What kind of Hemi exhaust mods affect mileage? Just changing out the muffler, or exhaust tip, or full systems?

I had wanted to dual out my exhaust. I was thinking of leaving the stock muffler in place and removing the resonator. Then install a Y-pipe at the end of the muffler and install some chrome echo tips, 3" dia. and 24" long. This would provide the "look" and add some rumble without being loud or causing drone? It worked on a previous GM 6.0L great.

Any thoughts?

 

A good free flowing muffler will help your mpg alittle, not much. The way you were talking about doing your set up, is the way I have mine done.

 

there will be a slight MPG gain if
the exhaust mods lower the already low
backpressure that exists during 'daily driving'
but removing the resonator won't change the backpressure
enough to be a measureable change

there is a slight MPG improving effect
if the exhaust outlet goes straight back
(notice most cars do this.... think of it as a tiny jet engine exhaust)
but on a truck that may sometimes tow a trailer
the exhaust is angled out the side
to prevent the possibility that
carbon monoxide gas would build up in the trailer

notice how 18 wheel trucks
run the exhausts upward (like a smoke stack)
and then angle the exhaust backwards?
... that combination of 'natural draft' and 'scavenging'
results in a slightly lower backpressure
while still keeping carbon monoxide gas away from
potential build up in a trailer

 

Your modding the stock muffler will do exactly what you want. It should also keep drone down. A lot of people here have gone back to their stock muffler becuse of muffler drone with after market muffler.

 

how did it work out? I want just a little rumble

 

I haven't done the mod yet. Still contemplating...

 

That's pretty much what I wanted. Went with this kit from Summit:

http://store.summitracing.com/partde...5&autoview=sku

The muffler is an Imco T-914 turbo series. To me is about what a stock system should sound like. At idle, it is just a little louder than stock. When you gas it , it has a nice tone that is not crazy. At cruise you can hear it, but has no drone. Used band clamps to install the kit(the kit comes with regular clamps) , in case I didn't like the way the muffler sounded, I could change it.

 

I have an aero turbine 3030. Picked up about 2 mpg. A little louder than i had expected, but still sound good - like a motor boat sound.

 

This sounds like the deal for me. I just went to the mountains for my first road trip and I really wished I had some rumble up there.
Thanks

 

I just had a flowmaster 40 series replace the large canister under the truck before the axle, and my mpgs has dropped by 5 mpg. i'm hoping it is just due to a leak somewhere around one of the welds. I'll be taking it back to the shop this week to have it checked out.