Rubrignitz

I removed my cats and added an o/r h-pipe a few weeks ago. In the meantime my nice chrome plated axle backs have turned black around the outside tips due to unburned fuel/rich condition. DoI need to re-tune after the O/R h-pipe install??? I know I FEEL a difference in output for sure. A re-tune would probably be in my best interest correct? Or is it just a way of life when you run catless?

jmk3

Congradulations you have taken you car back to 1974 when everyone belched black stuff from their tailpipes.

rshamekh

It's normal. You only need a tune to turn off your O2 sensors.

Rubrignitz

Nah, I had to use a "stock" SCT tune and disable my O2's. It's running perfect, no cels. It's a beautiful thing, sounds really sick at part throttle. Scares people. I really don't want to hear about how I'm killin the ozone folks because theres much greater powers than my little car doing that.

I hear that <3psi of backpressure will cause a rich condition and need to tune it out. Guess I'm back to the tuner.....

ShadyNinja

yeah like volcanoes ~

Rubrignitz

Tha's right baby!!!

There are many thing belching black smoke, but it's not my Stang'!!

tungsten07

if you're using a mail order tune they tune them to run richer to avoid detonation and that causes the good old black stuffas well...

GTstangB.F.D.M.

just becareful.. i did this for liek a day and half, and the guy i work with (advance auto parts).. said that it can really fck things up in the mid/long run..

cuase you to loose compression over time, no backpressue, bad for head gasket, and burns the valves...

but i agree with you.. the sound is AMAZING!.. and FCK THE TREE HUGGERS... me/you not having cats, compared to having cats, is like taking a grain of sand from the beach and calling it beach erosion.........

Rubrignitz

I think he got that backwards. Too MUCH backpressure can cause loss of compression, head gasket issues and valve problems.

GTstangB.F.D.M.

no he is right.. with no back pressure, there is nothing to help push the valves, which causes them to get burnt.. what happens is fire ends up coming down the exhuast.. instead of staying in the cylinder (notice the dragsters and other cars that have straight headers coming out side.. when they run you can see the fire).. also, bc the valve isnt pushed back, you loose compression, bc some of it is escaping.. and im guessing the fire is what kills the gasket... not 100% sure on all of this, but its something along those lines.. but too much back pressure wont do that.. if you dont have enough, the car wont even run.. this happen to my buddy in a s10.. put some big piping, i think like 3 inch on a small block, and the engine wouldnt even start bc there was no back pressure..