180 degree headers. adds 40-50 lb.-ft of tourque! - Third Generation F-Body Message Boards

jeepguy · 08-15-2007, 04:46 PM

Firts of all i own a 1986 z28 camaro. my name is alexander and im new to this forum. Ive learned a lot and have taken tons of great advice from a lot of the smart guys on the board so thank you.

in the august issue of grass roots motorsports theres an issue (linear solution) about a car that participated in the 2006 challenge. Its a datsun 260z with a 350 small block. The owner fabbed some custom headers that sends exhaust pulses 180 degress out of phase with the crank. he claims a 50lb. ft tourque increase!

" The primary tube size is matched to the head flow; the cubic inches and head flow determine an ideal peak power rpm. The cubic inches, peak power rpm and primary diameter determine the primary tube length" he begins. " The eqaul length [primary tubes] are rotationally timed 180 degrees out of phase with the crankshaft. The eqaul length secondary piping goes into a single four inch exhaust thats routed over the rear axel and the rear panhard bar. it exits out the rear valance panel." Andrew goes on to explain that a chevy v8 makes its distinctive whomp whomp whomp because, "cylinders eight-four on the right bank and five-seven on the left bank are firing 90 degrees out of phase in their respective bank, opposing an exhaust stroke event that is 270 degrees out of phase for the one-three and six-two discharges." "The way you unbundle the head is to build 180 degree header. That takes 3 and 5 from the left bank and ties them to 2 and 8 from the right bank. Then you take 4 and 6 and they get piped together with 1 and 7 from the left bank." The end result sounds like a four cylinder, he explains, since four equally spaced pulses enter the collector. "it's a huge amount of effort and there's not a lot of oppurtuninty to use it on a car this small," he says. "I have not been able to qauntify it, but it probably adds 40 to 50 lb. ft. of tourque through the midrange." - GRM

very intresting article whats your idea on how this would affect performance? has anyone of you seen the phenomena of 180 headers?

- jeepguy

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Apeiron · 08-15-2007, 05:23 PM

They were experimented with in the 60s and 70s, before everyone realized they weren't worth the expense and fitment nightmares.

I like how he says "I haven't been able to quantify it", and then goes on to quantify it anyway.