Hey guys, I was wondering what sort of advantages/or disadvantages if any are there when making a custom 2.5"- 3" J-pipe to fit (Evo 9 turbo - BBK Full turbo)?
Will increasing the diameter increase flow?decrease?stress the turbo?

 

What is the ID of the stock piece? Im not sure if/when it becomes a restriction. If it is(which I have no idea) then sure there could be HP gains to be had. IMO I dont see it as a restriction and think that it will only add lag.

 

I myself don't know about any advantages or disadvantages but I had to make one. I have an ATP GTX3071R and went from an Injen LICP to an ETS LICP. The piece that was cut before wouldn't line up and the only way to make it work as it was would have made multiple unnecessary bends. I made the decision to buy a straight piece of piping and a couple silicone couplers from siliconeintakes.com and made my own j-pipe. I don't know if the diameter will make a difference but I'm sure taking out the cluster of crazy bends should help out. I won't have a great comparison when I finish tuning since a few other parts have been changed at the same time since I was last tuned but I definitely don't think it would hurt much if at all. Especially if you are taking out any unnecessary bends in the process. Just my .02.

 

Thanks guys, I've seen a few example and I'm sure you guys seen as well; I see large J pipes and usually on a foward facing turbo- and thought if its not packaging of the turbo under bumper, than some sort of benefits can be had.