i just got a 3inch flowmaster 40 series.
3in 3out.
what do you guys think is best for my Cat decision?
push out the guts, or take it off....
if take it off then where do i mount the o2 sensor?

 

You can always go with high flow cats

 

Go with a high flow cat, they are cheap.

 

I saw this one thing on that fastman TB website, I think thats what it was called, but anyways, there was this device that allowed you to bypass the O2 sensor to thinking you have a really efficient cat on, go and look for that if you are interested.

 

How do you like the 40 series on it? How loud is it in the cab?

 

I believe they are called O2 Simulators. From what I understand, you can use them on the post cat O2 sensor, but you should not use them on the pre cat sensor. The PCM needs the pre cat one to make your truck run right.

 

What does the o2 sensor due for you, and what is the difference between a high flow cat, and normal cat, and a piece of pipe in place of a cat?

This is my first time looking at hotrodding a new motor, and I am used to the old style engine where you had a carb and some springs and and you messed with timing and cams...all these cars are smarter than me! heheh

-adam

 

O2 sim makes the computer think that the cat is working at 110%, and will give the engine a little more fuel if I am thinking right for more power.

 

high flow cat=self explanitory...its a replacement for your OEM cat, has higher flow for better performance

oem cat=restrictive as hell, everything is restrictive (airbox, exhaust system, manifold) so it can the lowest possible emissions (environmental reasons)

straight piping the cat= completely taking the cat off, maximum flow, more exhaust sound. you can always smell a car with no cats, regardless what people say. Cats are made to 'treat' the exhaust that runs through it so (like i said) when it leaves your vehicle, has the lowest possible pollution to the environment.

o2 sensor= the sensor that detects the oxygen content in the automobile’s exhaust gases and sends a low voltage reading to the computer

And yes, the bypass for that is called an o2 simulator

 

Just a friendly reminder, cat "maintenace" is a federal no-no. Most franchise shops wont even replace a working cat with a less restrictive, even if it is DOT approved. But hey, my for off-road use only "redneck" exhaust violates a few rules too. hahahah