2.5" downpipe vs. 3" downpipe

Jay Whitely jwhitely2000@yahoo.com
Sun, 20 Oct 2002 10:00:58 -0500

Hey guys,

I recently switched from the older style 5 bolt
turbine housing to the newer Garrett 4 bolt turbine
housing.  With the 5 bolt housing, I was able to run a
3" downpipe right off the turbine outlet flange, using
allen bolts for extra clearance.

It appears that with the 4 bolt flange, I will not be
able to run 3" pipe right off the flange....as the
bolt holes would be in the way of the 3" pipe.  So, I
am thinking of running 2.5" right off the turbo and
then flare it out to 3". So, the downipe would be 2.5"
for only about 1.5 feet.

Do you think this will hinder power any or is the
short section of smaller piping negligible here
because it is so short?

My other option is to use 3" piping off the turbo and
heat up and indent the pipe where the bolts need room.

Thanks for your help,

Jay Whitely
Tampa, FL
1996 200SX SE-R
GTi-R powered, F-MAX Stage 2