$800 -1000 for custom true dual exaust sound right

[Knautical2001]

I only paid $350 for mine and it looks and sounds great with flow masters. You can see in the picture below.

 

[Bojo]

Hey, you guys are pretty close. I'm in Rockford.

 

[rca510]

does any one have more pics of dual exhaust for a 2nd gen expedition. i have a 05 that i want to get it done but just looking for ideas. i want to maybe go with a flowmasters muffler but a dual in and dual out...

 

[GAINMOB]

you wont see but 1 or 2...due to the IRS it isnt ideal to do duals...but can be done if you do a smaller diameter pipe...larger pipe will require loosing your spare underneath...i've been to several shops and several ppl on here has said the same...i'm going to drop my spare and run duals turned out behind each wheel...

 

[rca510]

yeah i have heard of maybe losing the spare...but i saw the pic knautical2001 posted of his and it looks like his spare is still there but wat size piping did he use like u said maybe smaller to get it to work

 

[GAINMOB]

he went under the suspension...he's a contractor and works overseas in the desert so he hasnt been on for a while...he may have said in another thread...you may have to search his name for posts...im willing to guess standard 3" piping?

 

[rca510]

well if not when i get home from deployment ill go to a muffler shop that does custom exhaust for muscle cars and see how much but yeah i seen it go under the pumpkin and around the spare just not sure wat size piping

 

[tallsville]

standard on 2nd gen at least for the 2v valve i believe is 2 1/4". usually for duals you use 2 1/2" and for single you use 3".

 

[rca510]

ohhh alright i have the 5.4 3v so maybe 2 1/2 then

 

[ELVATO]

I'd heard you want to stay with 2 1/4" for duals so as to not loose too much low end grunt, unless you were doing FI.

 

[Bowesmobile]

I'd heard you want to stay with 2 1/4" for duals so as to not loose too much low end grunt, unless you were doing FI.

That only seems to apply to Chevys. There's a lot more behind it. Its more like the peak torque moves up in the RPM when you make the pipes larger. You gain more torque, but its higher in the RPM range. So people "feel" like they lost power. When that is not the case. The easier an engine breaths the more power it makes. Period.

 

[toms89]

Pipe diameter should be based on hp level combination is at. Some may believe that you can put 500hp exhaust on 300 hp vehicle now you will 500 hp right?! Sorry it doesnt work that way.... lol.

OK.. kidding..... somewhat anyways... hopefully people dont believe that.


Some interesting facts as I understand it.

The exhaust needs to be properly sized to help maintain velocity and heat in the pipes. The cooler the exhaust gets the more dense which in turn "slows" down flow making it more difficult to expel. Hotter exhaust is less dense and easier to move. Larger pipes not only reduce velocity but have much more cooling surface. Velocity is your friend... back pressure is not. Too small and it restricts exhaust flow at high rpms limiting hp potential. We are shooting for high velocity and heat with lowest back pressure. Obviously its a balancing act and compromise.

I have always known velocity is important when it comes to exhaust but did more research several months back to understand why I get more a bit more condensation than most from my exhaust on cool days. After researching some more and understanding that my exhaust is cooling down (at idle & low speeds) in turn condensating before it exits the pipes it all made sense. H20 by the way is one of the byproducts of combution. Never really considered exhaust heat from the headers back as a factor in performance before but it is.....

The concensus seems to be 2.25" - 2.5" dual exhaust or 3" single for around 300 hp vehicles. Plenty info online about properly sizing exhaust.

Check out my video shot on a 40 degree day. Exhaust goes from heavy condensation at idle to rich (11.8 ish air/fuel ratio) when opened up. No coolant loss since built...I checked. lol. Its the large 3" dual exhaust pipes allowing it to cool more than average at low loads.

Supercharged Expedition 1/4 mile pass. - YouTube

Sorry about the shameless video plug......I cant help myself sometimes.

 

[tallsville]

tom my dad use to do lots of racing, especially bonneville in the 60's. one trick they used to use, was taking a crayon or grease pen and mark the exhaust pipe(s). the point where the crayon melted vs where it stayed is where they would cut the pipe(s).

 

[rca510]

good info toms89...i will take that into account when i try to get my exhaust done...i might go with 2.5 but ill see wat the exhaust shop says...but thanks for the info...n nice video