Installed X pipe
Thread Starter
Racer
Joined: Jul 2015
Posts: 296
Likes: 6
From: Valencia CA
Installed X pipe
I just installed an X pipe on my 01 base coupe. I'm running Borla stingers and noticed the sound is mellower and less noise in the interior than before. I heard the original H pipe had a 1/2" hole for flow which is restrictive. I looked at mine (which is original) and it has a fairly large (bigger than 1" hole on both sides of the H pipe)? Is there certain years that came with a larger holes on the H pipe? I haven't noticed any performance issues yet. Was hoping for slightly more volume, but now it's quieter. LOL...
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
You fell for the old X pipe trap! 
The X pipe will not necessarily increase HP. Your OEM exhaust system is NOT all that restrictive on a basically stock engine. The X pipe will allow the exhaust to use BOTH banks (mufflers ) to expel the exhaust gasses thus making the engine see a LARGER VOLUME Exhaust system.. That makes the exhaust note more mellow and have less gurgle and pop!
Until you add a LOT more breathing mods to the engine, bigger valves, more lift, more compression, monster cam, better intake manifold,, ect.. exhaust mods wont make that much difference.
It all depends on what workers installed the HOLE in the midpipe. Some were really small while others were larger and jagged. Our H pipe is more for exhaust system balance than a performance enhancement.
The raw jagged hole also made another issue in some C5. Some owners were hearing a jingling noise like keys jingling. After much research, GM determined that the irregular jagged hole in the mid pipe was causing that noise and issues a TSB to fix it if the owner complained.
The X pipe will not necessarily increase HP. Your OEM exhaust system is NOT all that restrictive on a basically stock engine. The X pipe will allow the exhaust to use BOTH banks (mufflers ) to expel the exhaust gasses thus making the engine see a LARGER VOLUME Exhaust system.. That makes the exhaust note more mellow and have less gurgle and pop!
Until you add a LOT more breathing mods to the engine, bigger valves, more lift, more compression, monster cam, better intake manifold,, ect.. exhaust mods wont make that much difference.
It all depends on what workers installed the HOLE in the midpipe. Some were really small while others were larger and jagged. Our H pipe is more for exhaust system balance than a performance enhancement.
The raw jagged hole also made another issue in some C5. Some owners were hearing a jingling noise like keys jingling. After much research, GM determined that the irregular jagged hole in the mid pipe was causing that noise and issues a TSB to fix it if the owner complained.
Last edited by Bill Curlee; Jul 14, 2016 at 03:10 PM.
