Thrush Glasspacks

[kennythewelder]

Mine are welded, but after all I am a welder. You can clamp them on though. Straight pipes are fine as long as the cats. are still in place, and your state will allow this.

 

[GMRedline]

if anything, step UP the diameter as you go back...
2" Y pipe - 2.25 collector - 2.5" catt -3" muffler - 3.5 tail pipe
(as an example)

The only thing that will accomplish is making noise. When building a performance exhaust, it is most important to have the best flowing components closest to the engine and then step down from there. Exhaust gases are the hottest (most excited) right as they leave the engine. (X)cfm at 900* needs more space then (X)cfm at 200*. Any bottleneck in the whole system should be the very last component (muffler).

 

[steampunk1375]

The only thing that will accomplish is making noise. When building a performance exhaust, it is most important to have the best flowing components closest to the engine and then step down from there. Exhaust gases are the hottest (most excited) right as they leave the engine. (X)cfm at 900* needs more space then (X)cfm at 200*. Any bottleneck in the whole system should be the very last component (muffler).

GM redline is right. Start 3" at the engine and then step down like he says, this will help maintain exhaust velocity.

 

[dylan94sierra]

Mine are welded, but after all I am a welder. You can clamp them on though. Straight pipes are fine as long as the cats. are still in place, and your state will allow this.

That's what I was hoping to delete the cats...
And that's the best thing about Florida, no inspections at all

 

[kennythewelder]

94 you can. 96 or newer can not, obd 2 system wont let you.

 

[dylan94sierra]

Ok Ill probabaly delete the cat and muffler, straight pipe it, and put a down pipe just after the cab

 

[Teal97k1500]

lol yeah, screw autozone knowledge...

I found out why backpressure is important though... it gives your O2 sensor the ability to communicate and tune your engine better.. zero back pressure can throw a "too lean AFM" code...

THANK YOU!!! iv been pulling my hair out trying to figure out why im getting to lean bank 1 and bank 2!!! my truck came with true duals with thush 25'' glass packs on it, which i can NOT wait to remove.......


haha sorry to thread jack but thanks blazer i had no idea this would cause the o2 sensors to do that....