I was wondering where are the Y's in your stock exhaust? Mine are in front of what looks like two identical cats. I'm assuming this would leave no problem for a true dual exhaust? questions? comments? HELP?

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1998 F150 XLT, extended cab 3 door,Pacific Green, towing package, 4.6L V8, 3.55 LS, Bosh Platinum +4 spark plugs ,Lund deflector, Profile Windstream side window air deflectors, Prostripe silver multistripe, K&N Air Filter, Diamond Plate Toolbox, Diamond Blue(HID) simulator Fog Lights , Whistler Radar Dectector, Uniden Police Scanner, 29WX-ST Cobra CB Radio, with a Texas Star 100watt modulator and a Wilson 2000 Trucker antenna. A Clarion Security System with Keyless Entry,
Audio Mods
Kenwood KDC-6011 CD player/changer control head unit.
JL 10" sub-woofer
Fultron "Depth Charge" amp 200w max.
4, TR570-CX JL Audio Coaxial Speakers (factory location)

Comming VERY soon are a pair of high output headlights (80watt low/ 100watt high)and a K&N FIPK!
Next will be a catback exhaust and a superchip.

Go see my truck and my Grandfather's truck at <A HREF="http://www.geocities.com/Vienna/Strasse/1992" TARGET=_blank>

Http://www.geocities.com/Vienna/Strasse/1992


</A>

 

My Y-intersection is behind the 4)pre and reg cats. You can modify any part behind the cats. You can get higher flowing cats also after 5yr/or/50K miles. True duals (completely separate pipes) from front to back can be made at a muffler shop; have not seen any kits for this. With a 1998 4.6 you must be careful with pipe size and muffler flow rates so you won't loose low-end torque. 2.25" max, 2.5" or bigger is not necessary unless many high horse power mod were added. Pipe size, muffler size, and flow rates are a hot topic with the F-150 crowd. Many muffler web sites have charts for this, but they are mostly for single pipes. Example (Edelbrock), I have it right here. Single pipe/300-350 cubic inches/250HP=2.5"/300-350HP=3.00". Also, most 3" single pipe cat-back systems still hook up to your 2.5" factory exhaust right behind the Y-pipe. What some don't seem to understand about flow, is that your most forward restriction is what you are stuck with from there back.( your factory 2.5" ) Magnaflow's website will confirm this. If you put a giant hose at the end of your garden hose, it still can only flow what the first hose limits it to.

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2000 F-150 XL,RC,LB,5.4,4R70W,3.55LS,
4-wheel disc/ABS,Chestnut/Parchment,
Ford bedliner & gas/wheel/spare locks,
3" cold air box modification,Superchip,
Dynomax ultra-flow welded 3" cat-back.

 

I'm not sure yet what size pipe I'm going with. My exhaust guy is ASE or whatever certified and know's his stuff. I may go with a bigger pipe since I have added a few HP mods. (FIPK, Superchip).

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1998 F150 XLT, extended cab 3 door,Pacific Green, towing package, 4.6L V8, 3.55 LS,

Performance Mods
SUPERCHIP, K&N FIPK, Bosh Platinum +4 spark plugs

Apearance Mods
Lund deflector, Profile Windstream side window air deflectors, Prostripe silver multistripe, Diamond Plate Toolbox, Diamond Blue(HID) simulator Fog Lights, High output headlights (80watt low/ 100watt high)

Electronic Mods
Whistler Radar Dectector, Uniden Police Scanner, 29WX-ST Cobra CB Radio, with a Texas Star 100watt modulator and a Wilson 2000 Trucker antenna. A Clarion Security System with Keyless Entry,

Audio Mods
Kenwood KDC-6011 CD player/changer control head unit.
JL 10" sub-woofer
Fultron "Depth Charge" amp 200w max.
4, TR570-CX JL Audio Coaxial Speakers (factory location)

True dual glasspacks VERY soon.
Wish list:
Grill Guard
Chrome Rails
BFG Tires

Go see my truck and my Grandfather's truck at <A HREF="http://www.geocities.com/Vienna/Strasse/1992" TARGET=_blank>
Http://www.geocities.com/Vienna/Strasse/1992
</A>

 

I don't have it, but the Dynomax rep at their tech line told me that the ultimate F-150 exhaust system is this: 1) 3" pipe, replace the Y-intersection with Walker part #41710 which is 2)2.5"in/1)3"out compared to the stock 2)2.5"in/1)2.5"out(this is the most forward restrictive part of the whole factory system), then the 3" cat-back system of your choice. If you want top flow from a 3" cat-back system, you must have 3" pipe from the Y to the 3" cat-back, not the 2.5" factory pipe. True duals(completely separate pipes front to back) also put one pipe very close to 30 gallons of gas in a plastic tank. My opinion only; others will for sure vary. Dynomax is the only company that understood what I was talking about, and told me that all these backpressure concerns were not warranted (Their opinion not mine).

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2000 F-150 XL,RC,LB,5.4,4R70W,3.55LS,
4-wheel disc/ABS,Chestnut/Parchment,
Ford bedliner & gas/wheel/spare locks,
3" cold air box modification,Superchip,
Dynomax ultra-flow welded 3" cat-back.

 

That's pretty much what I ended up doing. I talked it over with my mechanic and we decided to go from behind the Y into a single 18" glasspack and then into the dual exhaust out the back. the glasspack that we decided on is specificaly made to keep enough of the backpressure to not loose tourque. 3" pipe into the pack and two 2.5" pipes going out from there.

Gotta love that rumble!

------------------
1998 F150 XLT, extended cab 3 door,Pacific Green, towing package, 4.6L V8, 3.55 LS,

Performance Mods
SUPERCHIP, K&N FIPK, Bosh Platinum +4 spark plugs

Apearance Mods
Lund deflector, Profile Windstream side window air deflectors, Prostripe silver multistripe, Diamond Plate Toolbox, Diamond Blue(HID) simulator Fog Lights, High output headlights (80watt low/ 100watt high)

Electronic Mods
Whistler Radar Dectector, Uniden Police Scanner, 29WX-ST Cobra CB Radio, with a Texas Star 100watt modulator and a Wilson 2000 Trucker antenna. A Clarion Security System with Keyless Entry,

Audio Mods
Kenwood KDC-6011 CD player/changer control head unit.
JL 10" sub-woofer
Fultron "Depth Charge" amp 200w max.
4, TR570-CX JL Audio Coaxial Speakers (factory location)

True dual glasspacks VERY soon.
Wish list:
Grill Guard
Chrome Rails
BFG Tires

Go see my truck and my Grandfather's truck at <A HREF="http://www.geocities.com/Vienna/Strasse/1992" TARGET=_blank>
Http://www.geocities.com/Vienna/Strasse/1992
</A>

 

That sounds great!! I smile every time I drive since I modified my exhaust. Unlike some other mods, you can enjoy this at every speed. Happy trucking.

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2000 F-150 XL,RC,LB,5.4,4R70W,3.55LS,
4-wheel disc/ABS,Chestnut/Parchment,
Ford bedliner & gas/wheel/spare locks,
3" cold air box modification,Superchip,
Dynomax ultra-flow welded 3" cat-back.