so, got new cat conv. on my 95 auto 4x4 today...magnaflow cat. after the install, I have lost all power and smoothness I worked so hard to get back after buying this 4runner w/200k.. Yesterday I could burnout and beat some cars off the line, now its all gone!! (i know..its not the point to be fast)...
So my mechanic (who has done much work for me and my company, very trusted) tells me my old cat had a 3" reducer or 2" reducer, cant remember? The old exhaust sytem was an aftermarket 3" setup from front to back.. in an effort to put this truck back to OEM, I had new exhaust and muffler put on a few months back.,, but kept the cat on (no $$)... my guy said he left that reducer out of the new install today and now I may have "too much" flow??? Can someone help explain what is going on?
He is totally good on his word and wants to pick up the truck and fix it, just curious and want to learn about the airflow, diameters, and back pressure, etc..

anyone help on this one? sorry if my explanation is so distorted, been a long day and a horrible ride home in the runner.
yota

 

A reducer in the cat? Hmm, sounds odd. 3" is WAY to big for the v6, what size exhaust pipes are you running now?

 

2" I believe... running well until today's new cat....probably not explaining it all right, sorry

 

Well, 2" is too small for your truck bud. 2 1/8th is stock. 2.25" is probibly the best size.
The reason you lost power is the cat is restricting your exhaust even more now. I would recomend a 2.25" system, or at least stock size.