Hey all i have a 99 GS right now and im looking to turbo it prolly this summer. I plan on getting an exaust this christmas and i wanted to know if i get the 2.5" Apexi N1 (2.5" so i wont lose power) Will 2.5" be enough when i get the turbo kit on??
PLEASE ADVISE

yes but 3 is better.

Originally posted by mcgyvr
yes but 3 is better.

not on all cases. if youre only running "bitch boost" (10 or less psi) 3inch is not needed. but if you plan on rebuilding and upping the boost 3inch is neccesary

What kit and how much boost. Like said before the more boost the more your going to want to flow.

Originally posted by Mattchew
What kit and how much boost. Like said before the more boost the more your going to want to flow.

Im gonna go with the HRC Stage I, then upgrade with the FMIC later. I prolly wont go above 10 psi too often since its my daily driver for now. But i dont want to be hurting anything because i only have 2.5" instead of 3". But i also dont wanna have to buy 2 systems

Honestly if your going to get the stage one and still keep a stock bottom end your not going to want to boost much over 7-8psi. Also you are not going to outflow that exhaust with only 8-10psi and the HRC 16G anyway. Just make sure you have mandrel bent 2.5" because press bent will bottleneck much smaller.

Originally posted by Mattchew
Honestly if your going to get the stage one and still keep a stock bottom end your not going to want to boost much over 7-8psi. Also you are not going to outflow that exhaust with only 8-10psi and the HRC 16G anyway. Just make sure you have mandrel bent 2.5" because press bent will bottleneck much smaller.

the bottom end will be rebuilt later. I do believe the Apexi N1 is mandrell bent but im not positive.

The 2.5" N1 is a great choice. For whatever minor performance gain you might see going to 3", on a new turbokit car, it will be outweighed by the noise and fitment annoyance.

If you ever get to the point where you actually need 3" piping, you'll be looking at a custom replacement anyways.

Edit: Don't EVER go above 9psi on a Stage 1 or 2 car. Stick with 5-6 psi non-intercooled.

Originally posted by thedawg
Edit: Don't EVER go above 9psi on a Stage 1 or 2 car. Stick with 5-6 psi non-intercooled.

Well stage II is intercooled. And depending on how much shipping is, i might go stage II right away. But thanks You said exactly what i was looking for.

i have a greddy SP cat back for an RS, and the piping is no bigger than stock :o

2.5" or bigger is absolutely fine. go for it!