2003 F150 XLT FX4
5.4L
Regular cab, short wheelbase

I'm interested in having a custom bent true dual system put on my truck. I've been researching this but haven't gotten a consensus. I've been told by the exhaust shops that there will be no problems with power loss. I've been told the same thing by about half the Ford dealerships. The other half predict a loss of low-end torque. I've been told by some of the shops that I should get the Magnaflow X pipe integrated into this system for maximum benefit. I want to dual from the cats back into a pair of Flowmaster or Dynomax mufflers. Anyone know the facts on this? Are there any adverse affects to power from going to a true dual system on my truck? I'm concerned because I pull a 20ft travel trailer.

 

I don't quite have as new of a truck as yours but I am running true duals on my '99 (5.4) 2.5" with no loss of power. Actually I have run three different exhausts on this truck and this is the best performing one I have found for this truck. I am running straight pipes so I can't help ya with your muffler selection. Also I do not have an X pipe.

 

i second the x pipe.

 

I had switched from stock to a Gibson ST cat-back within 500 miles. 01 SCrew w/ 5.4L
That was a nice system, but I wanted a bit more umph to it, so I went with a Bassani Dual kit. This is the system for the L.
X pipe is included with the kit. It took cutting the factory Y pipe out, adding in a 90* on the driver's side xhst output, and extending the pass side straight back.
A few feet of SS pipe was needed for the SCrew vs the L. If you have a std cab, short bed, the system after cutting the stock Y pipe would be a drop in basically.

This dumps in front of the rear tire.
X pipe to 2 SI/SO mufflers then to the dumps.

I don't know what makes the 50% of the dealers say you will loose TQ, true duals are a HP and TQ add-ons, not loosers.

If true duals created TQ loss, why would the HD and L have true duals from the factory to a DI/DO muffler ? Also why is one of the big upgrades to them a X pipe and 2 SI/SO mufflers ?

Seems that the dealer that say it will cause a loss of TQ don't know what the other trucks that Ford makes have on them.

Go for the change out. it is worth the money, sorry I ever wasted time with the cat back system, the factory Y pipe is a joke. The drivers side into the Y is about 1.5" when it mates up with the pass side 2.5" pipe.

I did mufflers and the X pipe, just be sure to go all 16 Ga 304 SS on the pipe and the X pipe, keep up the heat level in the pipe which adds to the scavenger effects of the X pipe. If you go Aluminized pipe on this, it may not work as well.

Pictures are in my gallery of the install if you want to see it.

Waiting on nicer weather for the Dyno pull, so it is apples to apples with the last one.

Steve

 

With true duals, there is the potential to lose some low end torque, but gain in the high end when compared to stock.

The L's and the HD's are not really concerned with the low end. They want all the power they can get at WOT. They also have the assistance of a nice little blower to help them out of the hole.....

Towing a 20' trailer, you don't really want to be at WOT that much.......

I tow a #4500 22' travel trailer and I'm doing very well with a single 3" system. Started out with a Gibson muffler, but it started to rattle, so got a Flo Pro. All I can say is it tows better with the Flo Pro then it did with the Gibson.

You might also want to consider the exits for a dual setup. Straight out the back is not the best when towing a trailer. Out the side, in front of the rear tire will make it pretty loud in the cab.

Good Luck!

 

5.4L True dual will work, but I highly reocmmend a good x-pipe. If you are not going stainless, pick up the Magnaflow pre-bent tail pipes at Bigexhaust.

 

Huh ?
When doing 1/4 miles, the start is at about 50% TPS, then after about 30', WOT run.

Take a read through the L forum to find out why they do the Bassani or JDM silver bullet conversions ( this is where I started on the dual conversion research )

Lots also go the route of high flow cats and Kooks / JDM long tube headers, which were also claimed to be a TQ loss item, not any more. Dyno sheets show better info then guesses.
TQ out of the hole is part of a good 60' and 1/8 mile times, the high side is the 1/8 to 1/4 mile area of the run.

The other is look at Neal's setup, Kooks headers, high flow cats, and true duals. He has got some nice TQ going on with his setup, and took a SOTP dyno swag at the HP and TQ increase of the setup ( the second place I looked for info on duals before proceeding ).

 

I don't want to sound irrational and stir up a big debate but think this subject was discussed before. Someone asked if putting a stock HD exhaust (DIDO muffler) on his truck would work. A response dictated that it would not work because the HD has a super-charged engine and the dynamics are totally different (HD's inhale a greater volume of air compared to our trucks. This goes the same with the L's. ...and no, I do not have any numbers to show, nor have I seen any, but it's just a thought since that's what I read in the past. I don't have an opinion nor a reccomendation, but perhaps you can consider this as helpful information.

-Mike

 

Mike,
Do you happen to know about the title of that thread ?

I don't recall that one myself.

Steve

BTW : The same type of duals that are on a N/A 5.4 are the same as what would go on a S/C 5.4. 2.5" pipe to an X pipe to dual SI/SO mufflers to dumps.

Nothing different about it.
Check out Neal and Beastie's setups on N/A engines.

 

Oh, I'm sure there are lots of variables to consider and all I was trying to relate to was that Sneaky 03 F150 tows as well. Just wanted to give my comments on how I improved on the low end without having to go to duals.

Hey, if you got the money to go that route, that's great! I think that's probably the correct way to do it if you are really serious about it. But just cutting out the Y and welding up some pipe and a couple mufflers will probably not net the same results.

