downpipe size question (searched) - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

bobafett · 04-04-2005, 09:29 PM

ok i have a t3/t04e turbo with a 2.25" 4 bolt turbine dicharge flange....

the downpipe i had made ended up coming with a 2.25 5 bolt flange

i have access to a 4 bolt 2.5" flange, but im wondering since they arent really close to the same size if it will be a problem..

im thinking it might be ok, but i dont see what other options i have, since after searching a ton of stores i cant find anyone who sells a 2.25" 4 bolt flange.

just the 2.5"

what is the easiest solution for this problem? im sure there is something simple, but this is my first turbo project, so im a bit overwhelmed...

orion::S14 · 04-05-2005, 08:18 AM

As long as it will bolt up and seal...BIGGER is BETTER.

So use the 2.5" 4-bolt flange...and use 2.5" piping (maybe 10-12" of it), until a point in your DP where there's room to pump it up to 3".

- Brian

bobafett · 04-05-2005, 08:55 AM

my dp is already set up 2.25 > 3 after less than 6" of smaller pipe.

is there an easy way to weld a 2.25" circle into a 2.5" hole that i am not aware of? or will they just have to use a shitload of welding? just seems like an ugly gap. oh well, maybe they can hog out the pipe to make it fit...

thanks for your reply though, at least i know the idea will work if i can get the flange on there!

WeldingHank · 04-05-2005, 01:02 PM

your exhaust is only as good as its smallest part. the shorter the amount of 2.5" or whatever piping the better.

04-04-2005, 09:29 PM	#1
bobafett Zilvia Member Join Date: May 2004 Location: Vancouver WA Posts: 179 Trader Rating: (0) Feedback Score: 0 reviews	downpipe size question (searched) ok i have a t3/t04e turbo with a 2.25" 4 bolt turbine dicharge flange.... the downpipe i had made ended up coming with a 2.25 5 bolt flange i have access to a 4 bolt 2.5" flange, but im wondering since they arent really close to the same size if it will be a problem.. im thinking it might be ok, but i dont see what other options i have, since after searching a ton of stores i cant find anyone who sells a 2.25" 4 bolt flange. just the 2.5" what is the easiest solution for this problem? im sure there is something simple, but this is my first turbo project, so im a bit overwhelmed...

04-05-2005, 08:18 AM	#2
orion::S14 Nissanaholic! Join Date: May 2003 Location: Orange Park, FL Posts: 1,666 Trader Rating: (0) Feedback Score: 0 reviews	As long as it will bolt up and seal...BIGGER is BETTER. So use the 2.5" 4-bolt flange...and use 2.5" piping (maybe 10-12" of it), until a point in your DP where there's room to pump it up to 3". - Brian __________________ www.KA24DEvelopment.com

04-05-2005, 01:02 PM	#4
WeldingHank Leaky Injector Join Date: Feb 2004 Location: Massachusetts Posts: 137 Trader Rating: (0) Feedback Score: 0 reviews	your exhaust is only as good as its smallest part. the shorter the amount of 2.5" or whatever piping the better. __________________ 1989 240sx:CA18DET My Cardomain

04-05-2005, 08:55 AM	#3
bobafett Zilvia Member Join Date: May 2004 Location: Vancouver WA Posts: 179 Trader Rating: (0) Feedback Score: 0 reviews	my dp is already set up 2.25 > 3 after less than 6" of smaller pipe. is there an easy way to weld a 2.25" circle into a 2.5" hole that i am not aware of? or will they just have to use a shitload of welding? just seems like an ugly gap. oh well, maybe they can hog out the pipe to make it fit... thanks for your reply though, at least i know the idea will work if i can get the flange on there!