I currently have a 2003 F150 with a 4.6 and an Eaton M90 supercharger with 9 lbs of boost. I currently have the Magnaflow 15609 system which is the SISO. How much power do you think I would see if I went to running true dual exhaust? I've had several people tell me to run true duals but I never have as of yet. Please let me know what you think.

bixbystx

 

If ya wanna pic up some power,,you will need long-tube headers and high flow cats.
Then with the duals you should pic up about 30HP

Phil

 

Unless you plan on building up the stock short block, leave your factory manifolds and just add high flow cats and true duals. If you want to add long tubes you can, they will help no doubt. Just depends on your power level.

 

Does anyone offer the longtubes for a 2003 with a 4.6? I have heard that pacesetter makes a pair but I was wondering if anyone else does?

Thanks,

bixbystx

 

summit racing brand headers for our trucks our made by pacesetter just some info for you to save some doe.

 

On your setup...probably about 20 RWHP.

On the 5.4's a lot more. The exhaust on these trucks are so restrictive it's not even funny. Run DIDO with an x pipe or x muffler. High flow cats can get you more power, but be careful as you can lean out the motor more than you want. A re-tune would be recommended.

With this combination you'll get viscious power up top. You'll really feel it in the 3-5K RPM range. But keep in mind it will be loud. Not raspy loud but you won't be able to sneek back into the house as your significant other will know you're coming a mile away.

 

As fare as I know,Pacesetter is the only long-tube header made specifically for the 4.6
A lot of companies make shorty headers for the 4.6 but there a wast of money.If you don't run the long-tubes,,,just stay with the stock manifolds with high flow cats and duals.
The loudness will depend on what muffler you go with.

Phil

 

Thank you everyone for your information and help. I'm currently running 2 cats on my truck as of a few months ago. I think it has helped with the restriction. I'm running the high-flow cats made by Magnaflow and they really seem to be a good product. I'm going to check into getting some longtube pacesetter headers from Summit. Does every suggest running an X-pipe also?

bixbystx

 

I ran without an X for a long time.But when I added the long-tubes I put an X pipe in.
I like it better with the X. Better torque.
You can run 2 mufflers with an X or get 1 muffler with a built in X.
You'll probably save some money with the muffler with built in X pipe.Then you only need 1 muffler.

I had to buy 2 mufflers and an X pipe.

Phil

 

One more question. I looked on the Summit website and I see the pair for the 5.4. Will these work on the 4.6 also or do they have a pair specifically for the 4.6?

Thanks,

bixbystx

 

I see a pair of longtube headers on the Summit website for the 5.4. Will this set also work on my 4.6?

Thanks,

bixbystx

 

The only ones I could find for the 4.6 were ceramic coated.
http://store.summitracing.com/partde...5&autoview=sku
You can try searching in the exhaust forum. I think some were using the 5.4 on the 4.6 but I'm not certain.

Phil

 

You know if you use full length headers your going to have to change allot of your cat back system? Shorty headers will bolt up in place of your manifolds and you can keep your hole cat back system. To answer your question i dont see why the long tube headers wouldnt bolt up because its the same bolt patern and block pretty much just 1 inch wider than the 4.6l you will have to have some custom exhaust work done to finish your true duals or cat back system what ever you decide. If anyone knows something more about why they wouldnt fit please chime in.

 

http://www.autoanything.com/exhausts...0A2131179.aspx
They also have a off road y pipe on pacesetters web site.