ChevyRyda99LS1

Quick question I have a 99 z28 I have the slp flow pac with lid bellow and the scoop and a cat back I am going to be adding the pacesetter longtube headers with the off road y-pipe and removing my cats what a good guess of power I should be working with after those mods

landonew

Depends on your base. Headers are worth 10-15 and y-pipe + !cats is worth 5-10. I would say 15-25hp, depending on your setup. Will definately be able to tell the difference, and the sound will be noticably different.

ChevyRyda99LS1

sounds good wish I knew someone to give me a good tune I might have to purchase a tuner and learn hey do headers help improve your gas mileage

RedRallyeZ

iTrader: (20)

headers can or cant improve gas mileage depending on whose car they are on.

they do increase the amount of air going through the motor so that should help, but most of us love the sound of our new exhaust and cant keep our foot out of it, so i ended up losing a few mpg's. also when you put in an ORY the car tends to run a little rich since it no longer has cats and the rear o2's are still there.

you can tune those out though, post up in your regional forum and see if there is anyone around you with hptuners that may be willing to help you out. thats gonna be alot more beneficial than buying one and srewing around with it until something happens good luck bud