Hey everyone,

I've been thinking about what I'm going to do next on my exhaust. My idea is long tube headers (which replaces all 4 cats) to 3in true duals with some sort of muffler on each piece of pipe, no cats just mufflers. Thoughts? I currently have the stock front cats and straight back from there with PLENTY of exhaust leaks I want to hear if anyone has a similar setup or if this is a bad idea...

Thanks!

 

I forgot to mention the truck is a 2004 f150 with the 5.4 triton. And i only have two of the 4 stock cats which is where the exhaust leaks are. Back 2 cats removed.

 

If you're even thinking of going catless, I take it you don't need inspections, so -

General consensus is long tubes won't do much for you and even rob power unless your engine is modified for power. But they sound great. Same can be said for that upsized dual exhaust.

With no cats and long tubes, I'd get a muffler that has a pretty good sound reduction, unless you're one of those who likes it obnoxious.

And Of course you know what some folks will say about running no cats.

Can't really think of much else. I guess you can't do too much worse than a leaky stock setup

 

Take it from a guy who has long tubes and no cats. The long tubes are great and sound amazing couple with the CAI I have. The combination of these means absolutely nothing without a proper tune, and that I have. However, I will tell you that you will need some sort of noise reduction and to exit the exhasut as far away from the cab as possible. I had mine straight piped and it exitted out the side for a while. I couldnt have conversations in my truck just driving down the road and the truck felt like a dog. I put my 3" Banks muffler on it with a turn down underneath the bed and it woke it up tremendously. If you really are considering replacing stock manifolds with long tubes, get stainless headers, get good gaskets, and get good replacement studs.

 

I will most likely put some mufflers on. I also have a k&n CAI and a Hypertech tuner. When you say tune do you mean by programmer or something else? Sorry if that was a dumb question I hear about a tune all the time I just don't know what it is.

 

3" true duals is too big. You'll loose all of your bottom end.

 

X2. This is only a 329 cubic inch engine. I would not go bigger than 2-1/4" if running duals. You need to keep some gas column velocity at lower RPM of you will experience reversion and your low speed torque will become non-existant. As previously stated, you will also need a proper tune because its going to run lean and stumble without it.
Long tube headers and a properly designed exhaust system can make a nice improvement in midrange torque if you get the fuel curve matched up properly.
P.S. If you want the look of 3" pipes, have them stepped up the last 2 feet or so where you can see them.

 

I did headers on my '08. If you are 4x4, find a friend with small hands, extensions, and u joints. Rather than beer, I would suggest something to take the edge off... Stanley makes a nice twist handle ratchet, and ratcheting box end wrenches will help. The Pass side is a *****. I had to separate from the motor mount and lift the motor. Also needed to mod my bell housing, headers, and trans dip stick.. I will never do another set of headers unless they are coming with a blow job or 300+whp.

You will also need to delete or disable the rear o2 from your tune. I do not see anyone else making mention of this....the front o2 are primarily responsible for your AFR, the rear validate the afr and also check for presence of the catalyst. You will have a CEL.

For tubing size, it really depends on what you are after. I am running 3" from my collectors to a y pipe and 3" all the way back. I have no loss of TQ, but, I am also blown and tuned.

With NO cats expect your exhaust to be significantly louder, crackle, and cabin volume to increase.

 

I already bought and was just going to put in long tube headers too this week and experiment with different mufflers to achieve a nice loud rumble but not obnoxiously loud you cant talk inside vehicle at highways speeds but i recently found a stripped stud bolt on my passenger side exhaust manifold which is going to complicate things.

Anyways, I agree other guy, 3 inch duals is WAY TOO big unless you run a blower or something similar. I made a similar mistake and put 3 inch system on my non blown 4.6, it sounded great but lost bottom end tq noticeably and any hp gains were only felt during WOT acceleration.

Area of a circle =pie x Radius squared
i believe stock is 2 3/8 which equals 4.427 sq inches
if stock is 2.5 thats 4.9 sq inches
2.75 " =5.9 sq inches
a single 3" system equals 7.065 sq inches
A dual setup of 2" each side would be 3.14x2=6.28" total
so if you run true dual 3" setup thats 14 sq inches vs stock 4.9 / 4.427

Unless you are building a stroker engine or using a blower /turbo setup or both,
i would think a quality built exhaust system that is mandrel bent and only .25 inches bigger than stock is plenty big enough to realize both HP & TQ gains.
Any much bigger than that and you CAN gain a marginal bit more high rpm [peak] HP but will already be sacrificing the tq gains from before and will now be losing tq [less than stock]

Better plan, combine a slightly bigger , say 2.75 inch exhaust system with long tube headers, straight thru exhaust, high flow cats, CAI and a tune and you probly have your best case scenario for more HP AND TORQUE without resorting to blowers, turbos or stroking internals.
In this case the logic of BIGGER IS BETTER does not apply.
in the case of diesels it is more apt to apply but not on a normally aspirated 5.4 L gas.

BTW; i may have a set of long tube headers for sale since i probly wont install mine now until i blow the engine.
they are stil in box stainless steel, 3/8 thick manifold less prone to warping cracking or leaking
comes with gaskets, new studs, instructions, o2 wire extension kit,
I have pics, text/call Curt 1 306 314 9697 if interested

 

What brand headers Scobar? I used Dynatechs and did not have any trouble at all. Took all afternoon but wasn't bad. A buddy of mine went with stainless works headers and no issues with install.