Exhaust options?

evolDiesel · **Posted:** Mon Feb 22, 2010 2:18 am

Hey guys,

Just got my GDE hot tune ECU and my next item to tackle is the exhaust. Before I do, I'd like to hear what other owners have done and how it turned out.

Was it bought or fabricated or a combo?
Headers or cat back?
Diameters
Cost
Time
Level of skill involved
Performance improvements
Did the tone/sound change? What about the turbo?
Cat delete?
EGT changes?

Any guidance would be greatly appreciated - thanks,

Jack

RTStabler51 · **Posted:** Mon Feb 22, 2010 10:00 am

I have the MBRP Catback. It was an easy install and looks good. tone is a bit different from the outside. You can probably get the same from just replacing the muffler. Since I wanted to do it myself and have it look halfway decent I went the catback route.

Trav1s · **Posted:** Mon Feb 22, 2010 10:33 am

Custom header and turbo = BIG $$$

I have read tons on these and I would run the opposite way. www.turbododge.com has tons of stuff that talks about a header and turbos. Welds crack along with many other things. If you wanted to do something to the intake and or exhaust manifolds you could extruhone them but that still is significant $$ for little gains.

Cowpie1 · **Posted:** Mon Feb 22, 2010 3:02 pm

Oregon probably has issues with this one, but I removed everything from the turbo back and replaced with new pipe and magnaflow muffler. I heat wrapped about 2 feet of the pipe from the turbo on back to maintain exhaust flow (old racing technique recommended by Pittsburgh Power). I did this after cleaning up the exhaust on my '06 International with Cummins ISX and seeing the improved results. You can do these type of mods in a state like mine, Iowa, since there is no emissions/DOT inspections required and I am not sure that they would know that a diesel ever came with a CC.

linewarbr · **Posted:** Mon Feb 22, 2010 3:13 pm

I'm very happy with my Magnaflow catback. Did the install in my garage; it is bolt-up. I did not gut the cat, I just "clean" it every once in a while with my right foot. . .

evolDiesel · **Posted:** Mon Feb 22, 2010 3:21 pm

Cowpie1,

We have DEQ in Portland (unfortunately) but every time I've gone they only check ODB2 in which case pass/fail is dictated by whether you have a CEL. I really doubt they would catch any changes in exhaust unless it was insanely loud, smokey, or smelly.

I'm a little concerned with what GDE said in another post about how pungent (eye watering) it can get without a Cat.

I'd like to reduce back pressure and hear the turbo respond. Doing it cheaply would be nice too.

Thanks for the input so far

Jack

CRD Joe · **Posted:** Mon Feb 22, 2010 4:49 pm

I put in a 2.5" cat back no muffler six months ago. I like the sound. Im not sure but I THINK Ive lost some power through the loss of back pressure.

evolDiesel · **Posted:** Mon Feb 22, 2010 5:38 pm

CRD Joe wrote:

I put in a 2.5" cat back no muffler six months ago. I like the sound. Im not sure but I THINK Ive lost some power through the loss of back pressure.

I'm not sure how you could lose power from a loss of back pressure in a turbo-based system.

racertracer · **Posted:** Mon Feb 22, 2010 6:25 pm

I had the local Midas shop remove the stock muffler and replace it with a magnaflow #12226 2.5" that I procured. I must say that I went from 21.2 mpg to an inprovement of 23.8 mpg in town. The noise and rattle I was hearing from the muffler area is gone and engine noise and wabble is reduced.

If I knew the noise would have been reduced this much, I would have had the muffler replaced from the start.

This little beast Flys and I am loving it.

Muffler purchased from Amazon.com - $66.00 delivered.

Installation - $75.00

P.S. The 2 1/4" existing flange on the muffler does not require to be enlarged to 2 1/2". The existing muffler is the culprit and it is where the flow restriction occurs.

liberty2.8 · **Posted:** Mon Feb 22, 2010 11:17 pm

Quote:

I'm a little concerned with what GDE said in another post about how pungent (eye watering) it can get without a Cat.

evolDiesel,

That is exactly why mine is gutted, because of the pungent smell. Now it smells like diesel exhaust should smell. Really, my exhaust smelled really strange before the gutting.

