well, soon I have to start work on a custom design for my v6, these will need to be a 3 into 1 design, both of which will merge down the line to feed the turbo, since I am a newbie at this type of thing I wanted to ask some advice as to the size of the primaries I should use as well as the length they should be before merging, in this case flow is more important than quick spool time since the turbo I'm using will spool fairly quick in any case, if it matters, the motor is a 3.0(bored to 3.2L) v6 from a Ford Taurus SHO, any help is appreciated

 

Well coming off the heads you will want the primaries about the same size as the port or very slightly larger. The secondaries will kind of depend on what size Turbo you are going to run and how you want to build your final 2 into 1 collector. With a T3 Turbine turbine your secondaries should probable be 2" Pipe if you are building it out of sch40 or sch10 pipe.

 

well, I'm planning on using a t4 turbo or t3/t4 large enough to support 500HP or so, maybe something like a t61 or possibly a t76, dont know how fast something that size would spool though(as long as it gets 15psi by 3600rpm I dont care) so roughly port size to 2" to whatever the final turbo exhaust flange is?