T25 turbo sizing help
 

Ok, so I'm new here, a bit green when it comes to turbos, however have been currently enjoying my setup. However a resent snapped shaft negates a turbo purchase and I'm a bit befuddled by the options, looking for recommendations. Currently running an Isuzu 4fb1 ( diesel 1.8 from a chevette/Imark/Gemini) and a t25 .48c .41h from a 87-93 Benz 2.5 diesel, waste gate deleted,( trim unknown but from what I can gather through forum info is it should be about 50-55), in a 92 Volvo 740 wagon. Boost spools in nice and low, tops at around 29psi and holds nicely right through this little diesel's 6200rpm max speed(well... Now 6200, original was 5500). Exhaust does run a bit warm during full load in the hills, occasional creeping to 1300, but stays in the 3-5 hundred range cruising.

Finding a/r ratios this "small" have proven difficult and just looking to get my daily battle wagon back on the road ASAP.

The closest I'm able to locate is a .48c and a .49h with a 42/36 and a 46/38 respective trim (not sure how to exactly figure that to a correct number).

I understand that this setup will be a bit more laggy from what is current.

My my options seem to be:

1. Direct bolt up
2. Use exhaust housing from original turbo and center/ wheels and intake housing from "new above"
3. Option 2 only with a larger .64 /70c .6/76h turbo
4. Some weird combo of old/new parts based upon suggestions of this forum.


I realize that option 2 will get me very close to my original/current setup however I'm always up for a bit of an increase in performance while buying necessary parts.


Open to all suggestions, including junkyard options, as long as two points be maintained: MUST have t25 flanges(not looking to remake my manifold or exhaust...did that once already, not trying to do that again) and that performance should be equal to or slightly more favorable than current, for daily driving(not a strip car, so not looking to spool very late in rpm range).

Any assistance or helpful insight would be greatly appreciated.

29 Psi ?!?!?! In your tires that is, right? ;D

A bit more than that in the tires haha. No, that (was) manifold pressure. A bit lower now with the t28 chinacharger I settled upon.