As some of you know I'm gathering parts to make a decent little lq9 NA setup. Already have 1 7/8 headers to 2.5" true duals, x pipe, to dual borla pro xs. Will this setup flow well enough for 450whp or do I just need to step up to single 4" and be done?

 

Either of those will flow plenty enough for that power.

 

yea dual 2.5 will flow enough for 450 to the wheels. Dual 2.5 flows about as well we a single 3.5, if not better.

 

I've got a regular cab Lq9, 243 heads, and a 230's cam putting down mid 400's on low timing (nitrous tune). I'm running the Kooks 1-7/8's headers into there 3" Y-Pipe now. I've been thinking about swapping out the 3" intermediate pipe to 4" or running dual 3" with an X-pipe. Still unsure if the gains are worth the cost and extra weight...

 

swap to a single 3.5". Being NA I would think 4" is overkill.

 

Thanks for the input guys! I'll stick with what I have then.

 

You gotta love the sound of a good dual exhaust, cammed and dumped tho. Ive been havin the same dilema as you!

 

It's honesty not as loud as I would hope for it to be. It's way louder inside than it is outside even with the borlas cuz it's dumped. With my magnaflows my wife said you couldn't even hear my truck on the track (which is pretty cool at the same time also)

 

if you plan to grow into exhaust

i did a 1 7/8 into a 3" y pipe into a single 4" exhaust dumped before axle

no restriction on a 6.0....thru a 4000 stall it made 470 rwhp sae same setup uses dual 4" into single 4" feeding the 102mm tb....single 4" showed to be a restriction

 

I remember you saying that about the air filter. By any chance have a few pics of that setup? I run a single 4" now. Do you just have one running behind each headlight with the battery relocated?