Catless Si ebay downpipe?

[ex5coupe]

If you were to install a T1r style downpipe, could you simply leave the rear o2 just in free air? I have heard that this works. anyone tried it? Also, how is it known that the car doesnt compensate for incorrect values associated with the removal of a cat. Even with the Defouler some say that the light still comes on. I have experience with downpiped vehicles but never did a before and after with a wideband. What I would like to see is a datalog or at least some information on what the A/Rs were before and after a downpipe install.

I have heard what they sound like with stock exhaust on a video, but I cant tell if its raspy or not in person. anybody have this setup? thanks. Also I did see the dyno of no real major gain after install, but the question is did the car have time to adjust for the now additional flow? I would imagine it would take a little while for it to adjust but I have no factual data to prove or disprove that this would change any power output.

[ex5coupe]

delete this post. no responses just a bunch of views

[XSRCivic]

Originally Posted by ex5coupe

If you were to install a T1r style downpipe, could you simply leave the rear o2 just in free air? I have heard that this works. anyone tried it? Also, how is it known that the car doesnt compensate for incorrect values associated with the removal of a cat. Even with the Defouler some say that the light still comes on. I have experience with downpiped vehicles but never did a before and after with a wideband. What I would like to see is a datalog or at least some information on what the A/Rs were before and after a downpipe install.

I have heard what they sound like with stock exhaust on a video, but I cant tell if its raspy or not in person. anybody have this setup? thanks. Also I did see the dyno of no real major gain after install, but the question is did the car have time to adjust for the now additional flow? I would imagine it would take a little while for it to adjust but I have no factual data to prove or disprove that this would change any power output.

You will throw a cel if you leave the sensor without a simulator. There is really no difference in power.

My dyno run with catless downpipe

There's the dyno I did with the downpipe I made. I did a seperate dyno run 2 weeks later with stock equipment, same temperature conditions and made NO MORE peak HP then over stock. I only gained about 6 whp in the midrange for maybe 500 rpm. Totally not worth the money or time.

My dyno... Red is Stock mid pipe, Green is Test pipe..
ImageShack - Hosting :: dynonp8.jpg

[ex5coupe]

I put the stock cat back on. The car was running weird. the throttle would go dead while out of gear. So I figured something was not working right. perhaps an 08 issue. I know you dynoed the setup but after going back to stock I find it has more torque.