On my built H22A, I just installed a Garrett T4 60mm with a .81 ar exhaust side and my turbo starts to spool at about 5200 rpm. Honestly, I do not like it like this for a street driven car. So if I change to a .68 ar housing what will this lower the rpm range to / when will it start to spool then?

 

I had a friend do this but he went from a .82 to a .63 and it spooled about 1400 rpms sooner which was almost what he wanted and barely had any difference power wise. I have a boosted H22 as well and trust me, you do not want a too early spool - all you will do is spin tires! You are better off building boost once you get traction. I assume that .68 ar T4 housing will put you in the 3800 to 4200 rpm range which seems good to me

 

not quite. full pressure by about 5500rpms on a T4 with that H22A

 

I have a .58 on my 62/62 and see 25psi at 5500rpms. 10psi @ 4600rpms.

H22 btw

 

C'mon he just said his .81 spools at 5200 rpm and you're saying the SMALLER housing is gonna do it at 5500 rpm? Are you serious?

THANK YOU. That is what I was basically trying to say but what do I know since I don't have a gazillion posts LOL.

 

I'm saying that in the T4 foot print like that the difference in size of interior volute for that P-trim exhaust wheel, is going to make a minimal difference for that engine. (At least from what I've experienced with the two housings). Call me nuts if you want, but perhaps his version of "spool", and what I know as "spool" may have different meaning. He may mean when turbo starts to see positive pressure. I'm looking at maximum pressure acheived at a consistant rpm. That may be where we're seeing the same rpm level differently.

 

Oh ok I see what you mean - yes I was thinking about when it starts to spool and you were talking about max. psi spool correct? My bad Shodan