GT2259 Turbo Update
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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!