BVCRD · **Posted:** Mon Feb 22, 2010 11:58 pm

liberty2.8 wrote:

Quote:

I'm a little concerned with what GDE said in another post about how pungent (eye watering) it can get without a Cat.

evolDiesel,

That is exactly why mine is gutted, because of the pungent smell. Now it smells like diesel exhaust should smell. Really, my exhaust smelled really strange before the gutting.

To me, it smells like a nitro methane funny car.

evolDiesel · **Posted:** Tue Feb 23, 2010 2:30 am

liberty2.8 wrote:

Quote:

I'm a little concerned with what GDE said in another post about how pungent (eye watering) it can get without a Cat.

evolDiesel,

That is exactly why mine is gutted, because of the pungent smell. Now it smells like diesel exhaust should smell. Really, my exhaust smelled really strange before the gutting.

So you guys are running no muffler? What diameter pipe? Is that cat back or did you delete that too?

Jack

liberty2.8 · **Posted:** Tue Feb 23, 2010 7:00 pm

No muffler and gutted cat with factory size pipe (straight-piped)

evolDiesel · **Posted:** Tue Feb 23, 2010 7:07 pm

How's the tone? Did it make the turbo more noticeable/louder?

dgeist · **Posted:** Thu Feb 25, 2010 3:43 pm

evolDiesel wrote:

So you guys are running no muffler? What diameter pipe? Is that cat back or did you delete that too?
Jack

2.5" (which is the same as most of the rest of the pipe). I had the flange between the cat and muffler cut off and replaced with a new "full-diameter" flange. The original flange neck was at least 1/4" narrower (which is silly) and the muffler shop charged me 5 bucks extra for that addition, which is well worth it in my book. They cut the pipe just after the muffler (again, where it was full-diameter) and simply bent a section of mild steel pipe to fit, tacked, and arc-welded it in place.

I'm 95% happy with the mod. The other 5% was from the slightly sloppy welding and some workmanship issues, but I don't think either effect the end result performance-wise, for which I have no complaints.

Dan

evolDiesel · **Posted:** Thu Feb 25, 2010 5:38 pm

dgeist -

How was the tone/volume? I like the sound of an aftermarket exhaust, but I don't like it loud and dissonant when stuck on the hwy. That gets old quick. So I'm curious about a delete mod like yours. And then how about effects to the turbo? Did reducing that back pressure have any increase in spool time or how loud it is?

Thanks for the replies guys... I'm really torn btw a delete-fab job and spending a few hundred on an aftermarket cat-back.

Jack

warp2diesel · **Posted:** Thu Feb 25, 2010 7:39 pm

Open up the choke point in the flange directly behind the Cat. I ran a bunch of tests with a boost gauge plumbed into the head pipe between the turbo and cat. Put on a 2 1/2" Magnaflow and open up the restriction directly behind the cat and your back pressure will drop to "0" PSI. If your cat gets loaded up with junk a quick acceleration up an express way ramp is all it takes to burn up the junk.
You will pick up a little low pitched rumble that will disappear when the wind and road noise kicks in at 45MPH.
If you have boost gauge, it will climb faster.

evolDiesel · **Posted:** Thu Feb 25, 2010 9:14 pm

warp2diesel wrote:

It will climb faster.

Hey - out of curiousity, what sort of range do you see on your boost gage? I'm debating about whether to go 0-15 or 0-30/35 or so.

Thanks warp,
Jack

Rixram · **Posted:** Mon Mar 08, 2010 3:49 pm

Pardopn my interruption, but has anyone deleted the OEM muffler and replaced it with a glass pack? Curious if it'd give a mileage boost and a sound mod as well.

*Personal rule: All my mods must pay for themselves with fuel savings in a reasonable amount of time. I usually own vehicles for 4-6 years, so somewhere in that time at the latest*

racertracer · **Posted:** Mon Mar 08, 2010 8:36 pm

Rixram,

Now, that would be a good sound clip to explore.

Exhaust options?

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