I have a 1999 F150. I've been planning on purchasing a Cat-Back system to get some better sound and hopefully pick up an extra mile or two per gallon of gas.

I spoke to my local muffler shop about exhaust options. They recommended cutting out the "Y" joint and running dual pipes into one DIDO muffler. They said the left side motor exhaust pipe that is welded into the long right side is very restricted at the joint. Are there any problems or benefits in doing this type of exhaust system over a bolt-on Cat-Back system? I don't want to lose any low-end torque and I don't plan on doing any other performance mods other than my K&N air filter.

Thanks,
Mark

 

The mechanic @ your muffler shop is correct.There are no draw backs from cutting the "Y" out and installing a true dual system.I cut out the Y on my 2000F-150,installed a set of high flow cats,they flow into a Magnaflow X pipe into a set of 50 series FM's over the axle,no tips,they dump right in front of the rear bumper.I have a nice rumble @ idle and no drone in the cab @ highway speeds,and when I mash my right foot to the floor,a nice roar fills the cab w/ sound.I really like this setup.My performance has increased,and my fuel economy also has increased.This is a good basic setup for your exhaust.With so many mufflers out on the market,you have several choices for sound and performance,whatever you like the best.Cutting the Y works.I hope this helped,good luck w/ your exhaust.

 

instead of a DI/DO muffler, ma I suggest two SI/SO muffler,s much cleare sound and deeper

 

Thanks Vincent. It's good to know there will be no loss in low-end torque and still gain mileage with this set-up. Without me installing any other performance mods, is there any advantage to going with true duals -vs- going with just a bolt-on cat-back system? I prefer to do buy a cat-back system and install it myself if there is no performance or mileage difference.

 

my bottom end increased -i did go 2.25" for this reason-look in my galler- on my y- the drivers side pipe blocked into the passenger pipe about 1"-poor build quality-phil

 

IMHO there's even a benefit of just replacing the restrictive factory "Y" with an aftermarket one, and keeping a single-out exhaust or going with a cat-back.

The "Y" on these trucks sux.

 

i cut my y off and drove for a while...then re-piped it...true duals are the shiznit

 

How does more flow and a little more power increase fuel economy?
it doesn`t, don`t expect any significant diference.

 

Without doing the other performance mods, will my 5.4 perform any differently between cutting out the factory "Y" pipe with DIDO -vs- just adding a bolt-on Cat-Back? My main goal is to get better sound, but if the performance is really better removing "Y" pipe over the Cat-Back system, I'll go that route.

 

I'm not sure, but I've heard many on the forum that have claimed an additional 1 to 2 miles per gallon. My main goal is to get some added sound without it being too loud. If I happen to end up with better mileage and performance, all the better.

 

What did you end up doing with your exhaust? The muffler shop suggested running both new pipes into a single DIDO "X" internal design muffler or single DISO muffler.

 

Back in the day, I put a single-out Magnaflow cat-back on my truck, and had the factory "y" replaced with a Magnaflow "y"

But after I put the supercharger on, I had a dual setup fabricated with an x-pipe. It's duals all the way back, with two outlets and two tiny Magnaflow mufflers that are too loud. I need to put some resonators on, or larger mufflers.

The DIDO mufflers with an x-pipe are pretty cool. I prefer to have the x-pipe as close to the engine as possible, but really it shouldn't make much difference on a stock-ish motor.