Contour Enthusiasts Group Archives Forums Modifications Forced Induction Did he say twin turbo?

6-2-1 isnt as efficient as 6-1 That is a fact. Youll never find a 6-2-1 on a race vehicle. Higher back pressure = more reversion. More reversion = 6-2-1. 6-2-1 = less power. Id also like to say that its harder to make a 6-2-1 header then 2 3-1`s simply because you have to make a 3-1 for each bank then shrink it into secondaries then route those to where the turbo is. Then merge the secondaries into a turbo flange.

For reasons of retaining heat and thus pressure a 6-1 v style engine setup will never be as efficient at spooling the turbo which means you have to run higher a/r`s then nessasary. This means... less power. again.

Ontop of this all testing in highperformance vehicles has definatly showed substantial performance and durability improvements from using individaul exhaust runners. Much less problems with cracking and warping do to the uneven heating of pipes such as in log style. Also the secondaries of a 6-2-1 header will get extremely hot because all exhaust gases are passing through them. They will break down over time and cause failure.