I removed one of the mufflers yesterday from my exhaust system. The one b/t the cat and the final muffler. It is the section right after the exhaust comes out of the tunnel and crosses over to the driver side. I replaced with 2 1/2 exhaust tubing. I did it to get better flow and a better exhaust note. It sounds good, but seems to be a lot slower and a lot less top end. Is this b/c I need more backpressure, or b/c I need to compensate with a free flow air intake?

 

Seems weird I have seen it done before with out any problems.
But yes you might need more air.
Do you have a cone filter on?

 

Stock filter. I probably need to upgrade. I also figured maybe the computer needs time to map it out also. Just weird that I used to be able to get up to 110 on the road by my house at a certain point and this time it was only up to about 90.

 

I would install a K&N filter and give the computer time to learn and see what happens.