I assume my truck is the same for others with the same engine and year model. The dual cat setup seems to BEG for true duals! I have not heard about anything but single in dual out setups. I would be looking for something with a crossover and pipes out the back. Any help would be appreciated.

------------------
99 sc, sb, XLT. 3.55 ls, dark blue. bed X-tender only as of yet!

 

visit a local exhaust shop. I had true duals put on my truck for 150.00. although I dont have flowmasters I got a similar brand with like construction. sounds the same as the two chamber flowmaster.

 

94fan,
thanks for the reply. you notice any gains as of yet (mpg, torque)?


------------------
99 sc, sb, XLT. 3.55 ls, dark blue. bed X-tender only as of yet!

 

surprisingly I havent noticed any torque gains,havent checked mpgs yet. winter driving will make it hard to get a true mpg figure.

 

true duals for ony $150???

------------------
'97 F150 4x4 Off-Road Extended Cab Lariat Flareside white/tan, tan leather, 4.6

bedliner
single-lid toolbox
Gibson split-rear exit cat-back exhaust
K&N Air Filter

Many more modifications to come

 

it helps to be close friends with the muffler shop owner.

 

I guess so. You must be good friends. I paid $85 just for the tips on my exhaust

------------------
'97 F150 4x4 Off-Road Extended Cab Lariat Flareside white/tan, tan leather, 4.6

bedliner
single-lid toolbox
Gibson split-rear exit cat-back exhaust
K&N Air Filter

Many more modifications to come

 

I had the true duals put on my 4.6. I've noticed a very slight power gain, and about .5 to 1 mpg increase. You fella's got some good deals on your system mine hit me for $350.00 and that was by far the best price I could find. Most were over $400.00

------------------
'97 Ford SC 4X4 XLT Off Road pkg., 4.6,A/OD, 3:55, premium sound w/CD chg, Black clct,towing pkg., hvy duty elec. pkg., Bridestone dueler AT's, line X, Flowmaster true duals, chip, K&N air filter, smittybilt stainless nerf bars

 

Nickster,

I'm looking at installing a true-dual system using Flowmaster 30's. The shop I'm dealing with (http://www.pro-max.com) proposed cutting the pipe just before the 'Y' and running 2.5" pipe into a pair of side-by-side Flowmasters and 2.5" pipe out (either the back, both out the right side, or one out each rear corner - I haven't decided yet).

Does this sound similar to your setup? Reason I ask is because of the concerns that I (and alot of others) have about loss of low-end.

Tom in Tacoma

------------------
1998 F150 XLT S/C 4.6L Auto, 3.55LS, 4X2, Moonlight Blue, all the factory bells & whistles except for leather seats. Lund Deflector, Lund Premier Tonneau, K&N, Body-color painted Throttle Cover, blue wire-looms, Pentaliner S/R, Window tint, factory side-steps, Infiniti component speakers up front, Polk Audio speakers in back, Superchip on an FOU1 code(same as NASCAR edition). Tom in Tacoma (Washington not Toyota)
Go check out http://communities.msn.com/SS97FordsPics for the second best website for F150's

 

I dont know how 99's exhaust are set up, but on 98's the Y pipe is just WAY to close to the 02 sensor to mess with. A single in dual out flowmaster will give you plenty of gain over a stock muffler. Taking the chance of making true duals isnt worth the very few hp, if any, you will gain.

 

Black and Tan - that's something I hadn't considered. I'd like to know more about how extending 2.5" pipe past the point where it would enter the factory collector would have an effect on the O2 sensor.

You mention taking a 'chance' by installing true duals. What are the dangers? Are there known problems with changing exhaust configurations within a certain distance of an O2 sensor?

It's the same basic setup that the 4.6L Mustang GTs are running and is also the same as the 4.6L Crown Victorias.

I'm also a bit confused by your statement that a single-in, dual-out will provide "plenty of gain", but a true dual will provide "very few hp, if any". How so? Help me understand.

Tom in Tacoma

 

I ran duals on my 97 with the 4.6L.. I cut the Y out and added the dual pipes. I installed a crossover right about where the Y was. Never had a problem. The second O2 sensor is for checking the cat not engine function.(the 1st one is before the cat, second one after) I seriously doubt you could tell the difference between a good cat back and true duals so if it makes you nervous then go with a quality cat back.

 

Thanks V10 man, THAT's the kind of testimonial I was looking for!

Ya just gotta love this website!

Tom in Tacoma

 

Well there is the chance that, when you cut that Y pipe off, the O2 sensor could read the exhaust incorrectly, and then all that money you spent at the muffler shop will just increase cause you have to put the original set up back. What I meant to say about the true dual set-up, is that putting true duals over the single inlet dual outlet muffler wouldnt gain much hp. A single inlet dual outlet cat back system from flowmaster is $275. It has 3" mandrel bent pipe exiting in the rear. My truck has 4 02 sensors,one on each manifold, and 1 after each cat.

 

Been running true duals on the Expedition for over 2 years. Not one single problem. Paid $150 despite not being good friends with the shop owner. Will do the same for my '00 5.4L pretty soon.

Food for thought:
If a single pipe flows better (more HP) or provides higher backpressure (more torque) than dual pipes, why would you want a single-inlet / dual-outlet muffler?

Me thinks people read too much advertising propaganda.

Neal

------------------
1997 4x4 Expedition- 4.6L, true dual exhaust w/glass-packs, K&N air filter, SuperChip, airbox mods, Edelbrock shocks, 285/75R16 BFG ATs, Optima "T-Bone" wheels, 4.10 gears, Auburn LS, Clarion In-dash CD player, Smitty Bilt push bars and nerf bars!!

2000 4x2 F150 XLT Reg. Cab LWB- 5.4L, Tow Pkg, 3.55LS, CD player,Remote Keyless Entry, Sliding back glass, Special Appearance Pkg.

http://members.visualcities.com/NoMo