How many boosts am I gonna lose?
 

I bought a sr20 T25 a while back that had a bunch of seized bolts in the turbine housing. I bought a T25 housing off a fellow member and tried fitting it to my CHRA today. It fits, but I noticed there is quite a bit more clearance around the turbine wheel. I'd say another 2mm between exducer and housing (See img). This has got to make performance suffer, but I wonder how much? Anyone have something damning to say?

http://i66.tinypic.com/2h7e9ef.jpg

Doubt anyone will be able to tell you cause I've yet to see anyone here try something that silly.

I'm guessing it's going to be pretty bad. I'm also guessing you were sent a gt28 hotside made for the 53.90mm exducer vs the gt2560 which uses the 53.0mm

haha, it didn't seem so silly before when I was going to have a seemingly healthy T25 for less then $200. Oh well.

I'm really curious what it will be like. Post log or boost plot if/when you can lol

PS: I'm in sacramento too :)

In a past life I made an Evo III 16G fit center section fit into a stock Chrysler Conquest turbine housing.

I ended up with a closer fit than what you have pictured and the turdbo still hit the 20psi peak that I was running on the factory rig, but it spooled atrociously. So much so that I just bought the correct turdbine housing so I could resume the wins.

From that experience I'd venture the guess that you won't lose peak boost so much as you'll decimate your spool capabilities. I would suggest trolling Zilvia.net for the appropriate unit.

better pic of the housing?

18psi- GT housing should not fit on a standard t25. Journal bearing vs ball bearing center section sizing. Last time i checked anyhow. The t25 has the same turbine wheel size as a t28(2560). Link below for info.

Stock T25/28 Turbo Specs - Nissan 240SX Forums

I can snap some pictures later. Housing says 449010-1, M3, .64 on stamped into T2 flange side. Stamped TBO on side of scroll. I measured turbine wheel inducer to be 41.5mm, exducer was 52.8mm giving me approx 60 trim.

I never visit the 240 forums for fear of catching aids/herpes/retardation.

those specs I posted were from garrett tho

Now you know why I don't want to hunt down another sr20 t25...

why not extract the bolts on your original housing and re tap the threads? or helicoil the threads?

my 2560 had 2 seized studs, i redrilled and re tapped one, the other one i fucked up and drilled at an angle, then broke a tap inside.

brought it to a machine shop, and $40 later, tap extracted, helicoil installed and re tapped. working perfectly fine for 6 months already.

When I saw the housing didn't fit I started pulling the broken studs on the old one. Problem with it is one of the studs was on the CHRA side. I tried drilling it but the bit drifted due to my half-a** attemp and now I have an oblong hole. At this point I'd have to go full haggard garage on it. I'll leave it as is and lurk for another housing eventually. My build won't take place for a few month anyway.