i just built my new 3" downpipe and exhaust for my integra, and now my boost level has changed. i have a tial 9 psi spring in my ebay 38mm wastegate. when i had the 2.5 inch downpipe an world sport exhaust, it made 9 psi on the gauge, boost controller installed, backed out. now that i have the 3", its more like 11 psi on the gauge, but holds steady there even in the upper rpms in the higher gears. does this make sense? my dumptube isnt the best, but it worked mint with the old exhaust.

 

Sweeter free flow for your GM-8 I guess. 2.5inches may have been chocking your truck turbo.

 

possible, but its got a 2.5 inch outlet, i had to rig up a reducer for the 2.5 inch flange and the 3" piping.

 

is it just 2.5 a few inches after the turbo?

how bout some pics? gotta build mine real soon.

 

its 2.5 at the turbo outlet, i welded the reducer direct onto the flange. there is no 2.5 inch piping in my exhaust

thanks for your help jon

 

and heres a pic of the car in its current form, no pics of the exhaust yet though

 

it will look like crap with the cut out bumper. once i get a new bumper/intercooler and get the car re-sprayed then thats the route i'll be going

 

Turbo hondas love the 3" downpipe plus full 3" exhaust , it the only way I'd ever run a turbo setup.