Is the stock "muffler" that restrictive?

[jcain]

Ever since going to the bigger 2015 turbo, my exhaust has been separating at the delete pipe band clamp. I still have the stock over-axle muffler and stock dp back (minus dpf). Is it possible that the stock muffler is out of its league with this little jump in power?

 

[drunk on diesel]

no, just replace the clamp with a guillotine style clamp or tack weld the connection

 

[truckmaniac]

I believe that the muffler you're referring to is more of a resonator, which quietens some of the exhaust pulses and drone. I highly doubt that it is restrictive enough to cause enough back-pressure to blow your exhaust pipe apart at the connection.

Eat your Wheaties and get the clamp good and tight, without busting a knuckle or stripping the threads, otherwise you will experience :cursing:

You might also check the exhaust pipe hangers and rubber isolators. You want the hangers to be located about mid-way in the isolators, with the isolators hanging vertical. If the isolators are "stretched" forward, they could possibly pull-back on the pipe when you're running and cause connection issues. I've personally seen this happen on a friends truck.

 

[SEABEE08FX4]

Its not so much the muffler as it is the diameter of the piping. The muffler ( a resonator really ) is a straight through design, however the 3.5" piping becomes the limiting factor when you start increasing air and fuel to gain power.

 

[jcain]

Clamp is bottomed out. Just find it odd that it's never done this before, but has 3 times since the turbo swap. I didn't even touch this section during the swap. I guess I'll drill a couple holes and put sheet metal screw in to help hold it.

 

[SEABEE08FX4]

Think of it this way, I have a 5" exhaust on mine, and even with the 5" diameter I still can fine small leaks around the clamps that you can't even fit a hair in between. So just to give you a reference on the amount of flow and pressure that is in an exhaust at WOT.

 

[jcain]

Very few of the trucks in this section can fully tap out a 4" dp back, let alone need a 5". I was just unsure of the design of the stock resonator and wether or not anyone had flowed one or had one get clogged/damaged resulting in high back pressure.

 

[drunk on diesel]

I'm guessing when you did the turbo install, you moved/tweaked that connection enough to cause it to give. once the clamp is stretched/bottomed out, that's all she wrote.

I would just put a guillotine clamp or tack weld on it and roll out.

4" and 5" obviously flow better than 3.5", but on a tune-only 6.7, I feel it's kinda splitting hairs

I run factory muffler/tailpipe on most of my 6.4's. A couple of them, I grafted/welded on a 6.7 tailpipe section so I have the 6.4 "muffler" and the 6.7 resonator.

a tune-only 6.4 is considerably more powerful than a tune-only 6.7, and I've never felt like I was leaving a whole lot on the table by doing so.

my 6.4 with full 3.5" exhaust including 6.4 and 6.7 muffler/resonator will put a hurting on the one I have with full 4". I account that to the No Limit intake vs. the AFE on the other truck.

*cliff notes: the 6.7 resonator isn't causing any measurable increase in back pressure vs. 3.5" straight pipe

 

[SEABEE08FX4]

The power difference between a 4-5" exhaust on your average truck is slim to none. Its mostly sound. I was just illustrating the amount of velocity and pressure the exhaust sees, not suggesting you need a sewer pipe sized exhaust. But that said 3.5" is pretty small for a 400+ ci turbocharged engine, especially when you start turning the wick up on it.

 

[08Monster]

I felt a pretty large gain in power by going from 3.5" to 5" on my 6.4 FWIW.

 

[bigrpowr]

I felt a pretty large gain in power by going from 3.5" to 5" on my 6.4 FWIW.

it was all in your head .

 

[SEABEE08FX4]

Going from a stock exhaust to a 4 or 5 I'm sure there is more than enough there to feel something on the butt dyno. But your biggest gains will be from reduced EGT's and back pressure post turbo. Now if you went from not deleted to deleted at the same time your feeling the biggest gain from the tune alone.

 

[WhiteMamba_Scorpion]

Are you using a u-bolt style or a band clamp?

Get yourself some of these and torque the living F*** outta them.

 

[08Monster]

Its was tuned/deleted with just a delete pipe. I know I gained SOME sort of HP from it. I could definitely feel a difference, also, EGTs and EBP are WAY better now too.

 

[jcain]

Are you using a u-bolt style or a band clamp?

Get yourself some of these and torque the living F*** outta them.

That's what's on there.

 

[sootie]

get the exhaust in the position you want and then drill a 1/8" hole thru the clamp, the outside pipe and the inside pipe. install a pop rivet and you will be golden.

 

[WhiteMamba_Scorpion]

That's what's on there.

Hmm... idk I've never had one come apart on me. Disregard what I said then haha

 

[drunk on diesel]

The power difference between a 4-5" exhaust on your average truck is slim to none. Its mostly sound. I was just illustrating the amount of velocity and pressure the exhaust sees, not suggesting you need a sewer pipe sized exhaust. But that said 3.5" is pretty small for a 400+ ci turbocharged engine, especially when you start turning the wick up on it.

it is on the small side for sure when you consider Dodge has been putting 4" on since 04...

I'm sure I would pick up some more throttle response, etc. stepping up on my truck, but I just like the OEM tips