5.9L Rotary Performance Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with Rotary Injection Pumps Related To Performance And Longevity

home built 4 inch exhaust

Old Dec 31, 2010 | 06:48 AM
  #1  
elalr's Avatar
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Default home built 4 inch exhaust

well i got the 4 inch on the truck. i decided to cut and weld in my home built 3-4 adapter after the first elbow at the down tube. total length of 3 inch is about 2 feet long. did i waste my time by doing this? should i have just came all the way up? next, does a pyrometer go in the manifold or the exhaust? thank you all for your help!
 
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Old Dec 31, 2010 | 07:21 AM
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Most people put the pyro in the exh.manifold pre turbo,drill it out and tap it ,I built a 3-4"the same way you did a few yrs. ago and one from the turbo back 3-4"and I don't think you would gain much by doing it from the turbo,other then a couple of more hr. fitting and welding
 
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Old Dec 31, 2010 | 08:48 AM
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I bought an MBRP 4" down pipe when i did my home built 4" exhaust... I found it new for $105 at a local diesel shop and cudn't pass it up. EGT's stay in check and it sounds really good
 
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Old Dec 31, 2010 | 05:03 PM
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I didn't notice any improvement with 4" after the stock downpipe. Right now i'm running a 2nd gen 4" downpipe and it dropped the the egt's quite a bit. If you dont tow heavy your setup is fine.
 
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Old Dec 31, 2010 | 06:59 PM
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what would the happen if i did tow heavy? high egt? from the short peice of 3 inch. it sounds pretty good and it looks pretty good.
 
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Old Dec 31, 2010 | 07:44 PM
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need some pics!
 
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Old Dec 31, 2010 | 10:57 PM
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The stock pipe has a bend in it that reduces it to 2.5 in. When I still had it on I could hit 1500+ towing 10000lbs,but I have bigger than stock injectors and a turned up pump. Now it only does 1000-1200 wot and I went from 18mpg to 21mpg empty just changing to a bigger pipe. It took me six month's to get the nerve to hit the buy button for my downpipe but i'm glad I did because its the best mod ive done so far.
 
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Old Jan 1, 2011 | 03:04 PM
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Here what it looks like.
 
Attached Thumbnails home built 4 inch exhaust-small-pipe.jpg  
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Old Jan 1, 2011 | 05:00 PM
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that looks great! where did you get the first 45 elbow from the turbo? mine comes out horizontal.

---AutoMerged DoublePost---

i cant seem to get pics on here!
 

Last edited by elalr; Jan 1, 2011 at 05:00 PM. Reason: Automerged Doublepost
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Old Jan 1, 2011 | 05:45 PM
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here are some pics. cant see it verry good.
 
Attached Thumbnails home built 4 inch exhaust-exhaust.jpg   home built 4 inch exhaust-exhaust-2.jpg  
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