grumpyvette
Well-known member
Ive played around with different versions for years, results vary with the design features and how well the systems thought thru and built, but correctly designed they do get impressive results, badly designed they can hurt performance.
keep in mind your cam timing, intake runner design,displacement,compression, and other factors help or hinder the results youll get.
low and mid rpm torque increases are comon in a well designed set of AR headers,high rpm power loss is comon in badly designed headers
for those that don,t know what were refering to its headers/exhaust designed to flow only in one direction, baffles are designed into the primary and collectors to break up or retard reversion pulses.
your goal is to keep the exhaust speed/energy high to maximize cylinder scavaging yet restriction low to reduce back pressure to the minimum and to control and direct reversion pulse energy to assist in that scavaging
generally its done by extending the primary header tubes at some point into a larger primary tube (steping up, so as to leave a sharp edge that the reversion pulse generated at some rpm ranges has difficulty traveling back over. or installing venturis (tappered cones) in the exhaust headers that accomplish the same effect or BOTH
yes you really do need to read thru the links
http://www.headerdesign.com/extras/design.asp
http://www.burnsstainless.com/Xdesign/xdesign.html
http://www.vetteguru.com/mods/headers/
http://www.boatheaders.com/reversionbody.htm
http://www.burnsstainless.com/dynosys/dynosys.html
http://www.headersbyed.com/bildbetr.htm
http://victorylibrary.com/mopar/header-tech-c.htm
http://www.headersbyed.com/stepped.htm
http://www.burnsstainless.com/MergeCollectors/mergecollectors.html
http://www.holley.com/HiOctn/ProdLine/Products/ES/ESHHA/SplitFlow.html
as a simple example of a mod that usually gets results if the reduction is smooth/gradual, if its fairly abrupt the reduction acts as a restriction or even causes reversion to some extent
install one of these venturies in the 3" exhaust pipe(small end toward the rear)where the 3" collector mates to the 3" exhaust pipe to form a lip or step in the exhaust so any reversion pulse tends to have difficulty traveling from the exhaust to the collector
adding an (X) just past the anti reverion venturies reduces or at least tends to reduce reversion pulse strength also
keep in mind your cam timing, intake runner design,displacement,compression, and other factors help or hinder the results youll get.
low and mid rpm torque increases are comon in a well designed set of AR headers,high rpm power loss is comon in badly designed headers
for those that don,t know what were refering to its headers/exhaust designed to flow only in one direction, baffles are designed into the primary and collectors to break up or retard reversion pulses.
your goal is to keep the exhaust speed/energy high to maximize cylinder scavaging yet restriction low to reduce back pressure to the minimum and to control and direct reversion pulse energy to assist in that scavaging
generally its done by extending the primary header tubes at some point into a larger primary tube (steping up, so as to leave a sharp edge that the reversion pulse generated at some rpm ranges has difficulty traveling back over. or installing venturis (tappered cones) in the exhaust headers that accomplish the same effect or BOTH
yes you really do need to read thru the links
http://www.headerdesign.com/extras/design.asp
http://www.burnsstainless.com/Xdesign/xdesign.html
http://www.vetteguru.com/mods/headers/
http://www.boatheaders.com/reversionbody.htm
http://www.burnsstainless.com/dynosys/dynosys.html
http://www.headersbyed.com/bildbetr.htm
http://victorylibrary.com/mopar/header-tech-c.htm
http://www.headersbyed.com/stepped.htm
http://www.burnsstainless.com/MergeCollectors/mergecollectors.html
http://www.holley.com/HiOctn/ProdLine/Products/ES/ESHHA/SplitFlow.html
as a simple example of a mod that usually gets results if the reduction is smooth/gradual, if its fairly abrupt the reduction acts as a restriction or even causes reversion to some extent
install one of these venturies in the 3" exhaust pipe(small end toward the rear)where the 3" collector mates to the 3" exhaust pipe to form a lip or step in the exhaust so any reversion pulse tends to have difficulty traveling from the exhaust to the collector
adding an (X) just past the anti reverion venturies reduces or at least tends to reduce reversion pulse strength also
