High Flow Muffler on a 2006 Dakota

[dwhitney89]

I am looking at putting a Moroso 94050 High Flow Stainless Steel Muffler on my 2006 V8 Dakota. I was wondering exactly what kind of results people have seen from this muffler or any other high flow mufflers. I've read that there is a good chance of getting an increase but I wasn't sure if it would be worth the effort and cost.

I would most likely DIY it but I don't work on cars regularly so I wanted to be sure that I know what I am getting into. Is it really just as simple as bolting a new one in place or do I have to mess around with welding on the o2 bungs and stuff. If so can anyone suggest a highflow Muffler that already has the bungs in place. I cant really tell if the Moroso one does or not, they sell the weld in bungs separate.

From what I can tell from looking at this forum there are a lot of smart people on hear. I hope somebody can help me before I go spending money on something that won't work for me.

Thanks in advance
-David

[MadisonMPG]

I don't think it will help you, most of the time the RPM band that you should drive in the stock intake and exhaust flows plenty.

[dwhitney89]

Thanks, I keep hearing mixed reviews on this. Some people say that it will help because the stock muffler creates most of the back pressure while others say just what you are saying. I probably won't do anything until this spring anyway so I'd love to hear anyone else's opinion. Any real world experience on a similar truck out there? I'm pretty happy with my current economy, I knew what I was getting into with getting a truck but it serves my needs better then a car.

[dwhitney89]

On a related subject... would I see better results adding a Tonneau or truck cap? (would this be a better investment vs. the Muffler) I like the look of Tonneaus but the usability of the bed is reduced. would I see any gain from a cap or will the extra weight, drag, etc cancel it out. I saw the MythBusters episode...HaHa, but I don't remember them testing caps.

[Daox]

There have been a bunch of truck guys that have come here and asked the exact same question about exhaust. Some of them have tried it. I'd do some searching.

[JeepNmpg2]

dcwhittney89 - If the muffler mod is done in conjunction with a high-flow intake, yes it may help your economy (when I did mine, I seem to recall it bumping up 2-3%), but for the cost a tonneau would be a better mod if you have a longer bed. A truck cap while it decreases the air trapped in the bed, will give you what the SUV's (including mine) have an issue with is the "bluff tail syndrome", where the back of the vehicle is flat, and it causes a lot of drag. Depending on the aero of your vehicle already, it may increase or decrease your FE.

Now don't get me wrong, I love the sound of my engine with my done up exhaust, I just didn't really do it for eco purposes originally.

Oh, and if you do decide to do the muffler, find a local shop to weld it in, usually for around $20 since it'll be pretty quick and easy for them.

Lastly, I would remind you that the first, and often best adjustment you can make is to the nut behind the wheel. Check out the 65+ driving tips, and you may find some that will help you to increase your FE without spending any cash.

[NeilBlanchard]

Some backpressure is a good thing -- the engine often needs it to run well at lower RPM's.

I think that if better FE is your goal, changing mufflers won't help.

[aerohead]

engine tuning is kinda like algebra,whatever you do to one side of the equation,you've got to do to the other.
In the olden days of carburetors,you would have to re-meter the intake and probably change ignition timing to get the full benefit of the muffler,if not alter the whole intake tract.
With modern EFI you're probably safer there,although you are physically altering the tuning of the entire engine,and could stand to lose some low end and mid-range performanece as you kill back-pressure and it's beneficial scavenging effects.
And for "normal" rpm range driving,I suspect it will make no improvement.
Calculate your flow rate,and internal velocities based on the inside diameter of stock vs new muffler for say 2,000-2,500 rpm.I think you'll be amazed at how slow those gases flow after initial blowdown.

[dwhitney89]

Thanks, I kind of had a feeling this was the case. I had a hard time buying into the hype that a simple muffler change would make much difference on its own. I don't have the money to do a whole cat back overhaul and stuff. I think a Tonneau is the way to go, they've been proven to have a big time ROI.

[mpgking]

If you keep the stock tubing size and don't go to a bigger diameter pipe you should be fine with changing the muffler. Depending on how many miles you have on your truck I would look at changing your O2 sensors. They can have a huge effect on FE.