silveradorealist

ASV, technically speaking you've hit the nail on the head. my only argument is my personal experience I have a 5.3 Silverado with 33'' tires 4.88 gear ratio( I know everybody says overgeared but its really great and you should try it ) and the bull mods like cold air intake granetelli maf. and about 1000 lbs lighter than factory.... but anyway I had stock exhaust and did a dyno pull the night before I was going to do my exhaust system and pulled 278rw, did 1 3/4 primary headers, 3'' ory, and 3'' pipe with a borla and a aero resonator, and elec cutout. with the cutout closed I made 296 and gained 24ftlbs over stoc and with the cutout opened I made an amazing 298 lol with a loss of 2 ft lbs of torque from with it closed, with basically identical weather conditions. my point is ,making a change in the air pump we call an engine, and saying that there wont be any different outcome than prior to the change is a foolish statement, it may be a measly 20 hp. 20 hp is 20 hp idc if you get it by pushing it in the front or blowing it out the back. please research scavenging and velocity and you will slightly better understand why these changes in flow and gains in horsepower occur. and why backpressure is truly the enemy. but your right in it not being anywhere near the gains of a internal modification of almost any kind or forced induction, n2o or anything else. I run n20 and my exhaust is for just that if I were running n/a I would have tried to run 2 3/4 piping for increased velocity
just my 2 cent didn't mean to go off on a rant or call anyone wrong not trying to offend but "changing things changes numbers on the dyno and at the strip its up to you to make those numbers go in the right direction" _me

oh yeah those dyno numbers are n/a with 273000 miles on engine and trans and truck. fresh rear end and the mods listed with the 100shot nx n20 it made 105 more hp and have put 10 or so bottles through it since still running strong

silveradorealist

lol asm, headers affect fuel curve and spark timing, ill tell you what affects that nelson performance tuning. 300 cash for a custom tune to your exact setup that's the cheapest part of performance. you cant change anything with gains without reprogramming the pcm to accept the new paramaters. just like changing a cam if you don't tune it will make very little power and run like dog $%!+. tune and wow is all I have to say.

so to everyone wanting headers buy em. get a tune be happy. just keep that velocity up as much as possible and don't go too so small to create backpressure. good luck