better breathing

CATCRD · **Posted:** Mon Apr 11, 2011 11:34 pm

Darthyota wrote:

so is the o2 sensor before or after the cat?

There isn't one.

SLS · **Posted:** Mon Apr 11, 2011 11:46 pm

Some good info here.
Perhaps some should be added to the tech section.

racertracer · **Posted:** Tue Apr 12, 2011 5:45 am

The muffler is where most of the exhaust congestion occurs.

The standard muffler in our vehicle is the same one used in the gas version of our Liberty. It works well in the Gas version but it is too restrictive for our CRD and where the Daimler Chrysler engineers did not give the design enough thought. :2cents:

Remove or replace the muffler with a 2 1/2" flow through one or remove and do not replace the muffler at all, but instead straight pipe it and you will notice a difference in performance, with a smoother running motor and reduced engine rattle / chatter.

ajk381 · **Posted:** Fri Apr 22, 2011 2:48 am

Like it was said i couldnt get 3in before the first 90 cause the outlet is 2.5 so there isnt enough room to downsize and have a bend. Well not without having an exhaust shop at my house

it is btw a big pita to get it in i had to take the tcase xmember down. As far as not making a diffrence like any performance turboed vehicle will tell you bigger is better granted overkill isnt but if stock is 2.5 then why wouldnt 3in be an improvement? And as for pictures i can take a few tomorrow if your intrested.

Darthyota · **Joined:** Wed Apr 06, 2011 6:12 pm **Posts:** 11

sure that would be great

flman · **Posted:** Fri Apr 22, 2011 6:47 am

3" would give you better breathing, but like every one else says, you might not gain nothing. Larger diameter pipe will reduce static pressure and therefor flow easier at a lower feet per minute. But I think your only gain is going to be the coolness factor.

Roostre · **Joined:** Sun Oct 24, 2010 3:57 pm **Posts:** 195

I also cut the pipe just behind the cat and used a 2.5" to 3" step up to my muffler. Only reason I went 3" was because the local bargain store had 3" aeroturbine stainless mufflers for $21. I ordered the mandrel bends from Summit and used the stock tailpipe for a pattern. It turned out pretty nice and only cost me about $120 total. If I had to do it over again I should have just adapted the 3" muffler outlet down to 2.5" and reused the stock tailpipe. Live and learn.

My EGT (post turbo) is about 450 F cruising down the highway. I have nothing to compare this to except other trucks I have owned. Even with the 3" cat back I have seen 1300+ pulling over steep passes. Just for a few seconds...I backed off and it dropped quickly to under 1100.

mustang_gt_350 · **Joined:** Tue Jun 01, 2010 8:47 am **Posts:** 191

Roostre wrote:

I also cut the pipe just behind the cat and used a 2.5" to 3" step up to my muffler. Only reason I went 3" was because the local bargain store had 3" aeroturbine stainless mufflers for $21. I ordered the mandrel bends from Summit and used the stock tailpipe for a pattern. It turned out pretty nice and only cost me about $120 total. If I had to do it over again I should have just adapted the 3" muffler outlet down to 2.5" and reused the stock tailpipe. Live and learn.

My EGT (post turbo) is about 450 F cruising down the highway. I have nothing to compare this to except other trucks I have owned. Even with the 3" cat back I have seen 1300+ pulling over steep passes. Just for a few seconds...I backed off and it dropped quickly to under 1100.

So you have hit 1300+ deg POST TURBO? Just bringing this up because of all of the people saying " you don't need gauges for GDE's Tunes" sorry for the hijack, kinda.

I just have the stock pipe with the restriction cut out, no muffler and the stock tail pipe. I just "cleaned out" the cat as my cheap flex pipe rusted out that I had in place of the muffler. I'll just be putting a section of solid in it with no muffler most likely, as its not that loud.

Roostre · **Joined:** Sun Oct 24, 2010 3:57 pm **Posts:** 195

mustang_gt_350 wrote:

So you have hit 1300+ deg POST TURBO? Just bringing this up because of all of the people saying " you don't need gauges for GDE's Tunes" sorry for the hijack, kinda.

Yes, it was still climbing as I pulled my foot out. Keep in mind that these are not the highest quality gauges so who knows how high it really got.

I do know that pulling the same pass prior to the exhaust and gauges it got hot enough that I could feel the ECU backing the fuel down. Which is why I bought a gauge... pulling heavy too often to take any chances. :2cents:

better breathing

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