 

I dont know how to post the thread but do a search on "Harley exhaust" in this forum.



BTW, Steve, thanks for the info on intakes. Looks like im going to order the K&N FIPK gen II.

 

kaliscrew2k2,

I found one thread on the HD system, but it never said anything beyond 1 parts counter guy saying it would cause a loss of TQ.
That one I knew about, as I posted in the thread. I thought there was another thread with a dyno sheet posted.

https://www.f150online.com/forums/sh...threadid=80727

No problem on the FIPK, hope you get where you were looking to go. Did you check in with Mike Troyer before buying one ?

 

MitchF150,

Did you do the change out of the factory Y pipe to a Magnaflow dual 2.5" in and a 3" out when you did the 2nd system ?
On the dyno sheet how much more did you pick up over the Gibson alone ?
Mine is a SOTP dyno, and G-Tech are my only testing right now. I am up over the Gibson ST, but I don't like using that as the final answer. My lauches might be getting better, and my gains could be all in foot times, not engine improvements. Until I get to the similar weather for a dyno pull I won't know for sure. I rather start out similar with the temp and as close as I can get with the baro pressure so my conversions to normalized numbers are as close as I can get to a Washington Apple to Washington Apple comparison. If I did it now I'd have a Washington Red Apple to a South American Apple comparison, which could be skewed ??

As for the system being a kit, the 90* were pre-bent, some straight 16 ga 304 SS pipe ( ~ 33" each side for the SCrew ) and the X pipe to dumps was a kit, but so far I am the only goof ball to spend that type of cash on the dual system. All the others to date are bent on site, and fabricated from the pile-o-parts from Magnaflow. There was some additional bending needed to line up the cat dumps to mate up with what a L would look like.

Neal did his own system in his garage, and Beastie I think had a shop do his. This is a set of SI/SO mufflers, X pipe, tips, and if applicable high flow cats and headers ( depends on which member you are talking about as to how far the conversion went )
All other items are done local. Neal seems to have a guesstimate on the improvement of the Magnaflow mufflers over his flow he had on before. He is waiting on the break in the weather for track times to tell how much better it is.

ChiDiver had a local place around his house do his improved Y pipe ( dual 2.5" to 3" ) and 3" SI/SO to dump system all on site.

Another member went the route of dual straights right now the back, sans the X pipe. Haven't seen the dyno sheet on that one yet.

So the improvements seem to be either in kit form or in built on site form. It is more a matter of getting a reputable shop to do it, so the bends are not jacking up the xhst flow.

Steve

 

My only dyno is the SOTP method too. All I've done is the Cat back exhaust and a drop in K&N. No Y pipe change at all.

I can only speak from how my truck drives before and after the muffler change.

Before (with the Gibson), going up particular hills in my area, I would have to give it more gas and then it would downshift. While towing on the highway and encountering a hill, I'd give it gas, and nothing..... Then the downshift and revving almost 4000 rpms to maintain speed.

After (with the Flo Pro), going up the same hills, I just have to give it a touch more gas and I can now maintain speed and no downshifting. I can even pick up speed in third going up the hill. Towing is the same deal. On the same hills that caused a downshift, I can now maintain speed in third and even gain speed if I give it some more gas, and not downshift.

Towing in third and going 60 mph, I'm pulling just under 2500 rpms. Stock, my peak torque (according to the manual) is 330@3000 rpms. Well, my SOTP dyno tells me I've either increased this or at least lowered my peak to around the 2500 rpm range. I just seem to have much better low end now. Maybe it's because my truck just rolled over 100k miles!

I've never done any official timed run with my rig either. Just some stop light launches and some parking lot burnouts...... It does seem to take off better now and I can break 'em loose with very little effort on wet. (It did take more pedal to break 'em loose before too). This is with 31" tires, 3.55 LS and the additional weight of 4x4.

Anyway, I never meant to imply that those who have done their own systems and who know what they are doing have done a "hack job". I realize Neal is very knowledgeable about these things and am very sure he's done it right. Your setup sounds very well engineered too. I think that's key in any system. I had mine done at a shop that does nothing but custom systems. The only pre bent pipe the guy has is what comes off the new rigs he does.

I seem to recall someone going through quite a bit of work to tune their dual system. Finding that when he opened the system up too much, he lost some low end. He had come up with a "Trap" type exhaust using plates in the tips to control the backpressure or something...... Wish I can remember the member, but it was at least a year ago.

I guess I'm just coming from a different camp in that I don't want all out speed or quickness off the line. I just want to be able to tow my trailer and get away from the Rat Race for a weekend!
The rest of the time, it's my daily driver and I put on over 50 miles a day with it.

But, I do like and appreciate a well tuned exhaust that has been well thought out and of course, a powerful rumble to it.

Can't wait for Winter to end either! Keep us all posted with your Wa Apple to Wa Apple dyno numbers! Always like to hear when someone can improve there numbers! All it takes is more cash!

Mitch

 

I was worried about loosing low end torque by going to a true dual setup, but I took the gamble and it paid off. I went with 2.25" piping and Magnaflow High Flow Cats, Magnaflow X-Pipe, Dual Magnaflow Mufflers and Magnaflow Tips. I gained a nice amount of low end power, but I gained an incredible amout of high end. Look in my gallery for pics of my setup. If I could do this again, I would in a second.