Exhaust Header "Theory" and "Practicum" Discussion

[Hog]

I decided to start my own thread instead of cluttering others.

Speaking of restriction which causes backpressure. "The 1993MY upgrades included going to an exhaust that reduced backpressure by 2" of hg(mercury) was responsible for 6 bhp of the total power increase" of 20 sae net hp.

When the Engineer responsible for the MY1993 power upgrades (Mr. Graham Behan made the above statements, he uses bhp(brake horsepower). I have no idea if a brake horsepower is the same as a SAE net hp or not. If a BHP=SAE net hp, then the reduction in backpressure by 2" of hg, was responsible for 30% of the 20 sae net hp upgrades for MY1993.

I think that many people swap out exhausts (myself included), because it one of the few ways to completley change the personality of a car. While power increases are often stated as a main reason, in reality the search for the desired audible characteristics are the heart of the matter.

Some the nicest LT5 LT headers I have seen are the Baker Racing longtubes that member TPEPMEIE used on his custom-cammed 703hp dyno proven 427 monster.




The addition of longtube headers over OEM manifolds should increase scavenging of the exhaust gasses from the combustion chamber.

Will increased exhaust scavenging increase power output even if the total backpressure of the exhaust system remains the same?

There is no right or wrong in this thread, post up you "theory" and/or "Practical experience", all input and "ne off weirdo"or "cookie cutter system" discussion/dyno sheets/pics/magazine articles all welcome.