I am putting together a set of twins. I finally have the piping figured out all except the intake. I decided to move the battery (have another post on this) and bring the intake to the battery's old location. I got 5" tubing to fit out through but it is really tight. I was wondering if I could drop back to 4" tubing to make a little more room. I am not sure if 4" will allow enough air into the primary. One more question what air filter should I run? I did a search and narowed it down the the AFE ProGaurd oilless and the Amzoil nanofiber filters. Is the a specific size I need to get or just whatever I can get to fit?
Thanks in advance,
Joe
Oh by the way expect more questions when I get to the tuning stage, seeing how this is all new to me.

 

I have seen a few setups that had 4" tubing for the primary inlet, as far as the filter get the biggest one you can IMO.

 

My inlet into the turbo was 5in, so I went with a 5in pipe. I didn't want to have any flow restrictions. I had to move my battery.

 

I was checking into the Amzoil filters and they have 4", 4.5", and 6" flange diameter filters but no 5". I guess I will have to go with an AFE if I go the 5" route. I was really hoping to go the oilless route as i really dislike servicing an oiled filter.
Joe