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Otto, if you have the space, Magnaflow has a 30" long round case muffler that is real mellow. On my truck, i dont have room, so i have a 14" about 2.5" ahead of where the tailpipe would bend up to go over the axle, and then replaced th UP part of the tailpipe with a 16" long Magnaflow. Very quiet.
I'll have room. I had a 22" oval body on my last truck and it was good volume wise, but there was some drone. I'm between the round or oval body Magnaflow or the Ultra flo Dynomax. I could add a bullet or short body Mag after, but once I touch it I'll never get back to changing it.
Quote:
Dam auto correct. Sorry. Would it be bad to take off the muffler and leave just the resonator?
No it's not bad as long is there is enough pipe still there to keep the pulse in the system while in lower rpms. Might not sound the best, but that's your call to make.
No it's not bad as long is there is enough pipe still there to keep the pulse in the system while in lower rpms. Might not sound the best, but that's your call to make.[/QUOTE]
The pulse will leave the system before the next pulse has a chance to leave the cylinder at lower rpms. This means extra force is needed to expel the gases out of the combustion chamber instead of being pulled out with scavenging. At higher rpms the pulses are quick enough not to worry, but you're driving a vehicle with the aerodynamics of a wall so keeping the power band lower is best. Keeping the system long enough to keep good scavenging without being restrictive, along with sizing it correctly to promote good velocity throughout the power band is the goal.
If it's cut extremely short (like open headers), burnt valves can result.
i like this thread. very informative. so my question, after reading 6 pages is, what is the best (performance wise) "straight through" muffler? i've got a 2010 FX2 with the 4.6 3v V8 and am looking to pick up additional power anywhere i can. gonna do volant intake next week, upgrade exhaust (unless we're deciding that the original exhaust is as good as it gets), and VMP custom tune when all is done. should i go with a magnaflow muffler then? or, is there a better option out there? i LOVE the sound of the flowmasters, but it sounds like the only benefit there is the sound (and possibly even a loss in performance).
The pulse will leave the system before the next pulse has a chance to leave the cylinder at lower rpms. This means extra force is needed to expel the gases out of the combustion chamber instead of being pulled out with scavenging. At higher rpms the pulses are quick enough not to worry, but you're driving a vehicle with the aerodynamics of a wall so keeping the power band lower is best. Keeping the system long enough to keep good scavenging without being restrictive, along with sizing it correctly to promote good velocity throughout the power band is the goal.
If it's cut extremely short (like open headers), burnt valves can result.
Hey otto!
Firstly, regardless of me being a Moderator here, My forte is MSU & OBD1 ECU related & MSU & OBD1 Ignition system tweaking. If I spout something regarding exhaust that you have issue with, or less than accurate, please correct me.
Now, my questions is regarding clogged/ back pressuring Cat converters.
What are the symptoms?
How to determine?
What can happen if someone continues to ignore the problem?
__________________ "Saving the World....One Ford Truck at a Time."
i like this thread. very informative. so my question, after reading 6 pages is, what is the best (performance wise) "straight through" muffler? i've got a 2010 FX2 with the 4.6 3v V8 and am looking to pick up additional power anywhere i can. gonna do volant intake next week, upgrade exhaust (unless we're deciding that the original exhaust is as good as it gets), and VMP custom tune when all is done. should i go with a magnaflow muffler then? or, is there a better option out there? i LOVE the sound of the flowmasters, but it sounds like the only benefit there is the sound (and possibly even a loss in performance).
help me out here guys.
thanks,
Daniel
Daniel,
2009 and up already has a straight through muffler from the factory.
Firstly, regardless of me being a Moderator here, My forte is MSU & OBD1 ECU related & MSU & OBD1 Ignition system tweaking. If I spout something regarding exhaust that you have issue with, or less than accurate, please correct me.
Now, my questions is regarding clogged/ back pressuring Cat converters.
What are the symptoms?
How to determine?
What can happen if someone continues to ignore the problem?
I've seen you around ymeski, you're a rockstar, no need for the intro
The symptoms of a clogged cat can vary widely. Most obvious is a glowing red cat from excess fuel being caught and burned in the cat. Also a rattling sound when driving, or when the cat is struck with an object can mean the honeycomb inside the cat is broken and clogging.
The tricky symptoms are what most people get though. Sluggish performance is one sign especially at low rpms or WOT. A decrease of mpgs is a side effect of the lacking performance. A change in tone of the exhaust may occur. Poor idle is another symptom that frustrates people as most think it is a misfire, cam phaser (for the 04-08 guys), or MAF/throttle body issue. Many also characterize the loss in performance as "seems like it's not getting enough fuel". Black smoke on startup or acceleration can also be a sign since the O2 sensors aren't reading right.
This article explains pretty well how to test for a bad cat and saves me typing
If a person ignores the issue it most likely won't get better unless the honeycomb gets blown out the back. The engine won't run correctly and causes increased wear over the long term along with the poor mpgs and lack of power. A new cat is about the only cure.
*Note this is just for a clogged cat. A poisoned cat isn't serious in terms of engine performance, just usually increased emissions as long as it isn't clogged*
Otto, tell me what you think of my setup. I noticed a marked drop in torque off idle when this was installed.
'06 F150 4X4, 5.7l, 3.73 gears, Injen cold air intake, stock tires and lift, no programmer. Yet....
Exhaust: Stock manifolds and cats. I'm wanting as much mileage as possible so I thought it would be best to go with true duals. 2.5" pipe from the cats into a DI/DO Magnaflow that has the crossover built into it. 2.5" pipes all the way out the back. All mandrel bent.
I'm thinking that the pipe from the cats to the muffler would be better if they were 2.25" dia. but since Magnaflow doesn't make a DI muffler for 2.25" I went with 2.5" everywhere. I also believe the crossover in the muffler is doing about nothing for me being so far back. Would a crossover up where the original was help? Now it's still not a total slouch for torque, but it was just a torque monster off idle before I had this installed.
Otto, tell me what you think of my setup. I noticed a marked drop in torque off idle when this was installed.
'06 F150 4X4, 5.7l, 3.73 gears, Injen cold air intake, stock tires and lift, no programmer. Yet....
Exhaust: Stock manifolds and cats. I'm wanting as much mileage as possible so I thought it would be best to go with true duals. 2.5" pipe from the cats into a DI/DO Magnaflow that has the crossover built into it. 2.5" pipes all the way out the back. All mandrel bent.
I'm thinking that the pipe from the cats to the muffler would be better if they were 2.25" dia. but since Magnaflow doesn't make a DI muffler for 2.25" I went with 2.5" everywhere. I also believe the crossover in the muffler is doing about nothing for me being so far back. Would a crossover up where the original was help? Now it's still not a total slouch for torque, but it was just a torque monster off idle before I had this installed.
All help appreciated! Thanks much!
Your loss of off idle torque(not really lost, just moved up th RPM band) is from going to single 2.5(I think) to dual 2.5, which is not by any means overkill for a 5.4.
The best thing you can do with modern truck exhaust is to just change the muffler to straight through, and leave the stock pipe alone,(scavenging is at its best with a single system) or, if you insist on the look of duals, changing from single 2.5 to dual 2" would have been the ideal thing to do.
That being said, a proper tune with your current exhaust may get you some of your losses back.
Last edited by jameslleary; 06-22-2012 at 11:55 AM.
"Saving the World....One Ford Truck at a Time."
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