Installed a 3" o2 and downpipe. Now my car feels slower.

[JNZTRBO]

I installed a Hahn 3" o2 housing and downpipe yesterday after porting the wastegate and doing a little porting on the stock manifold. Now my car feels noticeably slower. My setup was a Big 16g, Greddy big fmic, Injen intake, and a 3" Thermal exhaust with the stock downpipe and 2" test pipe. All I switched was the o2, dp, and a 3" carsound cat. I was running 10psi before, and am still getting a reading of 10 psi. Does anyone have a clue? Thanks.

 

[TurBoGs-T]

Were you running a 2 inch test pipe or a 2.5??. I know when i upgraded my exhaust it felt alot weaker but it was really alot faster when i looked at my rpms. It just felt alot smoother so i though it was slower. Adding a cat will take away just a tad bit also.

 

[JNZTRBO]

My old cat back setup was the stock o2 and stock downpipe, a 2"(maybe a little larger), and a Thermal 3" wich bottlenecked to meet with the test pipe. The new setup is a straight 3" all the way back, but with a cat now.