exhaust and sizing on dc2 vti-r

Hi guys i want to get an after market header and exhaust on my dc2 vti-r but im a little confused with the sizing. The previous owner changed the exhaust to an oem audm ITR exhaust and i was just wondering what size piping are they? Also im not sure if he also changed the cat converter to the ITR one but are they any different? And when ive been reading around most headers have a 2.5" collector so how does that fit to the remaining of the exhaust if say i had a 2.25" exhaust? they are different sizing? and does anyone know why full exhaust systems don't include cat converters? just makes all the sizes confusing to understand.. :S could someone please help me with some answers? Thanks in advance! sorry for all the questions :S

ITR (AUDM) Cat converter is longer than VTIR. From memory ITR is 45cm and VTIR is 30cm

ITR piping (B-pipe) 44mm inlet and 47mm outlet

See this thread for more detailed info http://www.ozhonda.com/forum/showthr...st-differences

Just buy.mu 5-zigen headers, get a 100cel metal cat in 2.5inch or 3inch & have someone make up a 3inch cat bak for u...

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Originally Posted by IEVAQ8

Just buy.mu 5-zigen headers, get a 100cel metal cat in 2.5inch or 3inch & have someone make up a 3inch cat bak for u...

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3" cat back for stock Vtir man? :s

I'd probably stick to 2.25. 2.5 is alright might be pushing it a bit. No way 3 inch though.

Cause different states have different laws with the cat
2.25 inch with bolts ons are good
2.5 with head work or future tune

2.25 gains more torque over 2.5 but 2.5 in the higher rpm gains more power.

most aftermarket are around 2.25-2.5 anyways

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Originally Posted by CRXDEL501

3" cat back for stock Vtir man? :s

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Originally Posted by BennyH

I'd probably stick to 2.25. 2.5 is alright might be pushing it a bit. No way 3 inch though.

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Once u both have experience then can u plz comment....
No hard feelings...
But i have just done this on my bros stock vtir integra...
It has stock headers, stock cat, stock airbox minus resonator box under front guard...and a true 3inch cat back...
It breaths really well n makes noticable gains...
Dyno run still to b done...