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-   -   True duals on '03 f-150 (https://www.f150online.com/forums/exhaust-intake-systems/199332-true-duals-03-f-150-a.html)

Mervin 05-30-2005 12:06 PM

True duals on '03 f-150
I just got off the phone with a local muffler shop and the guy told me I couldn't go with true duals on my 2003 F-150 (single cab, short wheel base, 5.4l, auto.) He said i would have to add another converter because there must be a converter for every pipe coming out of the engine. He told me that you cant run true duals on newer vehicles that i would just have to go with single in dual out but i dont think this will give me the sound i want. I was wondering if i could run two pipes out of engine, both with converters, straight back into mufflers then out the back of the truck, use like an H-design on it? would this work or is the muffler shop guy right?

max mitchell 05-30-2005 01:22 PM

He's incorrect. Your truck has cats on BOTH head pipes from the factory. Converting to true duals is a common exhaust mod on these trucks. You simply chop each head pipe off behind the cats, but before they Y-intersection. Then, you add your system of choice. Crawl under your truck and you can examine the multi-cat setup, individual head pipes, and Y-intersection. Also, you may want to deal with a different muffler shop that's familiar with this set up.

GoRacer 05-31-2005 09:02 PM

Borla makes true duals but they are extremely expensive.


joebronco94 06-02-2005 10:08 PM

find a different shop. mine is done with true duals. all the new fords from 97 and up can be done. i couldnt do my bronco like that because it only has one cat on it.

Mervin 06-04-2005 01:55 PM

I just went over today to get the single in dual out exhaust, before i checked my replies. The exhaust setup sounds okay but it is not loud at all. I think i just wasted my money. Ive got 2 converters from both head pipes, how many is required by law or whatever to get it inspected? Is there anything i can do to save my exhaust and make it loud? It has a good sound, just not loud enough. You cant even hear it idle. PLEASE RESPOND

Bartak1 06-04-2005 02:54 PM

If you dont have emission checks, rip the cats off. If you do, take em off, gut them, and put them back on.

Since your pickup has 4 cats on it total, thats whats required by law. You have to have how ever many came on the vehicle stock. I think thats how it is evrywhere, but your state might be different.

Or rip off the muffler and put a y pipe there so the 1 pipe splits back into two.

Or finally, take it back to the shop, and have them put in 2 pipes where they put the 1 pipe. Its not illegal to do this.

fordninja 06-04-2005 11:45 PM

I have single that splits to dual with a Y pipe and it is quite loud. I only have the 4.6 too!

Regulator54 06-05-2005 03:14 PM

As everyone else is saying, duals are a real possibility for your truck. I ran dual 2 1/2" pipes to a DI/SO Flowmaster with a single 3" tailpipe. All is fine. See my posts on the results.

Green_98 06-05-2005 11:57 PM

I have a 4.6 with the cut out muffler/Y pipe/dual tail pipes, sounds great, nice and loud rumble. Going to true dual straight pipes soon off of the stock cats...true duals sound better!

CEE21 06-06-2005 04:47 PM

If you do true duels, be sure to install a h or x pipe to keep your power on the low end because everyone on here that have done duels without them say that they have lost some low end torque.

GoRacer 06-06-2005 06:54 PM

If you wanted loud, you should have bought a Roush. It is off road only, wich means "loud". http://www.roushperf.net/ :bandito:

Texzin 06-06-2005 10:40 PM

I just had duels installed from the cats to the new flowmasters and just dumped them out 4 inches behind the flowmasters on my 2004 F150 FX4 screw I will get pics when i get time.

Sound is great and did not lose any low end. I will let yal know how the mufs do as I have some time to test things out.

4x4SUPERCREW01 06-07-2005 07:56 PM

I just had duals put on my 01 f150 5.4 from the cats back to two 1 chamber flowmasters with 5 inch tips.Sounds great and did not affect the low end or anything else.

Mervin 06-07-2005 11:11 PM

appreciate all the advice. i am going to have to do something now to fix my exhaust. either gut the cats or might try to go ahead and get the duals. havent decided. let ya know how it turns out.

higdogg 06-12-2005 10:17 PM

'04 True Duals?

Originally Posted by Texzin
I just had duels installed from the cats to the new flowmasters and just dumped them out 4 inches behind the flowmasters on my 2004 F150 FX4 screw I will get pics when i get time.

Sound is great and did not lose any low end. I will let yal know how the mufs do as I have some time to test things out.


I have an '04 5.4 new body style f150, and was told on the phone by flowmaster that it would rob me of power to run a true dual setup, because I was wanting that good sound of true duals. He told me that 1 muffler is sufficient for the engine, sounds good, and will not cause the engine to lose any power or torque, but that 2 mufflers would cause this. I was disappointed, always wanted exhaust that sounds mean with a growl to it, not like these softer sounding magnaflows that everyone is getting. So are you really sure that you aren't losing anything, were you told this at the exhaust shop or what? I am going to buy flowmaster for sure, just not sure what my setup will be, and hopefully I won't lose any power. Did you buy the original 40 series or the super 40 series? What is the big difference in them? I have heard the super 40 has that "delta flow" technology or whatever?? and that it is supposed to be quieter or something. I am trying to find out which one sounds best. Anyone who has any help on this please post, I am really lost for what to do. I also considered the banks monster exhaust, but have never heard one on a new f150, plus they don't offer a SI/DO package like I want.

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