cutting cats

[KyleUSAF]

also, is a microtuner hard to learn to use using instructions and such, i dont know if i should get a microtuner or chip

[Monkey]

The reason you need backpressure is due to physics. The more backpressure you have in your exhaust, the more suction the exiting exhaust gasses create. This in turn PULLS exhaust out of your combustion chamber and sucks it into the exhaust manifold/header. The GT take-offs are the proper size diameter for duals. The 2.25" exhaust is large enough to flow freely, but is also small enough to create backpressure and improve torque. (Remember, horsepower is derived from torque and the more air in and out = more tq = more hp)

If an N/A v6 mustang were to use dual 3" exhaust, then you would see a loss of backpressure. This would slow down exhaust gasses and not create the sucking effect out of the combustion chamber. You would see your upper hp figures increase slightly (above 5k rpms) but your tq would significantly decrease.

On FI cars, the large the exhaust, the better. I could run 5" exhaust out of my car and see more hp and tq than the 3.1" I have right now. FI cars need as free flowing exhausts as possible

[Brent]

Quote: Originally Posted by KyleUSAF alright, I don't know if this muffler shop guy know what he is talking about but... (for those who haven't heard, I have MAC lontube headers and an H-Pipe waiting to be put on. the guy at the muffler shop said the H pipe would make my car not run right going from 4 cats to 2. He said he'd do the job but it would make it not run right.) I emailed the guy at American Motorsport asking if a chip will fix the problem of the car running rich, because I thought, with the H, the O2 sensors would pick up more oxygen and would add more fuel to the cylinders. The guy at the place said O2 sensors have nothing to do with the air/fuel mix, they just tell if my cats are working properly and if not, the check engine light will come on. Is this true? and Does anybody know WHAT THE HECK THE MUFFLER SHOP GUY WAS TALKING ABOUT? Maybe I should just ask him but he is kinda stubborn and I don't know if he would explain it to me. Help greatly appreciated

Al the o2 sensors do is tell you if your cats are working properly. So just have the guy put on the stuff and you won't run rich