Ok so I'm running a 18g Greddy Turbo Kit on my LS. I'm looking to upgrade my downpipe to a 3inch before I tune it. What material should I use for the downpipe? Also will I have any fitment issues when I upgrade to a 3inch? Where can I find the flange? Any connection problem when you connect the 3inch dp to the flange?

 

Anyone know??

 

what kind of power are you looking for, and what size is the rest of your exhaust. If you dont have a full 3inch ex theres no need for a 3in. downpipe. also with a 18g greddy kit there isnt going to be much need for one either.

 

Got a 3inch exhaust and test pipe.. Shooting for 250-275whp...

 

IMO a 3" downpipe isnt going to help much with going for 250-275. you could save yourself money and just leave w/e you have on. the difference is going to me minimal to none what size downpipe do you run now. 2 1/2 ???

 

Um a 3inch dp will get me to the numbers I want.. You cant tell me it's not gonna help much because I read of a lot of people running a 3inch dp and hitting those numbers with ease.. I believe it's a 2inch dp which is very power restrictive..
Here's someone who hit 249.2whp/246.5wtq running a 3inch dp..
http://forum.ectune.com/viewtopic.ph...b11ce7994f32d4

 

not saying it wouldn't help. just saying it would be minimal power gain. you could just turn the boost up to get to your power. 2in is small. if you have the material then make a new one. it will help carry your rpms better with 3

 

lol, I'm trying to make a new one that's kind of the reason why I made this thread asking questions on how to make it, and too see if I will have any problems making it..

 

hmmm. sorry.. you shouldnt have any problems. if you could find a 2 1/2 to 3in section it will be easier for you to weld to the flange. with putting a 3in. pipe on the flange your running you are going to have to dent in the pipe where the holes are on your flange so that you can get your bolts/nuts on.

 

u can make 300 on ur set up no need for a 3inch dp if ur looking for 350+ then yes go for 3inch but save ur self the money and when ur ready to make more power then go to a 3inch

 

https://honda-tech.com/forums/forced-induction-16/help-greddy-tdo5-18g-2731896/

this thread has some decent information on downpipes and power capability's of the 18g from TheShodan