Ive got a dilemma, I my car is a 05 ls6 cts-v. Full bolt ons and a cam. The car will get some heads or some spray one day but not anytime soon.

Im shopping for a catback, I orderd a B&B catback a few weeks ago which is dual 3".
But the damm thing has been on back order for 4 weeks now and im not realy getting a straight up answer on when It will be ready.

Im debating just ordering a magnaflow catback which is dual 2.5".

What am I looking at in HP differance between the 2 on a cammed ls6 ?

 

Go w/ the bigger pipes..no one could tell you a hp differance but you'll be moving some pretty good air through there

 

https://ls1tech.com/forums/2987587-post19.html

 

Bigger the better, they love to breath. I have always known people to try the 2.5 then eventually go to the 3". better flo and deeper sound.

 

Ya I saw that, But I gained 5whp from a single cutout after the x-pipe just after the headers.

I wonder if the .5" will make a differance or not though . Or if the magnaflow bends and mufflers flow plenty.

 

A 3 inch pipe flows 160% of the volume of a 2.5 inch pipe, as else being equal. So there is no question that the 3 inch piping makes a difference in terms of flow capacity. What is not known with precision is the horsepower level at which the exhaust gases actually need the increased flow capacity. This is because the exhaust gases are cooling and shrinking as the distance from the motor increases.

 

At the very least, the bigger pipe is better for sound

 

Yeah pipe diameter can be quite deceiving. One 4" pipe is roughly 11% smaller than two 3" pipes.

You'll loose a tad bit of low end torque, or at least it will feel like it while you're driving around in the city, but once you open it up you will feel a significant difference on the top end. I can remember what it was like with crappy tires and just bolt ons (good flowing exhaust), it would hook up in the low RPM range and then break loose at about 4000 rpm. That was fun. You could really tell that the engine was developing a lot more power up top, and it came on pretty violently too... or as violently as a bolt on car can

Wait and go with 3".