kender

I have an opportunity to buy a t-25 turbo with a .89 on the exhaust side and .49 on compressor how does this compare to the typical t3/t4. I will be running it on 7-10 psi on a b16 crx daily driver. also has anyone ever heard of a IHI-Borgwarner hybrid turbocharger P/N 51T-32 it is advertised as equall to a t3 t4oe.

Matt Vassallo

.89 a/r exhaust side, i think he means .86 which is a standard t25 exhaust side. it's not very insane either, it's very much normal.

t25 exhaust hosuing and footprint is very small, the a/r is needed to allow it to flow worth anything

flubyux2

the T25 is weird... it depends on what car its off of. the T25's on a DSM are way different than a T25 from, say, a Mazdaspeed Protege.. at least as far as the exhaust housing is concerned.

a T25 is too small... its like smaller than a T3 turbo, like the T3 found on an Excort EXP and definitly smaller than the turbo found on the Thunderbirds and SVO mustangs.

a T25 only can push like 13 psi before its all hott air... you cant realy go too fast on a T25. just go and get a normal T3/T4, you can get them used for af ew hundred bucks and they are so common that its no problem to rebuild them.

.89AR on a garrett-based turbo is crazy big for anything smaller than 4.0liters. hell, i wouldnt run more than a .63 AR on my Supra, and thats a freakin 3.0. i dont want anything bigger than a .52 AR on the DSM... our car has like a .43 AR stock, at least, thats what the 6cm mitsu exhaust housing converts to, IIRC.

joeyk

.89 area to radius "oh my god " on a b16 daily what are you trying to do go with a t3/t4 with .42 or something

flubyux2

i wouldnt go anymore than a .53AR on the hot side for a motor that small... .53 is even pushing it for a little B16, but its ok if you have like 9.0:1 compression.

Regina

the sr20det's t25 has like a .68 and the s15 has like a .86 on its t28 exhaust

kender

if the a/r is like .63 or so what does that translate to, alot of lag or the total inability to spool up? if running a garrett t3 what a/r is good for stock internals. If the housing doesn't show the a/r how can I figure it out?

flubyux2

on a B16, a .63 wont really spool till 4500 im guessing. Shit, a .63 AR is what i would use for MY supra, and thats a 3.0 liter. a 1.6L is gonna have a helluva time pushing enough air thru that big of an exhaust housing, even if it is like 9.5:1 compression stock... or whatever the hell CR B16's come with.

a .63 AR is basically useless on the street and only good for maybe Drag racing... if you have a stutter box and N20 to spool it off the line. thats gonna be a huge single thats gonna be nothing on the bottom end and give you everthing on the top end... like a Supra power curve running a T88... i just hope you are geared for 180mph, cuz thats about what youll be running... its only good for a high-way warrior.

the way you can tell the AR of a turbine housing if its not obvious, is to measure. basically, you take the Area of a given cross section of the turbine. and divide it by how far away the center point of that cross section is away from the center of the turbine housing, the Radius.

A turbine housing is like a Funnel only wrapped around a center axis; the turbine wheel. If you unwrapped it, it would look like a cone, and the smallest side is where it ends. the biggest hole is where it bolts to the manifold collector. If you measured the area of the hole at any point in the cone, either close to the narrow end or the wide end, it wouldnt matter. Once you have that measurement of the area, take a measurement of the distance from the centerpoint of the cone (where you measured the cross section of the cone) to the center of thee turbine wheel. that will give you your Area-to-Radius ratio. since its a ratio, its the same value as long as you measuer from the same 2 points... if you measure the area of the turbien inlet, and then measure the distance from the center of the small end of the cone/funnel to the center axis, youll get the wrong answer.