why does it make a difference? how does it hinder performance?

 

Subscribing for Fabrik8's long and detailed response.

 

Which such a small plenum the air will want to go directly into the #1 cylinder, therefore making the ITB's virtually useless. When using a wider/larger plenum and putting the inlet closer to the middle of the runners, it makes for a substantial increase in air flow throughout all 4 cylinders, rather than having it all cram into 1 cylinder. Plus, with the larger plenum and placement of the inlet it makes the flow fairly even in the cyliders making it not such a complete bitch when it comes time to tune. I can go on and on, but I hope that sums it up for you. It's all about flow.

 

The air can't flow around the lip of the velocity stack very effectively because the walls are so close (and therefore so is most of the boundary layer) so the stacks can't 'gather' air very efficiently from all directions. You're only going to have good velocity around the center of the stack, not around the whole perimeter like you want. The radius profile on the lip on the stacks is very important in order to work well, so if you put that lip close to the other stacks and close to the wall, and you're not sitting in clean airflow, that lip might as well not be there and you could just as easily use a flat floor with a slight radius on the edge of the runners. There is a minimum spacing around the velocity stacks for them to actually have an advantage over a straight piece of tubing (of just a flat floor), it's usually 60-200% of their diameter, depending on the spacing above the plenum floor and the radius profile of the rolled lip.

 

both very informing..

 

all GTI-R motors came with ITB's and a T28 BB turbo

 

it's

insane testicular bashing.

 

i didnt read the whole thred but dont waste your time you can make over 600 on a type r/skunk manifold

 

Why read the thread when you can just reply out of context?

THe point isn't ultimate power, it's the instantaneous power that ITBs give. Transport delay and plenum volume don't really exist with ITBs..
Just because it's easier to do something, it doesn't mean there aren't better reasons for doing it the harder way.

 

Your a tool.

Shit is not always about what's easier, or what's "better", and things that are off the beaten path are not always a "waste of time". Some people are into this shit because of the challenge of doing something different, or because a certain design or layout is particularly interesting, not just because you can make over x hp on y part for z dollars.

next time someone tells me something is a waste of time because everyone else thinks something else is better, I'm gonna lose it.