i just put a 40 series single on my truck and i have the cat gutted i have the rear sensor pulled out and the front in and i have no check engine light coming on after 500 miles

 

i did true duals, and just cut a hole in one pipe, and welded on a bung and screwed it in. Works just fine for me. The only difference with a cat is A) much louder, more raw sound....and B) lower gas mileage by about 3 mpg.

 

Reading all the post about you guys running or wanting to put true duals without the cats just reminds me the MAIN reason I don't like living in Cali!!! You guys have it made!!!

 

So you get worse mileage without the cat in ?
I understand it being louder but not the gas mileage being worse.

 

it gets worse...trust me haha. either A)mechanical reasons, or B)the foot suddenly becomes heavier when the volume gets turned up a bit haha. others will explain as well

 

you saying because of back presser? i could see not cat no muffler and less mpgs

i say no cat 2.5 to 3in pipe nice muffler and keeping about the same mpgs

or im i wrong?

 

seems like it should work like this: lower backpressure = motor not working as hard = better fuel mileage

although, i imagine with no cat, engine gets louder = more ledfoot hehe

 

i will tell you i dont have as much power on acceleration but i still have high end... i used to could out run about any of my buddys trucks and now i get burned...but its all good cause true dual flow 40's and no cats drowned out their pipes aka give it hell

 

Had a bad experiance with an o2 simulator, wouldn't reccomend those to my worst enemy.

 

yea i understand given her hell, used to run a straight pipe, but got tired of ringing ears after towing wagons, was fun to scare people in town though

but as far as not having as much low to midrange power, it will prolly help on my truck removing the cat, its rattling like a bitch, prolly about to die