Yea I'd think so, especially having a set up that has 2 up pipes. I'd imagine merging them into a slightly larger single pipe will slow velocity.
Yeah, this is true, and it could depending on tubing size. I've done a lot of volume and cross sectional calculations and I would have to say that the 3" v band inlet of the Danville housing is right in between the cross sectional area of a t4 and t6 . (3" v band has opening area of right at 7 square inches, t4 open = 5.9 sq in, t4 divided = 2.7 sq in (x2= 5.4 sq in)...and T6 divided = 4.3 sq in(x2=8.6 sq in)). So, that being said, depending on up pipe size, we'll say 2" OD tube 16gauge (~.065 wall) so an ID of 1.880" would net a cross sectional area of 2.77 sq in, which is SUPER close to t4 divided. Going to a 3" tube would loose velocity, for sure. Even t4 open would technically be a hair too big, unless up pipes were closer to a 2.13 OD/2" ID 16g.
All the cummins guys use divided turbine inlets, and I can see using the theory of evening out pulses in alternate sides of the engine based on firing order, because their firing order (153624) would mean a pulse entering one side of the housing each time a cyl fired, alternating each time (though not necessarily evenly spaced/timed...hence equal length header theory) If you look at the firing order of the 6.0/6.4, (12734568, even # is drivers side, odd is pass side), you'll see that there will be 2 pulses in a row from each bank of the engine, which kind of negates some of the reason they say to use a divided housing. I'm not saying it's wrong, and the sizing and volume of the inlet seems to be a good match for our up-pipe sizes, but I think there would be little to no gains of t4 divided over t4 open for us, but obviously divided seems it's working ok for everyone. This is all way over analyzing all of this, but in a perfect world, I would like the turbine housing inlet to be the smallest part of the system, to maximize velocity/pressure as the gases enter the housing, rather than loose velocity.
