anti reversion exhaust designs

[grumpyvette]

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

[Cobra_Tim]

This is one hell of a post... I was already aware of the majority of the information, but reading it again always helps.