Before I begin, Yes, I know there are aftermarket exhausts that are out there and are direct bolt on (some cost more or less to $300). Yes, I know kteller has a mandrel bent kit. Though the eBay BBP exhaust may be half the price I would rather have quality parts with correct fitment. I know a crush bent system will suffice for my daily driver 1.7L motor I would rather have a true 2.5" stainless system. Finally I know that 2.5" may be too large a size for a 1.7L but luckily 2.25" tubing is also available if I do change my mind.
Here is my plan to do a T409 stainless steel catback following stock piping and in a three piece design. All ID size will be aprroximately 2.5" and stainless steel.
-Buy T409 stainless steel, 5ft tubing should suffice it all depends on length of the cat, resonator, and header.
-Magnaflow catalytic converter or equvialent, 12"-16" length.
-18"-22" resonator (unsure which brand at the moment).
-oval muffler with offset/center and 20"+ length (Thrush, Magnaflow, Dynomax).
-5 collectors.
-hangers.
My only road block is what and how many mandrel bent tubing would I need. If want to follow the stock routing I would need (4) 90 degree(*) bends after the resonator.
From the picture, mandrelexhaustsystems.com has a total of (3) 90* bends, and (3?) 45* bends. 1 attached to a 90* and looks like (2) 45* attached to eachother? Of course all with different arm lengths.
EDIT: So the ID all depends on the gauge (or thickness of the pipe). So technically a 16 gauge, 2.5" OD tube would have an ID of 2.435".
Also the veritcal bends going over the lower control arm will be difficult. Any suggestions here will help.
Estimated total for materials and labor is no more than $300.
Below is my design for an exhaust and a link to of the stock exhuast routing:
Also added is a picture of the crx/integra mandrel kit from mandrelexhaustsystems.
http://www.acurapartswarehouse.com/Page_Product/PartDetail.aspx?catalogID=6&productID=3&yearID=10&doorID=3&gradeID=18&areaID=1&transmissionID=4&originID=-1&colorLabelIDs=-1&colorLabelID=-1§ionID=5&idAndImageID=952%20223061&isBigPicture=False
Edit: On my picture there should be a collector by the end of the resonator.