The longer they are, the higher into the range they'll flow properly.
As we're dealing with a diesel, keeping them as short as possible from the main body will assist with low rpm power.
This information is contrary to what I have always known to be true but ill give it the benefit of the doubt since we are talking diesel engines.
Please, I am curious to see more information on this as.
You're right, I had my runner lengths backwards. D'Oh!
We'd actually want longer runners in a diesel. We're talking forced induction though, so things tend to go completely out the window with these tiny engines.
Years ago I got into intake and exhaust theory design when I had a 92 Q45. There is way more research and science behind these things that most people acknowledge. It's not a matter of simply bolting on a "freer flowing" component. That component needs to be designed and tuned to work properly with the rest of the system and, more importantly, in the desired powerband.
If you're interested in learning more I've found that just starting down the Rabbit hole with a Google search like "intake runner length theory" should get the ball rolling.
