DeanM45 wrote:So, long story---I have been doing general maintenance on the car to get the MPG up and have been fairly happy at a combined of 24 (60% highway/40% street) but as I just turned 70K I decided to replace the O2 sensors. The last one, drivers side after cat just would not come out. PB blaster and a long breaker bar got it out, along with the boss on the Y pipe. Doh!
So I pulled the stock Y out and tack welded the boss back on. I went ahead and grabbed a generic Y pipe off of Ebay to mess with (2 1/2" in, 3" out) and noticed just how close it is to the stock pipe. Got some 2 1/2" polished stainless pipe (Amazon RULES), some O2 standoff pipes, and flanges. Got most of the welding done today (use TIG for stainless) and I hope to finish, as long as it does not rain, tomorrow. The stock pipe necks down to 1 1/2" right after the cat and then in other places as well. Really weird design but I assume for noise abatement.
For anyone that wants to attempt this: the flanges off of the primary cats (on the exhaust manifolds) are weird, 2 3/8" opening with center to center bolt spacing of 4 5/8". I found some that will work but not in stainless on Amazon. Finally found some stainless at a custom exhaust shop.
Don't know how much louder it will be but I really don't care at this point as I am going for better flow and can deal with noise reduction later on (running Megan mid pipe back right now).
Should be fun and I'll keep you guys informed. I should be into it for about $350. Could have been done cheaper at an exhaust shop probably but I wanted stainless and secondary cat delete for when the car sees the track. Most shops will not touch anything with cats in California and besides, I like to do everything myself. I've already got replacement cats that will bolt in (similar to the M35) for street use (just need to weld the up pipe and O2 flanges on).
I know you put this in lame man's terms but is there any chance you can convert it to Y PIPE UPGRADE FOR DUMMIES ( links, sites url finished pics etc..) I'm brand new to this forum and have been reading posts for days and this one finally is the best step in the right direction
just ordered Megan mid and axle back exhaust , injen cai, and contacted Joe widal at uprev which he advised doing all this first then a tune so that in the works only thing holding me up is the damn y pipe and hi flow cat or stock cat dilemma, be greatly appreciated if I could pick your brain a lil or just advise me on what to do about the y pipe and cat siuaton went to Amazon and tried to piece together your y pipe picture just confused the s*** out of me!