Daez

I have Longtubes with about 1 1/2-2 feet of piping welded on each one. I've already read all the threads about scavenging x/h pipes bringing more power than a straight pipe set up. I would like to see some numbers, or runs or something though.. anyone have any before and afters, or at least a dyno run with straight pipes?

StreetStalkerZ

iTrader: (1)

I LOST 39rwhp when i ran straight headers compared to my H pipe setup. A/F ratio hardly changed between the runs.

447rwhp through 3 inch H pipe w/ Borla XR-1 mufflers
408rwhp through open cutouts off the headers

Daez

Damn.. Did you have the cutouts RIGHT off the edge of the headers though? Doesn't it need some piping so the O2's can read properly?

mchdg86

iTrader: (3)

Thats kind of odd. I had cut outs welded on to the header collectors my T/A that I had and dropped .1 and gained 1 mph by opening them at the track.

Daez

What was the rest of your system?

castine917

the rest of the setup could effect which way is faster? took the camaro to track with open only (not enough time to run closed)so i have not seen back to back results myself but was told by friend that his is faster through mufflers.

Daez

Yeah, for example.. if the rest of his set up is a Y-pipe into an 80 series flowmaster, then I could see him picking up power no matter what he did.

mchdg86

iTrader: (3)

It was 2 1/2" duals with an h-pipe and sweet thunder mufflers ran out the back over the axle.

Squirts11

iTrader: (14)

When at WOT, the o2 sensors aren't being used, so the cutout location wouldn't affect/be affected by o2's.

thunderstruck507

iTrader: (18)

that's a huge gain...could it be some sort of mistake?

really making me rethink my setup (2.25 duals with dual cutous 1 foot behind the headers)

StreetStalkerZ

iTrader: (1)

From what i have seen first hand these motors do not like open headers. I watched several cars pick up ET through the mufflers,true dual setups.

thunderstruck507

iTrader: (18)

I pick up between .15 and .2 and 1.5-2 mph with mine open...but we mostly bracket race so they are more for making street cars **** themselves in fear and on faster cars the sound of me leaving has led to several redlighting

I am thinking of going to a dual 3" setup with a H or X in the future, but I don't have evidence of it gaining me more than 15hp right now and it would be somewhat costly and much more of a pain than other mods I could do first (pulley, heads)

Also make transmission and driveshaft related tasks much more of a pain...

moeZ28

iTrader: (7)

I had dual cutouts right off the headers on my old car, heads/cam 347ci...picked up 21 rwhp on back to back dyno runs with the cutouts open over my slp loudmouth exhaust. Car had pacesetter long tubes and ORY and an original loudmouth.