I am saving money for a dynatech LT headers w/ hi-flow cats and a ROR exhaust. Now I need to gain TQ on my low end since I will be towing a
7000 lb. trailer once in a while, performance is more important to me over sound. It's my understanding that SI/DO its better for low end TQ than true duals with an X pipe. My question is what size pipes should I use throught out the whole exhaust system.

2006 F-150 FX4 25,000 miles, Edege Evo Gryphon tunes, JLT hot air intake (til I get a workable hood scoop).

Thanks for your time and advice.

 

A 3-3.5 inch SISO would be the best for towing, but a 2.25 inch true dual exhaust will still generate a good amount of low end torque as long as you have all the correct parts.

 

What are the correct parts required for a "True Dual Exhaust" on a 2004 and up 150 ?

 

Just straight-through mufflers and an X-pipe.

 

If you are looking for torque your money would be better spent in changing the gears in the differential.

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SIDO youll want 3" from the Y and 2.5" out. which im sure the ROR is.
true dual 2.25" works good with an X pipe and a straight through muffler (magnaflow, dynomax, borla, corsa) all what 4.6 punisher said
and yes, gears will make a difference with towing. 4.10s will give u that extra push off the line. your truck will be a monster with ROR, high flow cats, dynatech LTS, programmer, 4.10 gears and changing that hot air intake to a cold air intake..

 

Yeah... it will be very loud and pulling a trailer... prolly gonna be too loud because your gonna be in higher rpms while towning esp up hills. AS much as I love the ROR, a 22" maggie may be a better choice ( possibly an 18")

 

but an H-pipe wil help his low end

 

H-pipes are best on Mustangs with a symmetrical exhaust system. Sadly, not on a one sided exhaust system like our F150's have. H-pipes do sound WAAAAAAAAAAAAAAAAY better IMO.

 

installing 4.10s gears how would performance be affected w/o twoing? I am going to exit the exhaust in front of the pax tire for less drone in the cab. Borla makes ror but they dont offer the front tire exit? Thaks gentleman for all of your advice.

 

Better acceleration, better city MPG's, and more or less the same highway MPG's.

 

Overall 4.10 gears are better than OEM cool thanks. Will that change the speedometer reading?

 

no, the only change will be ur RPMS at higher rates on the freeway.

 

Actually it will as your PCM is programmed for a different differential gear. Take your current gear 3.55? Divide it by the 4.1 gears and it will provide the correction factor. So 3.55 / 4.1 = .866 At 100 mph you will only be traveling at 86.6 mph. A good programmer can correct for this. Mine does.


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First off, the gains from an exhaust while towing are barely noticable. Many times, detrimental. Gears would definately be a noticable gain, better if you're after towing power.


Second, no mention mandrel bent pipes? If you expect any gains, you need mandrel bent pipes. Otherwise you're paying $250-400 just for sound.

Like others have said: 2.25" mandrel pipes, X pipe as close to the motor as possible, and good flowing mufflers.