Is there any difference in one flowmaster muffler vs. two flowmaster mufflers? Im definatly going to route the pipes to dual exhaust, with 40series flows, but didnt know how much of a difference one muffler would make.

 

Welcome to the forum.

If your truck has MDS then don't touch it. It will sound like crap when you get it on the freeway and your running on 4 cyl.

I like Magnaflow, but each to there own. Ether way I don't find much difference.

 

I have mine set up with 2 flows (50 series). I think you'll like it eitherway, but I think you get better flow with two. Putting a muffler with one in and two out still restricts flow up until you reach the muffler. Not sure how loud you want it, but the 50's still sound sweet and have no drone. I had super 40's on my GTO and loved the performance but hated the drone that the 40 series mufflers are know for during freeway driving. Good luck in whatever you decide.

 

what is drone? did a search and no dice.....

 

KEEP your stock stainless exhaust system and fix what needs to be fixed!

Replace the stock "Y" pipe with a high flow "Y" Pipe.
Remove your muffler and install a staight pipe in its place.
Leave your resonator on the tail end as your muffler....

What you will get is the best all round performance at the fraction of the cost... With the money you saved you could put it towards a set of headers.

If you MUST go with a dual out cat back... then be smart about it! Your LITTLE 348ci does NOT need dual 2.5" pipes.. you will lose torque if you go with pipes that large. Again If you must have duals then 2.25ID duals are as large as you want to get if you wnat to keep your low end torque. Keep in mind that your goal should be NOT to exceed the VOLUME of the single 3" with the COMBINED volume of the duals. Keep the velocity high in the system and you will make the mose useable power. Also a good thing about a single exhaust system is that there is MORE heat in that system... the more heat you have... the more pressure you have... the more pressure you have the higher the velocity... ( There is more to it than that but in a nut shell thats whats going on)

go to large you will lose VELOCITY... go too small you gain "BACKPRESSURE" .... Chose the right size in between the two and you gain velocity without the back pressure and you then MAKE more power.

SPEED SAFE, AIR RAM

 

Airram...well I thought about doing the high flow y pipes but decided against it. I have had the 40 series on my last two cars and I am very satisfied with their sound. But as far as the right size, what would put out the best performace. I noticed on flowmasters website that the only dual out 40 series is 3" in and 2/5" out. From what Im understanding, those sizes are too big. Am I right, and if so what other options, other than the high flow y pipes do I have?

 

What airram is saying

if u were to run true duals all the way back then u should go no larger then 2.25 piping

but if u were to run a single exhaust then u should stick w/ the stock 3" piping

i have the si/do 40 series on my truck and it runs great


airram correct me if i'm wrong

 

question...what size pipe comes off the ex manifold's on a stock 5.7 Hemi?, if you by passed the Y pipe and kept the same size pipe from the cat's back into a dual ex set up and had the the muflers mounted side by side, on the flat, than had two ex pipes exit out the left hand side ( after wheel well ) would this work?

 

Drone in the exhaust is due to the engine driving the exhaust system at its resonant frequency. It's the monotonous low dull sound you get at certain RPM's. I had it on my GTO with the 40 series at about 2000 RPM's on the freeway. Was really annoying on long drives. As for the size of the pipes, I have dual 2.5's (with 2 50 series flows) on the 4.7 and love it. I don't feel any loss on low end (thank god) when towing and it runs better at hgher speeds. My milage has also improved (might be normal as engine works in). I won't dispute the others as they sound like they are extremely knowledgable. I can only tell you my SOP experience. Dyno might have told a different story than my assometer, but I am happy so maybe a dyno would just depress me.

 

Gordo does you r dual have an x or an h in it anywhere? What did you do for cats? Manifold or headers?

Hydrashocker can you give me a better description of what it sounds like with MDS? Does it get loud or pop or does it just sound like a rice burner?