97modifiedmustangGT

today i was talking to this painter who is painting my friends 5.0 because it was stolen and wreched and i was talking to him about my exhaust and i said i was getting an o/r h and he said that i should keep some high flow cats becouse without them you lose 15% of your horsepower and i thought it was only like 1 to 2 ponies. so is this correct or is it[sm=bs.gif]

so1o2k3

Umm unless he means it makes your O2 sensors trigger the check engine light, yes he is full of ****

idcoocheimonster

The only way you *would* lose power is because of back pressure, but then again on our cars, i think the H/X pipe takes care of that. But i maybe wrong.

97targa

I have an O/r X-pipe no cats and MIL eliminators and the thing screams!! I looked at tests that have been conducted before I purchased an X-pipe without cats to make sure it would be worth it and it is. I have gained roughly 3-4hp over someone with High Flow Cats!!! I still have enough backpressure with my 40 series flows and my puny 2.25in. exhaust which is stock for all those cars!

2000GT4.6

backpressure is on of those urban legend things.

There is no restriction (other than the pipes themselves) providing backpressure in my exhaust system, that is to say, its all hollow pipe. You don't need backpressure to make power.

A catless midpipe will make slightly more power than a catted one, but the differences are insignificant (compared to a high flow performance cat.

Triisomy21

Check out my thread here. https://mustangforums.com/m_1789889/tm.htm

I learned a lot from making it, and I think you will too. Enjoy.