poppy and I did loose a little low end torque (very little) until I added the X pipe. The X pipe made all the difference. The only time I think my straights are too loud is when I tow my travel trailer but that is my own fault for running them out the back bumper so they echo off the front of the trailer. It is not that bad but I turn up the radio to compensate. Since I only tow in the summer it is something I can live with because they look better to me straight out the back.
2003 F150 4x4 FX4 (White): 5.4L, Custom Tuned Gryphon Programmer, DIY Air Intake Mod, Dual 16" Derale Tornado E-fans with DD PAC-2700 Fan Controller, Custom True Duals with X-Pipe and Twin 18" Magnaflows, Factory Tech Separator Plate, F250 SD Trans Cooler, Digital Trans Temp Gauge, Timbren Rear Suspension Enhancement System, Mag-Hytech Rear Diff Cover.
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