I'm sure someone on here who has read maximum boost will be able to help me out. I've sat at Border's for a couple hours looking over it. Is there any benefit of using the same sized pipe all the way through your intake and exhaust components? Should certain areas be larger diameters then step down?

Air currently flows through my car through turbo, immediatly stepped up to 2.5", through the intercooler 2.5" in and out, then through the TB which is roughly 2.5", squeeze-bang-blow, 2.5" downpipe, no cat, 2.5" exhaust straight thru 2.5" muffler.

Would I benefit from having a 3" downpipe and step down to 2.5" around the cat area?

 

you want to reduce back pressure coming out of the turbo. It's not about equal amount of air going in must equal amount of air going out. There are too many combustion process inside the cylinder to make this happen perfectly everytime.

You want velocity driven intake, therefore, go with small to medium intake piping size. Turbo is a measure of pressure, hence pounds per square inch, smaller piping equals higher velocity and higher pressure, these two alone will make up for the volume..

Backpressure kills flows. Reduce your backpressure by having a larger exhaust diameter and smoother bend...the faster the exhaust travels as it exits, the quicker your spools up time is going to be.

My suggestion, run 2.25" intake piping to IC and TB, then run 3" out of the DP all the way through the exhaust

stan