Pay attention to willwren!!!
Originally Posted by willwren
But NOT a 3" downpipe with the simple mods he listed.
There is A LOT more going on than "Bigger pipe - Less restriction"!
The exhaust system is dealing with pressure pulses, inertia, and velocity (and other things as well). To oversimplify, a 3 inch pipe has WAY TOO MUCH volume for optimum velocity. The inertia of the pressure pulse and its associated low pressure that follows is ONE of the things that assists in EXTRACTING the exhaust out of the cylinders.
This is a DYNAMIC system and can therefore be COUNTER intuitive. You want to set up a pressure pulse moving down the exhaust pipe at high velocity and proper timing with the rest of the system. It is very similar to an acoustic system where the porting and volume are defined specifically for a frequency.
It isn't as simple as you think!
Listen to willwren. He not only knows from other people'* experience, he'* probably tried almost everything himself.
2001 Bonneville SE - Dark Bronzemist Metallic - Mods: 180* thermostat, iPod adapter, Digital OnStar Upgrade
Planned Audio System upgrades: Front & Rear 7 Band Equalizer, Amps, Hands Free Bluetooth Cell Phone kit
Planned mods: Front PEM, Ported LIM, Ported Heads, ZZP SR Rockers, Aluminum Gaskets & Reprogram PCM