Hey guys
I am built a tiny 1.8L 4FB1 diesel for a CJ5 conversion:
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I am not new to diesels being I service, repair, and operate medium to heavy duty diesel trucks and equipment. However, this is my first attempt to size a turbo to an N/A motor. I have done the math, but still would like some EDUCATED expert opinions from those who are in the know, who have done this before, in case i missed something

My only real goal is 2-3PSI boost at cruise, @ 2,000. Barely making boost. This is where the N/A cam makes the most power, and where it reaches peak fuel efficiency. BTW: the factory redline is a screaming 5,400 rpm.

So what I am asking about:

I have two tiny turbos that are very close to what I need. Both need to be rebuilt.

One is a Garrett TB2569 from a Saab.
It is .60 trim, .48 A/R; and exhaust .48 A/R, 54mm (2.12598) compressor wheel
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I was convinced it was ball bearing, but at another site I was told journal. Feels like the shaft has resistance vertically from rubber seals, but again, told otherwise.

The other is a TD04H 13G/6 from I believe a volvo. The exhaust is a .41 A/R(6cm^2 in MHI speak). Uncertain about the A/R of the compressor at this second. The 13G comp wheel has an exducer diameter or 2.000" and an inducer diameter of 1.580".

No pics of that but here is a map:

I need to decide which style of merge collector and flange to construct, as I can only afford to do this ONCE, and it has to be right the first time. I have considered building the header with a 1 1/2" merge collector, and ignore the T25 rectangle on the TD04, that way I could try both turbos out if I wanted. Or would that in any way hurt the operation of the TD04 if that is the best turbo to use? Or would that help keep the velocity and heat up, and maybe help with any reversion?

FYI the primary tubing looks like they might be a TINY 1.38"!!! The TD04 would be easier to install, as it has no water cooling. However, both wheels are larger, and seem to have more mass, ie slower spool. But then the smaller .41 A/R, and a larger compressor wheel. Which is what diesels like.

I dunno. Leaning toward the TB2569, but I am trying to make 2-3PSI at 2,000. Slightly worried it might be 4 or 5, and I might make 2 or 3 psi @ 1,200. I want no more than @ 10-15psi PSI boost max.

SO after all the ramblin', what turbo would YOU use?

 

The turbo's you are considering are WAY too big. The garrett has been tried on a Kubota 2.2 and the tdo4-13 as well. Any turbo from a gasser of similar displacement is going to be too big. I have the tdo3-10 on my 2.2 Kubota and it's on the edge of being too big, compared to the tdo4-13 it's tiny. Diesels don't require any water cooling.

 

I doubt THIS turbo. It was custom built for Saab.
This is called a TB2569, but is actually like a GT15 or GT17.

And the inducer of the compressor is 44.5 MM not 54MM.

The inlet for the turbine is only a 1 1/2" circle, not a full T25 rectangle. Being as my primaries are a tiny 1.38", I think 4 of 'em feeding an inlet of 1 1/2" I will be fine.