GT2259 Turbo Update

Legacy Blog Content!

You are viewing legacy content from The Art of Diesel’s blog site. Information and links may be outdated. Referenced video might no longer exist. Embedded photos might be missing. We are keeping this content available to our readers in case there might still be some valuable information contained.

******************************

Time for a quick update on the new turbo I'm installing.  First, though, a couple gratuitous photos of this nice-looking machine and the current 4BD1T installation.

The Isuzu 4BD1T installed in my Suburban.

Nice looking Suburban, if I say so myself!

Because this Hino version of the GT2259 has a T3 flange that's rotated 90 degrees, I picked up a pair of T3 flanges from Ebay to make an adapter. Tonight I spent some time grinding away material from both of them so that there will be a smoother transition from one rectangle-shaped opening to the other. I'll get a local guy to weld these together for me.

The flanges have been ground to help smooth the airflow.  When these are welded together, I'll have a makeshift adapter to deal with the Hino's unusual T3 flange angle.

The turbo arrived, recently. It took longer than the Ebay estimate, and I saw that it was actually shipped directly to me from Taiwan. I don't have a problem with buying stuff from overseas, but it would be better if the seller were up-front about it. It does appear to be a genuine Garrett turbo, though.

This is a Genuine Garrett GT2259 from a Hino truck

I took some time this past weekend to reclock the unit, as the oil drain flange was at the wrong angle for how this will be mounted on my 4BD1T.

As I took this nice, clean remanufactured unit apart to re-clock it, I took some snapshots and measurements. As a wastegated GT2259, I expected a turbine aspect ratio of 0.67, but was pleasantly surprised to see that this (Hino application-specific?) housing has an aspect ratio of 0.47. This should make for a nice, early spool! The wastegate should help me avoid too much backpressure as engine rpms increase.

The turbine housing markings indicate a 0.47 aspect ratio -- good for spooling at low rpm.

While the turbine impeller was exposed, I took measurements, confirming that this turbo matches Garrett's GT2259 specs.

The turbine specs are:

Inducer: 50.3 mm (confirmed) Exducer: 43.2 mm (confirmed) A/R: 0.47 (stamped on turbine housing)

There were no surprises with the compressor side.

Inducer: 42 mm (confirmed) Exducer: 59.4 mm (confirmed) A/R: 0.61 (stamped on compressor housing)

I also measured the compressor rotor, while it was exposed.

Because the compressor outlet came with just a flange on it, I picked up a coupler and installed it.

After the turbo was reassembled and clocked a coupler was added so that a hose can be attached later.

The actuator on this turbo seems to be very tightly sprung and lacks any adjustment feature. I may wind up swapping this component for one that I can tweak. I need to find out if the Garrett actuators are somewhat universal.

That's all for now.  I'll post more as things progress.

--Putting the "engine" back in engineering!