none of those exhaust s pictured above are "headers"
they are all exhaust manifolds of one type or another
real "headers" have equal length primary tubes
the volume of the equal length primary tubes is
the engine displacement divided by the number of cylinders
the displacement of 1 cylinder
in a 10G geo metro header , the volume of 1 primary tube should be
diameter of the primary tube should allow / force exhaust gas velocity to be right about 300 feet per second
at the rpm that the header is designed to provide peak performance at
the rpm that the header system is "tuned" for
it's just a word , words are our friend s - they all have meaning .
the 02 sensor must be mounted in the collector
not in a primary tube
if the ECM is to be in fuel control of the engine , not in fuel control for 1 cylinder
does it matter ?
Last edited by mwebb
on June 17th, 2012, 2:00 am, edited 1 time in total.
10g engine with 3tech economy cam and Singh Grooves otherwise stock
87 octane TOP Tier fuel with 1oz TCW3 synthetic marine 2stroke oil per 5 gallons of fuel
Base ignition timing set to 8 degrees BTDC .
summer wheels are 15" alloy sourced from a late 80s Acura legend
currently has -
185 60 15 Bridgestone RE 92 tires on Acura Legend alloy rims in front
195 55 16 conti pro tires on 16" Nissan Cube Alloy wheels in the rear
passenger side wiper is removed - makes no measurable difference - RAINX on the windshield
do not need the wipers anyway
to expand my posted images
click on image , select view image , click 2x
i have removed the 3tech +10 cam wheel - drivability is much better and FE appears to be UNchanged
EXHAUST PIPE diameter 0D = 1 1/8" made from 1" EMT conduit
unless you enjoy chasing your own tail without ever catching it
NEVER USE AN OHM METER TO TEST A BROKEN CAR