6.7L Cummins Forum

So spring has finally shown up here in Kansas and it's time to decide on an exhaust upgrade for my 3500 and wow is there a bunch of them on the market now. I won't go into the Stainless Steal (SS) or Aluminized choice since I covered SS here T-409 and T-304 Exhaust FAQ but I am now wondering about the decision between the 4" or 5" piping. Does anyone have any experience or knowledge about this? My concern with the 5" is clearance problems when I load her down in the back and since I live on a dirt road out in the boonies there's a lot of suspension movement.

At first I was going to just go with the stock look and get the MBRP DPF system but the SS is only the 4" pipe with the 5" being Aluminized.

Then I saw this.


This is the Banks dual and I checked and it safely clears the spare tire, shocks and brake lines but it only comes in the 4" version. They advertise that even being a 4" pipe there's still a 150% improvement in airflow and slashes backpressure up to 98% and the dual tailpipes have 52% more flow area than a single 4" tailpipe. Man I sure like that look.

Any insight would be appreciated

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

That looks good, does it change the sound?
How much?

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2008 Dodge 2500HD 6.7L 4X4 Laramie
Edge insight, Amp tailgate step, 4" Boss Bars, rear air bags with compressor, spray in bed liner

Very cool...How close does it come to the fuel tank?

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7.5 3500QC 6.7CTD 68RFE Build date June 2007
Superchips tuner 3808, Boost/EGT Laser Gauge, Airaid cold intake

It looks very cool, but if you are retaining the DPF, cool is all you'll get. All the installs that I have seen here, both 4" and 5" do very little if anything for the sound, mileage or HP. The DPF is the restriction.

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2007 Ram 2500 QC 4x4 SLT TRX4-Offroad 6.7L Automatic. '08 Jeep WK 3.0L diesel-wife's DD.
1998 Jeep ZJ 4.0L Automatic Selectrac-project for our son. '98 Jeep XJ-my wife's former DD.
1965 Dodge Polara 880 Convertible 383 Automatic.

Well yes that's also what I've read but in order to really know if it makes a difference you would have to run it in a controlled environment with the same temp, barometric pressure, humidity, etc. To say that there won't be any gains because of the DPF is being a little narrow minded. I bet in a controlled setting like F-1 uses to test engines you would most definitely see a performance gain just by reducing the bends, adding diameter to the outflow by splitting the pipe and throw in getting rid of the muffler(I'm going to cut mine to see). Plug in my Juice with attitude and Volant intake and I bet the flow will help more then you realize but if you're selling or are interested in getting rid of the DPF, EGR, heater, etc, etc then yes this isn't for you.

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

With all due respect, controlled testing does not mean sweet tweet to me. I like real world testing, day in, day out, real driving. In those situations a different DPF back exhaust has shown no improvement in mileage or horse power.
At this point the only things to add that will increase mileage and power, while still retaining the DPF are aftermarket air filters, some CAIs, some tuners. A boost fooler may help but I know of no 6.7s running one, at this point, around here. We've been told they are back ordered.
A buddy of mine just started using a Hypertech Max Energy on his '08. It is not a year old yet and has 70,000+kms on the clock. On his weekly sales trip up north, he claims that the Hypertech gave him an additional 100 kms on a tank of fuel. He's not the only one that has had good results with these. I'll watch this for another few weeks before I go in that direction.
With fuel here at 64.9/L, it's not as much of a panic. To put it further in perspective, my former DD was a 5.9L Grand Cherokee. Although it and had fun with it, the thing was a pig. Empty the truck gets about 3 to 5 mpg better and when towing about double. This, with a much larger trailer and a load in the box.
Sorry to ramble. These are m just my observations but prove me wrong.

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2007 Ram 2500 QC 4x4 SLT TRX4-Offroad 6.7L Automatic. '08 Jeep WK 3.0L diesel-wife's DD.
1998 Jeep ZJ 4.0L Automatic Selectrac-project for our son. '98 Jeep XJ-my wife's former DD.
1965 Dodge Polara 880 Convertible 383 Automatic.

This is a discussion forum so no biggey. I'll let you know what I find out after it's installed. Gives me something to do besides, don't these trucks already have enough giddy up?

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

So what was the outcome???? Like it, Love want some of it??? Fuel that is..... LOL
I am new as well, many mods to come.....

Best bet is to leave it stock. I did a bunch of upgrades to my old 6.0 ford powerstroke and it just caused a ton of problems down the road, hence is why i own a dodge now.

Saw the shot of the Banks dual system....I'm looking to replace the stock muffler/tailpipe on my '07.5 Quad-Cab LWB 4WD. I would like to go with a single DPF-back system. Deleting the muffler would be the easiest, but Texas is now mandating a "muffler" on all diesel pickups and won't inspect one of these trucks without it. Any suggestions?