Dual Exhaust 4.6

[cron9900]

I'm sure this has been beaten to death but.....
If you remove the spare tire and all associated parts, you can fit 2 pipes over the rear axle. My question though is about power and mpg. Will I see any gains? What about back pressure? I have a custom exhaust guy that can build just about anything.
I pull a 32 ft travel trailer on occasion for work. I’m looking at adding bigger tires with a few other mods down the road. I’m ok with losing mpg with bigger tires as long as I start off better than I am now.
Is there anyone out there that has some solid info on exhaust?

 

[GodStang]

I'm sure this has been beaten to death but.....
If you remove the spare tire and all associated parts, you can fit 2 pipes over the rear axle. My question though is about power and mpg. Will I see any gains? What about back pressure? I have a custom exhaust guy that can build just about anything.
I pull a 32 ft travel trailer on occasion for work. I’m looking at adding bigger tires with a few other mods down the road. I’m ok with losing mpg with bigger tires as long as I start off better than I am now.
Is there anyone out there that has some solid info on exhaust?

Not sure about fitment but I doubt you will see any gains or have any issues with back pressure. If I am understanding correctly you are wanting to put in a Y-pipe and run duel tips and not true dual exhaust? If you still have stock cats and you still have the stock manifolds and you still have stock single pipe running back to the back you are not really freeing up any of the true restrictions in the system. I am sure it will look good and sound good though.

 

[cron9900]

Not sure about fitment but I doubt you will see any gains or have any issues with back pressure. If I am understanding correctly you are wanting to put in a Y-pipe and run duel tips and not true dual exhaust? If you still have stock cats and you still have the stock manifolds and you still have stock single pipe running back to the back you are not really freeing up any of the true restrictions in the system. I am sure it will look good and sound good though.

I haven’t heard of headers except for some over priced custom ones from some place in Chicago. I can’t justify that. But I am looking at doing true dual exhaust from my stock manifolds. Possibly keeping the same diameter pipes going all the way out the back. I’m sure not having headers won’t do me any good, but I’ve got to try something. Plus it will help my manifolds bolts from backing off creating a leak.

 

[07EddyB]

Maybe things are different these days but adding dual exhaust in the old days wasn't anything that would help you with towing without also tearing into the engine. A freer flowing exhaust with stock everything else will slightly help your high RPM performance and slightly hurt your low RPM performance.
Of course, it sounds meaner off the line and that's enough for most people using their "ear and butt dyno" to gauge performance. If you want to hang duals under your Ex then that is certainly your prerogative - but I don't think you will see any usuable performance increase unless you start messing with tunes and cams.

 

[MotorCityFats13]

back pressure is a myth that needs to die already and if you get a single 3" catback with a straight through exhaust like a magnaflo you will never feel a difference unless you weigh your wallet, yes I believe a flomaster would sound better but they do flow less

 

[GodStang]

back pressure is a myth that needs to die already and if you get a single 3" catback with a straight through exhaust like a magnaflo you will never feel a difference unless you weigh your wallet, yes I believe a flomaster would sound better but they do flow less

I think most people use "Back Pressure" and "Scavenging" as the same term when it is not and that is where the myth comes from.

As far as the OP I think true Dual exhaust would be a pain to install because you should also run a crossover on our cars and as Motorcity said would be best just to run a single 3" back and if you want the looks of duels have it Y piped at the end.

 

[cron9900]

I’m not after looks at all. My manifold bolts keep backing off causing leaks. I have done everything I can think of, but the leaks keep coming back. The main thing I want is fuel mileage. I know our trucks aren’t great in this area, but I’d like to squeeze every mile I can. I do a lot of driving up and down the eastern seaboard.

 

[Arod230]

I'm sure this has been beaten to death but.....
If you remove the spare tire and all associated parts, you can fit 2 pipes over the rear axle. My question though is about power and mpg. Will I see any gains? What about back pressure? I have a custom exhaust guy that can build just about anything.
I pull a 32 ft travel trailer on occasion for work. I’m looking at adding bigger tires with a few other mods down the road. I’m ok with losing mpg with bigger tires as long as I start off better than I am now.
Is there anyone out there that has some solid info on exhaust?

I’m late to the party lol, but I had my spare removed and I was able to run 3 inch pipes, that split to a Y just before the spare. Looks great, sounds great, but honestly I can’t notice a difference in performance.