Both of these mufflers (Dynomax Bullet and Magnaflow) are straight through design, right? So is there any real difference in performance between the two, or is it just personal preference as to the sound?
Also, what is the point of purchasing cat-back systems? Are the bends not mandrel in stock? Does a cat-back system have fewer bends or less radical bends in it to improve flow/performance over stock? Otherwise, doesn't it just make sense to buy a free flowing muffler and replace the stock muffler for way less money if you're going to see the same improved flow/performance results?...
For example: I've read a lot of people saying that the Roush offroad cat-back is the best cat-back you can buy (it's expensive as hell, imo). Why is that exactly - is it really going to far and away out perform a totally stock system that's had the muffler swapped out for a Dynomax bullet, or a Magnaflow 14" body?
Clarification would be greatly appreciated...

 

The main point of a cat-back is to get rid of the rusty factory exhaust, and to increase the intermediate pipe width to 3" for better flow and velocity.

The Roush Off-Road is a great cat-back, exept for the fact that its all 304 stainless, but its still a great cat-back. It wont rust out and it will shine on. The muffler in the Off-Road sounds great and flows freely, keeping interior sound low, and exterior sounds nice, loud, deep, and rich/clear sounding.

The Dynomax bullet is a good muffler for those that want rebel loud sounds at an affordable cost.

Magnaflow mufflers are great and i'm quite happy with mine, but the idle is pathetic on a warm engine, but they keep the annoying out of the cab pretty well, and sound great, deep, and metallic sounding outside, with a great flowing internal design.

 

I was under the impression (after reading a number of threads) that increasing the size of the exhaust - unless really necessary due to heavily modified engine with high #'s - might result in loss of bottom end power/torque? What's your take on this - anything to it, or might it not be noticeable at all?

 

yes increaseing you pipe size when you dont have the power required to have to bump up the pipe size will lose you low end. i have 3" True duals on my truck im sure if i went downt o 2 1/2" or even 2 1/4" pipe id gain some low end. my collectors were 3" so to make my life easy i just got all 3" sounds really good too. but 3" true duals wouldnt tech. be needed till about 350-420 HP range. thats why you see diesels with 4-5" pipe well when your pushing 600-800 HP they need that big of pipe. Its about exhuast gas volicty not back pressure. it also can hurt you the other way to if you dont have a big enogh pipe you can choke out your truck. So unless you have the power to fill the pipes keep um smaller adn you wont loose the bottom end. Hope that helps

 

That is true in the case of true dual exhaust. But 2.5" downpipes catted merging to a all 2.5" Y pipe isn't real healthy for performance. Increasing the mid-pipe to a single 3" pipe will have better performance because it will flow better and its not too thick for great velocity. That going to a 3" muffler inlet and out a 2.5" dual outlets will flow great and keep everything equal.

 

Is there an advantage to 3" in/ 2.5" dual out over just upsizing to 3" all the way back? Do the 2.5" duals (from the muffler back) retain bottom end power better than 3" single? I guess the main question is: out of the three options (3"in/2.5" dual out, 3" all the way cat-back, and just swapping to a straight-through muffler and staying 2.5" all the way back; which retains the most bottom end power/tq while improving performance for a mildly modified engine(planning on ud pulleys, efans, cai, tuner)?

 

a single 3" system will perform better that a SI/DO system. Tailpipes take away minor pressure, and are just for sound and looks. Amuffler swap only with 2.5" will run fine.

 

After researching this topic, and purchasing a magnaflow kit for my Dakota, I came to the conclusion that the catback, while expensive, offers convenience and expediency. You don't have to take the truck in or search for pipes and adapters/hangers. In my case, what I assumed to be the muffler was actually a resonator. My truck has two resonators. So, one has to make-up the difference in pipe where the resonators used to be, possibly bended pipe. Also, if I want to go up or down in sound, it seems like it will be easier with a kit because the muffler is bolted vs welded. Even with my F250, which does not have resonators, I still have to find a muffler with proper hangers and a tailpipe that fits. I just seen that Dynomax makes a kit for this which is convenient and expedient for me. Albeit, $250

 

Thats true. Cat-backs are quite convenient. Though I prefer designing my own exhaust and buying my muffler(s) and tips and instructing my installer how I want things ran and installed.