So when I bought my 02 1500 QC 4wd with 4.7L it had a K&N drop in and a flowmaster (what I think is a 40 series as its loud as a **** !) with 3" single inlet and 2.5" dual outlet on the truck.

Since owning it I have changed out the drop in for a Cone filter .
I wan to go with a single outlet and a quieter muffler as I think the sheer amount of flow Im getting at the outlet is killing my bottom end for towing.
I think the 4.7L could use alittle more back pressure .

Thoughts ?

 

Flowmaster actually flows about the same as a stock if not a little worse.

 

Yeah, believe me, you're probably getting less flow and more backpressure than the stock muffler with that rustmaster in there. Magnaflow or go slow!

And no, the 4.7 certainly does not need more BP. It's pretty restricted from the factory, especially the "Y" that's in there.

 

"Rustmaster"

 

"Dronemaster".

Most Chambered mufflers cause turbulence and reduce flow. There is a point where too much flow is bad, but I think you would benefit from more flow. Any normal oval bodied muffler will help you out. Go on Magnaflow's website and they show pictures of what their mufflers look like on the inside(cut-aways). You don't want a bullet straight through muffler. Those do flow alot and will hurt your bottom end slightly.
With some more flow, you'll get better throttle response as well.

 

Well for now Im just going to remove the flowmaster an one of the outlet pipes and replace it with a magnaflow or any 4 chamber muffler and a single 3" outlet pipe.

 

If you've still got the factory "Y" and a Flowmaster chambered muffler, then lack of backpressure is NOT your problem. Trust me - you have PLENTY of backpressure - too much IMO.

Lack of low end torque is not surprising, the 4.7 and Hemi pretty much come from the factory setup for very good mid and upper end HP at the expense of low end torque. Couple that with paltry gearing (usually 3.55) and low end is pretty **** poor for a truck. If you can swing the cost, regearing to at least 4.10 gears would be your single, best bet for low end as this gearing will get your RPMs up into the power-band much sooner...

 

My last truck was a dodge dakota with the 4.7, 5 speed fun little truck but anyways i had a Magnaflow single in single out installed and it sounded great on that 4.7 but i did lose low end with that truck and the magnaflow mufflers make a lot of drone on the highway.

 

So would I be killing my low end torque going to a magnaflow x pipe with a magnaflow di/do exhaust and magnaflow cats? Is that to much flow?